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  • problems with openGl on eclipse

    - by lego69
    I'm working on Windows XP I have portable version of Eclipse Galileo, but I didn't find there glut so I decided to add it using this link I made all steps and and now I'm trying to compile this code #include "GL/glut.h" #include "GL/gl.h" #include "GL/glu.h" /////////////////////////////////////////////////////////// // Called to draw scene void RenderScene(void) { // Clear the window with current clearing color glClear(GL_COLOR_BUFFER_BIT); // Flush drawing commands glFlush(); } /////////////////////////////////////////////////////////// // Setup the rendering state void SetupRC(void) { glClearColor(0.0f, 0.0f, 1.0f, 1.0f); } /////////////////////////////////////////////////////////// // Main program entry point void main(int argc, char* argv[]) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(800,600); glutCreateWindow("Simple"); glutDisplayFunc(RenderScene); SetupRC(); glutMainLoop(); } and I have this errors Simple.o: In function `RenderScene': C:/Documents and Settings/Administrator/Desktop/workspace/open/Debug/../Simple.c:16: undefined reference to `_imp__glClear' C:/Documents and Settings/Administrator/Desktop/workspace/open/Debug/../Simple.c:20: undefined reference to `_imp__glFlush' Simple.o: In function `SetupRC': C:/Documents and Settings/Administrator/Desktop/workspace/open/Debug/../Simple.c:27: undefined reference to `_imp__glClearColor' Simple.o: In function `main': C:/Documents and Settings/Administrator/Desktop/workspace/open/Debug/../Simple.c:34: undefined reference to `glutInit' C:/Documents and Settings/Administrator/Desktop/workspace/open/Debug/../Simple.c:35: undefined reference to `glutInitDisplayMode' C:/Documents and Settings/Administrator/Desktop/workspace/open/Debug/../Simple.c:36: undefined reference to `glutInitWindowSize' C:/Documents and Settings/Administrator/Desktop/workspace/open/Debug/../Simple.c:37: undefined reference to `glutCreateWindow' C:/Documents and Settings/Administrator/Desktop/workspace/open/Debug/../Simple.c:38: undefined reference to `glutDisplayFunc' C:/Documents and Settings/Administrator/Desktop/workspace/open/Debug/../Simple.c:42: undefined reference to `glutMainLoop' collect2: ld returned 1 exit status please can somebody help me, thanks in advance

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  • Wrong getBounds() on LineScaleMode.NONE

    - by ghalex
    I have write a simple example that adds a canvas and draw a rectangle with stroke size 20 scale mode none. The problem is that if I call getBounds() first time I will get a correct result but after I call scale(); the getBounds() function will give me a wrong result. It will take in cosideration the stroke but stroke has scalemode to none and on the screen nothing happens but in the result I will have a x value smaller. Can sombody tell me how can I fix this ? protected var display :Canvas; protected function addCanvas():void { display = new Canvas(); display.x = display.y = 50; display.width = 100; display.height = 100; display.graphics.clear(); display.graphics.lineStyle( 20, 0x000000, 0.5, true, LineScaleMode.NONE ); display.graphics.beginFill( 0xff0000, 1 ); display.graphics.drawRect(0, 0, 100, 100); display.graphics.endFill(); area.addChild( display ); traceBounce(); } protected function scale():void { var m :Matrix = display.transform.matrix; var apply :Matrix = new Matrix(); apply.scale( 2, 1 ); apply.concat( m ); display.transform.matrix = apply; traceBounce(); } protected function traceBounce():void { trace( display.getBounds( this ) ); }

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  • Rails 2.3.2 trying to render ERB instead of HAML

    - by c00lryguy
    Rails is suddenly trying to render ERB instead of Haml and I can't figure out why. I've created new rails projects, reinstalled Haml, and reinstalled Rails. Here's exactly the steps I take when making my application (Rails 2.3.2): rails> rails test rails> cd test rails\test> haml --rails . rails\test> ruby script\generate model user email:string password:string rails\test> ruby script\generate controller users index rails\test> rake db:migrate Here's what the UsersController looks like: class UsersController < ApplicationController def index @users = User.all end end My routes: ActionController::Routing::Routes.draw do |map| map.resources :users end I now create views\users\index.html.haml: %table %th(style="text-align: left;") %h1 Users - for user in @users %tr %td= user.email %td= user.password Annnd run the server... I navigate to localhost:3000\users and I get this error message: Template is missing Missing template users/index.erb in view path app/views For some reason Rails is trying to find and render .erb files instead of .haml files. vendor\plugins\haml\init.rb exists, untouched. I've reinstalled Haml (Pretty Penny) multiple times and still get the same results. I've also tried adding config.gem 'haml' to my environment.rb but this also doesn't work. I can't figure out why suddenly rails will not render haml for me.

