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List:       koffice-devel
Subject:    Re: [RFC] Limiting the file formats used by KoPicture (KWord/KPresenter)
From:       Clarence Dang <dang () kde ! org>
Date:       2003-01-26 23:34:32
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On Sun, 26 Jan 2003 01:15 am, Nicolas Goutte wrote:
> Currently in KoPicture, we assume that QImageIO can handle all image
> formats used in KWord and KPresenter. However, it limits the portability of
> KWord and KPresenter file formats, as a non-QT application could suddenly
> have to deal with an image file format that it does not know.
>
> Therefore, I would like to limit the file formats used by KoPicture to:
>
Please, please, do not do this!

> PNG (image/png)
> JPEG (image/jpeg)
> JPEG2000 (image/j2k)
> EPS (image/x-eps)
> SVG (image/svg+xml)
>
> BMP (image/x-bmp)
> WMF (image/x-wmf)
> QPicture (image/x-vnd.trolltech.qpicture)
>
> In a distant future, I would like to remove WMF and QPicture, but
> currently it is not possible. 
I disagree.  If WMF support is removed, then certain filters would have to 
convert to e.g. BMP and then have to convert back to WMF on export (a real 
waste of time and effort).  In the general case, forcing filters to convert 
to certain types of images and back on export would surely increase the 
lossiness of the filters (which is already too high) and decrease their 
performace.

> In a less distant future and perhaps already
> for KOffice 1.3, I would like to remove BMP too.
>
But why?  Both WMF and BMP are well supported.  In both Windows and Linux.  
Certainly BMP support should not be removed since BMP is a fairly universal 
format.

> The advantage is, as already written, a better compactibility with non-QT
> applications and theirs import filters. (You can see it similar to why we
> limit KOffice's XML documents to be in UTF-8.)
>
If non-QT office suite applications can't read BMP, they probably won't be 
very popular anyway.  Admittedly, though, less so for WMF but each image 
format has its own characteristics and I think it would make filters too 
lossy (for people who work largely with foreign formats).

> An incovenient is that many image formats must be converted to PNG when an
> image is inserted by the user or when loading a document (possibly by a
> filter.)
>
Provide KoPicture methods that convert between the images.
I actually have to convert PNG to WMF...

> A second incovenient is that export filters might have to convert again the
> picture. However as no file format knows all of QT's image formats, all
> export filters will need to have code to convert images. So these export
> filters are not bloated.
>
There are too many different document formats that support different types of 
images.  If you are going to make it convenient for some export filters, then 
you are going to make it very hard for others e.g. for mswrite, the only 
format that is truely supported is Standard WMF/BMP.  I think the only 
solution is that have KoPicture handle everything and be able to convert 
between everything.  Maybe when an image is inserted into KWord, the user 
should be given the _option_ to convert it to something like PNG or JPEG (I 
guess a global option for filters would be good too) but I don't think we 
should restrict what images the KWord format supports at all.

Thanks,
Clarence


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