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New function to render a portion of a pixbuf to a drawable. Ignores alpha

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1999-10-28  Federico Mena Quintero  <federico@redhat.com>

	* src/gdk-pixbuf-render.c (gdk_pixbuf_render_to_drawable): New
	function to render a portion of a pixbuf to a drawable.  Ignores
	alpha information and takes in a GC.
	(gdk_pixbuf_render_to_drawable_alpha): New function to render a
	portion of a pixbuf to a drawable.  It automatically creates a GC
	and a clipping mask for alpha pixbufs.
This commit is contained in:
Federico Mena Quintero
1999-10-28 23:25:02 +00:00
committed by Arturo Espinosa
parent 7e96137070
commit ece5ac121a
3 changed files with 164 additions and 21 deletions
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9
gdk-pixbuf/ChangeLog
View File

@ -1,3 +1,12 @@
1999-10-28 Federico Mena Quintero <federico@redhat.com>
* src/gdk-pixbuf-render.c (gdk_pixbuf_render_to_drawable): New
function to render a portion of a pixbuf to a drawable. Ignores
alpha information and takes in a GC.
(gdk_pixbuf_render_to_drawable_alpha): New function to render a
portion of a pixbuf to a drawable. It automatically creates a GC
and a clipping mask for alpha pixbufs.
1999-10-28 Jonathan Blandford <jrb@redhat.com>
* src/gdk-pixbuf.h: turned convenience macros into convenience

14
gdk-pixbuf/gdk-pixbuf.h
View File

@ -97,15 +97,23 @@ void gdk_pixbuf_render_threshold_alpha (GdkPixbuf *pixbuf, GdkBitmap *bitmap,
int width, int height,
int alpha_threshold);
void gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf, GdkDrawable *drawable,
void gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf,
GdkDrawable *drawable, GdkGC *gc,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height,
GdkPixbufAlphaMode alpha_mode,
int alpha_threshold,
GdkRgbDither dither,
int x_dither, int y_dither);
void gdk_pixbuf_render_to_drawable_alpha (GdkPixbuf *pixbuf, GdkDrawable *drawable,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height,
GdkPixbufAlphaMode alpha_mode,
int alpha_threshold,
GdkRgbDither dither,
int x_dither, int y_dither);
/* Transformations */
#if 0
GdkPixbuf *gdk_pixbuf_scale (const GdkPixbuf *pixbuf, gint w, gint h);

