Robin Gareus
ad51c7c2ba
This is intended mainly for GNU/Linux distros who will remove GTK2 support in the near future.
564 lines
19 KiB
C
564 lines
19 KiB
C
/* GdkPixbuf library - Scaling and compositing functions
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*
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* Copyright (C) 1999 The Free Software Foundation
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*
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* Author: Owen Taylor <otaylor@redhat.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "config.h"
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#include <math.h>
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#include <string.h>
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#include "gdk-pixbuf-transform.h"
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#include "gdk-pixbuf-private.h"
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#include "pixops/pixops.h"
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/**
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* SECTION:scaling
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* @Short_description: Scaling pixbufs and scaling and compositing pixbufs
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* @Title: Scaling
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* @See_also: <link linkend="gdk-GdkRGB">GdkRGB</link>.
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*
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* The GdkPixBuf contains functions to scale pixbufs, to scale
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* pixbufs and composite against an existing image, and to scale
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* pixbufs and composite against a solid color or checkerboard.
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* Compositing a checkerboard is a common way to show an image with
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* an alpha channel in image-viewing and editing software.
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*
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*
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* Since the full-featured functions (gdk_pixbuf_scale(),
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* gdk_pixbuf_composite(), and gdk_pixbuf_composite_color()) are
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* rather complex to use and have many arguments, two simple
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* convenience functions are provided, gdk_pixbuf_scale_simple() and
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* gdk_pixbuf_composite_color_simple() which create a new pixbuf of a
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* given size, scale an original image to fit, and then return the
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* new pixbuf.
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*
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* If the destination pixbuf was created from a readonly source, these
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* operations will force a copy into a mutable buffer.
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*
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* Scaling and compositing functions take advantage of MMX hardware
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* acceleration on systems where MMX is supported. If gdk-pixbuf is built
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* with the Sun mediaLib library, these functions are instead accelerated
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* using mediaLib, which provides hardware acceleration on Intel, AMD,
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* and Sparc chipsets. If desired, mediaLib support can be turned off by
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* setting the `GDK_DISABLE_MEDIALIB` environment variable.
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*
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*
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* The following example demonstrates handling an expose event by
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* rendering the appropriate area of a source image (which is scaled
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* to fit the widget) onto the widget's window. The source image is
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* rendered against a checkerboard, which provides a visual
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* representation of the alpha channel if the image has one. If the
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* image doesn't have an alpha channel, calling
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* gdk_pixbuf_composite_color() function has exactly the same effect
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* as calling gdk_pixbuf_scale().
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*
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* ## Handling an expose event
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*
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* |[
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* gboolean
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* expose_cb (GtkWidget *widget, GdkEventExpose *event, gpointer data)
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* {
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* GdkPixbuf *dest;
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*
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* dest = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8, event->area.width, event->area.height);
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*
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* gdk_pixbuf_composite_color (pixbuf, dest,
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* 0, 0, event->area.width, event->area.height,
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* -event->area.x, -event->area.y,
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* (double) widget->allocation.width / gdk_pixbuf_get_width (pixbuf),
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* (double) widget->allocation.height / gdk_pixbuf_get_height (pixbuf),
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* GDK_INTERP_BILINEAR, 255,
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* event->area.x, event->area.y, 16, 0xaaaaaa, 0x555555);
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*
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* gdk_draw_pixbuf (widget->window, widget->style->fg_gc[GTK_STATE_NORMAL], dest,
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* 0, 0, event->area.x, event->area.y,
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* event->area.width, event->area.height,
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* GDK_RGB_DITHER_NORMAL, event->area.x, event->area.y);
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*
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* gdk_pixbuf_unref (dest);
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*
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* return TRUE;
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* }
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* ]|
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*/
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/**
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* gdk_pixbuf_scale:
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* @src: a #GdkPixbuf
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* @dest: the #GdkPixbuf into which to render the results
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* @dest_x: the left coordinate for region to render
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* @dest_y: the top coordinate for region to render
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* @dest_width: the width of the region to render
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* @dest_height: the height of the region to render
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* @offset_x: the offset in the X direction (currently rounded to an integer)
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* @offset_y: the offset in the Y direction (currently rounded to an integer)
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* @scale_x: the scale factor in the X direction
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* @scale_y: the scale factor in the Y direction
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* @interp_type: the interpolation type for the transformation.
