gdi

I'm currently updating a Windows GDI application to use Direct2D rendering and I need to support "transparent" bitmaps via color-keying for backwards compatibility. Right now I'm working with a HWND render target and a converted WIC bitmap source (to GUID_WICPixelFormat32bppPBGRA). My plan so far is to create a IWICBitmap from the converted bitmap, Lock() it, and then process each pixel setting it's alpha value to 0 if it matches the color key. This seems a bit "brute force" - Is this the best method of approaching this or is there a better way? Edit: In the interests of completeness here's an

Am i allowed to use a DC outside of a paint cycle? Is my window's DC guaranteed to be valid forever? i'm trying to figure out how long my control's Device Context (DC) is valid. i know that i can call: GetDC(hWnd); to get the device context of my control's window, but is that allowed? When Windows sends me a WM_PAINT message, i am supposed to call BeginPaint / EndPaint to properly acknowledge that i've painted it, and to internally clear the invalid region: BeginPaint(hWnd, {out}paintStruct); try //Do my painting finally EndPaint(hWnd, paintStruct); end; But calling BeginPaint also returns me

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: I've written a simple GDI-based data plotter using C++/CLI but it's not particularly fast (some basic profiling indicates it's the rendering to screen that's the problem). Is there any way to enable hardware acceleration for a UserControl or is there a .net interface for direct3D? ...or are there some other options I could consider. We're using managed code so the solution really needs to be CLI compatible if at all possible. [Edit] In case it helps, I'm rending strips (128 data points) of rectangles which are each 2x2 pixels using

just in pure gdi. thoughts or code are all welcome. Create a rounded rect as a path, select the path as the clipping path, then do a gradient fill of the same rectangle. Code with MFC would look like this: int top = 10; int left = 10; int right = 200; int bottom = 200; int radius = 20; pDC->BeginPath(); pDC->RoundRect(left, top, right, bottom, radius, radius); pDC->EndPath(); pDC->SelectClipPath(RGN_COPY); TRIVERTEX vertices[2]; vertices[0].x = left; vertices[0].y = top; vertices[0].Red = 0xffff; vertices[0].Green = 0; vertices[0].Blue = 0; vertices[0].Alpha = 0xffff; vertices[1].x = right;

I'd like to color blend (colorize by specified alpha value) the area of a canvas using pure Windows GDI (so without GDI+, DirectX or similar, no OpenGL, no assembler or a 3rd party libraries). I've created the following function and I'd like to know if there is a more efficient or easier way to do this: procedure ColorBlend(const ACanvas: HDC; const ARect: TRect; const ABlendColor: TColor; const ABlendValue: Integer); var DC: HDC; Brush: HBRUSH; Bitmap: HBITMAP; BlendFunction: TBlendFunction; begin DC := CreateCompatibleDC(ACanvas); Bitmap := CreateCompatibleBitmap(ACanvas, ARect.Right - ARect

Let's say I have a handle to device context (naturally, in Windows environment): HDC hdc; How can I get the width and height of it? A device context (DC) is a structure that defines a set of graphic objects and their associated attributes, and the graphic modes that affect output. By width and height I'm guessing you are referring to the bitmap painted ? If so then i guess you can try the following : BITMAP structBitmapHeader; memset( &structBitmapHeader, 0, sizeof(BITMAP) ); HGDIOBJ hBitmap = GetCurrentObject(hDC, OBJ_BITMAP); GetObject(hBitmap, sizeof(BITMAP), &structBitmapHeader); /

I'm trying to write, using DLL injection method, application which displays bitmaps used by another program and I want to get for this specific process list of GDI Handles which it is using (list like in GDIView.exe utility). I found article about NtQuerySystemInformation function, but this description only works with handles to Kernel Objects. Can somebody help? Here is a console application code that dumps all GDI handles out for a given process identifier. It should compile and work fine for 32 or 64-bit applications, as well as 32-bit application running on 64-bit OSes. It uses a lot of

Is it possible to use BitBlt to copy directly out of a GDI+ bitmap without using GetHBitmap? GetHBitmap is slow because it makes a new copy of the whole image, in addition to and slower than the BitBlt copy, and the given HBITMAP must be disposed. The image is large. Is there a way to point BitBlt to use the pixel data of the original GDI+ image? EDIT: I can get a pointer to where the GDI+ bitmap pixel data is in the memory. Can I create an HBITMAP that points to the GDI+ bitmap pixel data to avoid the extra copy, and BitBlt from that? jnm2 After searching for days, it suddenly hit me that the

We're maintaining an old video game that uses a full-screen 256-color graphics mode with DirectDraw. The problem is, some applications running in the background sometimes try to change the system palette while the game is running, which results in corrupted graphics. We can (sometimes) detect when this happens by processing the WM_PALETTECHANGED message. A few update versions ago we added logging (just log the window title/class/process name), which helped users identify offending applications and close them. MSN Live Messenger was a common culprit. The problem got worse when we found out that