How to zoom Image in TImage

[heejit]

I am using scrollbox to display Image various
image from database.

Image size are different size some are large
then the screen.

I want to zoom the image.

[jamie]

When you say ZOOM, is that Zoom in or Zoom out?

 There is many ways to interpret that?

 For some ideas

 The Canvas.StretchDraw wil force the image to fit the Rectangle size you give it..

 This includes making the image larger if need or smaller..

  other zooms are for large images where you want to move around inside the image, that would
require you to do a CopyRect, specifying the starting Lift, Top point of the source "The image" and
the direct it to the scrollbox.canvas.

 It would be better if you could give some more clues on how you would like this to zoom?

[heejit]

I want user to ZOOM IN so they can view the image without scrolling

[taazz]

Code: Pascal  [Select][+][-]

1. procedure TForm1.Image1PictureChanged(Sender :TObject);
2. begin
3.   //
4.   if (Image1.Picture.Graphic.Width > Image1.Width) or (Image1.Picture.Graphic.Height > Image1.Height) then begin
5.     Image1.Stretch := True;
6.     Image1.Proportional := True;
7.   end else begin
8.     Image1.Stretch := False;
9.     Image1.Proportional := False;
10.   end;
11. end;
12.  

or simply run the code after the image is loaded.

[heejit]

It working but image size is small not visible is there any way
we can set image size to FIT TO FORM SIZE

[taazz]

Code: Pascal  [Select][+][-]

1. image1.Align := alclient;
2.  

[heejit]

if i set align properly image size has increase and we need to scroll

How I can set ZOOM LEVEL so user can adjust ZOOM-IN/ZOOM-OUT
as per there requirement.

[taazz]

if i set align properly image size has increase and we need to scroll

You have something else going on. alClient can not resize the timage outside it's containers client area.

[heejit]

Here is my code

Code: Pascal  [Select][+][-]

1.  
2. On form create event I am adding timage to scroll box
3.  self.imgWidget := TImage.Create(self);
4.  self.ScrollBox1.InsertControl(self.imgWidget);
5.  
6. procedure TForm1.FormResize(Sender: TObject);
7. begin
8.     self.imgWidget.Width := self.Width - 150;
9.     self.imgWidget.Height := self.Height - 150;
10. end;
11.  
12. procedure TForm1.display_image();
13. var
14.     astream: TStream;
15.     atext: string;
16. begin
17.     if self.m_qry = nil then begin
18.         ShowMessage('No Rrecord');
19.         exit;
20.     end;
21.  
22.     if self.m_qry.EOF = True then begin
23.         ShowMessage('You are at end');
24.         exit;
25.     end;
26.  
27.     astream := self.m_qry.CreateBlobStream(self.m_qry.FieldByName('file_data'), bmRead);
28.     self.imgWidget.Picture.LoadFromStream(astream);
29.     self.imgWidget.Stretch := True;
30.     self.imgWidget.Proportional := True;
31.     self.imgWidget.Align:= alClient;
32.     atext := self.m_qry.FieldByName('file_id').AsString;
33.     self.imgWidget.Picture.Bitmap.Canvas.TextOut(0, 0, atext);
34.  
35.     //Record counter
36.     self.lblRecords.Caption := self.m_qry.RecNo.ToString + ' / ' + self.m_qry.RecordCount.ToString;
37. end;
38.  
39.  

[taazz]

multiple problems
1) imgWidget is not in the form its inside a scroll box I have no idea why.
2) alClient will resize the image to fill hte scrollbox client area no the forms.
3) the code in formresize is wasting cpu. If everything works as designed then setting the width and height of a component in alClient mode should be ignored if it is not then report a bug.

for further help please provide a complete compilable example.

[heejit]

1. ScrollBox required if user want to Zoom Image he/she can scroll

2. That means alClient will not work with scrollbox

3. form resize removed

I want to user to ZOOM the image if zoomed image is bigger than
the form size then scroll to view it.

[balazsszekely]

You should try ATImageBox, I believe it's exactly what are you looking for. You can find a demo folder inside the component, so you can run a few test.

[heejit]

@GetMem

Yes it is exactly what I am looking for

Only it is slow in zoom in/out

[balazsszekely]

Only it is slow in zoom in/out

I just tested with a 16.7 MB panoramic picture(10891x2197), zooms in/out fast. It's not slower then the built-in "Windows Photo Viewer". What is your configuration? Laz, FPC, OS, widgetset?

[heejit]

Lazarus Version : 1.9.0
FPC : 3.1.1
SVN Revision : 57501
OS : xubuntu 64bit
RAM : 8gb
CPU : i7
widgetset : x86_64-linux-gtk2