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*
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* Creates a transformation of the source image @src by scaling by
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* @scale_x and @scale_y then translating by @offset_x and @offset_y,
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* then renders the rectangle (@dest_x, @dest_y, @dest_width,
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* @dest_height) of the resulting image onto the destination image
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* replacing the previous contents.
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*
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* Try to use gdk_pixbuf_scale_simple() first, this function is
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* the industrial-strength power tool you can fall back to if
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* gdk_pixbuf_scale_simple() isn't powerful enough.
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*
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* If the source rectangle overlaps the destination rectangle on the
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* same pixbuf, it will be overwritten during the scaling which
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* results in rendering artifacts.
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**/
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void
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gdk_pixbuf_scale (const GdkPixbuf *src,
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GdkPixbuf *dest,
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int dest_x,
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int dest_y,
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int dest_width,
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int dest_height,
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double offset_x,
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double offset_y,
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double scale_x,
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double scale_y,
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GdkInterpType interp_type)
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{
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const guint8 *src_pixels;
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guint8 *dest_pixels;
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g_return_if_fail (GDK_IS_PIXBUF (src));
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g_return_if_fail (GDK_IS_PIXBUF (dest));
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g_return_if_fail (dest_x >= 0 && dest_x + dest_width <= dest->width);
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g_return_if_fail (dest_y >= 0 && dest_y + dest_height <= dest->height);
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offset_x = floor (offset_x + 0.5);
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offset_y = floor (offset_y + 0.5);
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/* Force an implicit copy */
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dest_pixels = gdk_pixbuf_get_pixels (dest);
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src_pixels = gdk_pixbuf_read_pixels (src);
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_pixops_scale (dest_pixels, dest->width, dest->height, dest->rowstride,
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dest->n_channels, dest->has_alpha, src_pixels, src->width,
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src->height, src->rowstride, src->n_channels, src->has_alpha,
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dest_x, dest_y, dest_width, dest_height, offset_x, offset_y,
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scale_x, scale_y, (PixopsInterpType)interp_type);
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}
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/**
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* gdk_pixbuf_composite:
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* @src: a #GdkPixbuf
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* @dest: the #GdkPixbuf into which to render the results
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* @dest_x: the left coordinate for region to render
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* @dest_y: the top coordinate for region to render
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* @dest_width: the width of the region to render
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* @dest_height: the height of the region to render
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* @offset_x: the offset in the X direction (currently rounded to an integer)
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* @offset_y: the offset in the Y direction (currently rounded to an integer)
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* @scale_x: the scale factor in the X direction
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* @scale_y: the scale factor in the Y direction
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* @interp_type: the interpolation type for the transformation.
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* @overall_alpha: overall alpha for source image (0..255)
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*
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* Creates a transformation of the source image @src by scaling by
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* @scale_x and @scale_y then translating by @offset_x and @offset_y.
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* This gives an image in the coordinates of the destination pixbuf.
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* The rectangle (@dest_x, @dest_y, @dest_width, @dest_height)
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* is then composited onto the corresponding rectangle of the
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* original destination image.
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*
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* When the destination rectangle contains parts not in the source
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* image, the data at the edges of the source image is replicated
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* to infinity.
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*
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* 
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*/
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void
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gdk_pixbuf_composite (const GdkPixbuf *src,
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GdkPixbuf *dest,
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int dest_x,
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int dest_y,
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int dest_width,
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int dest_height,
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double offset_x,
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double offset_y,
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double scale_x,
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double scale_y,
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GdkInterpType interp_type,
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int overall_alpha)
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{
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const guint8 *src_pixels;
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guint8 *dest_pixels;
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g_return_if_fail (GDK_IS_PIXBUF (src));
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g_return_if_fail (GDK_IS_PIXBUF (dest));
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g_return_if_fail (dest_x >= 0 && dest_x + dest_width <= dest->width);
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g_return_if_fail (dest_y >= 0 && dest_y + dest_height <= dest->height);
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g_return_if_fail (overall_alpha >= 0 && overall_alpha <= 255);
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offset_x = floor (offset_x + 0.5);
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offset_y = floor (offset_y + 0.5);
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/* Force an implicit copy */
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dest_pixels = gdk_pixbuf_get_pixels (dest);
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src_pixels = gdk_pixbuf_read_pixels (src);
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_pixops_composite (dest_pixels, dest->width, dest->height, dest->rowstride,
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dest->n_channels, dest->has_alpha, src_pixels,
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src->width, src->height, src->rowstride, src->n_channels,
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src->has_alpha, dest_x, dest_y, dest_width, dest_height,
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offset_x, offset_y, scale_x, scale_y,
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(PixopsInterpType)interp_type, overall_alpha);
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}
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/**
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* gdk_pixbuf_composite_color:
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* @src: a #GdkPixbuf
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* @dest: the #GdkPixbuf into which to render the results
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* @dest_x: the left coordinate for region to render
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* @dest_y: the top coordinate for region to render
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* @dest_width: the width of the region to render
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* @dest_height: the height of the region to render
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* @offset_x: the offset in the X direction (currently rounded to an integer)
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* @offset_y: the offset in the Y direction (currently rounded to an integer)
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* @scale_x: the scale factor in the X direction
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* @scale_y: the scale factor in the Y direction
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* @interp_type: the interpolation type for the transformation.
