[SOLVED] Need some help with my first lazarus project.

[panosdk]

I decided to learn lazarus and pascal in order to make a simple image compression program. Of course there are some programs that do that but...
1) I dont want to install .net framework
2) I want it to be crossplatform(win,linux) 
3) And most important i want to have a good time creating something.

After i made the basic stuff, like opening an image show it on a picture box then compress and save it, i decided to try and add features. One feature that i am writing right now is the ability to paste an image from clipboard and then compressed it. I will add here the paste procedure and the compress procedure. My problem is that the compress procedure checks for Assigned(pic). Well i am a complete noob (3 days into lazarus) and i dont know how to tell my program that i have a pic from the clipboard so i can pass that check. So if anyone has time please give me a hand. Thank you.

[paste from clipboard code]

Code: Pascal  [Select][+][-]

1. procedure Tform1.menupasteclipClick(Sender: TObject);
2.  
3.   var
4.   tempBitmap: TBitmap;
5.   PictureAvailable: boolean = False;
6.  
7. begin
8.   // we determine if any image is on clipboard
9.   if (Clipboard.HasFormat(PredefinedClipboardFormat(pcfDelphiBitmap))) or
10.     (Clipboard.HasFormat(PredefinedClipboardFormat(pcfBitmap))) then
11.     PictureAvailable := True;
12.  
13.   if PictureAvailable then
14.   begin
15.  
16.     tempBitmap := TBitmap.Create;
17.     if Clipboard.HasFormat(PredefinedClipboardFormat(pcfDelphiBitmap)) then
18.       tempBitmap.LoadFromClipboardFormat(PredefinedClipboardFormat(pcfDelphiBitmap));
19.  
20.     if Clipboard.HasFormat(PredefinedClipboardFormat(pcfBitmap)) then
21.       tempBitmap.LoadFromClipboardFormat(PredefinedClipboardFormat(pcfBitmap));
22.  
23.     //Image1.Width := tempBitmap.Width;
24.     //Image1.Height := tempBitmap.Height;
25.  
26.  
27.     image1.Canvas.Draw(0, 0, tempBitmap);
28.    
29.     lbl_size.Caption:='Width x Height: ' + inttostr(tempbitmap.Width) + ' x ' +
30.     inttostr(tempbitmap.Height);
31.  
32.  
33.     image1.Picture.Bitmap.Assign(tempBitmap);
34.  
35.  
36.     tempBitmap.Free;
37.   end
38.   else
39.   begin
40.  
41.     ShowMessage('No image is found on clipboard');
42.  
43.   end;
44. end;                                        
45.  

[compression code]

Code: Pascal  [Select][+][-]

1. procedure Tform1.btn_convertClick(Sender: TObject);
2.   var
3.   MyStream: TMemoryStream;
4. begin
5.   if Assigned(pic) then begin
6.  
7.     if Assigned(jpg) then FreeAndNil(jpg);
8.     jpg:=TJPEGImage.Create;
9.  
10.     try
11.       jpg.CompressionQuality:=Slider.Position;
12.       jpg.Assign(pic.Bitmap);
13.       MyStream := TMemoryStream.create;
14.       jpg.SaveToStream(MyStream);
15.       MyStream.Position:=0;
16.     finally
17.       image2.Picture.LoadFromStream(MyStream);
18.       FreeAndNil(MyStream);
19.     end;
20.  
21.   end;
22.   btn_save.Enabled:=true;
23.   menusave.Enabled:=true;
24. end;                      
25.  

By the way its pretty impressive what a noob can do in lazarus. So a big thanks to all the devs for this amazing tool. http://tinypic.com/r/2vjq001/9

[wp]

If I understand you correctly you first paste the clipboard (which contains an image) into a TImage component, and then you want to convert this image to a compressed jpeg and you want to display this (lower-quality) image in another TImage component for comparison?

So what is "pic"? It is not declared anywhere in your code excerpt. But I guess you don't need it. Just assign the bitmap of the image (Image1.Picture.Bitmap) to a temporary jpg which you then can either SaveToStream or assign to the bitmap of another TImage component:

Code: Pascal  [Select][+][-]

1. procedure Tform1.btn_convertClick(Sender: TObject);
2. var
3.   jpg: TJPEGImage;   // make it local, I think you don't need the jpeg anywhere else.
4. begin
5.   // Create temporary jpeg
6.   jpg := TJPEGImage.Create;
7.   try
8.     // Set up jpeg compression & quality
9.     jpg.CompressionQuality := Slider.Position;
10.     // copy bitmap from Image1 to this jpeg
11.     // Note that this compresses the image according to the CompressionQuality.
12.     jpg.Assign(Image1.Picture.Bitmap);
13.     // Assign compressed image to a second TImage
14.     Image2.Picture.Bitmap.Assign(jpg);
15.     // Re-enable button and menu
16.     // Note: I am missing a bnt_save.enabled := false at the beginning of this procedure! Dto with menusave.
17.     btn_save.Enabled:=true;  
18.     menusave.Enabled:=true
19.   finally
20.     // destroy temporary jpeg image (Note: this does not affect Image2)
21.     jpg.Free;
22.   end;
23. end;

[panosdk]

Thank you for taking the time to help me. The code works but it doesnt compress images which is weird. I am using jpg to save the picture so i have it as a global. But it the code doesnt compress if its a global or a local variable.

Code: Pascal  [Select][+][-]

1. procedure Tform1.btn_saveClick(Sender: TObject);
2. begin
3.    if SaveDialog1.Execute then
4.    begin
5.       try
6.       jpg.SaveToFile(savedialog1.FileName);
7.       except
8.       on e: exception do // Exception handling
9.       begin
10.       showmessage('Error: ' + e.message);
11.       end;
12.       end;
13.    end;
14.  
15. end;                                        
16.  

By the way this program is based on an article on lazplanet (http://lazplanet.blogspot.gr/2014/03/how-to-compress-image-to-jpg-wo-preview.html)

[wp]

The code works but it doesnt compress images which is weird.

How can you tell? But it is true, my code compresses when the image is assigned to the jpg, but when the jpg is assigned to the other image it becomes a bitmap and expands again. Since you did not write the image to disk I thought your intention of showing the jpg in an image was to visualize the quality loss of the jpg...

Look here: this code writes the bitmap and jpg images to a temporay stream and determines their size this way:

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button2Click(Sender: TObject);
2. var
3.   jpg: TJpegImage;
4.   stream: TMemorystream;
5.   bmpSize: Integer;
6.   jpgSize: Integer;
7. begin
8. //  Image1.Picture.SaveToFile('d:\test.bmp');
9.   stream := TMemorystream.Create;
10.   Image1.Picture.SaveToStream(stream);
11.   bmpSize := stream.Size;
12.   stream.Free;
13.  
14.   jpg := TJpegImage.Create;
15.   jpg.CompressionQuality := 20;
16.   jpg.Assign(Image1.Picture.Bitmap);
17.   stream := TMemorystream.Create;
18.   jpg.SaveToStream(stream);
19.   jpgSize := stream.Size;
20.   stream.Free;
21.   //jpg.SaveToFile('d:\temp.jpg');
22.   jpg.Free;
23.  
24.   Label1.Caption := Format('Bitmap size: %d KB, jpeg size: %d KB', [bmpSize div 1024, jpgSize div 1024]);
25. end;

[panosdk]

Yes i added the stream from the example code before seeing your message and everything works smooth. Also you saved me of a great headache of trying to find a way to calculate the size of the image. I have a lot to learn from this code. Thank you once again.