asked on

why drawfocusrect can'nt work to image?

hi.
experts!i have some question in drawfocusrect,when a timage have assigned a picture these code can'nt work.
help!thanks!

unit Unitdrawfocusrect;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, RxGIF, ExtCtrls;

type
TForm1 = class(TForm)
Image1: TImage;
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);
private
{ Private declarations }
MyPoint:TPoint;
FDrawing:boolean;
MyDrawRect:TRect;
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Image1MouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
FDrawing:=true;
MyDrawRect.Left:=X;
MyDrawRect.Top:=Y;
MyDrawRect.BottomRight:=MyDrawRect.TopLeft;
MyPoint:=point(X,Y);
drawfocusrect(image1.Picture.Bitmap.Canvas.Handle,MyDrawRect);
// image1.picture.bitmap.Canvas.DrawFocusRect(MyDrawRect);

end;

procedure TForm1.Image1MouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
FDrawing:=false;
drawfocusrect(image1.Picture.Bitmap.Canvas.Handle,MyDrawRect);
// image1.picture.bitmap.Canvas.DrawFocusRect(MyDrawRect);

end;

procedure TForm1.Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
begin
if FDrawing=true then
begin
// image1.picture.bitmap.Canvas.DrawFocusRect(MyDrawRect);

drawfocusrect(image1.Picture.Bitmap.Canvas.Handle,MyDrawRect);
if X>MyPoint.X then
begin
MyDrawRect.Left:=MyPoint.X;
MyDrawRect.Right:=X;
end
else
begin
MyDrawRect.Left:=X;
MyDrawRect.Right:=MyPoint.X
end;
if Y>MyPoint.Y then
begin
MyDrawRect.Top:=MyPoint.Y;
MyDrawRect.Bottom:=Y;
end
else
begin
MyDrawRect.Top:=Y;
MyDrawRect.Bottom:=MyPoint.Y
end;
Drawfocusrect(image1.Picture.Bitmap.Canvas.Handle,MyDrawrect);
// image1.picture.bitmap.Canvas.DrawFocusRect(MyDrawRect);

end;
end;
end.

Fraction

Why can't you use the TCanvas.DrawFocusRect as disabled in your example?

jbas

ASKER

thanks,
use tcanvas.drawfocusrect or drawfocusrect(tcanvas.handle,r) all can'nt work well while a image assigned a picture.
i want to zoom out/in the region focused,but that code can'nt work.so i need help.
thanks.

ASKER CERTIFIED SOLUTION

DrDelphi

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jbas

ASKER

thanks.
you method can work well,later i will give you the points if the region can zoom in/out(can you help me too?:))

Fraction

Try something like this:

procedure TForm1.Image1MouseUp(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
var
Bmp: TBitmap;
begin
FDrawing:=false;
drawfocusrect(self.canvas.handle, MyDrawRect);
Bmp := TBitmap.Create;
Bmp.Width := MyDrawRect.Right-MyDrawRect.Left;
Bmp.Height := MyDrawRect.Bottom-MyDrawRect.Top;
Bmp.Canvas.CopyRect(Rect(0, 0, Bmp.Width, Bmp.Height),image1.Picture.Bitmap.Canvas, MyDrawRect);
image1.Picture.Bitmap.Canvas.StretchDraw(Rect(0, 0, image1.Width, image1.Height), Bmp);
Bmp.Free;
end;

jbas

ASKER

thanks to Fraction and DrDelphi !
to Fraction :
please talk the points in here.
https://www.experts-exchange.com/jsp/qManageQuestion.jsp?ta=delphi&qid=20306972