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  • Adding a font for use in ReportLab

    - by Jimmy McCarthy
    I'm trying to add a font to the python ReportLab so that I can use it for a function. The function is using canvas.Canvas to draw a bunch of text in a PDF, nothing complicated, but I need to add a fixed width font for layout issues. When I tried to register a font using what little info I could find, that seemed to work. But when I tried to call .addFont('fontname') from my Canvas object I keep getting "PDFDocument instance has no attribute 'addFont'" Is the function just not implemented? How do I get access to fonts other than the 10 or so default ones that are listed in .getAvailableFonts? Thanks. Some example code of what I'm trying to make happen: from reportlab.pdfgen import canvas c = canvas.Canvas('label.pdf') c.addFont('TestFont') #This throws the error listed above, regardless of what argument I use (whether it refers to a font or not). c.drawString(1,1,'test data here') c.showPage() c.save() To register the font, I tried from reportlab.lib.fonts import addMapping from reportlab.pdfbase import pdfmetrics pdfmetrics.registerFont(TTFont('TestFont', 'ghettomarquee.ttf')) addMapping('TestFont', 0, 0, 'TestFont') where 'ghettomarquee.ttf' was just a random font I had lying around.

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  • Show me your Linq to SQL architectures!

    - by Brad Heller
    I've been using Linq to SQL for a new implementation that I've been working on. I have about 5000 lines of code and am a little ways from a solid demo. I've been pretty satisfied with Linq to SQL so far -- the tools are excellent and pretty painless and it allows you to get a DAL up and running quickly. That said, there are some major draw backs that I just keep hitting over and over again. Namely how to handle separation of concerns between my DAL and my business layer and juggling that with different data contexts. Here is the architecture I've been using: My repositories do all my data access and they return Linq to SQL objects. Each of my Linq to SQL objects implements an IDetachable interface. A typical implementation looks like this: partial class PaymentDetail : IDetachable { #region IDetachable Members public bool IsAttached { get { return PropertyChanging != null; } } public void Detach() { if (IsAttached) { PropertyChanged = null; PropertyChanging = null; Transaction.Detach(); } } #endregion } Every time I do a DAL operation in my repository I "detach" when I'm done with the object (and it should theoretically detach from any child objects) to remove the DataContext's context. Like I said, this works pretty well, but there are some edge cases that seem to be a big pain in the ass. For instance, my Transaction object has many PaymentDetails. Even when there are no PaymentDetails in that collection it's still attached to the DataContext's context! Thus, if I try to update (I update by Attach()ing to the object and then SubmitChanges()) I get that dreaded "An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported." message. Anyway, I'm starting to doubt that this technology was a good gamble. Has anyone got a decent architecture that they're willing to share? I'd really love to use this technology but I feel like I spend 1/3 of my time just debugging is retarded quirks!

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  • how to initialize and implement the matrix inside the function in objective-C?

    - by Rajendra Bhole
    Hi, I want to develop an application in which i want to be initialize the matrix for manipulation. The code as follows, struct pixel { Byte r, g, b,a; int count; }; (NSInteger) processImage1: (UIImage*) image { struct pixel* pixels = (struct pixel*) calloc(1, image.size.width * image.size.height * sizeof(struct pixel)); if (pixels != nil) { // Create a new bitmap CGContextRef context = CGBitmapContextCreate( (void*) pixels, image.size.width, image.size.height, 8, image.size.width * 4, CGImageGetColorSpace(image.CGImage), kCGImageAlphaPremultipliedLast ); if (context != NULL) { // Draw the image in the bitmap CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, image.size.width, image.size.height), image.CGImage); NSUInteger numberOfPixels = image.size.width * image.size.height; while (numberOfPixels &gt; 0) { if (pixels->r == 254 || pixels->g == 77 || pixels->b==254) { numberOfRedPixels++; } pixels++; numberOfPixels--; } CGContextRelease(context); } free(pixels); } return 1; } I want to implement the matrix inside the function of - (NSInteger) processImage1: (UIImage*) image {} The matrix should have be row = image.size.width and column = image.size.height.

