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• How do I get jqGrid to work using ASP.NET + JSON on the backend?

  - by briandus

  Hi friends, ok, I'm back. I totally simplified my problem to just three simple fields and I'm still stuck on the same line using the addJSONData method. I've been stuck on this for days and no matter how I rework the ajax call, the json string, blah blah blah...I can NOT get this to work! I can't even get it to work as a function when adding one row of data manually. Can anyone PLEASE post a working sample of jqGrid that works with ASP.NET and JSON? Would you please include 2-3 fields (string, integer and date preferably?) I would be happy to see a working sample of jqGrid and just the manual addition of a JSON object using the addJSONData method. Thanks SO MUCH!! If I ever get this working, I will post a full code sample for all the other posting for help from ASP.NET, JSON users stuck on this as well. Again. THANKS!! tbl.addJSONData(objGridData); //err: tbl.addJSONData is not a function!! Here is what Firebug is showing when I receive this message: • objGridData Object total=1 page=1 records=5 rows=[5] ? Page "1" Records "5" Total "1" Rows [Object ID=1 PartnerID=BCN, Object ID=2 PartnerID=BCN, Object ID=3 PartnerID=BCN, 2 more... 0=Object 1=Object 2=Object 3=Object 4=Object] (index) 0 (prop) ID (value) 1 (prop) PartnerID (value) "BCN" (prop) DateTimeInserted (value) Thu May 29 2008 12:08:45 GMT-0700 (Pacific Daylight Time) * There are three more rows Here is the value of the variable tbl (value) 'Table.scroll' <TABLE cellspacing="0" cellpadding="0" border="0" style="width: 245px;" class="scroll grid_htable"><THEAD><TR><TH class="grid_sort grid_resize" style="width: 55px;"><SPAN> </SPAN><DIV id="jqgh_ID" style="cursor: pointer;">ID <IMG src="http://localhost/DNN5/js/jQuery/jqGrid-3.4.3/themes/sand/images/sort_desc.gif"/></DIV></TH><TH class="grid_resize" style="width: 90px;"><SPAN> </SPAN><DIV id="jqgh_PartnerID" style="cursor: pointer;">PartnerID </DIV></TH><TH class="grid_resize" style="width: 100px;"><SPAN> </SPAN><DIV id="jqgh_DateTimeInserted" style="cursor: pointer;">DateTimeInserted </DIV></TH></TR></THEAD></TABLE> Here is the complete function: $('table.scroll').jqGrid({ datatype: function(postdata) { mtype: "POST", $.ajax({ url: 'EDI.asmx/GetTestJSONString', type: "POST", contentType: "application/json; charset=utf-8", data: "{}", dataType: "text", //not json . let me try to parse success: function(msg, st) { if (st == "success") { var gridData; //strip of "d:" notation var result = JSON.parse(msg); for (var property in result) { gridData = result[property]; break; } var objGridData = eval("(" + gridData + ")"); //creates an object with visible data and structure var tbl = jQuery('table.scroll')[0]; alert(objGridData.rows[0].PartnerID); //displays the correct data //tbl.addJSONData(objGridData); //error received: addJSONData not a function //error received: addJSONData not a function (This uses eval as shown in the documentation) //tbl.addJSONData(eval("(" + objGridData + ")")); //the line below evaluates fine, creating an object and visible data and structure //var objGridData = eval("(" + gridData + ")"); //BUT, the same thing will not work here //tbl.addJSONData(eval("(" + gridData + ")")); //FIREBUG SHOWS THIS AS THE VALUE OF gridData: // "{"total":"1","page":"1","records":"5","rows":[{"ID":1,"PartnerID":"BCN","DateTimeInserted":new Date(1214412777787)},{"ID":2,"PartnerID":"BCN","DateTimeInserted":new Date(1212088125000)},{"ID":3,"PartnerID":"BCN","DateTimeInserted":new Date(1212088125547)},{"ID":4,"PartnerID":"EHG","DateTimeInserted":new Date(1235603192033)},{"ID":5,"PartnerID":"EMDEON","DateTimeInserted":new Date(1235603192000)}]}" } } }); }, jsonReader: { root: "rows", //arry containing actual data page: "page", //current page total: "total", //total pages for the query records: "records", //total number of records repeatitems: false, id: "ID" //index of the column with the PK in it }, colNames: [ 'ID', 'PartnerID', 'DateTimeInserted' ], colModel: [ { name: 'ID', index: 'ID', width: 55 }, { name: 'PartnerID', index: 'PartnerID', width: 90 }, { name: 'DateTimeInserted', index: 'DateTimeInserted', width: 100}], rowNum: 10, rowList: [10, 20, 30], imgpath: 'http://localhost/DNN5/js/jQuery/jqGrid-3.4.3/themes/sand/images', pager: jQuery('#pager'), sortname: 'ID', viewrecords: true, sortorder: "desc", caption: "TEST Example")};

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• C++ templated factory constructor/de-serialization

  - by KRao

  Hi, I was looking at the boost serialization library, and the intrusive way to provide support for serialization is to define a member function with signature (simplifying): class ToBeSerialized { public: //Define this to support serialization //Notice not virtual function! template<class Archive> void serialize(Archive & ar) {.....} }; Moreover, one way to support serilization of derived class trough base pointers is to use a macro of the type: //No mention to the base class(es) from which Derived_class inherits BOOST_CLASS_EXPORT_GUID(Derived_class, "derived_class") where Derived_class is some class which is inheriting from a base class, say Base_class. Thanks to this macro, it is possible to serialize classes of type Derived_class through pointers to Base_class correctly. The question is: I am used in C++ to write abstract factories implemented through a map from std::string to (pointer to) functions which return objects of the desired type (and eveything is fine thanks to covariant types). Hover I fail to see how I could use the above non-virtual serialize template member function to properly de-serialize (i.e. construct) an object without knowing its type (but assuming that the type information has been stored by the serializer, say in a string). What I would like to do (keeping the same nomenclature as above) is something like the following: XmlArchive xmlArchive; //A type or archive xmlArchive.open("C:/ser.txt"); //Contains type information for the serialized class Base_class* basePtr = Factory<Base_class>::create("derived_class",xmlArchive); with the function on the righ-hand side creating an object on the heap of type Derived_class (via default constructor, this is the part I know how to solve) and calling the serialize function of xmlArchive (here I am stuck!), i.e. do something like: Base_class* Factory<Base_class>::create("derived_class",xmlArchive) { Base_class* basePtr = new Base_class; //OK, doable, usual map string to pointer to function static_cast<Derived_class*>( basePtr )->serialize( xmlArchive ); //De-serialization, how????? return basePtr; } I am sure this can be done (boost serialize does it but its code is impenetrable! :P), but I fail to figure out how. The key problem is that the serialize function is a template function. So I cannot have a pointer to a generic templated function. As the point in writing the templated serialize function is to make the code generic (i.e. not having to re-write the serialize function for different Archivers), it does not make sense then to have to register all the derived classes for all possible archive types, like: MY_CLASS_REGISTER(Derived_class, XmlArchive); MY_CLASS_REGISTER(Derived_class, TxtArchive); ... In fact in my code I relies on overloading to get the correct behaviour: void serialize( XmlArchive& archive, Derived_class& derived ); void serialize( TxtArchive& archive, Derived_class& derived ); ... The key point to keep in mind is that the archive type is always known, i.e. I am never using runtime polymorphism for the archive class...(again I am using overloading on the archive type). Any suggestion to help me out? Thank you very much in advance! Cheers

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• Problem with incomplete type while trying to detect existence of a member function

  - by abir

  I was trying to detect existence of a member function for a class where the function tries to use an incomplete type. The typedef is struct foo; typedef std::allocator<foo> foo_alloc; The detection code is struct has_alloc { template<typename U,U x> struct dummy; template<typename U> static char check(dummy<void* (U::*)(std::size_t),&U::allocate>*); template<typename U> static char (&check(...))[2]; const static bool value = (sizeof(check<foo_alloc>(0)) == 1); }; So far I was using incomplete type foo with std::allocator without any error on VS2008. However when I replaced it with nearly an identical implementation as template<typename T> struct allocator { T* allocate(std::size_t n) { return (T*)operator new (sizeof(T)*n); } }; it gives an error saying that as T is incomplete type it has problem instantiating allocator<foo> because allocate uses sizeof. GCC 4.5 with std::allocator also gives the error, so it seems during detection process the class need to be completely instantiated, even when I am not using that function at all. What I was looking for is void* allocate(std::size_t) which is different from T* allocate(std::size_t). My questions are (I have three questions, but as they are correlated , so I thought it is better not to create three separate questions). Why MS std::allocator doesn't check for incomplete type foo while instantiating? Are they following any trick which can be implemented ? Why the compiler need to instantiate allocator<T> to check the existence of the function when sizeof is not used as sfinae mechanism to remove/add allocate in the overload resolutions set? It should be noted that, if I remove the generic implementation of allocate leaving the declaration only, and specialized it for foo afterwards such as struct foo{}; template< struct allocator { foo* allocate(std::size_t n) { return (foo*)operator new (sizeof(foo)*n); } }; after struct has_alloc it compiles in GCC 4.5 while gives error in VS2008 as allocator<T> is already instantiated and explicit specialization for allocator<foo> already defined. Is it legal to use nested types for an std::allocator of incomplete type such as typedef foo_alloc::pointer foo_pointer; ? Though it is practically working for me, I suspect the nested types such as pointer may depend on completeness of type it takes. It will be good to know if there is any possible way to typedef such types as foo_pointer where the type pointer depends on completeness of foo. NOTE : As the code is not copy paste from editor, it may have some syntax error. Will correct it if I find any. Also the codes (such as allocator) are not complete implementation, I simplified and typed only the portion which I think useful for this particular problem.

