Search Results

Search found 16643 results on 666 pages for 'stackoverflow answer'.

Page 548/666 | < Previous Page | 544 545 546 547 548 549 550 551 552 553 554 555  | Next Page >

  • adding stock data to amibroker using c#

    - by femi
    hello, I have had a hard time getting and answer to this and i would really , really appreciate some help on this. i have been on this for over 2 weeks without headway. i want to use c# to add a line of stock data to amibroker but i just cant find a CLEAR response on how to instantiate it in C#. In VB , I would do it something like; Dim AmiBroker = CreateObject("Broker.Application") sSymbol = ArrayRow(0).ToUpper Stock = AmiBroker.Stocks.Add(sSymbol) iDate = ArrayRow(1).ToLower quote = Stock.Quotations.Add(iDate) quote.Open = CSng(ArrayRow(2)) quote.High = CSng(ArrayRow(3)) quote.Low = CSng(ArrayRow(4)) quote.Close = CSng(ArrayRow(5)) quote.Volume = CLng(ArrayRow(6)) The problem is that CreateObject will not work in C# in this instance. I found the code below somewhere online but i cant seem to understand how to achieve the above. Type objClassType; objClassType = Type.GetTypeFromProgID("Broker.Application"); // Instantiate AmiBroker objApp = Activator.CreateInstance(objClassType); objStocks = objApp.GetType().InvokeMember("Stocks", BindingFlags.GetProperty,null, objApp, null); Can anyone help me here? Thanks

    Read the article

  • How to do Basic Authentication using FireWatir on Ubuntu Linux?

    - by lotharsmash
    Hi, I'm trying to use FireWatir (1.6.5) to access a site using Basic Authentication and I've been unable to find a solution that works on Firefox in Linux. Does FireWatir 1.6.5 support Basic Authentication on Linux? I've been searching the web for 2 days and can't get a straight answer anywhere as to how to do this. The only thread I found that seemed helpful was this one ( http://groups.google.com/group/watir-general/browse_thread/thread/d8ab9a177d282ce4/fc1bf2319fb387d8?lnk=gst&q=basic+authentication#fc1bf2319fb387d8). Aedorn Varanis says " Angrez's fork had the solution so I'm using that now. Thanks Angrez, works perfectly!", but he doesn't mention what he did to get things working. Initially I tried to bypass the authentication dialog box by using: browser.goto('http://admin:[email protected]') However, this generates a "Confirm" dialog which says: "You are about to log in to the site "172.20.1.1" with the username "admin"." [Cancel, OK] This dialog blocks, and the goto call won't return until I click "OK". Then I tried adding: browser.startClicker("ok") browser.goto('http://admin:[email protected]') But this ALSO generates the same "Confirm" dialog. I tested out the startClicker functionality using the unit test /var/ lib/gems/1.8/gems/firewatir-1.6.5/unittests/html/JavascriptClick.html and it worked fine, which makes me think that using the startClicker method is NOT the correct way to take care of the Confirm dialog. Anybody else found a way to get Basic Auth to work, or how to click the OK on the confirm dialog? I'm at my wits end...

    Read the article

  • window.onload seems to trigger before the DOM is loaded (JavaScript)

    - by Dr. Monkey
    I am having trouble with the window.onload and document.onload events. Everything I read tells me these will not trigger until the DOM is fully loaded with all its resources, it seems like this isn't happening for me: I tried the following simple page in Chrome 4.1.249.1036 (41514) and IE 8.0.7600.16385 with the same result: both displayed the message "It failed!", indicating that myParagraph is not loaded (and so the DOM seems incomplete). <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <script type="text/javascript"> window.onload = doThis(); // document.onload gives the same result function doThis() { if (document.getElementById("myParagraph")) { alert("It worked!"); } else { alert("It failed!"); } } </script> </head> <body> <p id="myParagraph">Nothing is here.</p> </body> </html> I am using more complex scripts than this, in an external .js file, but this illustrates the problem. I can get it working by having window.onload set a timer for half a second to run doThis(), but this seems like an inelegant solution, and doesn't answer the question of why window.onload doesn't seem to do what everyone says it does. Another solution would be to set a timer that will check if the DOM is loaded, and if not it will just call itself half a second later (so it will keep checking until the DOM is loaded), but this seems overly complex to me. Is there a more appropriate event to use?