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  • Cocoa/Objective-C - Child window with text input without main window becoming inactive

    - by Josh
    Hello All, I have a need to spawn a window that will hover just above my main window in a cocoa application. I want this main window to allow the user to enter some text in an input box. All is well until the text input box actually gains focus. The main window becomes "deactivated." This window is borderless and is a slightly custom shape -- its more like a hover card than anything else, I suppose. Basically, I'd like this thing to work almost exactly like Spotlight (Apple + Space) -- you can enter text, but this is such an an ancillary operation that in the context of the greater UX, you don't want the jarring effect of the main window graying out (becoming inactive). You'll notice when you have some application open and in-focus, spotlight will not cause the window of that application to become inactive. This problem arises because text input seems to REQUIRE that the child window become the key window (it will not let you place the cursor in the text input field). When it becomes key, the main window becomes inactive. So far I've tried: Subclassing NSWindow for my main application and overriding isKeyWindow such that it only loses key when the application is no longer the users focus (as opposed to the window). This had the unintended effect of colliding with key status of the child window and having very strange effects on the keyboard input (some keys are not captured, like delete) Creating a view instead of a window. Doesn't work because of this problem -- you cannot draw over a Webkit WebView these days. Anybody Cocoa/OSX wizards have any ideas? I've become a little obsessed with this one. An itch I can't scratch.

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  • OpenCV shape matching

    - by MAckerman
    I'm new to OpenCV (am actually using Emgu CV C# wrapper) and am attempting to do some object detection. I'm attempting to determine if an object matches a predefined set of objects (that I will have to define). The background is well lit and does not move. My objects that I am starting with are bottles and cans. My current approach is: Do absDiff with a previously taken background image to separate the background. Then dilate 4x to make the lighter areas (in labels) shrink. Then I do a binary threshold to get a big blog, followed by finding contours in this image. I then take the largest contour and draw it, which becomes my shape to either save to the accepted set or compare with the accepted set. Currently I'm using cvMatchShapes, but the double return value seems to vary widely. I'm guessing it is because it doesn't take into account rotation. Is this approach a good one? It isn't working well for glass bottles since the edges are hard to find... I've read about haar classifiers, but thinking that might be overkill for my task.

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  • GridView: How can I get rid of extra space from my GirdView object?

    - by Lajos Arpad
    Hello, I'm writing an application for Android phones for Human vs. Human chess play over the internet. I was looking at some tutorials, to learn how to develop Android applications and found a very nice example of making galleries (it was a GridView usage example for making a gallery about dogs) and the idea came to draw the chess table using a GridView, because the example project also handled the point & click event and I intended to use the same event in the same way, but for a different purpose. The game works well (currently it's a hotseat version), however, I'm really frustrated by the fact that whenever I rotate the screen of the phone, my GridView gets hysterical and puts some empty space in my chess table between the columns. I realized that the cause of this is that the GridView's width is the same as its parent's and the GridView tries to fill its parent in with, but there should (and probably is) be a simple solution to get rid of this problem. However, after a full day of researching, I haven't found any clue to help me to make a perfect drawing about my chess table without a negative side effect in functionality. The chess table looks fine if the phone is in Portrait mode, but in Landscape mode it's far from nice. This is how I can decide whether we are in Portrait or Landscape mode: ((((MainActivity)mContext).getWindow().getWindowManager().getDefaultDisplay().getWidth()) < ((MainActivity)mContext).getWindow().getWindowManager().getDefaultDisplay().getHeight()) In the main.xml file the GridView is defined in the following way: <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <GridView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/gridview" android:layout_width="wrap_content" android:layout_height="wrap_content" android:numColumns="8" android:verticalSpacing="0dp" android:horizontalSpacing="0dp" android:stretchMode="columnWidth" android:gravity="center" > </GridView> ... </LinearLayout> I appreciate any help with the problem and thank you for reading this.

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  • Android - Correspondence between ImageView coordinates and Bitmap Pixels

    - by Matteo
    In my application I want the user to be able to select some content of an Image contained inside an ImageView. To select the content I subclassed the ImageView class making it implement the OnTouchListener so to draw over it a rectangle with borders decided by the user. Here is an example of the result of the drawing (to have an idea you can think of it as when you click with the mouse on your desktop and drag the mouse): Now I need to determine which pixels of the Bitmap image correspond to the selected part. It's kind of easy to determine which are the points of the ImageView belonging to the rectangle, but I don't know how to get the correspondent pixels, since the ImageView has a different aspect ratio than the original image. I followed the approach described especially here, but also here, but am not fully satisfied because in my opinion the correspondence made is 1 on 1 between pixels and points on the ImageView and does not give me all the correspondent pixels on the original image to the selected area. Calling hoveredRect the rectangle on the ImageView the points inside of it are: class Point { float x, y; @Override public String toString() { return x + ", " + y; } } Vector<Point> pointsInRect = new Vector<Point>(); for( int x = hoveredRect.left; x <= hoveredRect.right; x++ ){ for( int y = hoveredRect.top; y <= hoveredRect.bottom; y++ ){ Point pointInRect = new Point(); pointInRect.x = x; pointInRect.y = y; pointsInRect.add(pointInRect); } } How can I obtain a Vector<Pixels> pixelsInImage containing the correspondent pixels?

