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112e74ed64
The documentation explicitly states that 0 is an allowed value for using the same scale as the window. This 0 value is also explicitly checked down in the call chain and handled.
528 lines
15 KiB
C
528 lines
15 KiB
C
/* GDK - The GIMP Drawing Kit
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* Copyright (C) 2005 Red Hat, Inc.
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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 "gdkcairo.h"
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#include "gdkinternals.h"
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#include <math.h>
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/**
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* SECTION:cairo_interaction
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* @Short_description: Functions to support using cairo
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* @Title: Cairo Interaction
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*
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* [Cairo](http://cairographics.org) is a graphics
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* library that supports vector graphics and image compositing that
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* can be used with GDK. GTK+ does all of its drawing using cairo.
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*
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* GDK does not wrap the cairo API, instead it allows to create cairo
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* contexts which can be used to draw on #GdkWindows. Additional
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* functions allow use #GdkRectangles with cairo and to use #GdkColors,
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* #GdkRGBAs, #GdkPixbufs and #GdkWindows as sources for drawing
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* operations.
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*/
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/**
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* gdk_cairo_get_clip_rectangle:
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* @cr: a cairo context
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* @rect: (out) (allow-none): return location for the clip, or %NULL
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*
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* This is a convenience function around cairo_clip_extents().
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* It rounds the clip extents to integer coordinates and returns
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* a boolean indicating if a clip area exists.
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*
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* Returns: %TRUE if a clip rectangle exists, %FALSE if all of @cr is
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* clipped and all drawing can be skipped
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*/
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gboolean
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gdk_cairo_get_clip_rectangle (cairo_t *cr,
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GdkRectangle *rect)
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{
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double x1, y1, x2, y2;
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gboolean clip_exists;
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cairo_clip_extents (cr, &x1, &y1, &x2, &y2);
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clip_exists = x1 < x2 && y1 < y2;
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if (rect)
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{
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x1 = floor (x1);
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y1 = floor (y1);
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x2 = ceil (x2);
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y2 = ceil (y2);
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rect->x = CLAMP (x1, G_MININT, G_MAXINT);
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rect->y = CLAMP (y1, G_MININT, G_MAXINT);
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rect->width = CLAMP (x2 - x1, G_MININT, G_MAXINT);
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rect->height = CLAMP (y2 - y1, G_MININT, G_MAXINT);
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}
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return clip_exists;
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}
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/**
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* gdk_cairo_set_source_color:
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* @cr: a cairo context
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* @color: a #GdkColor
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*
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* Sets the specified #GdkColor as the source color of @cr.
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*
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* Since: 2.8
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*
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* Deprecated: 3.4: Use gdk_cairo_set_source_rgba() instead
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*/
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void
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gdk_cairo_set_source_color (cairo_t *cr,
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const GdkColor *color)
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{
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g_return_if_fail (cr != NULL);
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g_return_if_fail (color != NULL);
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cairo_set_source_rgb (cr,
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color->red / 65535.,
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color->green / 65535.,
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color->blue / 65535.);
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}
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/**
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* gdk_cairo_set_source_rgba:
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* @cr: a cairo context
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* @rgba: a #GdkRGBA
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*
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* Sets the specified #GdkRGBA as the source color of @cr.
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*
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* Since: 3.0
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*/
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void
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gdk_cairo_set_source_rgba (cairo_t *cr,
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const GdkRGBA *rgba)
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{
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g_return_if_fail (cr != NULL);
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g_return_if_fail (rgba != NULL);
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cairo_set_source_rgba (cr,
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rgba->red,
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rgba->green,
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rgba->blue,
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rgba->alpha);
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}
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/**
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* gdk_cairo_rectangle:
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* @cr: a cairo context
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* @rectangle: a #GdkRectangle
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*
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* Adds the given rectangle to the current path of @cr.
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*
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* Since: 2.8
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*/
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void
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gdk_cairo_rectangle (cairo_t *cr,
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const GdkRectangle *rectangle)
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{
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g_return_if_fail (cr != NULL);
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g_return_if_fail (rectangle != NULL);
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cairo_rectangle (cr,
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rectangle->x, rectangle->y,
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rectangle->width, rectangle->height);
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}
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/**
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* gdk_cairo_region:
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* @cr: a cairo context
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* @region: a #cairo_region_t
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*
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* Adds the given region to the current path of @cr.
