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