再学 GDI+[66]: 路径画刷(6) - SetInterpolationColors、GetRectangle

本例效果图:

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代码文件:

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unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs;



type

  TForm1 = class(TForm)

    procedure FormPaint(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses GDIPOBJ, GDIPAPI;



procedure TForm1.FormPaint(Sender: TObject);

var

  g : TGPGraphics;

  path: TGPGraphicsPath;

  pb: TGPPathGradientBrush;

  rt: TGPRect;

const

  pts: array[0..2] of TGPPoint = ((X:90; Y:10), (X:10; Y:160), (X:160; Y:160));

  colors: array[0..2] of TGPColor = (aclGreen, aclAqua, aclBlue);

  pos: array[0..2] of Single = (0.0, 0.25, 1.0); {颜色位置需要 >=0、<=1, 是百分比}

begin

  {三角}

  g := TGPGraphics.Create(Canvas.Handle);

  path := TGPGraphicsPath.Create;

  path.AddPolygon(PGPPoint(@pts), Length(pts));

  pb:= TGPPathGradientBrush.Create(path);

  pb.SetInterpolationColors(@colors, @pos, Length(colors)); {SetInterpolationColors}

  g.FillPath(pb, path);



  {矩形}

  pb.GetRectangle(rt); {GetRectangle}

  path.Reset;

  path.AddRectangle(rt);

  pb.Free;

  pb:= TGPPathGradientBrush.Create(path);

  pb.SetInterpolationColors(@colors, @pos, Length(colors));

  g.TranslateTransform(160, 0);

  g.FillPath(pb, path);



  {椭圆}

  path.Reset;

  path.AddEllipse(rt);

  pb.Free;

  pb:= TGPPathGradientBrush.Create(path);

  pb.SetInterpolationColors(@colors, @pos, Length(colors));

  g.TranslateTransform(160, 0);

  g.FillPath(pb, path);



  pb.Free;

  path.Free;

  g.Free;

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 164

  ClientWidth = 491

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  Position = poDesktopCenter

  OnPaint = FormPaint

  PixelsPerInch = 96

  TextHeight = 13

end