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*
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* Since: 2.8
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*/
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void
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gdk_cairo_region (cairo_t *cr,
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const cairo_region_t *region)
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{
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cairo_rectangle_int_t box;
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gint n_boxes, i;
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g_return_if_fail (cr != NULL);
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g_return_if_fail (region != NULL);
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n_boxes = cairo_region_num_rectangles (region);
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for (i = 0; i < n_boxes; i++)
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{
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cairo_region_get_rectangle (region, i, &box);
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cairo_rectangle (cr, box.x, box.y, box.width, box.height);
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}
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}
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static void
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gdk_cairo_surface_paint_pixbuf (cairo_surface_t *surface,
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const GdkPixbuf *pixbuf)
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{
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gint width, height;
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guchar *gdk_pixels, *cairo_pixels;
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int gdk_rowstride, cairo_stride;
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int n_channels;
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int j;
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/* This function can't just copy any pixbuf to any surface, be
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* sure to read the invariants here before calling it */
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g_assert (cairo_surface_get_type (surface) == CAIRO_SURFACE_TYPE_IMAGE);
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g_assert (cairo_image_surface_get_format (surface) == CAIRO_FORMAT_RGB24 ||
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cairo_image_surface_get_format (surface) == CAIRO_FORMAT_ARGB32);
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g_assert (cairo_image_surface_get_width (surface) == gdk_pixbuf_get_width (pixbuf));
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g_assert (cairo_image_surface_get_height (surface) == gdk_pixbuf_get_height (pixbuf));
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cairo_surface_flush (surface);
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width = gdk_pixbuf_get_width (pixbuf);
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height = gdk_pixbuf_get_height (pixbuf);
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gdk_pixels = gdk_pixbuf_get_pixels (pixbuf);
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gdk_rowstride = gdk_pixbuf_get_rowstride (pixbuf);
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n_channels = gdk_pixbuf_get_n_channels (pixbuf);
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cairo_stride = cairo_image_surface_get_stride (surface);
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cairo_pixels = cairo_image_surface_get_data (surface);
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for (j = height; j; j--)
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{
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guchar *p = gdk_pixels;
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guchar *q = cairo_pixels;
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if (n_channels == 3)
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{
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guchar *end = p + 3 * width;
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while (p < end)
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{
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#if G_BYTE_ORDER == G_LITTLE_ENDIAN
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q[0] = p[2];
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q[1] = p[1];
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q[2] = p[0];
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#else
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q[1] = p[0];
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q[2] = p[1];
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q[3] = p[2];
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#endif
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p += 3;
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q += 4;
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}
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}
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else
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{
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guchar *end = p + 4 * width;
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guint t1,t2,t3;
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#define MULT(d,c,a,t) G_STMT_START { t = c * a + 0x80; d = ((t >> 8) + t) >> 8; } G_STMT_END
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while (p < end)
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{
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#if G_BYTE_ORDER == G_LITTLE_ENDIAN
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MULT(q[0], p[2], p[3], t1);
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MULT(q[1], p[1], p[3], t2);
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MULT(q[2], p[0], p[3], t3);
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q[3] = p[3];
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#else
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q[0] = p[3];
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MULT(q[1], p[0], p[3], t1);
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MULT(q[2], p[1], p[3], t2);
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MULT(q[3], p[2], p[3], t3);
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#endif
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p += 4;
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q += 4;
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}
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#undef MULT
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}
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gdk_pixels += gdk_rowstride;
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cairo_pixels += cairo_stride;
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}
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cairo_surface_mark_dirty (surface);
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}
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/**
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* gdk_cairo_surface_create_from_pixbuf:
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* @pixbuf: a #GdkPixbuf
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* @scale: the scale of the new surface, or 0 to use same as @window
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* @for_window: (allow-none): The window this will be drawn to, or %NULL
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*
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* Creates an image surface with the same contents as
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* the pixbuf.