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• C++ pimpl idiom wastes an instruction vs. C style?

  - by Rob

  (Yes, I know that one machine instruction usually doesn't matter. I'm asking this question because I want to understand the pimpl idiom, and use it in the best possible way; and because sometimes I do care about one machine instruction.) In the sample code below, there are two classes, Thing and OtherThing. Users would include "thing.hh". Thing uses the pimpl idiom to hide it's implementation. OtherThing uses a C style – non-member functions that return and take pointers. This style produces slightly better machine code. I'm wondering: is there a way to use C++ style – ie, make the functions into member functions – and yet still save the machine instruction. I like this style because it doesn't pollute the namespace outside the class. Note: I'm only looking at calling member functions (in this case, calc). I'm not looking at object allocation. Below are the files, commands, and the machine code, on my Mac. thing.hh: class ThingImpl; class Thing { ThingImpl *impl; public: Thing(); int calc(); }; class OtherThing; OtherThing *make_other(); int calc(OtherThing *); thing.cc: #include "thing.hh" struct ThingImpl { int x; }; Thing::Thing() { impl = new ThingImpl; impl->x = 5; } int Thing::calc() { return impl->x + 1; } struct OtherThing { int x; }; OtherThing *make_other() { OtherThing *t = new OtherThing; t->x = 5; } int calc(OtherThing *t) { return t->x + 1; } main.cc (just to test the code actually works...) #include "thing.hh" #include <cstdio> int main() { Thing *t = new Thing; printf("calc: %d\n", t->calc()); OtherThing *t2 = make_other(); printf("calc: %d\n", calc(t2)); } Makefile: all: main thing.o : thing.cc thing.hh g++ -fomit-frame-pointer -O2 -c thing.cc main.o : main.cc thing.hh g++ -fomit-frame-pointer -O2 -c main.cc main: main.o thing.o g++ -O2 -o $@ $^ clean: rm *.o rm main Run make and then look at the machine code. On the mac I use otool -tv thing.o | c++filt. On linux I think it's objdump -d thing.o. Here is the relevant output: Thing::calc(): 0000000000000000 movq (%rdi),%rax 0000000000000003 movl (%rax),%eax 0000000000000005 incl %eax 0000000000000007 ret calc(OtherThing*): 0000000000000010 movl (%rdi),%eax 0000000000000012 incl %eax 0000000000000014 ret Notice the extra instruction because of the pointer indirection. The first function looks up two fields (impl, then x), while the second only needs to get x. What can be done?

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• Double Linked List header node keeps returning first value as 0

  - by Craig

  I will preface to say that this is my first question. I am currently getting my Masters degree in Information Security and I had to take C++ programming this semester. So this is homework related. I am not looking for you to answer my homework but I am running into a peculiar situation. I have created the program to work with a doubly linked list and everything works fine. However when I have the user create a list of values the first node keeps returning 0. I have tried finding some reading on this and I cannot locate any reference to it. My question is then is the header node(first node) always going to be zero? Or am I doing something wrong. case: 'C': cout<<"Please enter a list:"<<endl; while(n!=-999){ myList.insert(n); cin>> n;} break; I now enter: 12321, 1234,64564,346346. The results in 0, 12321, 1234, 64564,346346. Is this what should happen or am I doing something wrong? Also as this is my first post please feel free to criticize or teach me how to color code the keywords. Anyway this is a homework assignment so I am only looking for guidance and constructive criticism. Thank you all in advance So I cannot figure out the comment sections on this forum so I will edit the original post The first section is the constructor code: template <class Type> doublyLinkedList<Type>::doublyLinkedList() { first= NULL; last = NULL; count = 0; } Then there is my insert function : template <class Type> void doublyLinkedList<Type>::insert(const Type& insertItem) { nodeType<Type> *current; //pointer to traverse the list nodeType<Type> *trailCurrent; //pointer just before current nodeType<Type> *newNode; //pointer to create a node bool found; newNode = new nodeType<Type>; //create the node newNode->info = insertItem; //store the new item in the node newNode->next = NULL; newNode->back = NULL; if(first == NULL) //if the list is empty, newNode is //the only node { first = newNode; last = newNode; count++; } else { found = false; current = first; while (current != NULL && !found) //search the list if (current->info >= insertItem) found = true; else { trailCurrent = current; current = current->next; } if (current == first) //insert newNode before first { first->back = newNode; newNode->next = first; first = newNode; count++; } else { //insert newNode between trailCurrent and current if (current != NULL) { trailCurrent->next = newNode; newNode->back = trailCurrent; newNode->next = current; current->back = newNode; } else { trailCurrent->next = newNode; newNode->back = trailCurrent; last = newNode; } count++; }//end else }//end else }//end Then I have an initialization function too: template <class Type> void doublyLinkedList<Type>::initializeList() { destroy(); } Did I miss anything?

