Re: [gtk-list] Re: pixmap loading slowness

[raster redhat com]

On  9 Feb, Andreas Tille shouted:
->  On Sat, 7 Feb 1998 raster@redhat.com wrote:
->  
->  > On  7 Feb, ALT2376@ritvax.isc.rit.edu shouted:
->  > ->  Hello,
->  > ->  	has anyone noticed that gdk_create_pixmap_from_xpm_d() is very slow?.
->  > ->  Its like 10 times slower than gdk_create_pixmap_from_xpm(). Gimp doesnt even
->  > ->  use this routine to embed pixmap. Does anyone else have an alternative
->  > ->  way(shorter) other than what gimp does?. 
->  > 
->  > use imlib - I am about to release imlib 1.0. I am working on
->  > documentation right now. I loads pixmaps fast xpm's, gif's, png's,
->  > ppm's jpeg's, pgm's etc. :) It also has the added bonus of doing a LOT
->  > of other things. :)
->  What is imlib and where can I found it?

currently a preliminary release is in the CVS tree for gnome.

->  I want to do the following:
->  
->    1) Reading some TIFF-Files (I want to do it myself using tifflib.
->    2) Do some modifications with the Images in memory ending in
->       a buffer (char *) of 8-bit-gray values.

can be done. But you'll have to convert to RGB triples first. Imlib
works in full color - then you can create an image and render it. The
best solution is to create an image to start with, and just play with
the RGB data it points to - you are limited to the original data
remaining a certain size and creating an Imlib image out of data does
invole a memcpy operation (as the data may be static and Imlib will try
to free static data if you try and free an image pointing to static
data - then the program will segfault).

->    3) I want to write this buffer as fast as possible into a window
->       (rectangle of width*height=sizeof(buffer)) of the screen.
->    4) I have tried this by using gdk_create_pixmap_from_data() but
->       failed.  It seems that I havn't understand the tutorial completely
->       but I didn't understand the philosophy and ended in a core dump
->       anyway.

no - the pixmap data is just an xpm's data segemnt (compiled) in a
program. it won't work like this.

->    5) As the discussion above shows, the gdk_create_pixmap_...() functions
->       aren't optimized for speed and so I'm now looking for an appropriate
->       way to solve my problem.

despite the memcpy and the grey -> RGB triples Imlib will probably still
be faster.

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