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*
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* Returns: a new cairo surface, must be freed with cairo_surface_destroy()
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*
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* Since: 3.10
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*/
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cairo_surface_t *
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gdk_cairo_surface_create_from_pixbuf (const GdkPixbuf *pixbuf,
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int scale,
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GdkWindow *for_window)
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{
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cairo_format_t format;
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cairo_surface_t *surface;
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g_return_val_if_fail (GDK_IS_PIXBUF (pixbuf), NULL);
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g_return_val_if_fail (scale >= 0, NULL);
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g_return_val_if_fail (for_window == NULL || GDK_IS_WINDOW (for_window), NULL);
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if (gdk_pixbuf_get_n_channels (pixbuf) == 3)
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format = CAIRO_FORMAT_RGB24;
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else
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format = CAIRO_FORMAT_ARGB32;
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surface =
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gdk_window_create_similar_image_surface (for_window,
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format,
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gdk_pixbuf_get_width (pixbuf),
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gdk_pixbuf_get_height (pixbuf),
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scale);
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gdk_cairo_surface_paint_pixbuf (surface, pixbuf);
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return surface;
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}
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/**
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* gdk_cairo_set_source_pixbuf:
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* @cr: a cairo context
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* @pixbuf: a #GdkPixbuf
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* @pixbuf_x: X coordinate of location to place upper left corner of @pixbuf
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* @pixbuf_y: Y coordinate of location to place upper left corner of @pixbuf
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*
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* Sets the given pixbuf as the source pattern for @cr.
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*
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* The pattern has an extend mode of %CAIRO_EXTEND_NONE and is aligned
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* so that the origin of @pixbuf is @pixbuf_x, @pixbuf_y.
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*
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* Since: 2.8
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*/
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void
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gdk_cairo_set_source_pixbuf (cairo_t *cr,
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const GdkPixbuf *pixbuf,
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gdouble pixbuf_x,
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gdouble pixbuf_y)
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{
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cairo_format_t format;
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cairo_surface_t *surface;
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if (gdk_pixbuf_get_n_channels (pixbuf) == 3)
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format = CAIRO_FORMAT_RGB24;
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else
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format = CAIRO_FORMAT_ARGB32;
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surface = cairo_surface_create_similar_image (cairo_get_target (cr),
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format,
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gdk_pixbuf_get_width (pixbuf),
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gdk_pixbuf_get_height (pixbuf));
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gdk_cairo_surface_paint_pixbuf (surface, pixbuf);
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cairo_set_source_surface (cr, surface, pixbuf_x, pixbuf_y);
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cairo_surface_destroy (surface);
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}
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/**
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* gdk_cairo_set_source_window:
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* @cr: a cairo context
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* @window: a #GdkWindow
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* @x: X coordinate of location to place upper left corner of @window
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* @y: Y coordinate of location to place upper left corner of @window
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*
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* Sets the given window as the source pattern for @cr.
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*
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* The pattern has an extend mode of %CAIRO_EXTEND_NONE and is aligned
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* so that the origin of @window is @x, @y. The window contains all its
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* subwindows when rendering.
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*
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* Note that the contents of @window are undefined outside of the
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* visible part of @window, so use this function with care.
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*
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* Since: 2.24
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*/
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void
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gdk_cairo_set_source_window (cairo_t *cr,
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GdkWindow *window,
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gdouble x,
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gdouble y)
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{
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cairo_surface_t *surface;
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g_return_if_fail (cr != NULL);
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g_return_if_fail (GDK_IS_WINDOW (window));
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surface = _gdk_window_ref_cairo_surface (window);
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cairo_set_source_surface (cr, surface, x, y);
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cairo_surface_destroy (surface);
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}
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/*
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* _gdk_cairo_surface_extents:
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* @surface: surface to measure
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* @extents: (out): rectangle to put the extents
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*
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* Measures the area covered by @surface and puts it into @extents.
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*
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* Note that this function respects device offsets set on @surface.
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* If @surface is unbounded, the resulting extents will be empty and
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* not be a maximal sized rectangle. This is to avoid careless coding.
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* You must explicitly check the return value of you want to handle
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* that case.
