截取Delphi图象的步骤

(六)TMainForm的 (抓图)Action 事件
1)全屏抓图
[Capture Desktop] Action 事件
procedure TMainForm.cptDesktopExecute(Sender: TObject);
begin
inc(CaptureNum,1);
Application.Minimize ; //窗体最小化
Delay(500); //最小化后延时，为了全屏抓图不把自身抓进图中
FileName:='Capture'+IntToStr(CaptureNum)+'.bmp';
FileName:=DefaultDirectory+FileName;
CreateMDIChild(FileName,true);
StatusBar.SimpleText := FileName;
with ActiveMDIChild as TMDIChild do begin
Image1.Picture.Bitmap := CaptureScreen; //抓图
HorzScrollBar.Range := Image1.Picture.Width;
VertScrollBar.Range := Image1.Picture.Height;
end;
Child.Image1.Hint := 'Height:'+intToStr(child.Image1.Picture.Height)+'pixels'
+ ' Width:'+intToStr(child.Image1.Picture.Width)+'pixels';
application.Restore ;
end;

2)区域抓图
抓取区域图片，即要用到一个新的Form1，参见《Delphi图象截取编程示例(6)》 .
在Main单元implementation的uses中添加Capture1。
在Main单元添加私有过程CaptureArea :
procedure TMainForm.CaptureArea;
begin
with TForm1.Create(Application) do
try
if ShowModal=mrOK then
with fRect do begin
if (Right>Left)and(Bottom>Top) then begin
Delay(400);
ABitmap:=TBitmap.Create;
ABitmap.Assign(CaptureScreenRect(fRect));
Child.Image1.Picture.Bitmap:=ABitmap;
Child.ClientWidth := Child.Image1.Picture.Width ;
Child.ClientHeight:= Child.Image1.Picture.Height;
Child.HorzScrollBar.Range:=Child.Image1.Picture.Width ;
Child.VertScrollBar.Range:=Child.Image1.Picture.Height;
ABitmap.Free ;
end else begin
MessageDlg('选择图片区域错误，请重新选择！',mtInformation,[mbOK],0);
Child.Close ;
Form1.Free ;
exit;
end;
end;
finally
Free;
end;
end;

[Capture Area]区域抓图的Action 事件
procedure TMainForm.cptAreaExecute(Sender: TObject);
begin
Inc(CaptureNum,1);
Application.Minimize ;
Delay(500);
FileName:='Capture'+IntToStr(CaptureNum)+'.bmp';
FileName:=DefaultDirectory+FileName;
{ Create MDI Child Window }
CreateMDIChild(FileName,true);
StatusBar.SimpleText := FileName;

{ Capture Area of screen }
CaptureArea;
Child.Image1.Hint := 'Height:'+intToStr(child.Image1.Picture.Height)+'pixels'
+ ' Width:'+intToStr(child.Image1.Picture.Width)+'pixels';
application.Restore ;
end;