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  • Should I use a binary or a text file for storing protobuf messages?

    - by nbolton
    Using Google protobuf, I am saving my serialized messaged data to a file - in each file there are several messages. We have both C++ and Python versions of the code, so I need to use protobuf functions that are available in both languages. I have experimented with using SerializeToArray and SerializeAsString and there seems to be the following unfortunate conditions: SerializeToArray: As suggested in one answer, the best way to use this is to prefix each message with it's data size. This would work great for C++, but in Python it doesn't look like this is possible - am I wrong? SerializeAsString: This generates a serialized string equivalent to it's binary counterpart - which I can save to a file, but what happens if one of the characters in the serialization result is \n - how do we find line endings, or the ending of messages for that matter? Update: Please allow me to rephrase slightly. As I understand it, I cannot write binary data in C++ because then our Python application cannot read the data, since it can only parse string serialized messages. Should I then instead use SerializeAsString in both C++ and Python? If yes, then is it best practice to store such data in a text file rather than a binary file? My gut feeling is binary, but as you can see this doesn't look like an option.

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  • Why can't I open a JBoss vfs:/ URL?

    - by skiphoppy
    We are upgrading our application from JBoss 4 to JBoss 6. A couple of pieces of our application get delivered to the client in an unusual way: jars are looked up inside of our application and sent to the client from a servlet, where the client extracts them in order to run certain support functions. In JBoss 4 we would look these jars up with the classloader and find a jar:// URL which would be used to read the jar and send its contents to the client. In JBoss 6 when we perform the lookup we get a vfs:/ URL. I understand that this is from the org.jboss.vfs package. Unfortunately when I call openStream() on this URL and read from the stream, I immediately get an EOF (read() returns -1). What gives? Why can't I read the resource this URL refers to? I've tried trying to access the underlying VFS packages to open the file through the JBoss VFS API, but most of the API appears to be private, and I couldn't find a routine to translate from a vfs:/ URL to a VFS VirtualFile object, so I couldn't get anywhere. I can try to find the file on disk within JBoss, but that approach sounds very failure prone on upgrade. Our old approach was to use Java Web Start to distribute the jars to the client and then look them up within Java Web Start's cache to extract them. But that broke on every minor upgrade of Java because the layout of the cache changed.

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  • How to make a program not show up in Alt-Tab or on the taskbar.

    - by Scott Chamberlain
    I have a program that needs to sit in the background and when a user connects to a RDP session it will do some stuff then launch a program. when the program is closed it will do some housekeeping and logoff the session. The current way I am doing it is like this I have the terminal server launch this application. I have it set as a windows forms application and my code is this public static void Main() { //Do some setup work Process proc = new Process(); //setup the process proc.Start(); proc.WaitForExit(); //Do some housecleaning NativeMethods.ExitWindowsEx(0, 0); } I really like this because there is no item in the taskbar and there is nothing showing up in alt-tab. However to do this I gave up access to functions like void WndProc(ref Message m) So Now I can't listen to windows messages (Like WTS_REMOTE_DISCONNECT or WTS_SESSION_LOGOFF) and do not have a handle to use for for bool WTSRegisterSessionNotification(IntPtr hWnd, int dwFlags); I would like my code to be more robust so it will do the housecleaning if the user logs off or disconnects from the session before he closes the program. Any reccomendations on how I can have my cake and eat it too?

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  • Toggle image based on cookie value

    - by danit
    Im using a couple of JS functions to set a cookie named 'visible' with the value of either yes or no. Essentially Im using these values to decide if a <div> is visible or hidden. I've only just added the cookie, previously I had been using two images 1. Show 2. Hide as a button to hide and show the <div> like this: HTML: <img class="show" title="Show" alt="Show" src="images/show.png" /> <img class="hide" title="Hide" alt="Hide" src="images/hide.png" /> JQUERY: $("#tool").click(function() { $(".help").slideToggle(); $("#wrapper").animate({ opacity: 1.0 },200).slideToggle(200, function() { $("#tool img").toggle(); }); }); However I have now added the Cookie into the mix: $("#tool").click(function() { if(get_cookie('visible')== null) { set_cookie('visible','no'); } else { delete_cookie('visible'); } $(".help").slideToggle(); $("#wrapper").animate({ opacity: 1.0 },200).slideToggle(200, function() { $("#slider img").toggle(); }); }); So the .toggle() no longer matches the state of the <div> When the cookie value = no the show.png should be visible When the cookie value = yes then the hide.png should be visible Can anyone suggest how i can ammend this?