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• A Closable jQuery Plug-in

  - by Rick Strahl

  In my client side development I deal a lot with content that pops over the main page. Be it data entry ‘windows’ or dialogs or simple pop up notes. In most cases this behavior goes with draggable windows, but sometimes it’s also useful to have closable behavior on static page content that the user can choose to hide or otherwise make invisible or fade out. Here’s a small jQuery plug-in that provides .closable() behavior to most elements by using either an image that is provided or – more appropriately by using a CSS class to define the picture box layout. /* * * Closable * * Makes selected DOM elements closable by making them * invisible when close icon is clicked * * Version 1.01 * @requires jQuery v1.3 or later * * Copyright (c) 2007-2010 Rick Strahl * http://www.west-wind.com/ * * Licensed under the MIT license: * http://www.opensource.org/licenses/mit-license.php Support CSS: .closebox { position: absolute; right: 4px; top: 4px; background-image: url(images/close.gif); background-repeat: no-repeat; width: 14px; height: 14px; cursor: pointer; opacity: 0.60; filter: alpha(opacity="80"); } .closebox:hover { opacity: 0.95; filter: alpha(opacity="100"); } Options: * handle Element to place closebox into (like say a header). Use if main element and closebox container are two different elements. * closeHandler Function called when the close box is clicked. Return true to close the box return false to keep it visible. * cssClass The CSS class to apply to the close box DIV or IMG tag. * imageUrl Allows you to specify an explicit IMG url that displays the close icon. If used bypasses CSS image styling. * fadeOut Optional provide fadeOut speed. Default no fade out occurs */ (function ($) { $.fn.closable = function (options) { var opt = { handle: null, closeHandler: null, cssClass: "closebox", imageUrl: null, fadeOut: null }; $.extend(opt, options); return this.each(function (i) { var el = $(this); var pos = el.css("position"); if (!pos || pos == "static") el.css("position", "relative"); var h = opt.handle ? $(opt.handle).css({ position: "relative" }) : el; var div = opt.imageUrl ? $("<img>").attr("src", opt.imageUrl).css("cursor", "pointer") : $("<div>"); div.addClass(opt.cssClass) .click(function (e) { if (opt.closeHandler) if (!opt.closeHandler.call(this, e)) return; if (opt.fadeOut) $(el).fadeOut(opt.fadeOut); else $(el).hide(); }); if (opt.imageUrl) div.css("background-image", "none"); h.append(div); }); } })(jQuery); The plugin can be applied against any selector that is a container (typically a div tag). The close image or close box is provided typically by way of a CssClass - .closebox by default – which supplies the image as part of the CSS styling. The default styling for the box looks something like this: .closebox { position: absolute; right: 4px; top: 4px; background-image: url(images/close.gif); background-repeat: no-repeat; width: 14px; height: 14px; cursor: pointer; opacity: 0.60; filter: alpha(opacity="80"); } .closebox:hover { opacity: 0.95; filter: alpha(opacity="100"); } Alternately you can also supply an image URL which overrides the background image in the style sheet. I use this plug-in mostly on pop up windows that can be closed, but it’s also quite handy for remove/delete behavior in list displays like this: you can find this sample here to look to play along: http://www.west-wind.com/WestwindWebToolkit/Samples/Ajax/AmazonBooks/BooksAdmin.aspx For closable windows it’s nice to have something reusable because in my client framework there are lots of different kinds of windows that can be created: Draggables, Modal Dialogs, HoverPanels etc. and they all use the client .closable plug-in to provide the closable operation in the same way with a few options. Plug-ins are great for this sort of thing because they can also be aggregated and so different components can pick and choose the behavior they want. The window here is a draggable, that’s closable and has shadow behavior and the server control can simply generate the appropriate plug-ins to apply to the main <div> tag: $().ready(function() { $('#ctl00_MainContent_panEditBook') .closable({ handle: $('#divEditBook_Header') }) .draggable({ dragDelay: 100, handle: '#divEditBook_Header' }) .shadow({ opacity: 0.25, offset: 6 }); }) The window is using the default .closebox style and has its handle set to the header bar (Book Information). The window is just closable to go away so no event handler is applied. Actually I cheated – the actual page’s .closable is a bit more ugly in the sample as it uses an image from a resources file: .closable({ imageUrl: '/WestWindWebToolkit/Samples/WebResource.axd?d=TooLongAndNastyToPrint', handle: $('#divEditBook_Header')}) so you can see how to apply a custom image, which in this case is generated by the server control wrapping the client DragPanel. More interesting maybe is to apply the .closable behavior to list scenarios. For example, each of the individual items in the list display also are .closable using this plug-in. Rather than having to define each item with Html for an image, event handler and link, when the client template is rendered the closable behavior is attached to the list. Here I’m using client-templating and the code that this is done with looks like this: function loadBooks() { showProgress(); // Clear the content $("#divBookListWrapper").empty(); var filter = $("#" + scriptVars.lstFiltersId).val(); Proxy.GetBooks(filter, function(books) { $(books).each(function(i) { updateBook(this); showProgress(true); }); }, onPageError); } function updateBook(book,highlight) { // try to retrieve the single item in the list by tag attribute id var item = $(".bookitem[tag=" +book.Pk +"]"); // grab and evaluate the template var html = parseTemplate(template, book); var newItem = $(html) .attr("tag", book.Pk.toString()) .click(function() { var pk = $(this).attr("tag"); editBook(this, parseInt(pk)); }) .closable({ closeHandler: function(e) { removeBook(this, e); }, imageUrl: "../../images/remove.gif" }); if (item.length > 0) item.after(newItem).remove(); else newItem.appendTo($("#divBookListWrapper")); if (highlight) { newItem .addClass("pulse") .effect("bounce", { distance: 15, times: 3 }, 400); setTimeout(function() { newItem.removeClass("pulse"); }, 1200); } } Here the closable behavior is applied to each of the items along with an event handler, which is nice and easy compared to having to embed the right HTML and click handling into each item in the list individually via markup. Ideally though (and these posts make me realize this often a little late) I probably should set up a custom cssClass to handle the rendering – maybe a CSS class called .removebox that only changes the image from the default box image. This example also hooks up an event handler that is fired in response to the close. In the list I need to know when the remove button is clicked so I can fire of a service call to the server to actually remove the item from the database. The handler code can also return false; to indicate that the window should not be closed optionally. Returning true will close the window. You can find more information about the .closable class behavior and options here: .closable Documentation Plug-ins make Server Control JavaScript much easier I find this plug-in immensely useful especial as part of server control code, because it simplifies the code that has to be generated server side tremendously. This is true of plug-ins in general which make it so much easier to create simple server code that only generates plug-in options, rather than full blocks of JavaScript code.  For example, here’s the relevant code from the DragPanel server control which generates the .closable() behavior: if (this.Closable && !string.IsNullOrEmpty(DragHandleID) ) { string imageUrl = this.CloseBoxImage; if (imageUrl == "WebResource" ) imageUrl = ScriptProxy.GetWebResourceUrl(this, this.GetType(), ControlResources.CLOSE_ICON_RESOURCE); StringBuilder closableOptions = new StringBuilder("imageUrl: '" + imageUrl + "'"); if (!string.IsNullOrEmpty(this.DragHandleID)) closableOptions.Append(",handle: $('#" + this.DragHandleID + "')"); if (!string.IsNullOrEmpty(this.ClientDialogHandler)) closableOptions.Append(",handler: " + this.ClientDialogHandler); if (this.FadeOnClose) closableOptions.Append(",fadeOut: 'slow'"); startupScript.Append(@" .closable({ " + closableOptions + "})"); } The same sort of block is then used for .draggable and .shadow which simply sets options. Compared to the code I used to have in pre-jQuery versions of my JavaScript toolkit this is a walk in the park. In those days there was a bunch of JS generation which was ugly to say the least. I know a lot of folks frown on using server controls, especially the UI is client centric as the example is. However, I do feel that server controls can greatly simplify the process of getting the right behavior attached more easily and with the help of IntelliSense. Often the script markup is easier is especially if you are dealing with complex, multiple plug-in associations that often express more easily with property values on a control. Regardless of whether server controls are your thing or not this plug-in can be useful in many scenarios. Even in simple client-only scenarios using a plug-in with a few simple parameters is nicer and more consistent than creating the HTML markup over and over again. I hope some of you find this even a small bit as useful as I have. Related Links Download jquery.closable West Wind Web Toolkit jQuery Plug-ins © Rick Strahl, West Wind Technologies, 2005-2010Posted in jQuery   ASP.NET  JavaScript  

