Vcl.Skia.TSkPaintBox.OnDraw

• Up to Parent: TSkPaintBox

Delphi

property OnDraw;

C++

__property OnDraw;

Properties

Type	Visibility	Source	Unit	Parent
event	published	Vcl.Skia.pas Vcl.Skia.hpp	Vcl.Skia	TSkPaintBox

Description

Fires whenever the TSkPaintBox control is redrawn.

Use this event to perform custom painting using the Skia graphics library directly on the control. The VCL TSkPaintBox is pixel-independent, automatically applying screen scaling so your drawing logic remains consistent across different DPIs.

Parameters:

• ACanvas: An ISkCanvas interface used for drawing with Skia.
• ADest: A TRectF specifying the scaled drawing area.
• AOpacity: A floating-point value indicating the current opacity on the interval [0, 1].

Usage:

• Use ADest.Height and ADest.Width to get accurate scale size. This allows your code to seamlessly adapt to any screen scale factor and avoid pixel-dependent issues.
• The TSkPaintBox has an automatic cache system. Call Redraw to force redraw.

Example:

procedure TForm1.SkPaintBox1Draw(ASender: TObject; const ACanvas: ISkCanvas; const ADest: TRectF; const AOpacity: Single);
var
  LPaint: ISkPaint;
begin
  LPaint := TSkPaint.Create(TSkPaintStyle.Stroke);
  LPaint.AntiAlias := True;
  ACanvas.DrawCircle(ADest.CenterPoint, 20, LPaint);
end;

See Also

• TSkPaintBox
• Redraw