Delphi GDI + learning Record (25): Transform

Proportional change

var
　g: TGPGraphics;
　p: TGPPen;
　rect: TGPRect;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　p := TGPPen.Create(MakeColor(255,255,0,0),0);
　rect := MakeRect(10,10,100,100);
　g.DrawRectangle(p, rect); {原始}
　g.ScaleTransform(2, 0.5); {横向放大、纵向缩小}
　p.SetColor(aclBlue);　　　{变个颜色看清楚}
　g.DrawRectangle(p, rect); {重绘}
　g.ResetTransform;　　　　 {恢复变化, 不然下一个变化将基于现在的状态}
　p.Free;
　g.Free;
end;

Angle Change (rotation)

var
　g: TGPGraphics;
　p: TGPPen;
　rect: TGPRect;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　p := TGPPen.Create(MakeColor(255,255,0,0),0);
　rect := MakeRect(10,10,100,100);
　g.DrawRectangle(p, rect);
　g.RotateTransform(28); {旋转28度角, 正值顺时针、负值逆时针}
　p.SetColor(aclBlue);
　g.DrawRectangle(p, rect);
　g.ResetTransform;
　p.Free;
　g.Free;
end;

Position change (move)

var
　g: TGPGraphics;
　p: TGPPen;
　rect: TGPRect;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　p := TGPPen.Create(MakeColor(255,255,0,0),0);
　rect := MakeRect(10,10,100,100);
　g.DrawRectangle(p, rect);
　g.TranslateTransform(111,111); {移动}
　p.SetColor(aclBlue);
　g.DrawRectangle(p, rect);
　g.ResetTransform;
　p.Free;
　g.Free;
end;