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• A Closable jQuery Plug-in

  - by Rick Strahl

  In my client side development I deal a lot with content that pops over the main page. Be it data entry ‘windows’ or dialogs or simple pop up notes. In most cases this behavior goes with draggable windows, but sometimes it’s also useful to have closable behavior on static page content that the user can choose to hide or otherwise make invisible or fade out. Here’s a small jQuery plug-in that provides .closable() behavior to most elements by using either an image that is provided or – more appropriately by using a CSS class to define the picture box layout. /* * * Closable * * Makes selected DOM elements closable by making them * invisible when close icon is clicked * * Version 1.01 * @requires jQuery v1.3 or later * * Copyright (c) 2007-2010 Rick Strahl * http://www.west-wind.com/ * * Licensed under the MIT license: * http://www.opensource.org/licenses/mit-license.php Support CSS: .closebox { position: absolute; right: 4px; top: 4px; background-image: url(images/close.gif); background-repeat: no-repeat; width: 14px; height: 14px; cursor: pointer; opacity: 0.60; filter: alpha(opacity="80"); } .closebox:hover { opacity: 0.95; filter: alpha(opacity="100"); } Options: * handle Element to place closebox into (like say a header). Use if main element and closebox container are two different elements. * closeHandler Function called when the close box is clicked. Return true to close the box return false to keep it visible. * cssClass The CSS class to apply to the close box DIV or IMG tag. * imageUrl Allows you to specify an explicit IMG url that displays the close icon. If used bypasses CSS image styling. * fadeOut Optional provide fadeOut speed. Default no fade out occurs */ (function ($) { $.fn.closable = function (options) { var opt = { handle: null, closeHandler: null, cssClass: "closebox", imageUrl: null, fadeOut: null }; $.extend(opt, options); return this.each(function (i) { var el = $(this); var pos = el.css("position"); if (!pos || pos == "static") el.css("position", "relative"); var h = opt.handle ? $(opt.handle).css({ position: "relative" }) : el; var div = opt.imageUrl ? $("<img>").attr("src", opt.imageUrl).css("cursor", "pointer") : $("<div>"); div.addClass(opt.cssClass) .click(function (e) { if (opt.closeHandler) if (!opt.closeHandler.call(this, e)) return; if (opt.fadeOut) $(el).fadeOut(opt.fadeOut); else $(el).hide(); }); if (opt.imageUrl) div.css("background-image", "none"); h.append(div); }); } })(jQuery); The plugin can be applied against any selector that is a container (typically a div tag). The close image or close box is provided typically by way of a CssClass - .closebox by default – which supplies the image as part of the CSS styling. The default styling for the box looks something like this: .closebox { position: absolute; right: 4px; top: 4px; background-image: url(images/close.gif); background-repeat: no-repeat; width: 14px; height: 14px; cursor: pointer; opacity: 0.60; filter: alpha(opacity="80"); } .closebox:hover { opacity: 0.95; filter: alpha(opacity="100"); } Alternately you can also supply an image URL which overrides the background image in the style sheet. I use this plug-in mostly on pop up windows that can be closed, but it’s also quite handy for remove/delete behavior in list displays like this: you can find this sample here to look to play along: http://www.west-wind.com/WestwindWebToolkit/Samples/Ajax/AmazonBooks/BooksAdmin.aspx For closable windows it’s nice to have something reusable because in my client framework there are lots of different kinds of windows that can be created: Draggables, Modal Dialogs, HoverPanels etc. and they all use the client .closable plug-in to provide the closable operation in the same way with a few options. Plug-ins are great for this sort of thing because they can also be aggregated and so different components can pick and choose the behavior they want. The window here is a draggable, that’s closable and has shadow behavior and the server control can simply generate the appropriate plug-ins to apply to the main <div> tag: $().ready(function() { $('#ctl00_MainContent_panEditBook') .closable({ handle: $('#divEditBook_Header') }) .draggable({ dragDelay: 100, handle: '#divEditBook_Header' }) .shadow({ opacity: 0.25, offset: 6 }); }) The window is using the default .closebox style and has its handle set to the header bar (Book Information). The window is just closable to go away so no event handler is applied. Actually I cheated – the actual page’s .closable is a bit more ugly in the sample as it uses an image from a resources file: .closable({ imageUrl: '/WestWindWebToolkit/Samples/WebResource.axd?d=TooLongAndNastyToPrint', handle: $('#divEditBook_Header')}) so you can see how to apply a custom image, which in this case is generated by the server control wrapping the client DragPanel. More interesting maybe is to apply the .closable behavior to list scenarios. For example, each of the individual items in the list display also are .closable using this plug-in. Rather than having to define each item with Html for an image, event handler and link, when the client template is rendered the closable behavior is attached to the list. Here I’m using client-templating and the code that this is done with looks like this: function loadBooks() { showProgress(); // Clear the content $("#divBookListWrapper").empty(); var filter = $("#" + scriptVars.lstFiltersId).val(); Proxy.GetBooks(filter, function(books) { $(books).each(function(i) { updateBook(this); showProgress(true); }); }, onPageError); } function updateBook(book,highlight) { // try to retrieve the single item in the list by tag attribute id var item = $(".bookitem[tag=" +book.Pk +"]"); // grab and evaluate the template var html = parseTemplate(template, book); var newItem = $(html) .attr("tag", book.Pk.toString()) .click(function() { var pk = $(this).attr("tag"); editBook(this, parseInt(pk)); }) .closable({ closeHandler: function(e) { removeBook(this, e); }, imageUrl: "../../images/remove.gif" }); if (item.length > 0) item.after(newItem).remove(); else newItem.appendTo($("#divBookListWrapper")); if (highlight) { newItem .addClass("pulse") .effect("bounce", { distance: 15, times: 3 }, 400); setTimeout(function() { newItem.removeClass("pulse"); }, 1200); } } Here the closable behavior is applied to each of the items along with an event handler, which is nice and easy compared to having to embed the right HTML and click handling into each item in the list individually via markup. Ideally though (and these posts make me realize this often a little late) I probably should set up a custom cssClass to handle the rendering – maybe a CSS class called .removebox that only changes the image from the default box image. This example also hooks up an event handler that is fired in response to the close. In the list I need to know when the remove button is clicked so I can fire of a service call to the server to actually remove the item from the database. The handler code can also return false; to indicate that the window should not be closed optionally. Returning true will close the window. You can find more information about the .closable class behavior and options here: .closable Documentation Plug-ins make Server Control JavaScript much easier I find this plug-in immensely useful especial as part of server control code, because it simplifies the code that has to be generated server side tremendously. This is true of plug-ins in general which make it so much easier to create simple server code that only generates plug-in options, rather than full blocks of JavaScript code.  For example, here’s the relevant code from the DragPanel server control which generates the .closable() behavior: if (this.Closable && !string.IsNullOrEmpty(DragHandleID) ) { string imageUrl = this.CloseBoxImage; if (imageUrl == "WebResource" ) imageUrl = ScriptProxy.GetWebResourceUrl(this, this.GetType(), ControlResources.CLOSE_ICON_RESOURCE); StringBuilder closableOptions = new StringBuilder("imageUrl: '" + imageUrl + "'"); if (!string.IsNullOrEmpty(this.DragHandleID)) closableOptions.Append(",handle: $('#" + this.DragHandleID + "')"); if (!string.IsNullOrEmpty(this.ClientDialogHandler)) closableOptions.Append(",handler: " + this.ClientDialogHandler); if (this.FadeOnClose) closableOptions.Append(",fadeOut: 'slow'"); startupScript.Append(@" .closable({ " + closableOptions + "})"); } The same sort of block is then used for .draggable and .shadow which simply sets options. Compared to the code I used to have in pre-jQuery versions of my JavaScript toolkit this is a walk in the park. In those days there was a bunch of JS generation which was ugly to say the least. I know a lot of folks frown on using server controls, especially the UI is client centric as the example is. However, I do feel that server controls can greatly simplify the process of getting the right behavior attached more easily and with the help of IntelliSense. Often the script markup is easier is especially if you are dealing with complex, multiple plug-in associations that often express more easily with property values on a control. Regardless of whether server controls are your thing or not this plug-in can be useful in many scenarios. Even in simple client-only scenarios using a plug-in with a few simple parameters is nicer and more consistent than creating the HTML markup over and over again. I hope some of you find this even a small bit as useful as I have. Related Links Download jquery.closable West Wind Web Toolkit jQuery Plug-ins © Rick Strahl, West Wind Technologies, 2005-2010Posted in jQuery   ASP.NET  JavaScript  

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• Remote Desktop (Vino-Server) connects but display doesn't work?

  - by kmassada

  Ubuntu comes default with vino-server, I can remote into my machine, and connect to it, however, the display inside my remote client, is a mirror of my own desktop. I tried using one monitor, thinking that's what is the issue but still won't work. (vino-server:3608): EggSMClient-CRITICAL **: egg_sm_client_set_mode: assertion `global_client == NULL || global_client_mode == EGG_SM_CLIENT_MODE_DISABLED' failed 25/07/2012 12:23:58 PM Autoprobing TCP port in (all) network interface 25/07/2012 12:23:58 PM Listening IPv6://[::]:5900 25/07/2012 12:23:58 PM Listening IPv4://0.0.0.0:5900 25/07/2012 12:23:58 PM Autoprobing selected port 5900 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Re-binding socket to listen for VNC connections on TCP port 5900 in (all) interface 25/07/2012 12:23:58 PM Listening IPv6://[::]:5900 25/07/2012 12:23:58 PM Listening IPv4://0.0.0.0:5900 25/07/2012 12:23:58 PM Clearing securityTypes 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Clearing securityTypes 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Advertising authentication type: 'No Authentication' (1) 25/07/2012 12:23:58 PM Re-binding socket to listen for VNC connections on TCP port 5900 in (all) interface 25/07/2012 12:23:58 PM Listening IPv6://[::]:5900 25/07/2012 12:23:58 PM Listening IPv4://0.0.0.0:5900 25/07/2012 12:23:58 PM Clearing securityTypes 25/07/2012 12:23:58 PM Clearing authTypes 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Advertising authentication type: 'VNC Authentication' (2) 25/07/2012 12:23:58 PM Clearing securityTypes 25/07/2012 12:23:58 PM Clearing authTypes 25/07/2012 12:23:58 PM Advertising security type: 'TLS' (18) 25/07/2012 12:23:58 PM Advertising authentication type: 'VNC Authentication' (2) 25/07/2012 12:23:58 PM Advertising security type: 'VNC Authentication' (2) (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. 25/07/2012 12:24:16 PM [IPv4] Got connection from client static-XXXX.bltmmd.fios.verizon.net 25/07/2012 12:24:16 PM other clients: 25/07/2012 12:24:29 PM Client Protocol Version 3.7 25/07/2012 12:24:29 PM Advertising security type 18 25/07/2012 12:24:29 PM Advertising security type 2 25/07/2012 12:24:30 PM Client returned security type 18 25/07/2012 12:24:30 PM Advertising authentication type 2 25/07/2012 12:24:30 PM Client returned authentication type 2 25/07/2012 12:24:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -258 25/07/2012 12:24:37 PM Enabling NewFBSize protocol extension for client static-XXXX.bltmmd.fios.verizon.net 25/07/2012 12:24:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type 1464686185 25/07/2012 12:24:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -259 25/07/2012 12:24:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -257 (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. 25/07/2012 12:24:55 PM Client static-XXXX.bltmmd.fios.verizon.net gone 25/07/2012 12:24:55 PM Statistics: 25/07/2012 12:24:55 PM key events received 0, pointer events 80 25/07/2012 12:24:55 PM framebuffer updates 43, rectangles 152, bytes 292401 25/07/2012 12:24:55 PM tight rectangles 152, bytes 292401 25/07/2012 12:24:55 PM raw bytes equivalent 11621332, compression ratio 39.744502 25/07/2012 12:25:21 PM [IPv4] Got connection from client static-XXXX.bltmmd.fios.verizon.net 25/07/2012 12:25:21 PM other clients: 25/07/2012 12:25:28 PM Client Protocol Version 3.7 25/07/2012 12:25:28 PM Advertising security type 18 25/07/2012 12:25:28 PM Advertising security type 2 25/07/2012 12:25:28 PM Client returned security type 18 25/07/2012 12:25:29 PM Advertising authentication type 2 25/07/2012 12:25:29 PM Client returned authentication type 2 25/07/2012 12:25:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -258 25/07/2012 12:25:37 PM Enabling NewFBSize protocol extension for client static-XXXX.bltmmd.fios.verizon.net 25/07/2012 12:25:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type 1464686185 25/07/2012 12:25:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -259 25/07/2012 12:25:37 PM rfbProcessClientNormalMessage: ignoring unknown encoding type -257 (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. 25/07/2012 12:25:47 PM Client static-XXXX.bltmmd.fios.verizon.net gone 25/07/2012 12:25:47 PM Statistics: 25/07/2012 12:25:47 PM key events received 0, pointer events 7283 25/07/2012 12:25:47 PM framebuffer updates 27, rectangles 82, bytes 113354 25/07/2012 12:25:47 PM tight rectangles 82, bytes 113354 25/07/2012 12:25:47 PM raw bytes equivalent 5831432, compression ratio 51.444431 couple of things I notice, the following error occurs over and over again. the menu error seems to be caused by ubuntu, similar problems occur http://trac.wxwidgets.org/ticket/14292, (vino-server:3608): LIBDBUSMENU-GLIB-WARNING **: Trying to remove a child that doesn't believe we're it's parent. the second one also seem to be a display related issue, can't seem to figure out a solution. I really rather try to fix this issue than have to use the other vnc clients most suggest. (vino-server:3608): EggSMClient-CRITICAL **: egg_sm_client_set_mode: assertion `global_client == NULL || global_client_mode == EGG_SM_CLIENT_MODE_DISABLED' failed