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* @overall_alpha: overall alpha for source image (0..255)
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* @check_x: the X offset for the checkboard (origin of checkboard is at -@check_x, -@check_y)
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* @check_y: the Y offset for the checkboard
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* @check_size: the size of checks in the checkboard (must be a power of two)
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* @color1: the color of check at upper left
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* @color2: the color of the other check
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*
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* Creates a transformation of the source image @src by scaling by
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* @scale_x and @scale_y then translating by @offset_x and @offset_y,
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* then composites the rectangle (@dest_x ,@dest_y, @dest_width,
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* @dest_height) of the resulting image with a checkboard of the
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* colors @color1 and @color2 and renders it onto the destination
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* image.
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*
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* See gdk_pixbuf_composite_color_simple() for a simpler variant of this
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* function suitable for many tasks.
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*
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**/
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void
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gdk_pixbuf_composite_color (const GdkPixbuf *src,
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GdkPixbuf *dest,
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int dest_x,
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int dest_y,
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int dest_width,
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int dest_height,
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double offset_x,
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double offset_y,
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double scale_x,
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double scale_y,
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GdkInterpType interp_type,
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int overall_alpha,
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int check_x,
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int check_y,
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int check_size,
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guint32 color1,
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guint32 color2)
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{
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const guint8 *src_pixels;
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guint8 *dest_pixels;
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g_return_if_fail (GDK_IS_PIXBUF (src));
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g_return_if_fail (GDK_IS_PIXBUF (dest));
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g_return_if_fail (dest_x >= 0 && dest_x + dest_width <= dest->width);
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g_return_if_fail (dest_y >= 0 && dest_y + dest_height <= dest->height);
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g_return_if_fail (overall_alpha >= 0 && overall_alpha <= 255);
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offset_x = floor (offset_x + 0.5);
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offset_y = floor (offset_y + 0.5);
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/* Force an implicit copy */
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dest_pixels = gdk_pixbuf_get_pixels (dest);
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src_pixels = gdk_pixbuf_read_pixels (src);
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_pixops_composite_color (dest_pixels, dest_width, dest_height,
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dest->rowstride, dest->n_channels, dest->has_alpha,
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src_pixels, src->width, src->height,
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src->rowstride, src->n_channels, src->has_alpha,
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dest_x, dest_y, dest_width, dest_height, offset_x,
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offset_y, scale_x, scale_y,
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(PixopsInterpType)interp_type, overall_alpha,
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check_x, check_y, check_size, color1, color2);
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}
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/**
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* gdk_pixbuf_scale_simple:
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* @src: a #GdkPixbuf
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* @dest_width: the width of destination image
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* @dest_height: the height of destination image
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* @interp_type: the interpolation type for the transformation.
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*
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* Create a new #GdkPixbuf containing a copy of @src scaled to
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* @dest_width x @dest_height. Leaves @src unaffected. @interp_type
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* should be #GDK_INTERP_NEAREST if you want maximum speed (but when
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* scaling down #GDK_INTERP_NEAREST is usually unusably ugly). The
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* default @interp_type should be #GDK_INTERP_BILINEAR which offers
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* reasonable quality and speed.
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*
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* You can scale a sub-portion of @src by creating a sub-pixbuf
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* pointing into @src; see gdk_pixbuf_new_subpixbuf().
