BasicBitmap
As the purpose of providing a simple compact, high-performance and platform independent Bitmap library, BasicBitmap is created based on a subset of my vector graphic library: https://github.com/skywind3000/pixellib .
Features
- Highly optimized C++ code which could be compiled and executed in any platform
- Multiple pixel formats from 8 to 32 bits: A8R8G8B8, R8G8B8, A4R4G4B4, R5G6B5, A8, etc.
- Blit in opaque or transparent mode (with a maskcolor/colorkey)
- Converting between different pixel formats
- Blending with different compositors
- Scaling with different filters (nearest, linear, bilinear)
- High quality resampling to different size (Bicubic/Bilinear)
- Loading bmp/tga from memory or file and saving bmp to file
- Loading png/jpg with gdiplus (only in windows xp or above)
- Saving bmp/ppm files
- Self-contained and not rely on other libraries
- Compact and portable, just copy BasicBitmap.h/.cpp into your project
- Core routines can be replaced by external (eg. SSE2 implementations)
- Blitting is 40% faster than DirectDraw FastBlt (with AVX/SSE2 optimizing enabled).
- Blending is 34% faster than GDI's AlphaBlend (with SSE2 enabled).
Interfaces
The BasicBitmap class provides these public methods below:
| Method | Description |
|---|---|
| Fill | fill color in rectangle |
| Clear | clear the whole bitmap |
| Blit | blit from source bitmap with same bpp |
| Convert | convert from different pixel-format |
| SetPixel | draw pixel in raw color |
| GetPixel | read pixel in raw color |
| SetColor | draw pixel in A8R8G8B8 |
| GetColor | read pixel in A8R8G8B8 |
| Scale | scale bitmap using different filter and blend op |
| DrawLine | draw a line |
| QuickText | draw text with internal mini-8x8 ascii font |
| SampleBilinear | sample pixel with bilinear |
| SampleBicubic | sample pixel with bicubic |
| Resample | resample bitmap |
| LoadBmpFromMemory | load bmp file from memory |
| LoadTgaFromMemory | load tga file from memory |
| LoadBmp | load bmp file |
| LoadTga | load tga file |
| SaveBmp | save bmp file |
| SavePPM | save ppm file |
| DownSampleBy2 | down sample 2x2 pixels into one pixel |
| SetDIBitsToDevice | (windows) draw bitmap to hdc |
| GetDIBits | (windows) get DIB bits to bitmap |
| GdiPlusInit | (windows) initialize gdiplus |
| GdiPlusLoadImageFromMemory | (windows) load jpg/png from memory |
| GdiPlusLoadImage | (windows) use gdiplus to load jpg/png |
| CreateBitmapInDIB | (windows) create bitmap with DIB section |
Performance
Blit Performance
Full window (800x600) blitting (both opacity and transparent), compare to GDI/SDL/DirectDraw:
| 32 Bits Blit | Opacity | Transparent |
|---|---|---|
| BasicBitmap C++ | fps=2325 | fps=1368 |
| BasicBitmap AVX/SSE2 | fps=2904 | fps=2531 |
| GDI | fps=2333 | fps=1167 |
| SDL | fps=2671 | fps=1015 |
| DirectDraw | fps=2695 | fps=2090 |
Note: use BltFast with DirectDrawSurface7 in System Memory to perform Opacity & Transparent blit. BitBlt and TransparentBlt(msimg32.dll) are used in the GDI testing case.
| 16 Bits Blit | Opacity | Transparent |
|---|---|---|
| BasicBitmap C++ | fps=4494 | fps=1253 |
| BasicBitmap AVX/SSE2 | fps=9852 | fps=2909 |
| DirectDraw BltFast | fps=5889 | fps=861 |
Blitting performance in SDL & GDI are slower than DirectDraw, just compare to ddraw as well.
| 8 Bits Blit | Opacity | Transparent |
|---|---|---|
| BasicBitmap C++ | fps=11142 | fps=1503 |
| BasicBitmap AVX/SSE2 | fps=18181 | fps=5449 |
| DirectDraw BltFast | fps=14705 | fps=4832 |
DirectDrawSurface in Video Memory takes the benefit of hardware acceleration which is definitely faster than BasicBitmap. If you really need hardware acceleration, use OpenGL/DX as well.
BasicBitmap is a software implementation which aims to achieve the best performance in all other software implementations: like GDI/GDI+, SDL/DirectDraw in System Memory, for examples.
So just compare to DirectDrawSurface in System Memory. Use it in the condition that you only need a lightweight software solution: GUI/Cross Platform/hardware unavailable/image processing/video compositing, etc.
Blending Performance
| SRC OVER | FPS |
|---|---|
| BasicBitmap C++ | 594 |
| BasicBitmap SSE2 | 1731 |
| GDI (msimg32.dll) | 1137 |
note: 800x600 full window src-over blending vs GDI's AlphaBlend function (in msimg32.dll).