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  • How to update a custom dependency property when the datasource list changes

    - by John
    Hi We have a user control with a custom dependency property (DP). The DP is bound to an ObservableCollection. When a new item is added to the collection programatically, the databinding does not update the target DP. Why? We think it's because, unfortunately, in our case the target is not a ListBox or ListView, but a Canvas. The DP, when changed or initialized, is supposed to draw a Shape (!) onto the Canvas, and the shape's position and size is bound to the collection item's two properties: WIDTH, LEFT. Ideally we don't want to clear the Canvas and redraw all items just becasue one has been added (or deleted). But how? So: How can the custom DP take care of drawing the shape for the new collection item? What callback do we need, at what point in time does this have to happen, and what specific MetaDataOptions might there? Also, are there any good resources out there concerning all these dependency property options. They are quite confusing. MSDN does not really help with what we're trying to do. Thanks!

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  • Layering Cocoa WebView - Drawing on top?

    - by Josh
    http://stackoverflow.com/questions/1618498/webview-in-core-animation-layer The only other thread I can find is the above which doesn't necessarily fit my needs. Is there a reliable way to simply draw a view on top of a webview? I've tried to layer a regular NSView on top of WebView, and it draws right at first, but any movement in the webview (scrolling the page etc) appears to invalidate the view and produces visual artifacts. I've tried: [[[NSApp mainWindow] contentView] addSubview:view positioned:NSWindowAbove relativeTo:webView]; No luck there, same problems -- z-ordering doesn't seem to work unless I'm missing something. Is this just a limitation of webviews? I also tried implementing the view above as a window, which worked much better (just controlled the location of the window programmatically). However, the desired behavior is for the user to enter some text into this window, but for it not to steal "focus" -- ie the main window goes inactive (the x - + go gray) when the user clicks on the text field in the new window. Any way to avoid that? I've tried subclassing NSWindow and overriding canBecomeKey (return YES) and canBecomeMain (return NO) but the window still steals focus. Josh

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  • Insane Graphics.lineStyle behavior

    - by Simon
    Hi all, I'd like some help with a little project of mine. Background: i have a little hierarchy of Sprite derived classes (5 levels starting from the one, that is the root application class in Flex Builder). Width and Height properties are overriden so that my class always remembers it's requested size (not just bounding size around content) and also those properties explicitly set scaleX and scaleY to 1, so that no scaling would ever be involved. After storing those values, draw() method is called to redraw content. Drawing: Drawing is very straight forward. Only the deepest object (at 1-indexed level 5) draws something into this.graphics object like this: var gr:Graphics = this.graphics; gr.clear(); gr.lineStyle(0, this.borderColor, 1, true, LineScaleMode.NONE); gr.beginFill(0x0000CC); gr.drawRoundRectComplex(0, 0, this.width, this.height, 10, 10, 0, 0); gr.endFill(); Further on: There is also MouseEvent.MOUSE_WHEEL event attached to the parent of the object that draws. What handler does is simply resizes that drawing object. Problem: Screenshot When resizing sometimes that hairline border line with LineScaleMode.NONE set gains thickness (quite often even 10 px) + it quite often leaves a trail of itself (as seen in the picture above and below blue box (notice that box itself has one px black border)). When i set lineStile thickness to NaN or alpha to 0, that trail is no more happening. I've been coming back to this problem and dropping it for some other stuff for over a week now. Any ideas anyone? P.S. Grey background is that of Flash Player itself, not my own choise.. :D

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  • Select box is not working properly after including google custom search box in web page

    - by Vinay
    I have got a select box and google custom search box in a page, when i choose a option from select box and navigate away from the page and again if i come back to the same page the option will not be selected (violates the default functionality of select box), The code is below <script src="https://www.google.com/jsapi" type="text/javascript"></script> <script type="text/javascript"> google.load('search', '1', {language : 'en'}); google.setOnLoadCallback(function() { var customSearchControl = new google.search.CustomSearchControl('004920913350056953771:kpkclvhujzk'); customSearchControl.setResultSetSize(google.search.Search.FILTERED_CSE_RESULTSET); var options = new google.search.DrawOptions(); options.setAutoComplete(true); options.enableSearchboxOnly("<?=$homeurl?>my_results.php", "query"); customSearchControl.draw('cse-search-form', options); }, true); </script> <select multiple="yes"> <option>1</option> <option>2</option> </select> If i remove the custom search script, the select box selected option will be retained even after navigating away from the page. (default functionality) Its working fine in chrome, IE but not in Firefox. Is there any solution for this, so that select box must work fine even in the presence of search box, but the order must be same 1) Search box 2)Select Box