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  • Can one connection get details of another? Or, how can I get the most detailed pending transaction

    - by bob-the-destroyer
    Is there a Mysql statement which provides full details of any other open connection or user? For this particular case, on myisam tables specifically. Looking at Mysql's SHOW TABLE STATUS documentation, it's missing some very important information for my purpose. For example: remote odbc connection one is inserting several thousand records, which due to a slow connection speed can take up to an hour. Tcp connection two, using PHP on the server's localhost, is running select queries with aggregate functions on that data. Before allowing connection two to run those queries, I'd like connection two to first check to make sure there's no pending inserts on any other connection on those specific tables so it can instead wait until all data is available. If the table is currently being written to, I'd like to spit back to the user of connection two an approximation of how much longer to wait based on the number of pending inserts. Ideally by table, I'd like to get back using a query the timestamp when connection one began the write, total inserts left to be done, and total inserts already completed. Instead of insert counts, even knowing number of bytes written and left to write would work just fine here. Obviously since connection two is a tcp connection via a PHP script, all I can really use in that script is some sort of query. I suppose if I have to, since it is on localhost, I can exec() it if the only way is by a mysql command line option that outputs this info, but I'd rather not. I suppose I could simply update a custom-made transaction log before and after this massive insert task which the PHP script can check, but hopefully there's already a built-in Mysql feature I can take advantage of.

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  • Testing When Correctness is Poorly Defined?

    - by dsimcha
    I generally try to use unit tests for any code that has easily defined correct behavior given some reasonably small, well-defined set of inputs. This works quite well for catching bugs, and I do it all the time in my personal library of generic functions. However, a lot of the code I write is data mining code that basically looks for significant patterns in large datasets. Correct behavior in this case is often not well defined and depends on a lot of different inputs in ways that are not easy for a human to predict (i.e. the math can't reasonably be done by hand, which is why I'm using a computer to solve the problem in the first place). These inputs can be very complex, to the point where coming up with a reasonable test case is near impossible. Identifying the edge cases that are worth testing is extremely difficult. Sometimes the algorithm isn't even deterministic. Usually, I do the best I can by using asserts for sanity checks and creating a small toy test case with a known pattern and informally seeing if the answer at least "looks reasonable", without it necessarily being objectively correct. Is there any better way to test these kinds of cases?

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  • overwrite parameters passed by querystring

    - by opensas
    I have the following problem I have a web framework built with classic asp that saves the page state in hidden textboxes, and then issues a submit to itself. Before submitting, we have a javascript functions that saves the action in a hidden "action" input, and then performs the submit. The page loads the state from those hidden texts, reads the action issued, reads extra parameters, like the id of the record to edit, and then builds the page accordingly. I'd like to make a url link to automatically start the page with "edit" action on a "x" id. So I was thinking about building the following url, for example http://myapp/user?action=edit&id=23 the problem is that when the page auto-submits, que url string keeps the parameters. I'd like to achieve the following: when the user clicks on http://myapp/user?action=edit&id=23 my page should receive the posted values action=edit and id=23 but the url should be just http://myapp/user and both parameters should be kept in the hidden texts... (I wonder if I make myself clear...) thanks a lot saludos sas ps: I have a couple of ideas about how to solve it, but I'll post them as answers...