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*
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* For more complicated scaling/compositing see gdk_pixbuf_scale()
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* and gdk_pixbuf_composite().
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*
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* Return value: (transfer full): the new #GdkPixbuf, or %NULL if not enough memory could be
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* allocated for it.
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**/
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GdkPixbuf *
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gdk_pixbuf_scale_simple (const GdkPixbuf *src,
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int dest_width,
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int dest_height,
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GdkInterpType interp_type)
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{
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GdkPixbuf *dest;
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g_return_val_if_fail (GDK_IS_PIXBUF (src), NULL);
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g_return_val_if_fail (dest_width > 0, NULL);
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g_return_val_if_fail (dest_height > 0, NULL);
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dest = gdk_pixbuf_new (GDK_COLORSPACE_RGB, src->has_alpha, 8, dest_width, dest_height);
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if (!dest)
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return NULL;
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gdk_pixbuf_scale (src, dest, 0, 0, dest_width, dest_height, 0, 0,
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(double) dest_width / src->width,
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(double) dest_height / src->height,
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interp_type);
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return dest;
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}
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/**
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* gdk_pixbuf_composite_color_simple:
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* @src: a #GdkPixbuf
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* @dest_width: the width of destination image
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* @dest_height: the height of destination image
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* @interp_type: the interpolation type for the transformation.
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* @overall_alpha: overall alpha for source image (0..255)
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* @check_size: the size of checks in the checkboard (must be a power of two)
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* @color1: the color of check at upper left
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* @color2: the color of the other check
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*
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* Creates a new #GdkPixbuf by scaling @src to @dest_width x
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* @dest_height and compositing the result with a checkboard of colors
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* @color1 and @color2.
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*
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* Return value: (transfer full): the new #GdkPixbuf, or %NULL if not enough memory could be
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* allocated for it.
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**/
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GdkPixbuf *
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gdk_pixbuf_composite_color_simple (const GdkPixbuf *src,
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int dest_width,
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int dest_height,
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GdkInterpType interp_type,
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int overall_alpha,
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int check_size,
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guint32 color1,
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guint32 color2)
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{
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GdkPixbuf *dest;
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g_return_val_if_fail (GDK_IS_PIXBUF (src), NULL);
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g_return_val_if_fail (dest_width > 0, NULL);
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g_return_val_if_fail (dest_height > 0, NULL);
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g_return_val_if_fail (overall_alpha >= 0 && overall_alpha <= 255, NULL);
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dest = gdk_pixbuf_new (GDK_COLORSPACE_RGB, src->has_alpha, 8, dest_width, dest_height);
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if (!dest)
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return NULL;
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gdk_pixbuf_composite_color (src, dest, 0, 0, dest_width, dest_height, 0, 0,
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(double) dest_width / src->width,
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(double) dest_height / src->height,
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interp_type, overall_alpha, 0, 0, check_size, color1, color2);
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return dest;
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}
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#define OFFSET(pb, x, y) ((x) * (pb)->n_channels + (y) * (pb)->rowstride)
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/**
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* gdk_pixbuf_rotate_simple:
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* @src: a #GdkPixbuf
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* @angle: the angle to rotate by
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*
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* Rotates a pixbuf by a multiple of 90 degrees, and returns the
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* result in a new pixbuf.
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*
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* Returns: (nullable) (transfer full): the new #GdkPixbuf, or %NULL
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* if not enough memory could be allocated for it.
