gtk/gdk-pixbuf/pixops
Havoc Pennington e0fee22e78 Add built marshaller files to support GdkPixbufLoader signals
2001-01-22  Havoc Pennington  <hp@redhat.com>

	* Makefile.am: Add built marshaller files to support
	GdkPixbufLoader signals

	* gdk-pixbuf-io.c (gdk_pixbuf_load_module): have
	GDK_PIXBUF_MODULEDIR unconditionally replace the compiled-in
	module location, rather than acting as a fallback, because we are
	using GDK_PIXBUF_MODULEDIR to use gdk-pixbuf before installing it.

	* gdk-pixbuf.h: include gdk-pixbuf-loader.h

        * gdk-pixbuf-loader.h, gdk-pixbuf-loader.c: Move back over here
	from gtk, and add error to close(), because stop_load may do
	parsing of the image.

	* pixops/have_mmx.S (_pixops_have_mmx): add newline at end of file

        * io-*.c: make individual operations static, and add fill_vtable
	functions which are exported. Fix the collection of type warnings
	that surfaced, including a number of functions that didn't
	properly take a GError and some that weren't
	const-correct. Involved adding error handling for a few loaders.

	* gdk-pixbuf-io.h: Add error reporting to stop_load function

	* gdk-pixbuf-io.c (gdk_pixbuf_load_module): change to just look up
	a function that fills in the GdkPixbufModule vtable, instead of
	looking up all the image functions individually; this means we
	can get type safety within modules for the loader functions.
	Also it means you don't have to keep the statically compiled and
	GModule versions in sync.

	* test-gdk-pixbuf.c (main): remove gdk_pixbuf_init()

	* make-inline-pixbuf.c (main): remove call to gdk_pixbuf_init()

	* gdk-pixbuf.h: nuke gdk_pixbuf_init()

	* gdk-pixbuf-animation.c (gdk_pixbuf_frame_get_type): g_type_init
	() here

	* gdk-pixbuf.c (gdk_pixbuf_get_type): g_type_init () here

	* gdk-pixbuf-animation.c (gdk_pixbuf_animation_get_type):
	g_type_init() here


2001-01-22  Havoc Pennington  <hp@redhat.com>

	* demos/testanimation.c: fix to reflect gdk-pixbuf changes

	* demos/testpixbuf.c: fix to reflect gdk-pixbuf changes

	* gtk/gdk-pixbuf-loader.c, gtk/gdk-pixbuf-loader.h:
	Remove, move back to gdk-pixbuf

	* gtk/gtktextiter.c, gtk/gtktextiter.h: add sentence equivalents
	to all the word functions

	* gtk/gtktextview.c (gtk_text_view_start_cursor_blink): return
	before doing anything on NULL layout or if we don't have the focus

	* gtk/testtext.c (fill_example_buffer): "justification"

	* gtk/gtktexttag.h, gtk/gtktexttag.c: change the tag attribute
	to be called "justification" not "justify"

	* demos/gtk-demo/textview.c (create_tags): "justification"

	* gtk/gtktextlayout.c (set_para_values): Handle char-wise wrapping
2001-01-22 23:09:48 +00:00
..
.cvsignore Remove conftest* after use along the lines of AC_TRY_COMPILE. 2000-09-05 14:07:55 +00:00
composite_line_22_4a4_mmx.S Win32 build setup: 2000-07-22 23:50:19 +00:00
composite_line_color_22_4a4_mmx.S Win32 build setup: 2000-07-22 23:50:19 +00:00
DETAILS Add beginnings of file with detailed information about the structure and 2000-05-05 11:44:15 +00:00
have_mmx.S Add built marshaller files to support GdkPixbufLoader signals 2001-01-22 23:09:48 +00:00
Makefile.am remove unecessary rules for win32-specific config-substituted targets. If 2000-11-16 00:16:46 +00:00
makefile.mingw.in Win32 build setup: 2000-07-22 23:50:19 +00:00
pixops-internal.h Most of this patch is based on a patch by Havoc Pennington (hp@redhat.com) 2000-04-11 07:03:25 +00:00
pixops.c contrib subdir 2000-10-09 17:22:20 +00:00
pixops.h Most of this patch is based on a patch by Havoc Pennington (hp@redhat.com) 2000-04-11 07:03:25 +00:00
README quick fix for initializing arrays in benchmark. 2000-01-05 23:57:02 +00:00
scale_line_22_33_mmx.S Win32 build setup: 2000-07-22 23:50:19 +00:00
timescale.c Win32 build setup: 2000-07-22 23:50:19 +00:00