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  • QListWidget drag and drop items disappearing from list

    - by ppalasek
    Hello, I'm having trouble implementing a QListWidget with custom items that can be reordered by dragging and dropping. The problem is when I make a fast double click (a very short drag&drop) on an item, the item sometimes disappears from the QListWidget. This is the constructor for my Widget: ListPopisiDragDrop::ListPopisiDragDrop(QWidget *parent) : QListWidget(parent) { setSelectionMode(QAbstractItemView::SingleSelection); setDragEnabled(true); viewport()->setAcceptDrops(true); setDefaultDropAction(Qt::MoveAction); setDropIndicatorShown(true); setDragDropMode(QAbstractItemView::InternalMove); } also the drop event: void ListPopisiDragDrop::dropEvent(QDropEvent *event){ int startRow=currentIndex().row(); QListWidget::dropEvent(event); int endRow=currentIndex().row(); //more code... } Custom items are made by implementing paint() and sizeHint() functions from QAbstractItemDelegate. When the problem with disappearing items happens, the dropEvent isn't even called. I really don't know what is happening and if I'm doing something wrong. Any help is appreciated. Thanks! Edit: I'm running the application on a Symbian S60 5th edition phone. Edit2: If I add this line to the constructor: setDragDropOverwriteMode(true); the item in the list still disappears, but an empty row stays in it's place.

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  • C++ compiler unable to find function (namespace related)

    - by CS student
    I'm working in Visual Studio 2008 on a C++ programming assignment. We were supplied with files that define the following namespace hierarchy (the names are just for the sake of this post, I know "namespace XYZ-NAMESPACE" is redundant): (MAIN-NAMESPACE){ a bunch of functions/classes I need to implement... (EXCEPTIONS-NAMESPACE){ a bunch of exceptions } (POINTER-COLLECTIONS-NAMESPACE){ Set and LinkedList classes, plus iterators } } The MAIN-NAMESPACE contents are split between a bunch of files, and for some reason which I don't understand the operator<< for both Set and LinkedList is entirely outside of the MAIN-NAMESPACE (but within Set and LinkedList's header file). Here's the Set version: template<typename T> std::ostream& operator<<(std::ostream& os, const MAIN-NAMESPACE::POINTER-COLLECTIONS-NAMESPACE::Set<T>& set) Now here's the problem: I have the following data structure: Set A Set B Set C double num It's defined to be in a class within MAIN-NAMESPACE. When I create an instance of the class, and try to print one of the sets, it tells me that: error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'const MAIN-NAMESPACE::POINTER-COLLECTIONS-NAMESPACE::Set' (or there is no acceptable conversion) However, if I just write a main() function, and create Set A, fill it up, and use the operator- it works. Any idea what is the problem? (note: I tried any combination of using and include I could think of).

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  • JQuery Delegate and using traveral options in function

    - by Brian
    I am having trouble figuring out how to use the JQuery delegate function to do what I require. Basically, I need to allow users to add Panels (i.e. divs) to a form dynamically by selecting a button. Then when a user clicks a button within a given Panel, I want to be able to to something to that Panel (like change the color in this example). Unfortunately, it seems that references to the JQuery traversing functions don't work in this instance. Can anybody explain how to achieve this effect? Is there anyway to bind a different delegate to the each panel as its added. $('.addPanels').delegate('*', 'click', function() { $(this).parent.css('background-color', 'black'); $('.placeholder').append('Add item'); }); <div class="addPanels"> <div class="panel"> <a href="#" class="addLink">Add item</a> text</div> <div class="placeholder"/> </div> </div>

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  • How to fetch particular element from string after splitting it, using XSLT split() ?

    - by Vijay
    Hi All, I have one query regarding XSLT functions. I am using split function to fetch values from a string. I am using separator as "*". e.g. String : {"item1*item2*item3*item4"} split function I am using is as; <xsl:template name="SplitItemsCollection"> <xsl:param name="list" select="''"/> <xsl:param name="separator" select="'*'"/> <xsl:if test="not($list = '' or $separator = '')"> <xsl:variable name="head" select="substring-before(concat($list, $separator), $separator)"/> <xsl:variable name="tail" select="substring-after($list, $separator)"/> <xsl:value-of select="$head"/> <xsl:call-template name="split"> <xsl:with-param name="list" select="$tail"/> <xsl:with-param name="separator" select="$separator"/> </xsl:call-template> </xsl:if> </xsl:template> This function returns me all the items. Is there any way to fetch particular item from these separated items ? Say I want to fetch item3. Can we do it directly ? Thanks in advance.

