Graphics32

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GR32_Backends_LCL_Win🞂TLCLBackendClass

TLCLBackend

Default surface backend for Graphics32 on Windows under Lazarus LCL, utilizing LCLIntf DIB sections and device contexts.

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

Declaration ​

pascal
TLCLBackend = class(TCustomBackend, IPaintSupport, IBitmapContextSupport, IDeviceContextSupport, ITextSupport, IFontSupport, ITextToPathSupport, ICanvasSupport, IInteroperabilitySupport, IUpdateRectSupport)

Description ​

TLCLBackend is the default backend implementation for Graphics32 on Windows under Lazarus LCL (LCLWin32 / LCLWin64).

TLCLBackend manages 32-bit DIB surface buffers created via LCLIntf.CreateDIBSection and binds them to an LCL Memory Device Context (HDC).

It implements primary LCL surface interfaces:

  • IPaintSupport: Repainting invalid areas onto LCL TCanvas.
  • IBitmapContextSupport: Accessing TBitmapInfo headers and HBITMAP handles.
  • IDeviceContextSupport: Interoperating with device context handles (HDC) and blitting.
  • ITextSupport / IFontSupport: Native LCL font management and string rendering.
  • ITextToPathSupport: Converting TrueType font glyph outlines into vector paths.
  • IInteroperabilitySupport: Copying pixel content from LCL TGraphic objects into backend buffers.
  • ICanvasSupport: LCL TCanvas wrapper integration.
  • IUpdateRectSupport: LCL window control update region querying via GetRandomRgn(..., SYSRGN).