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  • Custom routes/paths/roads on Google Maps

    - by Douglas
    Hey guys. I need to know, and as quickly as possible, if what I need is achievable. I need to be able to, using either V2 OR V3 (preferably 3), create paths which ignore buildings in a sense. I was trying to create even a kml file to draw out all of the paths myself, and then find some way to turn them on/off as needed. For example. The user wants to go from point A to point B. Between these points is a number of buildings. The user physically CAN walk through these buildings(it's a campus). I want to show them that on the map. This way you don't have to do a loop-de-loop around, say, a parking lot, just to get to the other end of it. If there is ANY way AT ALL to do this, I'd love to know. An example of what I require can be found here: http://www.uottawa.ca/maps/ It's all pre-determined paths based on the two inputs from the user into the dropdown menu. I can plainly see this. But I have no clue if a) this can be done in v3, and b) how on earth they did it themselves. Assistance required, and greatly appreciated!

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  • How can I modify my code to line through the bezier control points?

    - by WillyCornbread
    HI all - I am using anchor points and control points to create a shape using curveTo. It's all working fine, but I cannot figure out how to get my lines to go through the center of the control points (blue dots) when the line is not straight. Here is my code for drawing the shape: // clear old line and draw new / begin fill var g:Graphics = graphics; g.clear(); g.lineStyle(2, 0, 1); g.beginFill(0x0099FF,.1); //move to starting anchor point var startX:Number = anchorPoints[0].x; var startY:Number = anchorPoints[0].y; g.moveTo(startX, startY); // Connect the dots var numAnchors:Number = anchorPoints.length; for (var i:Number=1; i<numAnchors; i++) { // curve to next anchor through control g.curveTo(controlPoints[i].x,controlPoints[i].y, anchorPoints[i].x, anchorPoints[i].y); } // Close the loop g.curveTo(controlPoints[0].x,controlPoints[0].y,startX,startY); And the shape I'm drawing for reference: How can I modify my code so that the lines go directly through the blue control points? Thanks in advance! b

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  • Self-describing file format for gigapixel images?

    - by Adam Goode
    In medical imaging, there appears to be two ways of storing huge gigapixel images: Use lots of JPEG images (either packed into files or individually) and cook up some bizarre index format to describe what goes where. Tack on some metadata in some other format. Use TIFF's tile and multi-image support to cleanly store the images as a single file, and provide downsampled versions for zooming speed. Then abuse various TIFF tags to store metadata in non-standard ways. Also, store tiles with overlapping boundaries that must be individually translated later. In both cases, the reader must understand the format well enough to understand how to draw things and read the metadata. Is there a better way to store these images? Is TIFF (or BigTIFF) still the right format for this? Does XMP solve the problem of metadata? The main issues are: Storing images in a way that allows for rapid random access (tiling) Storing downsampled images for rapid zooming (pyramid) Handling cases where tiles are overlapping or sparse (scanners often work by moving a camera over a slide in 2D and capturing only where there is something to image) Storing important metadata, including associated images like a slide's label and thumbnail Support for lossy storage What kind of (hopefully non-proprietary) formats do people use to store large aerial photographs or maps? These images have similar properties.

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  • Using custom coordinates with QGraphicsScene

    - by Rob
    I am experimenting with a WYSIWYG editor that allows a user to draw shapes on a page and the Qt graphics scene support seems perfect for this. However, instead of working in pixels I want all my QGraphicsItem objects to work in tenths of a millimetre but I don't know how to achieve this. For example: // Create a scene that is the size if an A4 page (2100 = 21cm, 2970 = 29.7cm) QGraphicsScene* scene = new QGraphicsScene(0, 0, 2100, 2970); // Add a rectangle located 1cm across, 1cm down, 5cm wide and 2cm high QGraphicsItem* item = scene->addRect(100, 100, 500, 200); ... QGraphicsView* view = new QGraphicsView(scene); setCentralWidget(view); Now, when I display the scene above I want the shapes to appear at correct size for the screen DPI. Is this simply a case of using QGraphicsView::scale or do I have to do something more complicated? Note that if I was using a custom QWidget instead then I would use QPainter::setWindow and QPainter::setViewport to create a custom mapping mode but I can't see how to do this using the graphics scene support.