    Read the article

  • How to make NAnt send an email using a real account

    - by Turro
    First of all, I have already seen this post: nant mail issues but the only answer is not satisfactory (i.e.: doesn't work for me). I am using NAnt to get latest version of source, upgrade version of the libraries and application, build the application, build the setups... all the usual things, I bet. I would like NAnt to send an email to some people confirming the conclusion of the build process; I've already checked the official (pretty ugly, IMHO) documentation for the task, but the example, once copied and customized, doesn't work. This are the NAnt target and task I'm using: <target name="sendMail" > <mail from="[email protected]" tolist="[email protected];[email protected]" subject="Subject of email" mailhost="smtp.gmail.com" message="Your new release is ready!"> </mail> </target> The error message I get is: 530 5.7.0 Must issue a STARTTLS command first. It looks like that the task was designed for use by an account whose provider doesn't need authentication; but what can I do if I must use an external smtp server which requires authentication (telling my boss I need an smtp server in house is not an option)? Can anybody help/teach me? Thanks in advance...

    Read the article

  • How to build an android test app with a dependency on another app using ant?

    - by Mike
    I have a module called MyApp, and another module called MyAppTests which has a dependency on MyApp. Both modules produce APKs, one named MyApp.apk and the other MyAppTests.apk. I normally build these in IntelliJ or Eclipse, but I'd like to create an ant buildfile for them for the purpose of continuous integration. I used "android update" to create a buildfile for MyApp, and thanks to commonsware's answer to my previous question I've been able to build it successfully using ant. I'd now like to build MyAppTests.apk using ant. I constructed the buildfile as before using "android update", but when I run it I get an error indicating that it's not finding any of the classes in MyApp. Taking a que from my previous question, I tried putting MyApp.apk into my MyAppTests/libs, but unfortunately that didn't miraculously solve the problem. What's the best way to build a test app APK using ant when it depends on classes in another APK? $ ant debug Buildfile: build.xml [setup] Project Target: Google APIs [setup] Vendor: Google Inc. [setup] Platform Version: 1.5 [setup] API level: 3 [setup] WARNING: No minSdkVersion value set. Application will install on all Android versions. dirs: [echo] Creating output directories if needed... resource-src: [echo] Generating R.java / Manifest.java from the resources... aidl: [echo] Compiling aidl files into Java classes... compile: [javac] Compiling 5 source files to /Users/mike/Projects/myapp/android/MyAppTests/bin/classes [javac] /Users/mike/Projects/myapp/android/MyAppTests/src/com/myapp/test/GsonTest.java:3: cannot find symbol [javac] symbol : class MyApplication [javac] location: package com.myapp [javac] import com.myapp.MyApplication; [javac] ^

    Read the article

  • IRC Server configuration possibilities

    - by Katai
    I need to know a couple of things, concerning IRC servers that I couldnt directly find out over google (or werent clear enough for me to be sure if it actually works) I'm working at a larger community site, and wanted to deliver an in-page chat. Since it would be a nice feature to let people access it from outside too, over their own clients, I tought implementing an IRC Server would be the best solution (probably dedicated, I'll have to teach myself a couple of things for that) I plan to include a Web-based IRC client over an APE Client / Server. The problem is, I want to strip down the user rights, to disallow many functionalities that IRC would offer: Change of nicknames: The user logs in over the Page login, and I'll automatically create an IRC auth for this user with that password. So basically, he would connect to the IRC client over a button. And after connecting, he shouldnt be able to change his nickname at all Creating channels: I want the possibility to create channels, but not from 'normal' users. Basically, I would prefer to set up basic channels that are public, and if a user really creates an own channel, that one should be private and via invitation (is that possible?) Private conversations: private conversations should be filtered out from the allaround IRC client, into separate 'in-browser-windows' that I create over JS. I guess I just have to filter the stuff coming from IRC - or is there a better solution to that? Only 'registered' users have access: Like I said, if someone registers on the page, I would like to create an IRC 'account' for him. Users that arent registered on the page, cant access the IRC server at all (or get thrown out). Mainly to avoid spammers or bots from outside. Is this stuff solvable over IRC? I've read some FAQ's and Instructions for IRC OP's and servers, but I couldnt find a clear answer - it seems that everyone can do pretty much everything - I would like to configure it in a way that user possibilities are more cut down. Basically, giving users the possibility to chat, but not more. So the Question basically is, how possible / solvable this issues are allaround, or if I have to find other solutions for this.

