gecko-dev/gfx/cairo/push-pop-group.patch
2006-02-10 02:57:07 +00:00

735 lines
23 KiB
Diff

Index: src/cairo-gstate-private.h
===================================================================
--- src/cairo-gstate-private.h.orig 2006-02-09 17:51:53.843750000 -0800
+++ src/cairo-gstate-private.h 2006-02-09 18:03:23.546875000 -0800
@@ -55,7 +55,9 @@
cairo_clip_t clip;
- cairo_surface_t *target;
+ cairo_surface_t *target; /* The target to which all rendering is directed */
+ cairo_surface_t *parent_target; /* The previous target which was receiving rendering */
+ cairo_surface_t *original_target; /* The original target the initial gstate was created with */
cairo_matrix_t ctm;
cairo_matrix_t ctm_inverse;
Index: src/cairo-gstate.c
===================================================================
--- src/cairo-gstate.c.orig 2006-02-09 18:01:01.859375000 -0800
+++ src/cairo-gstate.c 2006-02-09 18:03:23.562500000 -0800
@@ -119,6 +119,8 @@
_cairo_clip_init (&gstate->clip, target);
gstate->target = cairo_surface_reference (target);
+ gstate->parent_target = NULL;
+ gstate->original_target = cairo_surface_reference (target);
_cairo_gstate_identity_matrix (gstate);
gstate->source_ctm_inverse = gstate->ctm_inverse;
@@ -166,6 +168,9 @@
_cairo_clip_init_copy (&gstate->clip, &other->clip);
gstate->target = cairo_surface_reference (other->target);
+ /* parent_target is always set to NULL; it's only ever set by redirect_target */
+ gstate->parent_target = NULL;
+ gstate->original_target = cairo_surface_reference (other->original_target);
gstate->ctm = other->ctm;
gstate->ctm_inverse = other->ctm_inverse;
@@ -194,6 +199,12 @@
cairo_surface_destroy (gstate->target);
gstate->target = NULL;
+ cairo_surface_destroy (gstate->parent_target);
+ gstate->parent_target = NULL;
+
+ cairo_surface_destroy (gstate->original_target);
+ gstate->target = NULL;
+
cairo_pattern_destroy (gstate->source);
gstate->source = NULL;
}
@@ -248,94 +259,153 @@
gstate->target = cairo_surface_reference (target);
}
-/* Push rendering off to an off-screen group. */
-/* XXX: Rethinking this API
-cairo_status_t
-_cairo_gstate_begin_group (cairo_gstate_t *gstate)
+static cairo_status_t
+_cairo_gstate_recursive_apply_clip_path (cairo_gstate_t *gstate,
+ cairo_clip_path_t *cpath)
{
- Pixmap pix;
- unsigned int width, height;
-
- gstate->parent_surface = gstate->target;
-
- width = _cairo_surface_get_width (gstate->target);
- height = _cairo_surface_get_height (gstate->target);
+ cairo_status_t status;
- pix = XCreatePixmap (gstate->dpy,
- _cairo_surface_get_drawable (gstate->target),
- width, height,
- _cairo_surface_get_depth (gstate->target));
- if (pix == 0)
- return CAIRO_STATUS_NO_MEMORY;
+ if (cpath == NULL)
+ return CAIRO_STATUS_SUCCESS;
- gstate->target = cairo_surface_create (gstate->dpy);
- if (gstate->target->status)
- return gstate->target->status;
-
- _cairo_surface_set_drawableWH (gstate->target, pix, width, height);
-
- status = _cairo_surface_fill_rectangle (gstate->target,
- CAIRO_OPERATOR_CLEAR,
- CAIRO_COLOR_TRANSPARENT,
- 0, 0,
- _cairo_surface_get_width (gstate->target),
- _cairo_surface_get_height (gstate->target));
- if (status)
- return status;
+ status = _cairo_gstate_recursive_apply_clip_path (gstate, cpath->prev);
+ if (status)
+ return status;
- return CAIRO_STATUS_SUCCESS;
+ return _cairo_clip_clip (&gstate->clip,
+ &cpath->path,
+ cpath->fill_rule,
+ cpath->tolerance,
+ cpath->antialias,
+ gstate->target);
}
-*/
-/* Complete the current offscreen group, composing its contents onto the parent surface. */
-/* XXX: Rethinking this API
-cairo_status_t
-_cairo_gstate_end_group (cairo_gstate_t *gstate)
+/**
+ * _cairo_gstate_redirect_target:
+ * @gstate: a #cairo_gstate_t
+ * @child: the new child target
+ *
+ * Redirect @gstate rendering to a "child" target. The original
+ * "parent" target with which the gstate was created will not be
+ * affected. See _cairo_gstate_get_target().
