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 程式師世界 >> 編程語言 >> 更多編程語言 >> Delphi >> 再學 GDI+[4]: DrawEllipse - 繪制橢圓

再學 GDI+[4]: DrawEllipse - 繪制橢圓

編輯:Delphi

本例效果圖:

再學 GDI+[4]: DrawEllipse - 繪制橢圓

  代碼文件:unit Unit1;
interface
uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs;
type
 TForm1 = class(TForm)
  procedure FormPaint(Sender: TObject);
  procedure FormCreate(Sender: TObject);
  procedure FormDestroy(Sender: TObject);
  procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
   Shift: TShiftState; X, Y: Integer);
  procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
  procedure FormMouseUp(Sender: TObject; Button: TMouseButton;
   Shift: TShiftState; X, Y: Integer);
 end;
var
 Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var
 x: Integer = 20;
 y: Integer = 20;
 w: Integer = 100;
 h: Integer = 50;
 f: Byte;
 a,b: Integer;
 p: TGPPen;
procedure TForm1.FormCreate(Sender: TObject);
begin
 p := TGPPen.Create(MakeColor(255,0,0), 2);
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
 p.Free;
end;
procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
 Shift: TShiftState; X, Y: Integer);
begin
 f := 1;
 a := X;
 b := Y;
end;
procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
 Y: Integer);
begin
 if (f = 0) then Exit;
 if ssCtrl in Shift then
 begin
  f := 2;
  Text := 'Ctrl 鍵被按下, 鼠標可調整大小';
 end else Text := '沒有按下 Ctrl 鍵, 鼠標可調整位置';
 a := X - a;
 b := Y - b;
 Repaint;
 a := X;
 b := Y;
end;
procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
 Shift: TShiftState; X, Y: Integer);
begin
 f := 0;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
 g: TGPGraphics;
begin
 g := TGPGraphics.Create(Canvas.Handle);
 g.Clear(MakeColor(255,255,255));
 case f of
  1: begin
   Inc(x,a);
   Inc(y,b);
  end;
  2: begin
   Inc(w,a);
   Inc(h,b);
  end;
 end;
 g.DrawEllipse(p, x, y, w, h);
 g.Free;
end;
end.
窗體文件:object Form1: TForm1
 Left = 0
 Top = 0
 Caption = 'Form1'
 ClIEntHeight = 176
 ClIEntWidth = 337
 Color = clBtnFace
 Font.Charset = DEFAULT_CHARSET
 Font.Color = clWindowText
 Font.Height = -11
 Font.Name = 'Tahoma'
 Font.Style = []
 OldCreateOrder = False
 Position = poDesktopCenter
 OnCreate = FormCreate
 OnDestroy = FormDestroy
 OnMouseDown = FormMouseDown
 OnMouseMove = FormMouseMove
 OnMouseUp = FormMouseUp
 OnPaint = FormPaint
 PixelsPerInch = 96
 TextHeight = 13
end


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