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Re: [platform-swt-dev] swt on gtk slow

The problem with this is that, the Java editor is owned by JDT, whereas the GC.drawText call is in SWT. I could see the Java editor knowing that "if", "while", etc. are interesting, but it doesn't make sense to me for the generic text drawing routine to do this. In any case, the real issue with the strategy is that feels like it is optimizing for something that should just be fixed in the platform API. I recognize that SWT's use of Pango is atypical, but we can't be the only app that wants to control things at this level(?).


Steen Jansdal <steen@xxxxxxxxxx>
Sent by: platform-swt-dev-admin@xxxxxxxxxxx

15/12/03 09:40

Please respond to

Re: [platform-swt-dev] swt on gtk slow

Bradley Schatz wrote:
> Any suggestions on how to get eclipse running as snappily as it does on
> windows when running swt/gtk?
> thanks

Suggestion for the SWT developers:

The editor under GTK is painfully slow and I suspect
pango is to blame for this. When drawing the editor
a lot of slow GC.drawText calls are made. Each time
a GC.drawText call are made pango has to do a slow
relayout calculation because SWT is using the same
pango layout for all GC.drawText calls. Perhaps it
would be faster to implement some kind of cache of

For example when displaying a typical java source
file, it contains a lot of "if"'s, "while"'s, "int"'s,
equal-signs, parentheses,...
If it were possible to get a previously calculated
pango-layout of the same text and font, the drawing
would theoretically be faster. But would it be faster
than the added maintenance of the cache?

What do you think about this approach?

Steen Jansdal

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