TGPLinearGradientBrush.Create(
rect: TGPRect; {線性漸變的界限}
color1, color2: TGPColor; {線性漸變起始色與終止色}
mode: TLinearGradientMode {漸變方向, 見下表}
);
TGPLinearGradientBrush.Create(
rect: TGPRectF;
color1, color2: TGPColor;
mode: TLinearGradientMode
);
本例效果圖:
代碼文件:unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, TeCanvas;
type
TForm1 = class(TForm)
ComboBox1: TComboBox;
ButtonColor1: TButtonColor;
ButtonColor2: TButtonColor;
procedure FormCreate(Sender: TObject);
procedure FormPaint(Sender: TObject);
procedure ButtonColor1Click(Sender: TObject);
procedure ButtonColor2Click(Sender: TObject);
procedure ComboBox1Change(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI, TypInfo;
procedure TForm1.FormCreate(Sender: TObject);
var
i: Integer;
begin
for i := 0 to 3 do
ComboBox1.Items.Add(GetEnumName(TypeInfo(TLinearGradientMode), i));
ComboBox1.ItemIndex := 1;
ButtonColor1.Caption := '色1 ';
ButtonColor2.Caption := '色2 ';
ButtonColor1.SymbolColor := clYellow;
ButtonColor2.SymbolColor := clRed;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
g: TGPGraphics;
lb: TGPLinearGradientBrush;
c1,c2: TGPColor;
r: TGPRect;
begin
g := TGPGraphics.Create(Canvas.Handle);
r := MakeRect(60, 40, ClientWidth - 120, ClientHeight - 50);
c1 := ColorRefToARGB(ButtonColor1.SymbolColor);
c2 := ColorRefToARGB(ButtonColor2.SymbolColor);
lb := TGPLinearGradientBrush.Create(r, c1, c2, TLinearGradientMode (ComboBox1.ItemIndex));
g.FillEllipse(lb, r);
lb.Free;
g.Free;
end;
procedure TForm1.ButtonColor1Click(Sender: TObject);
begin
Repaint;
end;
procedure TForm1.ButtonColor2Click(Sender: TObject);
begin
Repaint;
end;
procedure TForm1.ComboBox1Change(Sender: TObject);
begin
Repaint;
end;
end.