    Read the article

  • How do I create a multi-level TreeView using F#?

    - by TwentyMiles
    I would like to display a directory structure using Gtk# widgets through F#, but I'm having a hard time figuring out how to translate TreeViews into F#. Say I had a directory structure that looks like this: Directory1 SubDirectory1 SubDirectory2 SubSubDirectory1 SubDirectory3 Directory2 How would I show this tree structure with Gtk# widgets using F#? EDIT: gradbot's was the answer I was hoping for with a couple of exceptions. If you use ListStore, you loose the ability to expand levels, if you instead use : let musicListStore = new Gtk.TreeStore([|typeof<String>; typeof<String>|]) you get a layout with expandable levels. Doing this, however, breaks the calls to AppendValues so you have to add some clues for the compiler to figure out which overloaded method to use: musicListStore.AppendValues (iter, [|"Fannypack" ; "Nu Nu (Yeah Yeah) (double j and haze radio edit)"|]) Note that the columns are explicitly passed as an array. Finally, you can nest levels even further by using the ListIter returned by Append Values let iter = musicListStore.AppendValues ("Dance") let subiter = musicListStore.AppendValues (iter, [|"Fannypack" ; "Nu Nu (Yeah Yeah) (double j and haze radio edit)"|]) musicListStore.AppendValues (subiter, [|"Some Dude"; "Some Song"|]) |> ignore

    Read the article

  • What makes these two R data frames not identical?

    - by Matt Parker
    UPDATE: I remembered dput() about the time Sharpie mentioned it. It's probably the row names. Back in a moment with an answer. I have two small data frames, this_tx and last_tx. They are, in every way that I can tell, completely identical. this_tx == last_tx results in a frame of identical dimensions, all TRUE. this_tx %in% last_tx, two TRUEs. Inspected visually, clearly identical. But when I call identical(this_tx, last_tx) I get a FALSE. Hilariously, even identical(str(this_tx), str(last_tx)) will return a TRUE. If I set this_tx <- last_tx, I'll get a TRUE. What is going on? I don't have the deepest understanding of R's internal mechanics, but I can't find a single difference between the two data frames. If it's relevant, the two variables in the frames are both factors - same levels, same numeric coding for the levels, both just subsets of the same original data frame. Converting them to character vectors doesn't help. Background (because I wouldn't mind help on this, either): I have records of drug treatments given to patients. Each treatment record essentially specifies a person and a date. A second table has a record for each drug and dose given during a particular treatment (usually, a few drugs are given each treatment). I'm trying to identify contiguous periods during which the person was taking the same combinations of drugs at the same doses. The best plan I've come up with is to check the treatments chronologically. If the combination of drugs and doses for treatment[i] is identical to the combination at treatment[i-1], then treatment[i] is a part of the same phase as treatment[i-1]. Of course, if I can't compare drug/dose combinations, that's right out.

    Read the article

  • Ruby on Rails / Yellow Maps For Ruby Plugin woes...

    - by Zach
    Okay I've read through the plugin comments and the docs as well and I have yet to come up with an answer as to how to do this. Here's my problem I want to use the :info_window_tabs and the :icon option, but I don't know what format to pass my information in. According to the documentation the following code should be correct. Here's my code: @mapper.overlay_init(GMarker.new([map.lat, map.lng], :title => map.name, :info_window_tabs => [ {:tab => "HTML", :content => @marker_html}, {:tab => "Attachments", :content => "stuff"}], :icon => { :image => "../images/icon.png" })) The readme and documentation can be viewed here. And the relevant ruby file that I am trying to interact with, including the author's comments, can be viewed here. I have tried the #rubyonrails channel in IRC as well as emailing the author directly and reporting an issue at GitHub. It really is just a question of syntax. Thanks!

