Description

The GR32_Rasterizers unit defines the rasterization infrastructure in Graphics32. Rasterizers bridge spatial samplers (TCustomSampler) and pixel buffers (TCustomBitmap32), evaluating surface samples across coordinates and writing formatted pixel colors to the target bitmap.

Key components in GR32_Rasterizers include:

• Base Class: TRasterizer provides abstract sampling loop mechanics, blend mode handling, and thread-safe persistent property management.
• Regular Rasterization: TRegularRasterizer evaluates samples sequentially scanline by scanline.
• Fractal / Swizzling Rasterization: TSwizzlingRasterizer visits pixel coordinates along space-filling fractal curves to optimize CPU cache locality.
• Progressive Subsampling: TProgressiveRasterizer performs multi-step subsampling for fast interactive coarse previews followed by refinement.
• Tesseral & Contour Sampling: TTesseralRasterizer applies recursive divide-and-conquer block decomposition, while TContourRasterizer traces pixel contours by color intensity difference.
• Draft Rendering: TDraftRasterizer renders coarse pixel blocks for low-cost live preview.
• Multi-Threaded Rasterization: Parallel scanline algorithms using system thread pools or worker threads (TMultithreadedRegularRasterizer, TParallelRegularRasterizer, TTaskRegularRasterizer, TThreadRegularRasterizer).
• Combination Infrastructure: TCombineInfo and helper routines for configuring drawing mode, master alpha, and pixel combination callbacks during sampling.