case WM_CREATE:
hdc = GetDC(hWnd);
hLogo = CreateCompatibleDC(hdc);
ReleaseDC(hWnd, hdc);
for (y = 0; y < logo_height; y++)
{
for (x = 0; x < logo_width; x++)
{
HEADER_PIXEL(logo_data, pixel);
SetPixel(hLogo, x, y, RGB(pixel[0], pixel[1], pixel[2]));
}
}
return 0;
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
BitBlt(hdc, 0, 0, logo_width, logo_height, hLogo, 0, 0, SRCCOPY);
EndPaint(hWnd, &ps);
Save bitmaps in HDC's
Author
Hi! Can anyone try to explain why you cannot do like this:
You must first select a bitmap of the appropriate dimensions and bitdepth into hLogo. The default bitmap in memory DCs is 1x1 and monochrome.
Like this?
And then just blit?
hdc = GetDC(hWnd); hLogo = CreateCompatibleDC(hdc); ReleaseDC(hWnd, hdc); hBitmap = CreateCompatibleBitmap(hLogo, logo_width, logo_height); SelectObject(hLogo, hBitmap); for (y = 0; y < logo_height; y++) { for (x = 0; x < logo_width; x++) { HEADER_PIXEL(logo_data, pixel); SetPixel(hLogo, x, y, RGB(pixel[0], pixel[1], pixel[2])); } }And then just blit?
If you create the bitmap to be compatible with hLogo then it will still be a monochrome bitmap. You'll need to create it so that it is compatible with your original DC. Do something like this instead:
Then you can blit
hdc = GetDC(hWnd);hLogo = CreateCompatibleDC(hdc);hBitmap = CreateCompatibleBitmap(hdc, logo_width, logo_height);ReleaseDC(hWnd, hdc);// Remember to store the old bitmap in hLogo so that you can properly// clean everything when you're doneHBITMAP hOldBMP = (HBITMAP)SelectObject(hLogo, hBitmap);Then you can blit
Author
It still doesn't work:
case WM_CREATE: hdc = GetDC(hWnd); hLogo = CreateCompatibleDC(hdc); hBitmap = CreateCompatibleBitmap(hdc, logo_width, logo_height); ReleaseDC(hWnd, hdc); hOldBMP = (HBITMAP)SelectObject(hLogo, hBitmap); for (y = 0; y < logo_height; y++) { for (x = 0; x < logo_width; x++) { HEADER_PIXEL(logo_data, pixel); SetPixel(hLogo, x, y, RGB(pixel[0], pixel[1], pixel[2])); } } return 0; case WM_PAINT: hdc = BeginPaint(hWnd, &ps); BitBlt(hdc, 0, 0, logo_width, logo_height, hLogo, 0, 0, SRCCOPY); EndPaint(hWnd, &ps); return 0;
Are hLogo and hBitmap local temporary variables? Make sure they aren't because then they will only refer to a valid bitmap during the WM_CREATE message.
Example:
I think that might have been the only problem in your last code actually [grin]
Example:
LRESULT CALLBACK WindowProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam){//static variablesstatic HDC hLogo;static HBITMAP hBitmap, hOldBMP;//temporary variablesHDC hdc;PAINTSTRUCT ps;int x, y;switch(msg){case WM_CREATE: hdc = GetDC(hWnd); hLogo = CreateCompatibleDC(hdc); hBitmap = CreateCompatibleBitmap(hdc, 100, 100); ReleaseDC(hWnd, hdc); hOldBMP = (HBITMAP)SelectObject(hLogo, hBitmap); for (y = 0; y < 100; y++) { for (x = 0; x < 100; x++) SetPixel(hLogo, x, y, RGB(255, 255, 0)); } return 0; case WM_PAINT: hdc = BeginPaint(hWnd, &ps); BitBlt(hdc, 0, 0, 100, 100, hLogo, 0, 0, SRCCOPY); EndPaint(hWnd, &ps); return 0;case WM_DESTROY: //free the created bitmap and device context DeleteDC(hLogo); DeleteObject(hBitmap); PostQuitMessage(0); return 0;}return DefWindowProc(hWnd, msg, wParam, lParam);}I think that might have been the only problem in your last code actually [grin]
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