    Read the article

  • ASP MVC: Submitting a form with nested user controls

    - by Nigel
    I'm fairly new to ASP MVC so go easy :). I have a form that contains a number of user controls (partial views, as in System.Web.Mvc.ViewUserControl), each with their own view models, and some of those user controls have nested user controls within them. I intended to reuse these user controls so I built up the form using a hierarchy in this way and pass the form a parent view model that contains all the user controls' view models within it. For example: Parent Page (with form and ParentViewModel) -->ChildControl1 (uses ViewModel1 which is passed from ParentViewModel.ViewModel1 property) -->ChildControl2 (uses ViewModel2 which is passed from ParentViewModel.ViewModel2 property) -->ChildControl3 (uses ViewModel3 which is passed from ViewModel2.ViewModel3 property) I hope this makes sense... My question is how do I retrieve the view data when the form is submitted? It seems the view data cannot bind to the ParentViewModel: public string Save(ParentViewModel viewData)... as viewData.ViewModel1 and viewData.ViewModel2 are always null. Is there a way I can perform a custom binding? Ultimately I need the form to be able to cope with a dynamic number of user controls and perform an asynchronous submission without postback. I'll cross those bridges when I come to them but I mention it now so any answer won't preclude this functionality. Many thanks.

    Read the article

  • setAttribute, onClick and cross browser compatability...

    - by Nicholas Kreidberg
    I have read a number of posts about this but none with any solid answer. Here is my code: // button creation onew = document.createElement('input'); onew.setAttribute("type", "button"); onew.setAttribute("value", "hosts"); onew.onclick = function(){fnDisplay_Computers("'" + alines[i] + "'"); }; // ie onew.setAttribute("onclick", "fnDisplay_Computers('" + alines[i] + "')"); // mozilla odiv.appendChild(onew); Now, the setAttribute() method (with the mozilla comment) works fine in mozilla but only if it comes AFTER the line above it. So in other words it seems to just default to whichever gets set last. The .onclick method (with the ie comment) does not work in either case, am I using it incorrectly? Either way I can't find a way to make this work at all in IE, let alone in both. I did change the function call when using the .onclick method and it worked fine using just a simple call to an alert function which is why I believe my syntax is incorrect. Long story short, I can't get the onclick parameter to work consistently between IE/Mozilla. -- Nicholas

    Read the article

  • Reference a Map by name within Velocity Template

    - by Wiretap
    Pretty sure there is an easy answer to this, but just can't find the right VTL syntax. In my context I'm passing a Map which contains other Maps. I'd like to reference these inner maps by name and assign them within my template. The inner maps are constructed by different parts of the app, and then added to the context by way of example public static void main( String[] args ) throws Exception { VelocityEngine ve = new VelocityEngine(); ve.init(); Template t = ve.getTemplate( "test.vm" ); VelocityContext context = new VelocityContext(); Map<String,Map<String,String>> messageData = new HashMap<String, Map<String,String>>(); Map<String,String> data_map = new HashMap<String,String>(); data_map.put("data_1","1234"); data_map.put("a_date", "31-Dec-2009"); messageData.put("inner_map", data_map); context.put("msgData", messageData); StringWriter writer = new StringWriter(); t.merge( context, writer ); System.out.println( writer.toString() ); } Template - test.vm #set ($in_map = $msgData.get($inner_map) ) data: $in_map.data_1 $in_map.a_date