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  • Compromising design & code quality to integrate with existing modules

    - by filip-fku
    Greetings! I inherited a C#.NET application I have been extending and improving for a while now. Overall it was obviously a rush-job (or whoever wrote it was seemingly less competent than myself). The app pulls some data from an embedded device & displays and manipulates it. At the core is a communications thread in the main application form which executes a 600+ lines of code method which calls functions all over the place, implementing a state machine - lots of if-state-then-do type code. Interaction with the device is done by setting the state/mode globally and letting the thread do it's thing. (This is just one example of the badness of the code - overall it is not very OO-like, it reminds of the style of embedded C code the device firmware is written in). My problem is that this piece of code is central to the application. The software, communications protocol or device firmware are not documented at all. Obviously to carry on with my work I have to interact with this code. What I would like some guidance on, is whether it is worth scrapping this code & trying to piece together something more reasonable from the information I can reverse engineer? I can't decide! The reason I don't want to refactor is because the code already works, and changing it will surely be a long, laborious and unpleasant task. On the flip side, not refactoring means I have to sometimes compromise the design of other modules so that I may call my code from this state machine! I've heard of "If it ain't broke don't fix it!", so I am wondering if it should apply when "it" is influencing the design of future code! Any advice would be appreciated! Thanks!

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  • Creating many polygons with OpenGL is slow?

    - by user146780
    I want to draw many polygons to the screen but i'm quickly noticing that it slows down quickly. As a test I did this: for(int i = 0; i < 50; ++i) { glBegin( GL_POLYGON); glColor3f( 0.0f, 1, 0.0f ); glVertex2f( 500.0 + frameGL.GetCameraX(), 0.0f + frameGL.GetCameraY()); glColor3f( 0.0f, 1.0f, 0.0f ); glVertex2f( 900.0 + frameGL.GetCameraX(), 0.0f + frameGL.GetCameraY()); glColor3f( 0.0f, 0.0f, 0.5 ); glVertex2f(900.0 + frameGL.GetCameraX(), 500.0f + frameGL.GetCameraY() + (150)); glColor3f( 0.0f, 1.0f, 0.0f ); glVertex2f( 500 + frameGL.GetCameraX(), 500.0f + frameGL.GetCameraY()); glColor3f( 1.0f, 1.0f, 0.0f ); glVertex2f( 300 + frameGL.GetCameraX(), 200.0f + frameGL.GetCameraY()); glEnd(); } This is only 50 polygons and already it's gtting slow. I can't upload them directly to the card because my program will allow the user to reshape the verticies. My question is, how can I speed this up. I'm not using depth. I also know it's not my GetCamera() functions because if I create 500,000 polygons spread apart t's fine, it just has trouble showing them in the view. If a graphics card can support 500,000,000 on screen polygons per second, this should be easy right? Thanks

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  • Combining Java hashcodes into a "master" hashcode

    - by Nick Wiggill
    I have a vector class with hashCode() implemented. It wasn't written by me, but uses 2 prime numbers by which to multiply the 2 vector components before XORing them. Here it is: /*class Vector2f*/ ... public int hashCode() { return 997 * ((int)x) ^ 991 * ((int)y); //large primes! } ...As this is from an established Java library, I know that it works just fine. Then I have a Boundary class, which holds 2 vectors, "start" and "end" (representing the endpoints of a line). The values of these 2 vectors are what characterize the boundary. /*class Boundary*/ ... public int hashCode() { return 1013 * (start.hashCode()) ^ 1009 * (end.hashCode()); } Here I have attempted to create a good hashCode() for the unique 2-tuple of vectors (start & end) constituting this boundary. My question: Is this hashCode() implementation going to work? (Note that I have used 2 different prime numbers in the latter hashCode() implementation; I don't know if this is necessary but better to be safe than sorry when trying to avoid common factors, I guess -- since I presume this is why primes are popular for hashing functions.)