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• How to use correctly the comments in C/++

  - by Lucio

  I'm learning to program in C and in my stage, the best form to use correctly the comments is writing good comments from the beginning. As the comments are not just for that one understands better the code but others too, I want to know the views of all of you to reach a consensus. So what I want is that the most experienced users edit the following code as you please. (If it's unnecessary, delete it; If it's wrong, correct it; If needed, add more) Thus there'll be multiple answers with different syntax and the responses with the most votes will be taken as referring when commenting. The code to copy, paste and edit to your pleasure is: (And I remark again, just import the comments, not the code) /* This programs find 1 number in 1 file. The file is binary type and has integers in series. The number is integer type and it's entered from the keyboard. When finished the program, a poster will show the results: Saying if the number is in the file or not. */ #include <stdio.h> //FUNCTION 1 //Open file 'path' and closes it. void openf(char path[]) { int num; //Read from Keyboard a Number and it save it into 'num' var printf("Ready for read number.\n\nNumber --> "); fflush(stdin); scanf("%d",&num); //Open file 'path' in READ mode FILE *fvar; fvar=fopen(path,"rb"); //IF error happens when open file, exit of function if (fvar==NULL) { printf("ERROR while open file %s in read mode.",path); exit(1); } /*Verify the result of 'funct' function IF TRUE, 'num' it's in the file*/ if (funct(path,fvar,num)) printf("The number %d it is in the file %s.",num,path); else printf("The number %d it is not in the file %s.",num,path); fclose(fvar); } /*FUNCTION 2 It is a recursive function. Reads number by number until the file is empty or the number is found. Parameters received: 'path' -> Directory file 'fvar' -> Pointer file 'num' -> Number to compare */ int funct(char path[],FILE *fvar,int num) { int compare; //FALSE condition when the pointer reaches the end if (fread(&compare,sizeof(int),1,fvar)>0) /*TRUE condition when the number readed is iqual that 'num' ELSE will go to the function itself*/ if (compare!=num) funct(path,fvar,num); else return 1; else return 0; } int main(int argc, char **argv) { char path[30]="file.bin"; //Direction of the file to process openf(path); //Function with algorithm return 0; }

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• (libgdx) Button doesn't work

  - by StercoreCode

  At the game I choose StopScreen. At this screen displays button. But if I click it - it doesn't work. What I expect - when I press button it must restart game. At this stage must display at least a message that the button is pressed. I tried to create new and clear project. Main class implement ApplicationListener. I put the same code in the appropriate methods. And it's works! But if i create this button in my game - it doesn't work. When i play and go to the StopScreen, i saw button. But if i click, or touch, nothing happens. I think that the proplem at the InputListener, although i set the stage as InputProcessor. Gdx.input.setInputProcessor(stage); I also try to addListener for Button as ClickListener. But it gave no results. Or it maybe problem that i implements Screen method - not ApplicationListener or Game. But if StopScreen implement ApplicationListener, at the mainGame I can't to setScreen. Just interests question: why button displays but nothing happens to it? Here is the code of StopScreen if it helps find my mistake: public class StopScreen implements Screen{ private OrthographicCamera camera; private SpriteBatch batch; public Stage stage; //** stage holds the Button **// private BitmapFont font; //** same as that used in Tut 7 **// private TextureAtlas buttonsAtlas; //** image of buttons **// private Skin buttonSkin; //** images are used as skins of the button **// public TextButton button; //** the button - the only actor in program **// public StopScreen(CurrusGame currusGame) { camera = new OrthographicCamera(); camera.setToOrtho(false, 800, 480); batch = new SpriteBatch(); buttonsAtlas = new TextureAtlas("button.pack"); //** button atlas image **// buttonSkin = new Skin(); buttonSkin.addRegions(buttonsAtlas); //** skins for on and off **// font = AssetLoader.font; //** font **// stage = new Stage(); stage.clear(); Gdx.input.setInputProcessor(stage); TextButton.TextButtonStyle style = new TextButton.TextButtonStyle(); style.up = buttonSkin.getDrawable("ButtonOff"); style.down = buttonSkin.getDrawable("ButtonOn"); style.font = font; button = new TextButton("PRESS ME", style); //** Button text and style **// button.setPosition(100, 100); //** Button location **// button.setHeight(100); //** Button Height **// button.setWidth(100); //** Button Width **// button.addListener(new InputListener() { public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) { Gdx.app.log("my app", "Pressed"); return true; } public void touchUp(InputEvent event, float x, float y, int pointer, int button) { Gdx.app.log("my app", "Released"); } }); stage.addActor(button); } @Override public void render(float delta) { Gdx.gl.glClearColor(0, 1, 0, 1); Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); stage.act(); batch.setProjectionMatrix(camera.combined); batch.begin(); stage.draw(); batch.end(); }

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• What are the disadvantages of self-encapsulation?

  - by Dave Jarvis

  Background Tony Hoare's billion dollar mistake was the invention of null. Subsequently, a lot of code has become riddled with null pointer exceptions (segfaults) when software developers try to use (dereference) uninitialized variables. In 1989, Wirfs-Brock and Wikerson wrote: Direct references to variables severely limit the ability of programmers to re?ne existing classes. The programming conventions described here structure the use of variables to promote reusable designs. We encourage users of all object-oriented languages to follow these conventions. Additionally, we strongly urge designers of object-oriented languages to consider the effects of unrestricted variable references on reusability. Problem A lot of software, especially in Java, but likely in C# and C++, often uses the following pattern: public class SomeClass { private String someAttribute; public SomeClass() { this.someAttribute = "Some Value"; } public void someMethod() { if( this.someAttribute.equals( "Some Value" ) ) { // do something... } } public void setAttribute( String s ) { this.someAttribute = s; } public String getAttribute() { return this.someAttribute; } } Sometimes a band-aid solution is used by checking for null throughout the code base: public void someMethod() { assert this.someAttribute != null; if( this.someAttribute.equals( "Some Value" ) ) { // do something... } } public void anotherMethod() { assert this.someAttribute != null; if( this.someAttribute.equals( "Some Default Value" ) ) { // do something... } } The band-aid does not always avoid the null pointer problem: a race condition exists. The race condition is mitigated using: public void anotherMethod() { String someAttribute = this.someAttribute; assert someAttribute != null; if( someAttribute.equals( "Some Default Value" ) ) { // do something... } } Yet that requires two statements (assignment to local copy and check for null) every time a class-scoped variable is used to ensure it is valid. Self-Encapsulation Ken Auer's Reusability Through Self-Encapsulation (Pattern Languages of Program Design, Addison Wesley, New York, pp. 505-516, 1994) advocated self-encapsulation combined with lazy initialization. The result, in Java, would resemble: public class SomeClass { private String someAttribute; public SomeClass() { setAttribute( "Some Value" ); } public void someMethod() { if( getAttribute().equals( "Some Value" ) ) { // do something... } } public void setAttribute( String s ) { this.someAttribute = s; } public String getAttribute() { String someAttribute = this.someAttribute; if( someAttribute == null ) { setAttribute( createDefaultValue() ); } return someAttribute; } protected String createDefaultValue() { return "Some Default Value"; } } All duplicate checks for null are superfluous: getAttribute() ensures the value is never null at a single location within the containing class. Efficiency arguments should be fairly moot -- modern compilers and virtual machines can inline the code when possible. As long as variables are never referenced directly, this also allows for proper application of the Open-Closed Principle. Question What are the disadvantages of self-encapsulation, if any? (Ideally, I would like to see references to studies that contrast the robustness of similarly complex systems that use and don't use self-encapsulation, as this strikes me as a fairly straightforward testable hypothesis.)