+ *
+ * Unless the redirected target has the same device offsets as the
+ * original #cairo_t target, the clip will be INVALID after this call,
+ * and the caller should either recreate or reset the clip.
+ **/
+void
+_cairo_gstate_redirect_target (cairo_gstate_t *gstate, cairo_surface_t *child)
{
- Pixmap pix;
- cairo_color_t mask_color;
- cairo_surface_t mask;
-
- if (gstate->parent_surface == NULL)
- return CAIRO_STATUS_INVALID_POP_GROUP;
-
- _cairo_surface_init (&mask, gstate->dpy);
- _cairo_color_init (&mask_color);
-
- _cairo_surface_set_solid_color (&mask, &mask_color);
-
- * XXX: This could be made much more efficient by using
- _cairo_surface_get_damaged_width/Height if cairo_surface_t actually kept
- track of such informaton. *
- _cairo_surface_composite (gstate->op,
- gstate->target,
- mask,
- gstate->parent_surface,
- 0, 0,
- 0, 0,
- 0, 0,
- _cairo_surface_get_width (gstate->target),
- _cairo_surface_get_height (gstate->target));
-
- _cairo_surface_fini (&mask);
-
- pix = _cairo_surface_get_drawable (gstate->target);
- XFreePixmap (gstate->dpy, pix);
-
- cairo_surface_destroy (gstate->target);
- gstate->target = gstate->parent_surface;
- gstate->parent_surface = NULL;
+ /* If this gstate is already redirected, this is an error; we need a
+ * new gstate to be able to redirect */
+ assert (gstate->parent_target == NULL);
+
+ /* Set up our new parent_target based on our current target;
+ * gstate->parent_target will take the ref that is held by gstate->target
+ */
+ cairo_surface_destroy (gstate->parent_target);
+ gstate->parent_target = gstate->target;
+
+ /* Now set up our new target; we overwrite gstate->target directly,
+ * since its ref is now owned by gstate->parent_target */
+ gstate->target = cairo_surface_reference (child);
+
+ /* Check that the new surface's clip mode is compatible */
+ if (gstate->clip.mode != _cairo_surface_get_clip_mode (child)) {
+ /* clip is not compatible; try to recreate it */
+ /* XXX - saving the clip path always might be useful here,
+ * so that we could recover non-CLIP_MODE_PATH clips */
+ if (gstate->clip.mode == CAIRO_CLIP_MODE_PATH) {
+ cairo_clip_t saved_clip = gstate->clip;
+
+ _cairo_clip_init (&gstate->clip, child);
+
+ /* unwind the path and re-apply */
+ _cairo_gstate_recursive_apply_clip_path (gstate, saved_clip.path);
+
+ _cairo_clip_fini (&saved_clip);
+ } else {
+ /* uh, not sure what to do here.. */
+ _cairo_clip_fini (&gstate->clip);
+ _cairo_clip_init (&gstate->clip, child);
+ }
+ } else {
+ /* clip is compatible; allocate a new serial for the new surface. */
+ if (gstate->clip.serial)
+ gstate->clip.serial = _cairo_surface_allocate_clip_serial (child);
+ }
+}
- return CAIRO_STATUS_SUCCESS;
+/**
+ * _cairo_gstate_is_redirected
+ * @gstate: a #cairo_gstate_t
+ *
+ * Return value: TRUE if the gstate is redirected to a traget
+ * different than the original, FALSE otherwise.