    Read the article

  • ai: Determining what tests to run to get most useful data

    - by Sai Emrys
    This is for http://cssfingerprint.com I have a system (see about page on site for details) where: I need to output a ranked list, with confidences, of categories that match a particular feature vector the binary feature vectors are a list of site IDs & whether this session detected a hit feature vectors are, for a given categorization, somewhat noisy (sites will decay out of history, and people will visit sites they don't normally visit) categories are a large, non-closed set (user IDs) my total feature space is approximately 50 million items (URLs) for any given test, I can only query approx. 0.2% of that space I can only make the decision of what to query, based on results so far, ~10-30 times, and must do so in <~100ms (though I can take much longer to do post-processing, relevant aggregation, etc) getting the AI's probability ranking of categories based on results so far is mildly expensive; ideally the decision will depend mostly on a few cheap sql queries I have training data that can say authoritatively that any two feature vectors are the same category but not that they are different (people sometimes forget their codes and use new ones, thereby making a new user id) I need an algorithm to determine what features (sites) are most likely to have a high ROI to query (i.e. to better discriminate between plausible-so-far categories [users], and to increase certainty that it's any given one). This needs to take into balance exploitation (test based on prior test data) and exploration (test stuff that's not been tested enough to find out how it performs). There's another question that deals with a priori ranking; this one is specifically about a posteriori ranking based on results gathered so far. Right now, I have little enough data that I can just always test everything that anyone else has ever gotten a hit for, but eventually that won't be the case, at which point this problem will need to be solved. I imagine that this is a fairly standard problem in AI - having a cheap heuristic for what expensive queries to make - but it wasn't covered in my AI class, so I don't actually know whether there's a standard answer. So, relevant reading that's not too math-heavy would be helpful, as well as suggestions for particular algorithms. What's a good way to approach this problem?

    Read the article

  • How Random is System.Guid.NewGuid()? (Take two)

    - by Vilx-
    Before you start marking this as a duplicate, read me out. The other question has a (most likely) incorrect accepted answer. I do not know how .NET generates its GUIDs, probably only Microsoft does, but there's a high chance it simply calls CoCreateGuid(). That function however is documented to be calling UuidCreate(). And the algorithms for creating an UUID are pretty well documented. Long story short, be as it may, it seems that System.Guid.NewGuid() indeed uses version 4 UUID generation algorithm, because all the GUIDs it generates matches the criteria (see for yourself, I tried a couple million GUIDs, they all matched). In other words, these GUIDs are almost random, except for a few known bits. This then again raises the question - how random IS this random? As every good little programmer knows, a pseudo-random number algorithm is only as random as its seed (aka entropy). So what is the seed for UuidCreate()? How ofter is the PRNG re-seeded? Is it cryptographically strong, or can I expect the same GUIDs to start pouring out if two computers accidentally call System.Guid.NewGuid() at the same time? And can the state of the PRNG be guessed if sufficiently many sequentially generated GUIDs are gathered?

    Read the article

  • How to launch multiple Internet Explorer windows/tabs from batch file?

    - by TheZenker
    I would like a batch file to launch two separate programs then have the command line window close. Actually, to clarify, I am launching Internet Explorer with two different URLs. So far I have something like this: start "~\iexplore.exe" "url1" start "~\iexplore.exe" "url2" What I get is one instance of Internet Explorer with only the second URL loaded. Seems the second is replacing the second. I seem to remember a syntax where I would load a new command line window and pass the command to execute on load, but can't find the reference. As a second part of the question: what is a good reference URL to keep for the times you need to write a quick batch file? Edit: I have marked an answer, because it does work. I now have two windows open, one for each URL. (thanks!) The funny thing is that without the /d approach using my original syntax I get different results based on whether I have a pre-existing Internet Explorer instance open. If I do I get two new tabs added for my two URLs (sweet!) If not I get only one final tab for the second URL I passed in.

    Read the article

  • how to find the height of html content

    - by ganapati hegde
    Hi, I am trying to display 10 html pages as a single document,with 10 chapters. I am using Webkitgtk+ engine to render the HTML pages. I am getting the content of each html files and concatenating all of them to create a single 'char *content' and using webkit_web_view_load_html_string(WebKitWebView *web_view, const gchar *content, const gchar *base_uri); this function to load all the HTML files, as a document. Now i am trying to build a 'table of contents(toc)' for this document, which displays all the chapter names in order. My requirement is, when i click on a particular chapter in toc, the document should scroll to that point. For that i need to know height of each chapter ( height of each html file content). The point to be noted here is, the width of the document can changed and as HTML is reflowable, as width increases height decreases and vice-versa. So each time when height changes i need to find out the current height of each HTML page(or chapter) and hence calculate the distance to be scrolled. How can i find out the height of content of HTML page dynamically ? Thank you for the answer....

