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Zooming TImage

Posted on 2006-06-24
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Last Modified: 2010-04-05
Hello Again,

 Can anybody show me how to create a Zoom for TImage? Drag the cursor and form a dotted box on the area where i want to zoom, when i release the left button, the TImage will zoom.

Can any body show me a source code for this?

Thanks in advance.
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Question by:ryan_sabarre
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10 Comments
 

Author Comment

by:ryan_sabarre
ID: 16977733
Hi everybody,

 First things first, Does mySQL accept jpg files?

I used this to save image in my Media (blob fieldtype)
   ms := TMemoryStream.Create;
   Image1.Picture.Graphic.SaveToStream(ms);
   ms.Position := 0;
   TBlobField(oTable.FieldByName('MEDIA')).LoadFromStream(ms);
-------------------------------------------------------
And used this to load my image in the TIMAGE

Procedure TfDigitalMed.InitializeForm;
var
  ms : TStream;
  gr : TBitmap;
begin
  ms := oTable.CreateBlobStream(oTable.FieldByName('MEDIA'), bmRead);
  gr := TBitmap.Create;
  gr.LoadFromStream(ms);
  Image1.Picture.Bitmap.Assign(gr);
  gr.Free;
  ms.Free;
end;
---------------------------------------------------------------
When any file(.jpg,etc..) except for ".bmp" is loaded using my (InitializeForm;) it will return a "Bitmap image is not valid".

0
 

Author Comment

by:ryan_sabarre
ID: 16977749
correction field "Media" is type LONGBLOB
0
 

Author Comment

by:ryan_sabarre
ID: 16979137
anybody?
0
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LVL 17

Accepted Solution

by:
mokule earned 500 total points
ID: 16980392
Place an image with bitmap on a form.
And below is code.

> gr := TBitmap.Create;
> gr.LoadFromStream(ms);
If You ceate bitmap You can only load bitmap.


unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Image1: TImage;
    procedure Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
    procedure Image1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Image1MouseUp(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    { Private declarations }
    x0,y0: integer;
    xp,yp: integer;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
  if ssLeft in Shift then
    begin
    Image1.Canvas.Pen.Mode := pmNot;
    Image1.Canvas.Brush.Style := bsClear;
    Image1.Canvas.Rectangle(Rect(x0,y0,xp,yp));
    Image1.Canvas.Rectangle(Rect(x0,y0,X,Y));
    xp := X;
    yp := Y;
    end;
end;

procedure TForm1.Image1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  x0 := X;
  y0:= Y;
  xp := x0;
  yp := y0;
end;

procedure TForm1.Image1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  StretchBlt(Image1.Canvas.Handle,0,0,Image1.Width,Image1.Height,Image1.Canvas.Handle,
  min(x0,xp)+1,min(y0,yp)+1,abs(xp-x0)-2,abs(yp-y0)-2,SRCCOPY);
  Image1.Invalidate;
end;

end.
0
 
LVL 17

Expert Comment

by:mokule
ID: 16980409
To load jpg image create TJPegImage
0
 

Author Comment

by:ryan_sabarre
ID: 16981334
Mokule,
  by the way how can i unzoom it?

thanks.


procedure TForm1.Button1Click(Sender: TObject);
begin
 IF OpenPictureDialog1.EXECUTE THEN
  BEGIN
   IMAGE1.Picture.LoadFromFile(OpenPictureDialog1.FILENAME);
  END;
end;

procedure TForm1.Image1MouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
function min(x1,x2:Integer):Integer;
 Begin
  if not (x1 < x2) then
  Begin
   result := x2;
  end
  else
  begin
    result :=  x1;
  end;
 End;
begin

StretchBlt(Image1.Canvas.Handle,0,0,Image1.Width,Image1.Height,Image1.Canvas.Handle,
  min(x0,xp)+1,min(y0,yp)+1,abs(xp-x0)-2,abs(yp-y0)-2,SRCCOPY);
  Image1.Invalidate;
 
end;

procedure TForm1.Image1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
 x0 := X;
  y0:= Y;
  xp := x0;
  yp := y0;
end;

procedure TForm1.Image1MouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
 if ssLeft in Shift then
    begin
    Image1.Canvas.Pen.Mode := pmNot;
    Image1.Canvas.Brush.Style := bsClear;
    Image1.Canvas.Rectangle (x0,y0,xp,yp);
    Image1.Canvas.Rectangle(x0,y0,X,Y);
    xp := X;
    yp := Y;
    end;
end;
0
 

Author Comment

by:ryan_sabarre
ID: 16981345
By the way, this does not work when JPG is used as image.
0
 

Author Comment

by:ryan_sabarre
ID: 16998831
hello anybody?
0
 
LVL 17

Expert Comment

by:mokule
ID: 17000680
You should always use bitmap.
first load to jpegimage and then assign it to bitmap.
To zoom out you must have original bitmap stored somewhere or load it again.
0
 

Author Comment

by:ryan_sabarre
ID: 17107944
Mokule, Thanks a lot.
0

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