162
gdk/gdkpixbuf-render.c
View File

@ -39,9 +39,10 @@
* @height: Height of region to threshold.
* @alpha_threshold: Opacity values below this will be painted as zero; all
* other values will be painted as one.
*
* Takes the opacity values in a pixbuf and thresholds them to produce a
* bi-level alpha mask that can be used as a clipping mask for a drawable.
*
* 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
* a drawable.
**/
void
gdk_pixbuf_render_threshold_alpha (GdkPixbuf *pixbuf, GdkBitmap *bitmap,
@ -119,23 +120,148 @@ gdk_pixbuf_render_threshold_alpha (GdkPixbuf *pixbuf, GdkBitmap *bitmap,
gdk_gc_unref (gc);
}
/* Creates a buffer by stripping the alpha channel of a pixbuf */
static guchar *
remove_alpha (ArtPixBuf *apb, int x, int y, int width, int height, int *rowstride)
{
guchar *buf;
int xx, yy;
guchar *src, *dest;
g_assert (apb->n_channels == 4);
g_assert (apb->has_alpha);
g_assert (x >= 0 && x + width <= apb->width);
g_assert (y >= 0 && y + height <= apb->height);
*rowstride = 4 * ((width * 3 + 3) / 4);
buf = g_new (guchar, *rowstride * height);
for (yy = 0; yy < height; yy++) {
src = apb->pixels + apb->rowstride * (yy + y) + x * apb->n_channels;
dest = buf + *rowstride * yy;
for (xx = 0; xx < width; xx++) {
*dest++ = *src++;
*dest++ = *src++;
*dest++ = *src++;
src++;
}
}
return buf;
}
/**
* gdk_pixbuf_render_to_drawable:
* @pixbuf: A pixbuf.
* @drawable: Destination drawable.
* @gc: GC used for rendering.
* @src_x: Source X coordinate within pixbuf.
* @src_y: Source Y coordinate within pixbuf.
* @dest_x: Destination X coordinate within drawable.
* @dest_y: Destination Y coordinate within drawable.
* @width: Width of region to render, in pixels.
* @height: Height of region to render, in pixels.
* @dither: Dithering mode for GdkRGB.
* @x_dither: X offset for dither.
* @y_dither: Y offset for dither.
*
* Renders a rectangular portion of a pixbuf to a drawable while using the
* specified GC. This is done using GdkRGB, so the specified drawable must have
* the GdkRGB visual and colormap. Note that this function will ignore the
* 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.
**/
void
gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf, GdkDrawable *drawable,
gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf,
GdkDrawable *drawable, GdkGC *gc,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height,
GdkPixbufAlphaMode alpha_mode,
int alpha_threshold,
GdkRgbDither dither,
int x_dither, int y_dither)
{
ArtPixBuf *apb;
ArtIRect dest_rect, req_rect, area_rect;
GdkBitmap *bitmap;
GdkGC *gc;
guchar *buf;
int rowstride;
g_return_if_fail (pixbuf != NULL);
apb = pixbuf->art_pixbuf;
g_return_if_fail (apb->format == ART_PIX_RGB);
g_return_if_fail (apb->n_channels == 3 || apb->n_channels == 4);
g_return_if_fail (apb->bits_per_sample == 8);
g_return_if_fail (drawable != NULL);
g_return_if_fail (gc != NULL);
g_return_if_fail (src_x >= 0 && src_x + width <= apb->width);
g_return_if_fail (src_y >= 0 && src_y + height <= apb->height);
/* This will have to be modified once libart supports other image types.
* Also, GdkRGB does not have gdk_draw_rgb_32_image_dithalign(), so we
* have to pack the buffer first.
*/
if (apb->has_alpha)
buf = remove_alpha (apb, src_x, src_y, width, height, &rowstride);
else {
buf = apb->pixels + src_y * apb->rowstride + src_x * 3;
rowstride = apb->rowstride;
}
gdk_draw_rgb_image_dithalign (drawable, gc,
dest_x, dest_y,
width, height,
dither,
buf, rowstride,
x_dither, y_dither);
if (apb->has_alpha)
g_free (buf);
}
/**
* gdk_pixbuf_render_to_drawable_alpha:
* @pixbuf: A pixbuf.
* @drawable: Destination drawable.
* @src_x: Source X coordinate within pixbuf.
* @src_y: Source Y coordinates within pixbuf.
* @dest_x: Destination X coordinate within drawable.
* @dest_y: Destination Y coordinate within drawable.
* @width: Width of region to render, in pixels.
* @height: Height of region to render, in pixels.
* @alpha_mode: If the image does not have opacity information, this is ignored.
* Otherwise, specifies how to handle transparency when rendering.
* @alpha_threshold: If the image does have opacity information and @alpha_mode
* is GDK_PIXBUF_ALPHA_BILEVEL, specifies the threshold value for opacity
* values.
* @dither: Dithering mode for GdkRGB.
* @x_dither: X offset for dither.
* @y_dither: Y offset for dither.
*
* 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.
**/
void
gdk_pixbuf_render_to_drawable_alpha (GdkPixbuf *pixbuf, GdkDrawable *drawable,
int src_x, int src_y,
int dest_x, int dest_y,
int width, int height,
GdkPixbufAlphaMode alpha_mode,
int alpha_threshold,
GdkRgbDither dither,
int x_dither, int y_dither)
{
ArtPixBuf *apb;
GdkBitmap *bitmap;
GdkGC *gc;
g_return_if_fail (pixbuf != NULL);
apb = pixbuf->art_pixbuf;
@ -163,15 +289,15 @@ gdk_pixbuf_render_to_drawable (GdkPixbuf *pixbuf, GdkDrawable *drawable,
gdk_gc_set_clip_mask (gc, bitmap);
gdk_gc_set_clip_origin (gc, dest_x, dest_y);
gdk_bitmap_unref (bitmap);
}
/* Sigh, GdkRGB does not have gdk_draw_rgb_32_image_dithalign(), so we
* have to pack the buffer first.
*/
if (apb->has_alpha) {
// buf = remove_alpha (apb, src_x, src_y, width, height, &rowstride);
} else {
buf = apb->pixels + src_y * apb->rowstride + src_x * 3;
rowstride = apb->rowstride;
}
gdk_pixbuf_render_to_drawable (pixbuf, drawable, gc,
src_x, src_y,
dest_x, dest_y,
width, height,
dither,
x_dither, y_dither);
gdk_gc_unref (gc);
}