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  • List modification in Python

    - by user2945143
    We are given an algorithm to modify a list of numbers from 1 to 28. There are 5 steps in the algorithm. We have written functions for each step (all correct). We need to write a function that combines all 5 steps. The algorithm modifies the list to get a value. Each time you get a new value, you use the list created by the algorithm from the previous step. This is what we have gotten so far for the code: get_card_at_top_index(insert_top_to_bottom(triple_cut((move_joker_2( move_joker_1(deck)))))) When we run the code to generate the get_card_at_top_index, the first answer is correct. However, the rest are not. Instead of using from the new list, python uses the value that it generated from the last step. What did we do wrong? UPDATE: The other 5 codes passed the tests, they are correct. Code 1 (List) = list1 Code 2 (list1) = list2 Code 3 (list2) = list3 Code 4 (list3) = list4 Code 5 (list4) = list5 we generate a number from 5. We need to run the algorithm again to generate 25 more numbers. We will use list 5 start from step 1

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  • friend declaration in C++

    - by Happy Mittal
    In Thinking in C++ by Bruce eckel, there is an example given regarding friend functions as // Declaration (incomplete type specification): struct X; struct Y { void f(X*); }; struct X { // Definition private: int i; public: friend void Y::f(X*); // Struct member friend }; void Y::f(X* x) { x->i = 47; } Now he explained this: Notice that Y::f(X*) takes the address of an X object. This is critical because the compiler always knows how to pass an address, which is of a fixed size regardless of the object being passed, even if it doesn’t have full information about the size of the type. If you try to pass the whole object, however, the compiler must see the entire structure definition of X, to know the size and how to pass it, before it allows you to declare a function such as Y::g(X). But when I tried void f(X); as declaration in struct Y, it shows no error. Please explain why?

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  • UML diagrams that are actually pretty?

    - by Borek
    I'm looking for a diagramming software that would produce good looking output. It doesn't need to support everything (or even much) from UML, is doesn't need to have code engineering functions or anything, it just needs to produce visually interesting output. Here is a couple of samples of products that I consider ugly / not good enough: Visio with default UML stencils (didn't find better looking ones), Enterprise Architect, Dia, ArgoUML and many other "professional" UML tools. A couple of visually compelling tools that I considered (but found issues with): Visual Studio class diagrams - just for .NET classes but the output is miles better than what UML tools typically produce NClass - similar to VS's class diagrams but I could not find the "pretty", blue skin anywhere yuml.me - very nice but lacking some advanced layout options. I have to say that I find their style almost ideal for high-level diagrams - they look sketchy which is good. Balsamiq - I think Joel used this for hginit.com and I liked it. However, it's not suited for creating software diagrams so I can imagine it would be quite a lot of work MS Word has actually quite a good graphics engine but I'd rather leave this as a choice of the last resort I'd be grateful for any good tips.

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  • Replacing symbol from object file at compile time. For example swapping out main

    - by Anthony Sottile
    Here's the use case: I have a .cpp file which has functions implemented in it. For sake of example say it has the following: [main.cpp] #include <iostream> int foo(int); int foo(int a) { return a * a; } int main() { for (int i = 0; i < 5; i += 1) { std::cout << foo(i) << std::endl; } return 0; } I want to perform some amount of automated testing on the function foo in this file but would need to replace out the main() function to do my testing. Preferably I'd like to have a separate file like this that I could link in over top of that one: [mymain.cpp] #include <iostream> #include <cassert> extern int foo(int); int main() { assert(foo(1) == 1); assert(foo(2) == 4); assert(foo(0) == 0); assert(foo(-2) == 4); return 0; } I'd like (if at all possible) to avoid changing the original .cpp file in order to do this -- though this would be my approach if this is not possible: do a replace for "(\s)main\s*\(" == "\1__oldmain\(" compile as usual. The environment I am targeting is a linux environment with g++.