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• Issues glVertexAttribPointer last 2 parameters?

  - by NoobScratcher

  Introduction Hello I will start out by explaining my setup, showing samples as I go along explaining the situation. I'm using these tools: OpenGL 3.3 GLSL 330 C++ Problem The problem is when I render the wavefront obj 3d model it gives a very weird visual glitch the model was supposed to be a square but instead its a triangluated mess with parts of the vertexes pointing in a stretched direction in massive amounts towards the bottom left side of the frustum.... Explanation: I'm using std::vectors to store my wavefront .obj model data using sscanf to get the floating point values into the structure members x,y,z and store them into the Points structure variable p; int index = IndexAssigner(1, 1); ifstream file (list[index].c_str() ); points.push_back(Point()); Point p; int face[4]; while (!file.eof() ) { char modelbuffer[10000]; file.getline(modelbuffer, 10000); switch(modelbuffer[0]) { case 'v' : sscanf(modelbuffer, "v %f %f %f", &p.x, &p.y, &p.z); points.push_back(p); break; case 'f': sscanf(modelbuffer, "f %d %d %d %d", face, face+1, face+2, face+3 ); faces.push_back(face[0]); faces.push_back(face[1]); faces.push_back(face[2]); faces.push_back(face[3]); } //Turn on FileReader aka "RENDER CODE" FileReader = true; } then I render the Points vector using the .data() member of std::vectors to the frustum. Other declarations: int numfloats = 4; float* point=reinterpret_cast<float*>(&points[0]); int num_bytes=numfloats*sizeof(float); Vector declarations: struct Point {float x, y , z; }; std::vector<int>faces; std::vector<Point>points; Render code: glGenBuffers(1, &vertexbuffer); glGenTextures(1, &ModelTexture); glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glBindTexture(GL_TEXTURE_3D, ModelTexture); glTexImage2D(GL_TEXTURE_2D, 0,GL_RGBA, ModelSurface->w, ModelSurface->h, 0, GL_BGR, GL_UNSIGNED_BYTE, ModelSurface->pixels); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glBufferData(GL_ARRAY_BUFFER, sizeof(points), points.data(), GL_STATIC_DRAW); glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE,num_bytes ,points.data()); glEnableVertexAttribArray(3); //Translation Process GLfloat TranslationMatrix[] = { 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0 }; //Send Translation Matrix up to the vertex shader glUniformMatrix4fv(translation, 1, TRUE, TranslationMatrix); glDrawElements( GL_QUADS, faces.size(), GL_UNSIGNED_INT, faces.data()); I tried looking at what was causing this and went through every function every parameter ,etc looked at the man pages. Then found out that it could be my glVertexAttribPointer. Here are the man pages for glVertexAttribPointer http://www.opengl.org/sdk/docs/man/xhtml/glVertexAttribPointer.xml The last 2 parameters is my problem How do I write those 2 last parameters do I try putting the data from Points into it?. glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE,num_bytes ,points.data()); How does it work with vectors? Is it fast?* if you can not be bothered too look at the man pages here is the scripts coming from the man pages directly. Stride Specifies the byte offset between consecutive generic vertex attributes. If stride is 0, the generic vertex attributes are understood to be tightly packed in the array. The initial value is 0. Pointer Specifies a pointer to the first component of the first generic vertex attribute in the array. The initial value is 0. If you want my full source - http://ideone.com/fPfkg Thanks Again if you do read this.

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• QT: trouble with qobject_cast

  - by weevilo

  I have derived QGraphicsItem and QGraphicsScene classes. I want the items to be able to call scene() and get a derviedGraphicsItem * instead of a QGraphicsItem *, so I reimplemented QGraphicsScene::itemAt to return a derived pointer. DerivedItem* DerivedScene::itemAt( const QPointF &position, const QTransform &dt ) const { return qobject_cast< DerivedItem * >( QGraphicsScene::itemAt(position, dt) ); } I get the following error (Qt 4.6, GCC 4.4.3 on Ubuntut 10.4) scene.cpp: In member function ‘DerivedItem* DerivedScene::itemAt(qreal, qreal, const QTransform&) const’: scene.cpp:28: error: no matching function for call to ‘qobject_cast(QGraphicsItem*)’ I then noticed QGraphicsItem doesn't inherit QObject, so I made my derived QGraphicsItem class have multiple inheritance from QObject and QGraphicsItem, and after adding the Q_OBJECT macro and rebuilding the project I get the same error. Am I going about this the wrong way? I know it's supposed to be bad design to try to cast a parent class as a child, but in this case it seems like what I want, since my derived item class has new functionality and its objects need a way to call that new functionality on items around themselves, and asking the items scene object with itemAt() seems like the best way - but I need itemAt() to return a pointer of the right type. I can get around this by having the derived items cast the QGraphicsItem * returned by QGraphicsScene::itemAt() using dynamic_cast, but I don't really understand why that works and not qobject_cast, or the benefits or disadvantages to using dynamic_cast vs. qobject_cast.

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• Call functions in AutoIt DLL using Python ctypes

  - by Josh

  I want to call functions from an AutoIt dll, that I found at C:\Program Files (x86)\AutoIt3\AutoItX\AutoItX3.dll using Python. I know I could use win32com.client.Dispatch("AutoItX3.Control") but I can't install the application or register anything in the system. So far, this is where I am: from ctypes import * path = r"C:\Program Files (x86)\AutoIt3\AutoItX\AutoItX3.dll" autoit = windll.LoadLibrary(path) Here are the methods that works: autoit.AU3_WinMinimizeAll() # windows were successfully minimized. autoit.AU3_Sleep(1000) # sleeps 1 sec. Here is my problem, python is crashing when I call other methods like this one. I get python.exe has stopped working from windows... autoit.AU3_WinGetHandle('Untitled - Notepad', '') And some other methods are not crashing python but are just not working. This one doesn't close the window and return 0: autoit.AU3_WinClose('Untitled - Notepad', '') And this other one return 1 but the window is still minimized: autoit.AU3_WinActivate('Untitled - Notepad', '') I've tested the examples with with Dispatch("AutoItX3.Control") and everything is working like expected. It seems like methods that should return something other than a string are crashing python. But still, others like WinClose are not even working... Thank you in advance for your help! EDIT: These methods are now working when using unicode strings: autoit.AU3_WinClose(u'Untitled - Notepad', u'') autoit.AU3_WinActivate(u'Untitled - Notepad', u'') And I found the prototype for AU3_WinGetHandle: AU3_API void WINAPI AU3_WinGetHandle(const char szTitle, /[in,defaultvalue("")]*/const char *szText, char *szRetText, int nBufSize); Now I see that I should get the handle from szRetText but I am not sure how... I tried the following without success: from ctypes.wintypes import LPCWSTR, INT, POINTER AU3_WinGetHandle.argtypes = (LPCWSTR, LPCWSTR, POINTER(LPCWSTR), INT) s = c_wchar_p() print AU3_WinGetHandle(u'Untitled - Notepad', u'', byref(s), 100) # prints 1 print s # prints c_wchar_p(u'') Any idea how to retrive the handle from szRetText?

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• Wpf: Why is WriteableBitmap getting slower?

