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In docs, explain what a dither offset is for.

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1999-11-04  Havoc Pennington  <hp@pobox.com>

* src/gdk-pixbuf-render.c (gdk_pixbuf_render_to_drawable): In
docs, explain what a dither offset is for.
(gdk_pixbuf_render_to_drawable_alpha): Explain why you would use
this function vs. gdk_pixbuf_render_to_drawable().
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Havoc Pennington 1999-11-04 20:16:17 +00:00 committed by Havoc Pennington
parent 38abc0dee0
commit 085a27d330
2 changed files with 20 additions and 0 deletions
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7
gdk-pixbuf/ChangeLog
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@ -1,3 +1,10 @@
1999-11-04 Havoc Pennington <hp@pobox.com>
* src/gdk-pixbuf-render.c (gdk_pixbuf_render_to_drawable): In
docs, explain what a dither offset is for.
(gdk_pixbuf_render_to_drawable_alpha): Explain why you would use
this function vs. gdk_pixbuf_render_to_drawable().
1999-11-04 Havoc Pennington <hp@pobox.com> 1999-11-04 Havoc Pennington <hp@pobox.com>
* configure.in: Use libart-config correctly; find gnome-config * configure.in: Use libart-config correctly; find gnome-config

13
gdk/gdkpixbuf-render.c
View File

@ -43,6 +43,7 @@
* Takes the opacity values in a rectangular portion of a pixbuf and thresholds * Takes the opacity values in a rectangular portion of a pixbuf and thresholds
* them to produce a bi-level alpha mask that can be used as a clipping mask for * them to produce a bi-level alpha mask that can be used as a clipping mask for
* a drawable. * a drawable.
*
**/ **/
void void
gdk_pixbuf_render_threshold_alpha (GdkPixbuf *pixbuf, GdkBitmap *bitmap, gdk_pixbuf_render_threshold_alpha (GdkPixbuf *pixbuf, GdkBitmap *bitmap,
@ -174,6 +175,11 @@ remove_alpha (ArtPixBuf *apb, int x, int y, int width, int height, int *rowstrid
* the GdkRGB visual and colormap. Note that this function will ignore the * the GdkRGB visual and colormap. Note that this function will ignore the
* opacity information for images with an alpha channel; the GC must already * opacity information for images with an alpha channel; the GC must already
* have the clipping mask set if you want transparent regions to show through. * have the clipping mask set if you want transparent regions to show through.
*
* For an explanation of dither offsets, see the GdkRGB documentation. In brief, the
* dither offset is important when scrolling (so you can redraw half an image but keep the
* dithering "lined up" between the part you drew first and the part you drew previously).
* For unscrolled images, the offset can always be 0.
**/ **/
void void
gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf, gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf,
@ -247,6 +253,13 @@ gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf,
* *
* Renders a rectangular portion of a pixbuf to a drawable. This is done using * Renders a rectangular portion of a pixbuf to a drawable. This is done using
* GdkRGB, so the specified drawable must have the GdkRGB visual and colormap. * GdkRGB, so the specified drawable must have the GdkRGB visual and colormap.
*
* This function has a performance penalty; it makes two synchronous
* round trips to the X server (creating a bitmask and a GC), and it
* draws the contents of the bitmask. If performance is crucial,
* consider handling alpha yourself and using
* gdk_pixbuf_render_to_drawable(). On the other hand it's more convenient
* than gdk_pixbuf_render_to_drawable() because it handles the alpha channel.
**/ **/
void void
gdk_pixbuf_render_to_drawable_alpha (GdkPixbuf *pixbuf, GdkDrawable *drawable, gdk_pixbuf_render_to_drawable_alpha (GdkPixbuf *pixbuf, GdkDrawable *drawable,