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  • C++ polymorphism, function calls

    - by moai
    Okay, I'm pretty inexperienced as a programmer, let alone in C++, so bear with me here. What I wanted to do was to have a container class hold a parent class pointer and then use polymorphism to store a child class object. The thing is that I want to call one of the child class's functions through the parent class pointer. Here's a sort of example of what I mean in code: class SuperClass { public: int x; } class SubClass : public SuperClass { public: void function1() { x += 1; } } class Container { public: SuperClass * alpha; Container(SuperClass& beta) { alpha = beta; } } int main() { Container cont = new Container(new SubClass); } (I'm not sure that's right, I'm still really shaky on pointers. I hope it gets the point across, at least.) So, I'm not entirely sure whether I can do this or not. I have a sneaking suspicion the answer is no, but I want to be sure. If someone has another way to accomplish this sort of thing, I'd be glad to hear it.

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  • Best way to associate data files with particular tests in RSpec / Ruby

    - by Bill T
    For my RSpec tests I would to automatically associate data files with each test. To clarify, if my tests each require an xml file as input data and then some xpath statements to validate the responses they get back I would like to externalize the xml and xpath as files and have the testing framework easily associate them with the particular test being run by using the unique ID of the test as the file(s) name. I tried to get this behavior but the solution isn't very clean. I wrote a helper method that takes the value of "description" and combines it with FILE to create a unique identifier which is set into a global variable that other utilities can access. The unique identifier is used to associate the data files I need. I have to call this helper method as the first line of every test, which is ugly. If I have an RSpec example that looks like this: describe "Basic functions of this server I'm testing" do it "should give me back a response" do # Sets a global var to: "my_tests_spec.rb_should_give_me_back_a_response" TestHelper::who_am_i __FILE__, description ... end end Is there some better/cleaner/slicker way I can get an unique ID for each test that I could use to associate data files with? Perhaps something build into RSpec I'm unaware of? Thank you, -Bill

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  • Faster quadrature decoder loops with Python code

    - by Kelei
    I'm working with a BeagleBone Black and using Adafruit's IO Python library. Wrote a simple quadrature decoding function and it works perfectly fine when the motor runs at about 1800 RPM. But when the motor runs at higher speeds, the code starts missing some of the interrupts and the encoder counts start to accumulate errors. Do you guys have any suggestions as to how I can make the code more efficient or if there are functions which can cycle the interrupts at a higher frequency. Thanks, Kel Here's the code: # Define encoder count function def encodercount(term): global counts global Encoder_A global Encoder_A_old global Encoder_B global Encoder_B_old global error Encoder_A = GPIO.input('P8_7') # stores the value of the encoders at time of interrupt Encoder_B = GPIO.input('P8_8') if Encoder_A == Encoder_A_old and Encoder_B == Encoder_B_old: # this will be an error error += 1 print 'Error count is %s' %error elif (Encoder_A == 1 and Encoder_B_old == 0) or (Encoder_A == 0 and Encoder_B_old == 1): # this will be clockwise rotation counts += 1 print 'Encoder count is %s' %counts print 'AB is %s %s' % (Encoder_A, Encoder_B) elif (Encoder_A == 1 and Encoder_B_old == 1) or (Encoder_A == 0 and Encoder_B_old == 0): # this will be counter-clockwise rotation counts -= 1 print 'Encoder count is %s' %counts print 'AB is %s %s' % (Encoder_A, Encoder_B) else: #this will be an error as well error += 1 print 'Error count is %s' %error Encoder_A_old = Encoder_A # store the current encoder values as old values to be used as comparison in the next loop Encoder_B_old = Encoder_B # Initialize the interrupts - these trigger on the both the rising and falling GPIO.add_event_detect('P8_7', GPIO.BOTH, callback = encodercount) # Encoder A GPIO.add_event_detect('P8_8', GPIO.BOTH, callback = encodercount) # Encoder B # This is the part of the code which runs normally in the background while True: time.sleep(1)

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  • QT NOOB: Add action handler for multiple objects of same type.