    Read the article

  • Am I under risk of CSRF attacks in a POST form that doesn't require the user to be logged in?

    - by Monika Sulik
    I'm probably being a total noob here, but I'm still uncertain about what a CSRF (Cross-Site Request Forgery) attack is exactly. So lets look at three situations... 1) I have a POST form that I use to edit data on my site. I want this data to be edited only by users that are logged in. 2) I have a site, which can be used by both users who are logged in as well as guests. Parts of the site are for logged in users only, but there are also POST forms that can be used by all users - anonymous and not (for example a standard contact form). Should the contact form be safeguarded against CSRF attacks? 3) I have a site which doesn't have an authentication system at all (well, perhaps that's unrealistic, so lets say it has an admin site which is separate from the rest of it and the admin part is properly safeguarded). The main part of the site is only used by anonymous users. Do the POST forms on it need to be safeguarded? In the case of 1) the answer is clearly yes. But in the case of 2 and 3 I don't know (and is the difference between 2 and 3 even significant?).

    Read the article

  • Why calling Process.killProcess(Process.myPid()) is a bad idea?

    - by Tal Kanel
    I've read some posts saying using this method is "not good", shouldn't been use, it's not the right way to "close" the application and it's not how android works... I understand and accept the fact that Android OS knows better then me when it's the right time to terminate the process, but I didn't heard yet a good explanation why it's wrong using the killProcess() method?. after all - it's part of the android API... what I do know is that calling this method while other threads doing in potential an important work (operations on files, writing to DB, HTTP requests, running services..) can be terminated in the middle, and it's clearly not good. also I know I can benefit from the fact that "re-open" the application will be faster, cause the system maybe still "holds" in memory state from last time been used, and killProcess() prevents that. beside this reason, in assumption I don't have such operations, and I don't care my application will load from scratch each run, there are other reasons why not using the killProcess() method? I know about finish() method to close an Activity, so don't write me about that please.. finish() is only for Activity. not to all application, and I think I know exactly why and when to use it... and another thing - I'm developing also games with the Unity3D framework, and exporting the project to android. when I decompiled the generated apk, I was very suprised to find out that the java source code created from unity - implementing Unity's - Application.quit() method, with Process.killProcess(Process.myPid()). Application.quit() is suppose to be the right way to close game according to Unity3d guides (is it really?? maybe I'm wrong, and missed something), so how it happens that the Unity's framework developers which doing a very good work as it seems implemented this in native android to killProcess()? anyway - I wish to have a "list of reasons" why not using the killProcess() method, so please write down your answer - if you have something interesting to say about that. TIA

    Read the article

  • TLS with SNI in Java clients

    - by ftrotter
    There is an ongoing discussion on the security and trust working group for NHIN Direct regarding the IP-to-domain mapping problem that is created with traditional SSL. If an HISP (as defined by NHIN Direct) wants to host thousands of NHIN Direct "Health Domains" for providers, then it will an "artificially inflated cost" to have to purchase an IP for each of those domains. Because Apache and OpenSSL have recently released TLS with support for the SNI extension, it is possible to use SNI as a solution to this problem on the server side. However, if we decide that we will allow server implementations of the NHINDirect transport layer to support TLS+SNI, then we must require that all clients support SNI too. OpenSSL based clients should do this by default and one could always us stunnel to implement an TLS+SNI aware client to proxy if your given programming language SSL implementation does not support SNI. It appears that native Java applications using OpenJDK do not yet support SNI, but I cannot get a straight answer out of that project. I know that there are OpenSSL Java libraries available but I have no idea if that would be considered viable. Can you give me a "state of the art" summary of where TLS+SNI support is for Java clients? I need a Java implementers perspective on this.