  - by fritz

  There is a simple MSDN example about WriteableBitmap. It shows how to draw a freehand line with the cursor by just updating one pixel when the mouse is pressed and is moving over a WPF -Image Control. writeableBitmap.Lock(); (...set the writeableBitmap.BackBuffers pixel value...) writeableBitmap.AddDirtyRect(new Int32Rect(column, row, 1, 1)); writeableBitmap.Unlock(); Now I'm trying to understand the following behaviour when moving the mouse pointer very fast: If the image/bitmap size is relatively small e.g. 800:600 pixel, then the last drawn pixel is always "synchronized" with the mouse pointers position, i.e. there is no delay, very fast reaction on mouse movements. But if the bitmap gets larger e.g. 1300:1050 pixel, you can notice a delay, the last drawn pixel always appear a bit delayed behind the moving mouse pointer. So as in both cases only one pixel gets updated with "AddDirtyRect", the reaction speed should be independent from the bitmap size!? But it seems that Writeablebitmap gets slower when it's size gets larger. Or does the whole bitmap somehow get transferred to the graphic device on every writeableBitmap.Unlock(); call , and not only the rectangle area speficied in the AddDirtyRect method? fritz

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• COM Object Clean Up

  - by Reggie McCray

  What is the difference between the two lines of code below: CComPtr< IInterface > m_interface; IInterface* m_interface; I know that CComPtr help eliminate memory leaks, but I am getting inconsistent results. When declaring the pointer with CComPtr< IInterface > m_interface; and using the interface in my C# code there are no errors, however using the Interface in VC++ I get an unhandled exception error, even if I comment out the instance creation of IInterface. I am pretty sure the problem is in here somewhere: STDMETHODIMP CSomeClass::get_IClass(IClass** var) { return m_class_var->QueryInterface(var); } STDMETHODIMP CSomeClass::putref_IClass(IClass* var) { m_class_var = var; return S_OK; } When I declare the interface pointer with: IInterface* m_interface; I get a RPC_E_SERVERFAULT error when testing the Interface in C# and have to explicitly call GC.Collect() to avoid the error being thrown after instantiation of a few objects. When testing the Interface in VC++ the error is consistent however when it occurs is different. If I comment out the instance creation of IInterface the code runs fine, however when I try to create an instance I get same error as before, just a vague unhandled exception error. What am I doing wrong here?

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• Generating %pc relative address of constant data

  - by Hudson

  Is there a way to have gcc generate %pc relative addresses of constants? Even when the string appears in the text segment, arm-elf-gcc will generate a constant pointer to the data, load the address of the pointer via a %pc relative address and then dereference it. For a variety of reasons, I need to skip the middle step. As an example, this simple function: const char * filename(void) { static const char _filename[] __attribute__((section(".text"))) = "logfile"; return _filename; } generates (when compiled with arm-elf-gcc-4.3.2 -nostdlib -c -O3 -W -Wall logfile.c): 00000000 <filename>: 0: e59f0000 ldr r0, [pc, #0] ; 8 <filename+0x8> 4: e12fff1e bx lr 8: 0000000c .word 0x0000000c 0000000c <_filename.1175>: c: 66676f6c .word 0x66676f6c 10: 00656c69 .word 0x00656c69 I would have expected it to generate something more like: filename: add r0, pc, #0 bx lr _filename.1175: .ascii "logfile\000" The code in question needs to be partially position independent since it will be relocated in memory at load time, but also integrate with code that was not compiled -fPIC, so there is no global offset table. My current work around is to call a non-inline function (which will be done via a %pc relative address) to find the offset from the compiled location in a technique similar to how -fPIC code works: static intptr_t __attribute__((noinline)) find_offset( void ) { uintptr_t pc; asm __volatile__ ( "mov %0, %%pc" : "=&r"(pc) ); return pc - 8 - (uintptr_t) find_offset; } But this technique requires that all data references be fixed up manually, so the filename() function in the above example would become: const char * filename(void) { static const char _filename[] __attribute__((section(".text"))) = "logfile"; return _filename + find_offset(); }

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• Comparing objects with IDispatch to get main frame only (BHO)

  - by shaimagz

  I don't know if anyone familiar with BHO (Browser Helper Object), but an expert in c++ can help me too. In my BHO I want to run the OnDocumentComplete() function only on the main frame - the first container and not all the Iframes inside the current page. (an alternative is to put some code only when this is the main frame). I can't find how to track when is it the main frame that being populated. After searching in google I found out that each frame has "IDispatch* pDisp", and I have to compare it with a pointer to the first one. This is the main function: STDMETHODIMP Browsarity::SetSite(IUnknown* pUnkSite) { if (pUnkSite != NULL) { // Cache the pointer to IWebBrowser2. HRESULT hr = pUnkSite->QueryInterface(IID_IWebBrowser2, (void **)&m_spWebBrowser); if (SUCCEEDED(hr)) { // Register to sink events from DWebBrowserEvents2. hr = DispEventAdvise(m_spWebBrowser); if (SUCCEEDED(hr)) { m_fAdvised = TRUE; } } } else { // Unregister event sink. if (m_fAdvised) { DispEventUnadvise(m_spWebBrowser); m_fAdvised = FALSE; } // Release cached pointers and other resources here. m_spWebBrowser.Release(); } // Call base class implementation. return IObjectWithSiteImpl<Browsarity>::SetSite(pUnkSite); } This is where I want to be aware whether its the main window(frame) or not: void STDMETHODCALLTYPE Browsarity::OnDocumentComplete(IDispatch *pDisp, VARIANT *pvarURL) { // as you can see, this function get the IDispatch *pDisp which is unique to every frame. //some code } I asked this question on Microsoft forum and I got an answer without explaining how to actually implement that: http://social.msdn.microsoft.com/Forums/en-US/ieextensiondevelopment/thread/7c433bfa-30d7-42db-980a-70e62640184c

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• Problem reading from two separate InputStreams

  - by Emil H

  I'm building a Yammer client for Android in Scala and have encountered the following issue. When two AsyncTasks try to parse an XML response (not the same, each task has it's own InputStream) from the Yammer API the underlying stream throws a IOException with the message "null SSL pointer", as seen below: Uncaught handler: thread AsyncTask #1 exiting due to uncaught exception java.lang.RuntimeException: An error occured while executing doInBackground() at android.os.AsyncTask$3.done(AsyncTask.java:200) at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:234) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:258) at java.util.concurrent.FutureTask.run(FutureTask.java:122) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:648) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:673) at java.lang.Thread.run(Thread.java:1060) Caused by: java.io.IOException: null SSL pointer at org.apache.harmony.xnet.provider.jsse.OpenSSLSocketImpl.nativeread(Native Method) at org.apache.harmony.xnet.provider.jsse.OpenSSLSocketImpl.access$300(OpenSSLSocketImpl.java:55) at org.apache.harmony.xnet.provider.jsse.OpenSSLSocketImpl$SSLInputStream.read(OpenSSLSocketImpl.java:524) at org.apache.http.impl.io.AbstractSessionInputBuffer.fillBuffer(AbstractSessionInputBuffer.java:103) at org.apache.http.impl.io.AbstractSessionInputBuffer.read(AbstractSessionInputBuffer.java:134) at org.apache.http.impl.io.ContentLengthInputStream.read(ContentLengthInputStream.java:174) at org.apache.http.impl.io.ContentLengthInputStream.read(ContentLengthInputStream.java:188) at org.apache.http.conn.EofSensorInputStream.read(EofSensorInputStream.java:178) at org.apache.harmony.xml.ExpatParser.parseFragment(ExpatParser.java:504) at org.apache.harmony.xml.ExpatParser.parseDocument(ExpatParser.java:467) at org.apache.harmony.xml.ExpatReader.parse(ExpatReader.java:329) at org.apache.harmony.xml.ExpatReader.parse(ExpatReader.java:286) at javax.xml.parsers.SAXParser.parse(SAXParser.java:361) at org.mediocre.util.XMLParser$.loadXML(XMLParser.scala:28) at org.mediocre.util.XMLParser$.loadXML(XMLParser.scala:12) ..... Searching for the error didn't give much clarity. Does this have something to do with the response from the server? Or is it something else? Complete code can be found at: http://github.com/archevel/YammerTime I get no error if I wait until the first repsponse is finished and then let the other complete. The request is made with the DefaultHttpClient, but this is supposedly thread safe. What am I missing? If anything needs to be clarified just ask :) Cheers, Emil H

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• Typedef and Struct in C and H files

  - by Leif Andersen

  I've been using the following code to create various struct, but only give people outside of the C file a pointer to it. (Yes, I know that they could potentially mess around with it, so it's not entirely like the private keyword in Java, but that's okay with me). Anyway, I've been using the following code, and I looked at it today, and I'm really surprised that it's actually working, can anyone explain why this is? In my C file, I create my struct, but don't give it a tag in the typedef namespace: struct LABall { int x; int y; int radius; Vector velocity; }; And in the H file, I put this: typedef struct LABall* LABall; I am obviously using #import "LABall.h" in the c file, but I am NOT using #import "LABall.c" in the header file, as that would defeat the whole purpose of a separate header file. So, why am I able to create a pointer to the LABall* struct in the H file when I haven't actually included it? Does it have something to do with the struct namespace working accross files, even when one file is in no way linked to another? Thank you.

