WinAPI: OffsetWindowOrgEx - 移动窗口坐标原点

最新推荐文章于 2024-04-29 22:06:48 发布

转载最新推荐文章于 2024-04-29 22:06:48 发布 · 616 阅读

文章标签：

#winapi #integer #button #delphi #div #object

本文介绍了一个使用 Delphi 进行绘图的应用案例，包括如何在图片中绘制文本，并通过鼠标操作实现图片在窗体上的移动。代码实现了加载位图、设置画布、绘制文本到图片上并在窗体中显示该图片的功能，同时利用 OffsetWindowOrgEx 函数实现图片随鼠标拖动而移动。

http://www.cnblogs.com/del/archive/2008/05/31/1211441.html

相关函数: OffsetViewportOrgEx

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