本例效果图:
代码文件:
unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ComCtrls, ExtCtrls; type TForm1 = class(TForm) Button1: TButton; procedure FormCreate(Sender: TObject); procedure FormDestroy(Sender: TObject); procedure FormPaint(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} var cvs: TCanvas; bit: TBitmap; f: Boolean; x1,y1: Integer; procedure TForm1.FormCreate(Sender: TObject); begin bit := TBitmap.Create; bit.LoadFromFile('c:\temp\test.bmp'); cvs := TCanvas.Create; cvs.Handle := GetDC(Handle); end; procedure TForm1.FormPaint(Sender: TObject); const str = 'Delphi'; var x,y: Integer; begin {在图片中绘制文本} bit.Canvas.Font.Size := 24; bit.Canvas.Font.Style := [fsBold]; bit.Canvas.Font.Color := 0; bit.Canvas.Brush.Style := bsClear; x := (bit.Width - bit.Canvas.TextWidth(str)) div 2; y := (bit.Height - bit.Canvas.TextHeight(str)) div 2 + 32; bit.Canvas.TextOut(x, y, str); {在窗体上绘制图片} x := (ClientWidth - bit.Width) div 2; y := (ClientHeight - bit.Height) div 2; cvs.Draw(x, y, bit); end; procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer); begin f := True; x1 := X; y1 := Y; end; procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer); begin if f then begin OffsetWindowOrgEx(cvs.Handle, -(X-x1), -(Y-y1), nil); x1 := X; y1 := Y; Repaint; end; end; procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton; Shift: TShiftState; X, Y: Integer); begin f := False; end; procedure TForm1.FormDestroy(Sender: TObject); begin bit.Free; cvs.Free; end; end.窗体文件:
object Form1: TForm1 Left = 212 Top = 116 Caption = 'Form1' ClientHeight = 204 ClientWidth = 262 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'Tahoma' Font.Style = [] OldCreateOrder = False Position = poDesigned OnCreate = FormCreate OnDestroy = FormDestroy OnMouseDown = FormMouseDown OnMouseMove = FormMouseMove OnMouseUp = FormMouseUp OnPaint = FormPaint PixelsPerInch = 96 TextHeight = 13 object Button1: TButton Left = 96 Top = 171 Width = 75 Height = 25 Caption = 'Button1' TabOrder = 0 end end