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  • Are licenses relevant for small code snippets?

    - by Martin
    When I'm about to write a short algorithm, I first check in the base class library I'm using whether the algorithm is implemented in it. If not, I often do a quick google search to see if someone has done it before (which is the case, 19 times out of 20). Most of the time, I find the exact code I need. Sometimes it's clear what license applies to the source code, sometimes not. It may be GPL, LGPL, BSD or whatever. Sometimes people have posted a code snippet on some random forum which solves my problem. It's clear to me that I can't reuse the code (copy/paste it into my code) without caring about the license if the code is in some way substantial. What is not clear to me is whether I can copy a code snippet containing 5 lines or so without doing a license violation. Can I copy/paste a 5-line code snippet without caring about the license? What about one-liner? What about 10 lines? Where do I draw the line (no pun intended)? My second problem is that if I have found a 10-line code snippet which does exactly what I need, but feel that I cannot copy it because it's GPL-licensed and my software isn't, I have already memorized how to implement it so when I go around implementing the same functionality, my code is almost identical to the GPL licensed code I saw a few minutes ago. (In other words, the code was copied to my brain and my brain after that copied it into my source code).

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  • Python: Memory usage and optimization when modifying lists

    - by xApple
    The problem My concern is the following: I am storing a relativity large dataset in a classical python list and in order to process the data I must iterate over the list several times, perform some operations on the elements, and often pop an item out of the list. It seems that deleting one item out of a Python list costs O(N) since Python has to copy all the items above the element at hand down one place. Furthermore, since the number of items to delete is approximately proportional to the number of elements in the list this results in an O(N^2) algorithm. I am hoping to find a solution that is cost effective (time and memory-wise). I have studied what I could find on the internet and have summarized my different options below. Which one is the best candidate ? Keeping a local index: while processingdata: index = 0 while index < len(somelist): item = somelist[index] dosomestuff(item) if somecondition(item): del somelist[index] else: index += 1 This is the original solution I came up with. Not only is this not very elegant, but I am hoping there is better way to do it that remains time and memory efficient. Walking the list backwards: while processingdata: for i in xrange(len(somelist) - 1, -1, -1): dosomestuff(item) if somecondition(somelist, i): somelist.pop(i) This avoids incrementing an index variable but ultimately has the same cost as the original version. It also breaks the logic of dosomestuff(item) that wishes to process them in the same order as they appear in the original list. Making a new list: while processingdata: for i, item in enumerate(somelist): dosomestuff(item) newlist = [] for item in somelist: if somecondition(item): newlist.append(item) somelist = newlist gc.collect() This is a very naive strategy for eliminating elements from a list and requires lots of memory since an almost full copy of the list must be made. Using list comprehensions: while processingdata: for i, item in enumerate(somelist): dosomestuff(item) somelist[:] = [x for x in somelist if somecondition(x)] This is very elegant but under-the-cover it walks the whole list one more time and must copy most of the elements in it. My intuition is that this operation probably costs more than the original del statement at least memory wise. Keep in mind that somelist can be huge and that any solution that will iterate through it only once per run will probably always win. Using the filter function: while processingdata: for i, item in enumerate(somelist): dosomestuff(item) somelist = filter(lambda x: not subtle_condition(x), somelist) This also creates a new list occupying lots of RAM. Using the itertools' filter function: from itertools import ifilterfalse while processingdata: for item in itertools.ifilterfalse(somecondtion, somelist): dosomestuff(item) This version of the filter call does not create a new list but will not call dosomestuff on every item breaking the logic of the algorithm. I am including this example only for the purpose of creating an exhaustive list. Moving items up the list while walking while processingdata: index = 0 for item in somelist: dosomestuff(item) if not somecondition(item): somelist[index] = item index += 1 del somelist[index:] This is a subtle method that seems cost effective. I think it will move each item (or the pointer to each item ?) exactly once resulting in an O(N) algorithm. Finally, I hope Python will be intelligent enough to resize the list at the end without allocating memory for a new copy of the list. Not sure though. Abandoning Python lists: class Doubly_Linked_List: def __init__(self): self.first = None self.last = None self.n = 0 def __len__(self): return self.n def __iter__(self): return DLLIter(self) def iterator(self): return self.__iter__() def append(self, x): x = DLLElement(x) x.next = None if self.last is None: x.prev = None self.last = x self.first = x self.n = 1 else: x.prev = self.last x.prev.next = x self.last = x self.n += 1 class DLLElement: def __init__(self, x): self.next = None self.data = x self.prev = None class DLLIter: etc... This type of object resembles a python list in a limited way. However, deletion of an element is guaranteed O(1). I would not like to go here since this would require massive amounts of code refactoring almost everywhere.