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• Delete array of size 1

  - by Arne

  This is possibly a candidate for a one-line answer. I would like know it anyway.. I am writing a simple circular buffer and for some reasons that are not important for the question I need to implement it using an array of doubles. In fact I have not investiated other ways to do it, but since an array is required anyway I have not spent much time on looking for alternatives. template<typename T> class CircularBuffer { public: CircularBuffer(unsigned int size); ~CircularBuffer(); void Resize(unsigned int new_size); ... private: T* buffer; unsigned int buffer_size; }; Since I need to have the buffer dynamically sized the buffer_size is neither const nor a template parameter. Now the question: During construction and in function Resize(int) I only require the size to be at least one, although a buffer of size one is effectively no longer a buffer. Of course using a simple double instead would be more appropriate but anyway. Now when deleting the internal buffer in the destructor - or in function resize for that matter - I need to delete the allocated memory. Question is, how? First candidate is of course delete[] buffer; but then again, if I have allocated a buffer of size one, that is if the pointer was aquired with buffer = new T[0], is it still appropriate to call delete[] on the pointer or do I need to call delete buffer; (without brackets) ? Thanks, Arne

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• Reinterpret a CGImageRef using PyObjC in Python

  - by Michael Rondinelli

  Hi, I'm doing something that's a little complicated to sum up in the title, so please bear with me. I'm writing a Python module that provides an interface to my C++ library, which provides some specialized image manipulation functionality. It would be most convenient to be able to access image buffers as CGImageRefs from Python, so they could be manipulated further using Quartz (using PyObjC, which works well). So I have a C++ function that provides a CGImageRef representation from my own image buffers, like this: CGImageRef CreateCGImageRefForImageBuffer(shared_ptr<ImageBuffer> buffer); I'm using Boost::Python to create my Python bridge. What is the easiest way for me to export this function so that I can use the CGImageRef from Python? Problems: The CGImageRef type can't be exported directly because it is a pointer to an undefined struct. So I could make a wrapper function that wraps it in a PyCObject or something to get it to send the pointer to Python. But then how do I "cast" this object to a CGImageRef from Python? Is there a better way to go about this?

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• "jpeglib.h: No such file or directory" ghostscript port in OPENBSD

  - by holms

  Hello I have a problem with compiling a ghostscript from ports in openbsd 4.7. SO i have jpeg-7 installed, I have latest port tree for obsd4.7. ===> Building for ghostscript-8.63p11 mkdir -p /usr/ports/pobj/ghostscript-8.63p11/ghostscript-8.63/obj gmake LDFLAGS='-L/usr/local/lib -shared' GS_XE=./obj/../obj/libgs.so.11.0 STDIO_IMPLEMENTATION=c DISPLAY_DEV=./obj/../obj/display.dev BINDIR=./obj/../obj GLGENDIR=./obj/../obj GLOBJDIR=./obj/../obj PSGENDIR=./obj/../obj PSOBJDIR=./obj/../obj CFLAGS='-O2 -fno-reorder-blocks -fno-reorder-functions -fomit-frame-pointer -march=i386 -fPIC -Wall -Wstrict-prototypes -Wmissing-declarations -Wmissing-prototypes -fno-builtin -fno-common -DGS_DEVS_SHARED -DGS_DEVS_SHARED_DIR=\"/usr/local/lib/ghostscript/8.63\"' prefix=/usr/local ./obj/../obj/gsc gmake[1]: Entering directory `/usr/ports/pobj/ghostscript-8.63p11/ghostscript-8.63' cc -I./obj/../obj -I./src -DHAVE_MKSTEMP -O2 -fno-reorder-blocks -fno-reorder-functions -fomit-frame-pointer -march=i386 -fPIC -Wall -Wstrict-prototypes -Wmissing-declarations -Wmissing-prototypes -fno-builtin -fno-common -DGS_DEVS_SHARED -DGS_DEVS_SHARED_DIR=\"/usr/local/lib/ghostscript/8.63\" -DGX_COLOR_INDEX_TYPE='unsigned long long' -o ./obj/../obj/sdctc.o -c ./src/sdctc.c In file included from src/sdctc.c:17: obj/jpeglib_.h:1:21: jpeglib.h: No such file or directory In file included from src/sdctc.c:19: src/sdct.h:58: error: field `err' has incomplete type src/sdct.h:70: error: field `err' has incomplete type src/sdct.h:72: error: field `cinfo' has incomplete type src/sdct.h:73: error: field `destination' has incomplete type src/sdct.h:84: error: field `err' has incomplete type src/sdct.h:87: error: field `dinfo' has incomplete type src/sdct.h:88: error: field `source' has incomplete type gmake[1]: *** [obj/../obj/sdctc.o] Error 1 gmake[1]: Leaving directory `/usr/ports/pobj/ghostscript-8.63p11/ghostscript-8.63' gmake: *** [so] Error 2 *** Error code 2 Stop in /usr/ports/print/ghostscript/gnu (line 2225 of /usr/ports/infrastructure/mk/bsd.port.mk). I tried to place one more param in CFLAGS in Makefile with value "-I/usr/local" but no luck =( People in irc [freenode server, #openbsd channel] refuses give any help for ports at all, and even more - because this is 4.7 unstable version. I have my reasons to use this version and ports believe me =) CFLAGS+= -DSYS_TYPES_HAS_STDINT_TYPES \ -I${LOCALBASE}/include \ -I${LOCALBASE}/include/ijs \ -I${LOCALBASE}/include/libpng \

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• Accessing a com object's vtable in c#

  - by Martin Booth

  I'm attempting to access a com object's vtable in memory and getting nowhere. From what I have read, the first 4 bytes in memory of a com object should be a pointer to the vtableptr, which in turn is a pointer to the vtable. Although I'm not sure I expect to find my test method at slot 7 in this com object I have tried them all and nothing looks like the address of my function. If anyone can make the necessary changes to this sample to get it to work (the aim is just to try and invoke the Test method on the Tester class by accessing the com object's vtable and locating the method in whichever row it turns up) I would be very grateful. I know it is rare that anyone would need to do this, but please accept I do need to do something quite similar and have considered the alternatives Thanks in advance [ComVisible(true)] public class Tester { public void Test() { MessageBox.Show("Here"); } } public delegate void TestDelegate(); private void main() { Tester t = new Tester(); GCHandle objectHandle = GCHandle.Alloc(t); IntPtr objectPtr = GCHandle.ToIntPtr(objectHandle); IntPtr vTable = (IntPtr)Marshal.ReadInt32(objectPtr); IntPtr vTablePtr = (IntPtr)Marshal.ReadInt32(vTable); IntPtr functionPtr = (IntPtr)Marshal.ReadInt32(vTablePtr, 7 * 4); // 7 may be incorrect but i have tried many different values TestDelegate func = (TestDelegate)Marshal.GetDelegateForFunctionPointer(functionPtr, typeof(TestDelegate)); func(); objectHandle.Free(); }

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• nasm/yasm arguments, linkage to C++

  - by arionik

  Hello everybody, I've got a question concerning nasm and its linkage to C++. I declare a litte test function as extern "C" void __cdecl myTest( byte i1, byte i2, int stride, int *width ); and I call it like this: byte i1 = 1, i2 = 2; int stride = 3, width = 4; myTest( i1, i2, stride, &width ); the method only serves to debug assembly and have a look at how the stack pointer is used to get the arguments. beyond that, the pointer arguments value shall be set to 7, to figure out how that works. This is implemented like this: global _myTest _myTest: mov eax, [esp+4] ; 1 mov ebx, [esp+8] ; 2 mov ecx, dword [esp+16] ; width mov edx, dword [esp+12] ; stride mov eax, dword [esp+16] mov dword [eax], 7 ret and compiled via yasm -f win32 -g cv8 -m x86 -o "$(IntDir)\$(InputName).obj" "$(InputPath)" , then linked to the c++ app. In debug mode, everything works fine. the function is called a couple of times and works as expected, whereas in release mode the function works once, but subsequent programm operations fail. It seems to me that something's wrong with stack/frame pointers, near/far, but I'm quite new to this subject and need a little help. thanks in advance! a.

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