Graphics32

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GR32_Backends_VCL🞂TGDIBackendClass

TGDIBackend

Default surface backend for Graphics32 on Windows, utilizing GDI DIB sections and device contexts.

Inheritance:TObject 🞂 TPersistent 🞂 TPlainInterfacedPersistent 🞂 TNotifiablePersistent 🞂 TThreadPersistent 🞂 TCustomBackend 🞂 TGDIBackend

Declaration ​

pascal
TGDIBackend = class(TCustomBackend, IPaintSupport, IBitmapContextSupport, IDeviceContextSupport, ITextSupport, IFontSupport, ICanvasSupport, ITextToPathSupport, ITextToPathSupport2, IUpdateRectSupport)

Description ​

TGDIBackend is the default backend implementation for Graphics32 on Windows VCL platforms.

TGDIBackend manages 32-bit Device Independent Bitmaps (DIB sections) created via Windows CreateDIBSection and pairs them with a GDI Memory Device Context (HDC) created via CreateCompatibleDC.

It implements all primary surface interfaces:

  • IPaintSupport: Repainting invalid areas onto TCanvas.
  • IBitmapContextSupport: Accessing TBitmapInfo headers and HBITMAP handles.
  • IDeviceContextSupport: Interoperating with GDI HDC handles and BitBlt/StretchBlt.
  • ITextSupport / IFontSupport: Native GDI font management and string rendering.
  • ITextToPathSupport / ITextToPathSupport2: Converting TrueType/OpenType font glyphs into vector paths using WinAPI GDI glyph outlines.
  • ICanvasSupport: VCL TCanvas wrapper integration.
  • IUpdateRectSupport: Windows control update region querying and invalidation.