Delphi GDI + Learning Records (11): Path Gradient Brush

Path Gradient Paint Brush

var
　 g: TGPGraphics;
　 path: TGPGraphicsPath;
　 pb: TGPPathGradientBrush; {声明渐变画刷}
　 num: Integer;
const
　 colors: array[0..0] of TGPColor = (aclAqua);
begin
　 g := TGPGraphics.Create(Canvas.Handle);
　 path := TGPGraphicsPath.Create;
　 path.AddEllipse(0,0,166,88);
　 pb := TGPPathGradientBrush.Create(path);　 {建立渐变画刷}
　 pb.SetCenterColor(MakeColor(255,0,0,255)); {中心颜色}
　 num := 1;
　 pb.SetSurroundColors(@colors, num); {周围的颜色}
　 {第二个参数, 不能用常数代替; 它好像是第一个数组参数的索引+1}
　 g.FillEllipse(pb, 0, 0, 166, 88); {需要和定义的渐变效果的大小一样}
//g.FillPath(pb,path); {直接画路径效果也一样}
　 path.Free;
　 pb.Free;
　 g.Free;
end;

You can create a path through the pointer of an array of points brush

var
　 g : TGPGraphics;
　 pts: array[0..2] of TGPPoint;
　 pb: TGPPathGradientBrush;
begin
　 g := TGPGraphics.Create(Canvas.Handle);
　 pts[0] := MakePoint(100, 0);
　 pts[1] := MakePoint(200, 200);
　 pts[2] := MakePoint(0, 200);
　 pb:= TGPPathGradientBrush.Create(PGPPoint(@pts), 3);
　 g.FillRectangle(pb, 0, 0, 200, 200);
　 {没有指定中心颜色和周边颜色, 将分别默认黑色和白色}
　 pb.Free;
　 g.Free;
end;