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*
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* Since: 2.6
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*/
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GdkPixbuf *
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gdk_pixbuf_rotate_simple (const GdkPixbuf *src,
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GdkPixbufRotation angle)
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{
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const guint8 *src_pixels;
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guint8 *dest_pixels;
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GdkPixbuf *dest;
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const guchar *p;
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guchar *q;
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gint x, y;
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src_pixels = gdk_pixbuf_read_pixels (src);
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switch (angle % 360)
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{
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case 0:
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dest = gdk_pixbuf_copy (src);
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break;
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case 90:
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dest = gdk_pixbuf_new (src->colorspace,
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src->has_alpha,
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src->bits_per_sample,
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src->height,
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src->width);
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if (!dest)
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return NULL;
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dest_pixels = gdk_pixbuf_get_pixels (dest);
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for (y = 0; y < src->height; y++)
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{
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for (x = 0; x < src->width; x++)
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{
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p = src_pixels + OFFSET (src, x, y);
|
||
q = dest_pixels + OFFSET (dest, y, src->width - x - 1);
|
||
memcpy (q, p, dest->n_channels);
|
||
}
|
||
}
|
||
break;
|
||
case 180:
|
||
dest = gdk_pixbuf_new (src->colorspace,
|
||
src->has_alpha,
|
||
src->bits_per_sample,
|
||
src->width,
|
||
src->height);
|
||
if (!dest)
|
||
return NULL;
|
||
|
||
dest_pixels = gdk_pixbuf_get_pixels (dest);
|
||
|
||
for (y = 0; y < src->height; y++)
|
||
{
|
||
for (x = 0; x < src->width; x++)
|
||
{
|
||
p = src_pixels + OFFSET (src, x, y);
|
||
q = dest_pixels + OFFSET (dest, src->width - x - 1, src->height - y - 1);
|
||
memcpy (q, p, dest->n_channels);
|
||
}
|
||
}
|
||
break;
|
||
case 270:
|
||
dest = gdk_pixbuf_new (src->colorspace,
|
||
src->has_alpha,
|
||
src->bits_per_sample,
|
||
src->height,
|
||
src->width);
|
||
if (!dest)
|
||
return NULL;
|
||
|
||
dest_pixels = gdk_pixbuf_get_pixels (dest);
|
||
|
||
for (y = 0; y < src->height; y++)
|
||
{
|
||
for (x = 0; x < src->width; x++)
|
||
{
|
||
p = src_pixels + OFFSET (src, x, y);
|
||
q = dest_pixels + OFFSET (dest, src->height - y - 1, x);
|
||
memcpy (q, p, dest->n_channels);
|
||
}
|
||
}
|
||
break;
|
||
default:
|
||
dest = NULL;
|
||
g_warning ("gdk_pixbuf_rotate_simple() can only rotate "
|
||
"by multiples of 90 degrees");
|
||
g_assert_not_reached ();
|
||
}
|
||
|
||
return dest;
|
||
}
|
||
|
||
/**
|
||
* gdk_pixbuf_flip:
|
||
* @src: a #GdkPixbuf
|
||
* @horizontal: %TRUE to flip horizontally, %FALSE to flip vertically
|
||
*
|
||
* Flips a pixbuf horizontally or vertically and returns the
|
||
* result in a new pixbuf.
|
||
*
|
||
* Returns: (nullable) (transfer full): the new #GdkPixbuf, or %NULL
|
||
* if not enough memory could be allocated for it.
|
||
*
|
||
* Since: 2.6
|
||
*/
|
||
GdkPixbuf *
|
||
gdk_pixbuf_flip (const GdkPixbuf *src,
|
||
gboolean horizontal)
|
||
{
|
||
const guint8 *src_pixels;
|
||
guint8 *dest_pixels;
|
||
GdkPixbuf *dest;
|
||
const guchar *p;
|
||
guchar *q;
|
||
gint x, y;
|
||
|
||
dest = gdk_pixbuf_new (src->colorspace,
|
||
src->has_alpha,
|
||
src->bits_per_sample,
|
||
src->width,
|
||
src->height);
|
||
if (!dest)
|
||
return NULL;
|
||
|
||
dest_pixels = gdk_pixbuf_get_pixels (dest);
|
||
src_pixels = gdk_pixbuf_read_pixels (src);
|
||
|
||
if (!horizontal) /* flip vertical */
|
||
{
|
||
for (y = 0; y < dest->height; y++)
|
||
{
|
||
p = src_pixels + OFFSET (src, 0, y);
|
||
q = dest_pixels + OFFSET (dest, 0, dest->height - y - 1);
|
||
memcpy (q, p, dest->rowstride);
|
||
}
|
||
}
|
||
else /* flip horizontal */
|
||
{
|
||
for (y = 0; y < dest->height; y++)
|
||
{
|
||
for (x = 0; x < dest->width; x++)
|
||
{
|
||
p = src_pixels + OFFSET (src, x, y);
|
||
q = dest_pixels + OFFSET (dest, dest->width - x - 1, y);
|
||
memcpy (q, p, dest->n_channels);
|
||
}
|
||
}
|
||
}
|
||
|
||
return dest;
|
||
}
|