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  • Select Multiple Images Using GalleryView

    - by hwrdprkns
    Hi guys, I was just wondering if Android had built in code so that I could select multiple images in a gallery-view and then have those images exported as filenames in a string array(ex /sdcard/~f1.jpg, /sdcard/~f2.jpg,...). I have the gallery code here, but I'm not sure what modifications need to be made. Any help is appreciated. Thanks! // take_picture = (Button)findViewById(R.id.take_picture); // Here we set up a string array of the thumbnail ID column we want to // get back String[] proj = { MediaStore.Images.Thumbnails._ID }; if(proj.length == 0) { nopic.setVisibility(View.VISIBLE); } // Now we create the cursor pointing to the external thumbnail store cursor = managedQuery( MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, proj, // Which // columns // to // return null, // WHERE clause; which rows to return (all rows) null, // WHERE clause selection arguments (none) null); // Order-by clause (ascending by name) /* take_picture.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { Intent i = new Intent(GalleryActivity.this, CameraActivity.class); startActivity(i); } }); */ // We now get the column index of the thumbnail id column_index = cursor .getColumnIndexOrThrow(MediaStore.Images.Thumbnails._ID); // Reference the Gallery view g = (Gallery) findViewById(R.id.gallery); if(proj.length == 0) { nopic.setVisibility(View.VISIBLE); g.setVisibility(View.GONE); } // Set the adapter to our custom adapter (below) g.setAdapter(new ImageAdapter(this)); // Set a item click listener, and just Toast the clicked position g.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView parent, View v, int position, long id) { // Now we want to actually get the data location of the file String[] proj = { MediaStore.Images.Media.DATA }; // We request our cursor again cursor = managedQuery( MediaStore.Images.Media.EXTERNAL_CONTENT_URI, proj, // Which // columns // to // return null, // WHERE clause; which rows to return (all rows) null, // WHERE clause selection arguments (none) null); // Order-by clause (ascending by name) // We want to get the column index for the data uri column_index = cursor .getColumnIndexOrThrow(MediaStore.Images.Media.DATA); // Lets move to the selected item in the cursor cursor.moveToPosition((int) g.getSelectedItemId()); // And here we get the filename String filename = cursor.getString(column_index); Log.v("GalleryActivity", filename); Toast.makeText(GalleryActivity.this, filename, Toast.LENGTH_SHORT).show(); setPrefs(filename); Intent i = new Intent(GalleryActivity.this, OtherClass.class); startActivity(i); } }); } And the ImageAdapter code here: public class ImageAdapter extends BaseAdapter { int mGalleryItemBackground; public ImageAdapter(Context c) { mContext = c; // See res/values/attrs.xml for the that defines // Gallery1. TypedArray a = obtainStyledAttributes(R.styleable.Gallery); mGalleryItemBackground = a.getResourceId( R.styleable.Gallery_android_galleryItemBackground, 0); a.recycle(); } public int getCount() { return cursor.getCount(); } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { ImageView i = new ImageView(mContext); if (convertView == null) { cursor.moveToPosition(position); int id = cursor.getInt(column_index); i.setImageURI(Uri.withAppendedPath( MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, "" + id)); i.setScaleType(ImageView.ScaleType.FIT_XY); i.setLayoutParams(new Gallery.LayoutParams(200, 200)); // The preferred Gallery item background i.setBackgroundResource(mGalleryItemBackground); } return i; } } Again any help is appreciateds! Just to let you guys know, the gallery works fine (for one image) as in it exports the filename correctly. Just need to know if there is an easy way to select multiples and export them. Thanks again!

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  • BitBlting multiple images to buffer

    - by Anonymous
    So I've made a class which draws a transparant image to a buffer. the buffer is a HDC which has been used blackness on. What I am trying to do is draw three images to this buffer. Which means I am using this function three times. After that's done, I output it to the screen (using SRCCOPYing the buffer). But what I get to see is just the third image and blackness. void draw_buffer(HDC buffer, int draw_x, int draw_y) { BitBlt(this-main, draw_x, draw_y, this-img_width, this-img_height, this-image, this-mask_x, this-mask_y, SRCAND); BitBlt(this-main, draw_x, draw_y, this-img_width, this-img_height, this-image, this-img_x, this-img_y, SRCPAINT); BitBlt(buffer, 0, 0, 800, 600, this-main, 0, 0, SRCCOPY); } At initiation, this-main becomes this: this->main = CreateCompatibleDC(GetDC(0)); this->bitmap = CreateCompatibleBitmap(GetDC(0),800,600); SelectObject(this->main, this->bitmap); What is wrong with my code?

