大侠帮忙，如何改变Image控件中图片的大小，并任意拖动显示图片？

[windofsun]

在Image控件大小固定的情况下，要按照用户操作放大或缩小图片。当图片不能全部显示出来时，用户可以用鼠标拖动图片，任意调整被显示的部分。就象ACDSee一样，当图片不能完全显示时用户可以拖动图片。各位大侠，帮帮忙！

注意！Image控件的大小和位置都是固定的

[netlib]

image1.Stretch:=True;

[taxi]

在鼠标事件中自己改变image的位置就可以了。

[王集鹄]

//不要复制注释
//请参考
//Unit1.dfm

object Form1: TForm1
Left = 192
Top = 107
Width = 426
Height = 411
Caption = 'Form1'
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
OldCreateOrder = False
PixelsPerInch = 96
TextHeight = 13
object Panel1: TPanel
Left = 0
Top = 41
Width = 418
Height = 343
Align = alClient
TabOrder = 0
object Image1: TImage
Left = 64
Top = 64
Width = 281
Height = 217
DragCursor = crUpArrow
Stretch = True
OnClick = Image1Click
OnMouseDown = Image1MouseDown
OnMouseMove = Image1MouseMove
OnMouseUp = Image1MouseUp
end
end
object Panel2: TPanel
Left = 0
Top = 0
Width = 418
Height = 41
Align = alTop
TabOrder = 1
object RadioButton3: TRadioButton
Left = 224
Top = 8
Width = 82
Height = 17
Caption = '缩小'
TabOrder = 0
OnClick = RadioButton3Click
end
object RadioButton2: TRadioButton
Left = 128
Top = 8
Width = 82
Height = 17
Caption = '放大'
TabOrder = 1
OnClick = RadioButton2Click
end
object RadioButton1: TRadioButton
Left = 24
Top = 8
Width = 82
Height = 17
Caption = '拖动'
Checked = True
TabOrder = 2
TabStop = True
OnClick = RadioButton1Click
end
object Button1: TButton
Left = 336
Top = 8
Width = 75
Height = 25
Caption = '载入图片'
TabOrder = 3
OnClick = Button1Click
end
end
object OpenPictureDialog1: TOpenPictureDialog
Left = 8
Top = 16
end
object Database1: TDatabase
SessionName = 'Default'
Left = 8
Top = 48
end
end

//Unit1.pas
unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls, ExtDlgs, DB, DBTables;

type
TForm1 = class(TForm)
Panel1: TPanel;
Image1: TImage;
OpenPictureDialog1: TOpenPictureDialog;
Database1: TDatabase;
Panel2: TPanel;
RadioButton3: TRadioButton;
RadioButton2: TRadioButton;
RadioButton1: TRadioButton;
Button1: TButton;
procedure Button1Click(Sender: TObject);
procedure Image1Click(Sender: TObject);
procedure Image1MouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
procedure Image1MouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
procedure Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
procedure RadioButton1Click(Sender: TObject);
procedure RadioButton2Click(Sender: TObject);
procedure RadioButton3Click(Sender: TObject);
private
{ Private declarations }
FMouseDown: Boolean;
FOldPoint: TPoint;
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
if not OpenPictureDialog1.Execute then Exit;
Image1.Picture.LoadFromFile(OpenPictureDialog1.FileName);
Image1.AutoSize := True;
Image1.AutoSize := False;
Image1.Left := 0;
Image1.Top := 0;
end;

procedure TForm1.Image1Click(Sender: TObject);
const
cOffset = 50;
begin
if RadioButton2.Checked then begin //放大
Image1.Width := Image1.Width + cOffset;
Image1.Height := Image1.Height + cOffset;
Exit;
end;
if RadioButton3.Checked then begin //放大
Image1.Width := Image1.Width - cOffset;
Image1.Height := Image1.Height - cOffset;
Exit;
end;
end;

procedure TForm1.Image1MouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
FMouseDown := Button = mbLeft;
FOldPoint := Point(X, Y);
end;

procedure TForm1.Image1MouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
FMouseDown := False;
end;

procedure TForm1.Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
begin
if not FMouseDown then Exit;
if not RadioButton1.Checked then Exit;
Image1.Left := Image1.Left + (X - FOldPoint.X);
Image1.Top := Image1.Top + (Y - FOldPoint.Y);
end;

procedure TForm1.RadioButton1Click(Sender: TObject);
begin
Image1.Cursor := crHandPoint;
end;

procedure TForm1.RadioButton2Click(Sender: TObject);
begin
Image1.Cursor := crCross;
end;

procedure TForm1.RadioButton3Click(Sender: TObject);
begin
Image1.Cursor := crUpArrow;
end;

end.

[smhpnuaa]

image1.Stretch:=True;

拖动的时候要注意边界检测，不能无限拖下去。

[FlyingQQ]

哇！
老师，你怎么把窗体文件也贴出来了！
楼主，我老师的回答是正确的，我试过啦！
：）
（回答问题的过程： zswang(伴水) 老师写代码，FlyingQQ(FlyingQQ)测试）
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[windofsun]

伴水：

Image1.AutoSize := True;
Image1.AutoSize := False;
这两句有什么作用？

[王集鹄]

Image1.AutoSize := True; //让图片控件和图片区域保持一样的大小
Image1.AutoSize := False; //恢复以前的状态，否则怎么改变它的大小？

[王集鹄]

具体的一些处理就由你自己来完成，唉～谁叫你老板不发工资给俺 :(

[zhhahuatian]

楼上的很利害,qq是多少

[surfguy]

to: zhhahuatian(华仔),那是帮主，不用怕，他跑不掉的，有什么问题来这里就行了。