    - by what
    I have a simple QT application with 10 radio buttons with names radio_1 through radio_10. It is a ui called Selector, and is part of a class called TimeSelector In my header file for this design, i have this: //! [1] class TimeSelector : public QWidget { Q_OBJECT public: TimeSelector(QWidget *parent = 0); private slots: //void on_inputSpinBox1_valueChanged(int value); //void on_inputSpinBox2_valueChanged(int value); private: Ui::Selector ui; }; //! [1] the commented out void_on_inputSpinBox1_valueChanged(int value) is from the tutorial for the simple calculator. I know i can do: void on_radio_1_valueChanged(int value); but I would need 10 functions. I want to be able to make one function that works for everything, and lets me pass in maybe a name of the radio button that called it, or a reference to the radio button so i can work with it and determine who it was. I am very new to QT but this seems like it should be very basic and doable, thanks.

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  • C++ design related question

    - by Kotti
    Hi! Here is the question's plot: suppose I have some abstract classes for objects, let's call it Object. It's definition would include 2D position and dimensions. Let it also have some virtual void Render(Backend& backend) const = 0 method used for rendering. Now I specialize my inheritance tree and add Rectangle and Ellipse class. Guess they won't have their own properties, but they will have their own virtual void Render method. Let's say I implemented these methods, so that Render for Rectangle actually draws some rectangle, and the same for ellipse. Now, I add some object called Plane, which is defined as class Plane : public Rectangle and has a private member of std::vector<Object*> plane_objects; Right after that I add a method to add some object to my plane. And here comes the question. If I design this method as void AddObject(Object& object) I would face trouble like I won't be able to call virtual functions, because I would have to do something like plane_objects.push_back(new Object(object)); and this should be push_back(new Rectangle(object)) for rectangles and new Circle(...) for circles. If I implement this method as void AddObject(Object* object), it looks good, but then somewhere else this means making call like plane.AddObject(new Rectangle(params)); and this is generally a mess because then it's not clear which part of my program should free the allocated memory. ["when destroying the plane? why? are we sure that calls to AddObject were only done as AddObject(new something).] I guess the problems caused by using the second approach could be solved using smart pointers, but I am sure there have to be something better. Any ideas?

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  • Set a color as transparent in palette-based image

    - by NeDark
    Hello there! I want to convert a alpha transparent png image to palette based png image. In GD I can do it easy: // We have already the image loaded in $source_img $w=200; $h=200; // We supose that img dimensions are 200x200 $img = imagecreatetruecolor($w, $h); // New black image list($r, $g, $b) = array(200, 200, 200); // Some color that doesn't appear in image to avoid conflict $color = imagecolorallocate($img, $r, $g, $b); imagefill($img, 0, 0, $color); // Fill the black image with the chosen color. imagecolortransparent($img, $color); // Set the chosen color as transparent $res = imagecopyresampled($img, $source_img, 0, 0, 0, 0, $w, $h, $w, $h); But in Imagick I don't know how set a color as transparent (imagecolortransparent() in GD). I have spent hours searching on the internet, but the help in the php site isn't very comphrensive and there are many undocumented functions. Thanks.

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  • Facebook fbAsyncInit firing twice

    - by JoelD
    I'm using Facebook's Javascript SDK to allow login/logout, and my problem is that when I use their window.fbAsyncInit call to initiate the FB session, it always fires twice. I've included a simplified code sample. I'd appreciate any help! <html><head> <script type="text/javascript"> ...some of my own functions, not related to Facebook... </script> </head> <body> <div id="fb-root"></div> <script> window.fbAsyncInit = function() { FB.init({ appId : '<?php echo FACEBOOK_APPID; ?>', session : <?php echo json_encode($session); ?>, status:false, cookie:true, xfbml: true }); alert("1"); FB.getLoginStatus(function(response) { if(response.session) { ...do stuff... } else { ...do other stuff...} }); }; alert("2"); </script> ...page contents... </body></html> The "2" alert fires a single time, and then the "1" alert fires twice.

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