    Read the article

  • How to temporarily replace one primitive type with another when compiling to different targets in c#

    - by Keith
    How to easily/quickly replace float's for doubles (for example) for compiling to two different targets using these two particular choices of primitive types? Discussion: I have a large amount of c# code under development that I need to compile to alternatively use float, double or decimals depending on the use case of the target assembly. Using something like “class MYNumber : Double” so that it is only necessary to change one line of code does not work as Double is sealed, and obviously there is no #define in C#. Peppering the code with #if #else statements is also not an option, there is just too much supporting Math operators/related code using these particular primitive types. I am at a loss on how to do this apparently simple task, thanks! Edit: Just a quick comment in relation to boxing mentioned in Kyles reply: Unfortunately I need to avoid boxing, mainly since float's are being chosen when maximum speed is required, and decimals when maximum accuracy is the priority (and taking the 20x+ performance hit is acceptable). Boxing would probably rules out decimals as a valid choice and defeat the purpose somewhat. Edit2: For reference, those suggesting generics as a possible answer to this question note that there are many issues which count generics out (at least for our needs). For an overview and further references see Using generics for calculations

    Read the article

  • Per-pixel per-component alpha blending in Windows

    - by Crend King
    I have a 24-bit bitmaps with R, G, B color channels and a 24-bit bitmap with R, G, B alpha channels. I want to alpha blend the first bitmap to a HDC in GDI or RenderTarget in Direct2D with the alpha channels respectively. For example, suppose for one pixel, the bitmap color is (192, 192, 192), the HDC color is (0, 255, 255) and the alpha channels are (30, 40, 50). The final HDC color should be (22, 245, 242). I know I can BitBlt the HDC to a memory HDC first, do alpha blending by manually calculating the color of each pixel and finally BitBlt back. I just want to avoid the additional blitting and leave APIs do their job (faster since they are in kernel space). The first idea comes to my mind is to split the source bitmap into 3 red-only, green-only and blue-only 8-bit bitmaps, do normal alpha blending, then composite the 3 output bitmaps into the HDC. But I don't find a way to do the splitting and composition natively in Windows (would Direct2D layer help?). Also, the splitting and compositing may require many additional copying. The performance overhead would be too high. Or maybe do the alpha blending in 3 passes. Each pass apply the blending for one channel, while maintaining the other 2 unchanged. Thanks for any comment. EDIT: I found this question, and the answer should be good reference to this problem. However, besides AC_SRC_OVER, there is no other blending operation supported. Why don't Microsoft improve their API?

    Read the article

  • Interface Casting vs. Class Casting

    - by Legatou
    I've been led to believe that casting can, in certain circumstances, become a measurable hindrance on performance. This may be moreso the case when we start dealing with incoherent webs of nasty exception throwing\catching. Given that I wish to create more correct heuristics when it comes to programming, I've been prompted to ask this question to the .NET gurus out there: Is interface casting faster than class casting? To give a code example, let's say this exists: public interface IEntity { IParent DaddyMommy { get; } } public interface IParent : IEntity { } public class Parent : Entity, IParent { } public class Entity : IEntity { public IParent DaddyMommy { get; protected set; } public IParent AdamEve_Interfaces { get { IEntity e = this; while (this.DaddyMommy != null) e = e.DaddyMommy as IEntity; return e as IParent; } } public Parent AdamEve_Classes { get { Entity e = this; while (this.DaddyMommy != null) e = e.DaddyMommy as Entity; return e as Parent; } } } So, is AdamEve_Interfaces faster than AdamEve_Classes? If so, by how much? And, if you know the answer, why?

    Read the article

  • How can I enable PHP5 for a site? Having problems with every single method.

    - by user347662
    I'm working on a client site that is hosted on someone's DIY Debian Linux server [Apache/1.3.33 (Debian GNU/Linux)], and I'm trying to install a script that requires PHP5. By default, the server parses .php files with PHP 4.3.10-22, which is configured at /etc/php4/apache/php.ini, according to phpinfo(). On the server I can see a config directory for PHP5 adjacent to the PHP4 directory: /etc/php5.0/apache2/php.ini. I have tried multiple methods to enable PHP5 for the document root where the site's files are hosted, including all available methods mentioned here. By far, the most common suggestion I've found is to add one or both of the following lines to the site's .htaccess file: AddHandler application/x-httpd-php5 .php AddType application/x-httpd-php5 .php Trouble is, when either or both of those lines are present, the site forces my browser to download any .php files requested, without parsing the PHP at all. All of the other methods mentioned in the above article cause a 500 Internal Server Error. There is no hosting control panel I can access in a browser to enable PHP5 for the site, but I do have shell access. When I asked the server administrator about this issue, he encouraged me to search for the answer on Google. Where could I begin to troubleshoot this issue? Are there ways to test or verify the server's specific PHP5 installation and configuration, using the command line or some other method? Do you have other suggestions to enable PHP5?

