[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Bitmap objects

From: Pete French
Subject: Re: Bitmap objects
Date: Mon, 28 Jan 2002 22:26:17 +0000

> Actually, I would change the xgps code.  It is not necessary to change the
> interface of the DPSimage method.

Thats the conclusion I came to in the end. Almost all the bits are there, you
just need to re-build the _bitmap_combine_alpha function (carefully) to
use them all.

Thanks for the copy of the documentation for DPSimage by the way, most useful.
I dont think I ahve that anywhere - got the "purple book" but it
doesnt seem to be doumented in there. I have the red book too whhich I can
take a look at as well.

The reason I jumoped onto this one (aside from needing the functionality) is
that I already have the code to unpack NSBitmapImageReps (and the old
NX ones too) so the hard part is already done. Its justa  matter of
dropping it in at the correct place.

On the other hane the argumenst to DPSimage do seem to be missing a couple
of fairly vital parameters. One is the number of bytes per row. For most
images this is going to be what you expect, but some use packing at the end
of a row. So I either have to pass that through as an extra or live
with the fact that I wont be able to display those bitmaps properly. The
other is the fact that the colourspace name does not appear to get passed
either. Does xgps support somewhere a "current colourspace" that can
be read ? I havent noticed anything, and certainly the image objecst
do not seem to set any colourspace before trying to draw themselves.

Would it be acceptable to extend the dictionary passed to DPSimage to
take these two values as optional extra parameters - i.e. if they are missing
they are assumed to be the way things are currently. ? That is my current
way of thinking on this anyway. I am hoping to get something working on this
tomorrow if possible, but would be intersted in any comment people have.

thanks for the reply, very useful,


PS: is the general feeling that bitmaps should be displayed as speedily as
    possible, or is a certain amoount of speed worth trading for a more
    faithful rendering of the original ?

reply via email to

[Prev in Thread] Current Thread [Next in Thread]