TGPLinearGradientBrush.Create(
rect: TGPRect; {變化范圍}
color1, color2: TGPColor; {起始色與終止色}
angle: Single; {旋轉角度}
isAngleScalable: BOOL = FALSE {是否受 TLinearGradientMode 的影響, 可選值, 默認不 受影響}
);
TGPLinearGradientBrush.Create(
rect: TGPRectF;
color1, color2: TGPColor;
angle: Single;
isAngleScalable: BOOL = FALSE
);
本例效果圖:
代碼文件:unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, TeCanvas, ExtCtrls, ComCtrls;
type
TForm1 = class(TForm)
ButtonColor1: TButtonColor;
ButtonColor2: TButtonColor;
TrackBar1: TTrackBar;
procedure FormCreate(Sender: TObject);
procedure FormPaint(Sender: TObject);
procedure TrackBar1Change(Sender: TObject);
procedure ButtonColor1Click(Sender: TObject);
procedure ButtonColor2Click(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI, TypInfo;
procedure TForm1.FormCreate(Sender: TObject);
begin
ButtonColor1.Caption := '色1 ';
ButtonColor2.Caption := '色2 ';
ButtonColor1.SymbolColor := clLime;
ButtonColor2.SymbolColor := clBlack;
TrackBar1.ShowSelRange := False;
TrackBar1.Min := 0;
TrackBar1.Max := 360;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
g: TGPGraphics;
lb: TGPLinearGradientBrush;
c1,c2: TGPColor;
r: TGPRect;
begin
g := TGPGraphics.Create(Canvas.Handle);
r := MakeRect(20, 40, ClientWidth - 40, ClientHeight - 50);
c1 := ColorRefToARGB(ButtonColor1.SymbolColor);
c2 := ColorRefToARGB(ButtonColor2.SymbolColor);
lb := TGPLinearGradientBrush.Create(r, c1, c2, TrackBar1.Position);
g.FillEllipse(lb, r);
lb.Free;
g.Free;
end;
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
Repaint;
end;
procedure TForm1.ButtonColor1Click(Sender: TObject);
begin
Repaint;
end;
procedure TForm1.ButtonColor2Click(Sender: TObject);
begin
Repaint;
end;
end.
窗體文件:object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 197
ClientWidth = 253
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
Position = poScreenCenter
OnCreate = FormCreate
OnPaint = FormPaint
PixelsPerInch = 96
TextHeight = 13
object ButtonColor1: TButtonColor
Left = 143
Top = 8
Width = 49
Caption = 'ButtonColor1'
TabOrder = 0
OnClick = ButtonColor1Click
end
object ButtonColor2: TButtonColor
Left = 198
Top = 8
Width = 49
Caption = 'ButtonColor2'
TabOrder = 1
OnClick = ButtonColor2Click
end
object TrackBar1: TTrackBar
Left = 1
Top = 9
Width = 137
Height = 24
TabOrder = 2
OnChange = TrackBar1Change
end
end