The code in this directory implements optimized, filtered scaling
for pixmap data. 

This code is copyright Red Hat, Inc, 2000 and licensed under the terms
of the GNU Lesser General Public License (LGPL).

(If you want to use it in a project where that license is not
appropriate, please contact me, and most likely something can be
worked out.)

Owen Taylor <otaylor@redhat.com>

PRINCIPLES
==========

The general principle of this code is that it first computes a filter
matrix for the given filtering mode, and then calls a general driver
routine, passing in functions to composite pixels and lines.

(The pixel functions are used for handling edge cases, and the line
functions are simply used for the middle parts of the image.)

The system is designed so that the line functions can be simple, 
don't have to worry about special cases, can be selected to
be specific to the particular formats involved. This allows them
to be hyper-optimized. Since most of the compution time is 
spent in these functions, this results in an overall fast design.

MMX assembly code for Intel (and compatible) processors is included
for a number of the most common special cases:

 scaling from RGB to RGB
 compositing from RGBA to RGBx
 compositing against a color from RGBA and storing in a RGBx buffer

TODO
====

* ART_FILTER_HYPER is not correctly implemented. It is currently
  implemented as a filter that is derived by doing linear interpolation
  on the source image and then averaging that with a box filter.

  It should be defined as followed (see art_filterlevel.h)

   "HYPER is the highest quality reconstruction function. It is derived
    from the hyperbolic filters in Wolberg's "Digital Image Warping,"
    and is formally defined as the hyperbolic-filter sampling the ideal
    hyperbolic-filter interpolated image (the filter is designed to be
    idempotent for 1:1 pixel mapping). It is the slowest and highest
    quality."

  The current HYPER is probably as slow, but lower quality. Also, there
  are some subtle errors in the calculation current HYPER that show up as dark
  stripes if you scale a constant-color image.

* There are some roundoff errors in the compositing routines. 
  the _nearest() variants do it right, most of the other code 
  is wrong to some degree or another.

  For instance, in composite line, we have:

    dest[0] = ((0xff0000 - a) * dest[0] + r) >> 24;

   if a is 0, then we have:

    (0xff0000 * dest[0] + r) >> 24

   which gives results which are 1 to low:

       255 => 254,   1 => 0.

   So, this should be something like:

     ((0xff0000 - a) * dest[0] + r + 0xffffff) >> 24;

   (Not checked, caveat emptor)

   An alternatve formulation of this as:

     dest[0] + (r - a * dest[0] + 0xffffff) >> 24

   may be better numerically, but would need consideration for overflow.

* The generic functions could be sped up considerably by
  switching around conditionals and inner loops in various
  places.

* Right now, in several of the most common cases, there are
  optimized mmx routines, but no optimized C routines.

  For instance, there is a 

    pixops_composite_line_22_4a4_mmx()

  But no 
  
    pixops_composite_line_22_4a4()

  Also, it may be desirable to include a few more special cases - in particular:

    pixops_composite_line_22_4a3()

  May be desirable.

* Scaling down images by large scale factors is _slow_ since huge filter
  matrixes are computed. (e.g., to scale down by a factor of 100, we compute
  101x101 filter matrixes. At some point, it would be more efficent to
  switch over to subsampling when scaling down - one should never need a filter
  matrix bigger than 16x16.