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*
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* Returns: %TRUE if the extents fit in a #GdkRectangle, %FALSE if not
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*/
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gboolean
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_gdk_cairo_surface_extents (cairo_surface_t *surface,
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GdkRectangle *extents)
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{
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double x1, x2, y1, y2;
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cairo_t *cr;
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g_return_val_if_fail (surface != NULL, FALSE);
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g_return_val_if_fail (extents != NULL, FALSE);
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cr = cairo_create (surface);
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cairo_clip_extents (cr, &x1, &y1, &x2, &y2);
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cairo_destroy (cr);
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x1 = floor (x1);
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y1 = floor (y1);
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x2 = ceil (x2);
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y2 = ceil (y2);
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x2 -= x1;
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y2 -= y1;
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if (x1 < G_MININT || x1 > G_MAXINT ||
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y1 < G_MININT || y1 > G_MAXINT ||
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x2 > G_MAXINT || y2 > G_MAXINT)
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{
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extents->x = extents->y = extents->width = extents->height = 0;
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return FALSE;
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}
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extents->x = x1;
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extents->y = y1;
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extents->width = x2;
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extents->height = y2;
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return TRUE;
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}
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/* This function originally from Jean-Edouard Lachand-Robert, and
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* available at www.codeguru.com. Simplified for our needs, not sure
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* how much of the original code left any longer. Now handles just
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* one-bit deep bitmaps (in Window parlance, ie those that GDK calls
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* bitmaps (and not pixmaps), with zero pixels being transparent.
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*/
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/**
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* gdk_cairo_region_create_from_surface:
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* @surface: a cairo surface
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*
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* Creates region that describes covers the area where the given
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* @surface is more than 50% opaque.
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*
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* This function takes into account device offsets that might be
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* set with cairo_surface_set_device_offset().
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*
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* Returns: A #cairo_region_t; must be freed with cairo_region_destroy()
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*/
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cairo_region_t *
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gdk_cairo_region_create_from_surface (cairo_surface_t *surface)
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{
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cairo_region_t *region;
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GdkRectangle extents, rect;
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cairo_surface_t *image;
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cairo_t *cr;
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gint x, y, stride;
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guchar *data;
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_gdk_cairo_surface_extents (surface, &extents);
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if (cairo_surface_get_content (surface) == CAIRO_CONTENT_COLOR)
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return cairo_region_create_rectangle (&extents);
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if (cairo_surface_get_type (surface) != CAIRO_SURFACE_TYPE_IMAGE ||
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cairo_image_surface_get_format (surface) != CAIRO_FORMAT_A1)
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{
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/* coerce to an A1 image */
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image = cairo_image_surface_create (CAIRO_FORMAT_A1,
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extents.width, extents.height);
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cr = cairo_create (image);
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cairo_set_source_surface (cr, surface, -extents.x, -extents.y);
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cairo_paint (cr);
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cairo_destroy (cr);
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}
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else
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image = cairo_surface_reference (surface);
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/* Flush the surface to make sure that the rendering is up to date. */
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cairo_surface_flush (image);
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data = cairo_image_surface_get_data (image);
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stride = cairo_image_surface_get_stride (image);
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region = cairo_region_create ();
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for (y = 0; y < extents.height; y++)
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{
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for (x = 0; x < extents.width; x++)
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{
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/* Search for a continuous range of "non transparent pixels"*/
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gint x0 = x;
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while (x < extents.width)
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{
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#if G_BYTE_ORDER == G_LITTLE_ENDIAN
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if (((data[x / 8] >> (x%8)) & 1) == 0)
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#else
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if (((data[x / 8] >> (7-(x%8))) & 1) == 0)
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#endif
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/* This pixel is "transparent"*/
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break;
|
|
x++;
|
|
}
|
|
|
|
if (x > x0)
|
|
{
|
|
/* Add the pixels (x0, y) to (x, y+1) as a new rectangle
|
|
* in the region
|
|
*/
|
|
rect.x = x0;
|
|
rect.width = x - x0;
|
|
rect.y = y;
|
|
rect.height = 1;
|
|
|
|
cairo_region_union_rectangle (region, &rect);
|
|
}
|
|
}
|
|
data += stride;
|
|
}
|
|
|
|
cairo_surface_destroy (image);
|
|
|
|
cairo_region_translate (region, extents.x, extents.y);
|
|
|
|
return region;
|
|
}
|