Re: tiff image blues

[Marko Riedel]

Hi there,

thanks for your feedback.

I deliberately chose to create a bitmap image rep. instead of using
NSDrawBitmap directly because (a) the Cocoa docs say that

"This function is marginally obsolete. Most applications are better
served using the NSBitmapImageRep class to read and display bitmap
images"

and (b) NSGraphicsContext.m, which provides the method that
NSDrawBitmap invokes says this

"Generic method to render bitmap images. This method shouldn't be used
anywhere except in the AppKit itself. It will be replaced by the more
flexible GSDrawImage method sometime in the future. (Quartz)."

BTW I forgot to release the bitmap image rep. in the code that I
posted.

I tested your suggestion to use a clip rect, but couldn't see much of
an improvement when I tested it with a remote display. Remember that
the temporary bitmap image rep. that I create does not allocate or
move any data. I also suspect that when a scrollview requests a few
lines at the upper end of the displayed rectangle, iterating over
those lines only might well be faster than iterating over a large
bitmap and checking whether pixels are clipped or not. Is this what
the backend does? It seems a bit naive but I am not familiar with
clipping algorithms.

BTW how about adding cursor movement to scoll views? It would be a
nice feature to have and probably does not conflict with existing
specs.

Best regards, 

-- 
+------------------------------------------------------------+
| Marko Riedel, EDV Neue Arbeit gGmbH, mriedel@neuearbeit.de |
| http://www.geocities.com/markoriedelde/index.html          |
+------------------------------------------------------------+