[SOLVED] Is this the best way to add TIFF support to imgviewer?
lazarus / 39-Graphics

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BigChimp · 2012-10-17 08:18

Am trying to extend the Lazarus examples\imgviewer application with
.tiff support.

Did this:
Housekeeping: let program try to load tiff files when loading
directories:
Code: [Select]procedure TMainForm.AddDir(Directory: string; Recurse:
boolean);
...
        Ext := ExtractFileExt(Info.Name);
        // Add tiff support to built-in image types:
        if Pos(Ext, ImageTypes+'.tif'+'.tiff') <> 0 then
          AddFile(Directory + Info.Name, false);

then this:
Code: [Select]procedure TMainForm.ShowFile(Index: integer);
var
  TIFF: TTiffImage;
...
        // TImage does not support the TIFF format natively
        if
pos(LowerCase(ExtractFileExt(LBFiles.Items[Index])),'.tif.tiff')<>0
then
        begin
          TIFF:=TTiffImage.Create;
          try
            TIFF.LoadFromFile(LBFiles.Items[Index]);
            IMain.Picture.Bitmap.Assign(TIFF);
          finally
            TIFF.Free;
          end;
        end
        else
        begin
          // existing code
          IMain.Picture.LoadFromFile(LBFiles.Items[Index]);
        end;

It works but is a bit slow. Perhaps the slowness is caused by the tiff
reading routines themselves or my way of coding.

Any suggestions to improve this?

Thanks,
BigChimp

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BigChimp · 2012-10-18 09:58

Solved thanks to post on ML; add fpreadtiff to your uses clause
instead gives support for timage.

See http://wiki.lazarus.freepascal.org/Developing_with_Graphics#Additi
onal_file_formats_for_TImage

Patch attached... I'll probably first have a look at a caching
mechanism because tiff reading is a bit slow (apart from that it
doesn't support all tiff subformats, but that's a known problem).

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Jose Mejuto · 2012-10-18 13:51

Quote from: BigChimp on October 17, 2012, 10:18:39 amAm trying to
extend the Lazarus examples\imgviewer application with .tiff support.
Code: [Select]procedure TMainForm.AddDir(Directory: string; Recurse:
boolean);
...
        Ext := ExtractFileExt(Info.Name);
        // Add tiff support to built-in image types:
        if Pos(Ext, ImageTypes+'.tif'+'.tiff') <> 0 then
          AddFile(Directory + Info.Name, false);

Hello,

This adds "*.ti" and "*.t" files as valid TIFF extensions, do not ?
And left out "*.TIF" and "*.TIFF".

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BigChimp · 2012-10-18 13:59

Yep, José, you're right. I blame the original coders though

something like (air code):
<code>
if Pos('.'+lowercase(Ext)+'.', '.'+ImageTypes+'.tif.tiff.') <> 0 then
</code>
.. may be better...

Thanks for the catch.

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BigChimp · 2012-12-04 15:28

Patch posted as http://bugs.freepascal.org/view.php?id=23433

No caching; perhaps somebody would like to contribute that