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  • Flash "visible" issue

    - by justkevin
    I'm writing a tool in Flex that lets me design composite sprites using layered bitmaps and then "bake" them into a low overhead single bitmapData. I've discovered a strange behavior I can't explain: toggling the "visible" property of my layers works twice for each layer (i.e., I can turn it off, then on again) and then never again for that layer-- the layer stays visible from that point on. If I override "set visible" on the layer as such: override public function set visible(value:Boolean):void { if(value == false) this.alpha = 0; else {this.alpha = 1;} } The problem goes away and I can toggle "visibility" as much as I want. Any ideas what might be causing this? Edit: Here is the code that makes the call: private function onVisibleChange():void { _layer.visible = layerVisible.selected; changed(); } The changed() method "bakes" the bitmap: public function getBaked():BitmapData { var w:int = _composite.width + (_atmosphereOuterBlur * 2); var h:int = _composite.height + (_atmosphereOuterBlur * 2); var bmpData:BitmapData = new BitmapData(w,h,true,0x00000000); var matrix:Matrix = new Matrix(); var bounds:Rectangle = this.getBounds(this); matrix.translate(w/2,h/2); bmpData.draw(this,matrix,null,null,new Rectangle(0,0,w,h),true); return bmpData; } Incidentally, while the layer is still visible, using the Flex debugger I can verify that the layer's visible value is "false".

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  • Performance issue on Android's MapView Navigation-App

    - by poeschlorn
    Hey Guys, I've got a question on making an navigation app more faster and more stable. The basic layer of my app is a simple mapview, covered with several overlays (2 markers for start and destination and one for the route). My idea is to implement a thread to display the route, so that the app won't hang up during the calculation of a more complex route (like it does right now). After implementing the thread there are no updates shows any more, maybe you can help me with a short glance at an excerpt of my code below: private class MyLocationListener implements LocationListener { @Override public void onLocationChanged(Location loc) { posUser = new GeoPoint((int) (loc.getLatitude() * 1E6), (int) (loc .getLongitude() * 1E6)); new Thread(){ public void run(){ mapView.invalidate(); // Erase old overlays mapView.getOverlays().clear(); // Draw updated overlay elements and adjust basic map settings updateText(); if(firstRefresh){ adjustMap(); firstRefresh = false; } getAndPaintRoute(); drawMarkers(); } }; } Some features have been summarized to a method like "drawMarkers()" or "updateText()"...(they don't need any more attention ;-))

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  • iPhone: variable type returned by yajl

    - by Luc
    Hello, I'm quite new to iphone programming and I want to do the following stuff: get data from a JSON REST web server parse the received data using YAJL Draw a graph with those data using core-plot So, 1th item is fine, I use ASIHttpRequest which runs as espected 3rd is almost fine (I still have to learn how to tune core-plot). The problem I have is regarding 2nd item. I use YAJL as it seems to be the faster parser, so why not give it a try :) Here is the part of code that gets the data from the server and parse them: // Get server data response_data = [request responseData]; // Parse JSON received self.arrayFromData = [response_data yajl_JSON]; NSLog(@"Array from data: %@", self.arrayFromData); The parsing works quite well in fact, the NSLog output is something like: 2010-06-14 17:56:35.375 TEST_APP[3733:207] Array from data : { data = ( { val = 1317; date = "2010-06-10T15:50:01+02:00"; }, { val = 1573; date = "2010-06-10T16:20:01+02:00"; }, ........ { val = 840; date = "2010-06-11T14:50:01+02:00"; }, { val = 1265; date = "2010-06-11T15:20:01+02:00"; } ); from = "2010-06-10T15:50:01+02:00"; to = "2010-06-11T15:20:01+02:00"; max = "2590"; } According to th yajl-objc explanations http://github.com/gabriel/yajl-objc, the parsing returns a NSArray... The thing is... I do not know how to get all the values from it as for me it looks more like a NSDictionary than a NSArray... Could you please help ? Thanks a lot, Luc edit1: it happens that this object is actually a NSCFDictionary (!), I am still not able to get value from it, when I try the objectFromKey method (that should work on a Dictionary, no ?) it fails.

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