    Read the article

  • Python metaclass for enforcing immutability of custom types

    - by Mark Lehmacher
    Having searched for a way to enforce immutability of custom types and not having found a satisfactory answer I came up with my own shot at a solution in form of a metaclass: class ImmutableTypeException( Exception ): pass class Immutable( type ): ''' Enforce some aspects of the immutability contract for new-style classes: - attributes must not be created, modified or deleted after object construction - immutable types must implement __eq__ and __hash__ ''' def __new__( meta, classname, bases, classDict ): instance = type.__new__( meta, classname, bases, classDict ) # Make sure __eq__ and __hash__ have been implemented by the immutable type. # In the case of __hash__ also make sure the object default implementation has been overridden. # TODO: the check for eq and hash functions could probably be done more directly and thus more efficiently # (hasattr does not seem to traverse the type hierarchy) if not '__eq__' in dir( instance ): raise ImmutableTypeException( 'Immutable types must implement __eq__.' ) if not '__hash__' in dir( instance ): raise ImmutableTypeException( 'Immutable types must implement __hash__.' ) if _methodFromObjectType( instance.__hash__ ): raise ImmutableTypeException( 'Immutable types must override object.__hash__.' ) instance.__setattr__ = _setattr instance.__delattr__ = _delattr return instance def __call__( self, *args, **kwargs ): obj = type.__call__( self, *args, **kwargs ) obj.__immutable__ = True return obj def _setattr( self, attr, value ): if '__immutable__' in self.__dict__ and self.__immutable__: raise AttributeError( "'%s' must not be modified because '%s' is immutable" % ( attr, self ) ) object.__setattr__( self, attr, value ) def _delattr( self, attr ): raise AttributeError( "'%s' must not be deleted because '%s' is immutable" % ( attr, self ) ) def _methodFromObjectType( method ): ''' Return True if the given method has been defined by object, False otherwise. ''' try: # TODO: Are we exploiting an implementation detail here? Find better solution! return isinstance( method.__objclass__, object ) except: return False However, while the general approach seems to be working rather well there are still some iffy implementation details (also see TODO comments in code): How do I check if a particular method has been implemented anywhere in the type hierarchy? How do I check which type is the origin of a method declaration (i.e. as part of which type a method has been defined)?

    Read the article

  • Delivery of JMS message before the transaction is committed

    - by ewernli
    Hi, I have a very simple scenario involving a database and a JMS in an application server (Glassfish). The scenario is dead simple: 1. an EJB inserts a row in the database and sends a message. 2. when the message is delivered with an MDB, the row is read and updated. The problem is that sometimes the message is delivered before the insert has been committed in the database. This is actually understandable if we consider the 2 phase commit protocol: 1. prepare JMS 2. prepare database 3. commit JMS 4. ( tiny little gap where message can be delivered before insert has been committed) 5. commit database I've discussed this problem with others, but the answer was always: "Strange, it should work out of the box". My questions are then: How could it work out-of-the box? My scenario sounds fairly simple, why isn't there more people with similar troubles? Am I doing something wrong? Is there a way to solve this issue correctly? Here are a bit more details about my understanding of the problem: This timing issue exist only if the participant are treated in this order. If the 2PC treats the participants in the reverse order (database first then message broker) that should be fine. The problem was randomly happening but completely reproducible. I found no way to control the order of the participants in the distributed transactions in the JTA, JCA and JPA specifications neither in the Glassfish documentation. We could assume they will be enlisted in the distributed transaction according to the order when they are used, but with an ORM such as JPA, it's difficult to know when the data are flushed and when the database connection is really used. Any idea?

    Read the article

< Previous Page | 544 545 546 547 548 549 550 551 552 553 554 555  | Next Page >