+ **/
+cairo_bool_t
+_cairo_gstate_is_redirected (cairo_gstate_t *gstate)
+{
+ return (gstate->target != gstate->original_target);
}
-*/
+/**
+ * _cairo_gstate_get_target:
+ * @gstate: a #cairo_gstate_t
+ *
+ * Return the current drawing target; if drawing is not redirected,
+ * this will be the same as _cairo_gstate_get_original_target().
+ *
+ * Return value: the current target surface
+ **/
cairo_surface_t *
_cairo_gstate_get_target (cairo_gstate_t *gstate)
{
return gstate->target;
}
+/**
+ * _cairo_gstate_get_parent_target:
+ * @gstate: a #cairo_gstate_t
+ *
+ * Return the parent surface of the current drawing target surface;
+ * if this particular gstate isn't a redirect gstate, this will return NULL.
+ **/
+cairo_surface_t *
+_cairo_gstate_get_parent_target (cairo_gstate_t *gstate)
+{
+ return gstate->parent_target;
+}
+
+/**
+ * _cairo_gstate_get_original_target:
+ * @gstate: a #cairo_gstate_t
+ *
+ * Return the original target with which @gstate was created. This
+ * function always returns the original target independent of any
+ * child target that may have been set with
+ * _cairo_gstate_redirect_target.
+ *
+ * Return value: the original target surface
+ **/
+cairo_surface_t *
+_cairo_gstate_get_original_target (cairo_gstate_t *gstate)
+{
+ return gstate->original_target;
+}
+
+/**
+ * _cairo_gstate_get_clip:
+ * @gstate: a #cairo_gstate_t
+ *
+ * Return value: a pointer to the gstate's cairo_clip_t structure.
+ */
+cairo_clip_t *
+_cairo_gstate_get_clip (cairo_gstate_t *gstate)
+{
+ return &gstate->clip;
+}
+
cairo_status_t
_cairo_gstate_set_source (cairo_gstate_t *gstate,
cairo_pattern_t *source)
Index: src/cairo.c
===================================================================
--- src/cairo.c.orig 2006-02-09 17:51:53.846750000 -0800
+++ src/cairo.c 2006-02-09 18:56:40.375000000 -0800
@@ -347,33 +347,133 @@
}
slim_hidden_def(moz_cairo_set_target);
-/* XXX: I want to rethink this API
+/**
+ * cairo_push_group:
+ * @cr: a cairo context
+ *
+ * Pushes a CAIRO_CONTENT_COLOR_ALPHA temporary surface onto
+ * the rendering stack, redirecting all rendering into it.
+ * See cairo_push_group_with_content().
+ */
+
void
cairo_push_group (cairo_t *cr)
{
- if (cr->status)
- return;
+ cairo_push_group_with_content (cr, CAIRO_CONTENT_COLOR_ALPHA);
+}
+slim_hidden_def(cairo_push_group);
- cr->status = cairoPush (cr);
- if (cr->status)
- return;
+/**
+ * cairo_push_group_with_content:
+ * @cr: a cairo context
+ * @content: a %cairo_content_t indicating the type of group that
+ * will be created
+ *
+ * Pushes a temporary surface onto the rendering stack, redirecting
+ * all rendering into it. The surface dimensions are the size of
+ * the current clipping bounding box. Initially, this surface
+ * is painted with CAIRO_OPERATOR_CLEAR.
+ *
+ * cairo_push_group() calls cairo_save() so that any changes to the
+ * graphics state will not be visible after cairo_pop_group() or
+ * cairo_pop_group_with_alpha(). See cairo_pop_group() and
+ * cairo_pop_group_with_alpha().
+ */
- cr->status = _cairo_gstate_begin_group (cr->gstate);
+void
+cairo_push_group_with_content (cairo_t *cr, cairo_content_t content)
+{
+ cairo_status_t status;
+ cairo_rectangle_t extents;
+ cairo_surface_t *group_surface = NULL;
+
+ /* Get the extents that we'll use in creating our new group surface */
+ _cairo_surface_get_extents (_cairo_gstate_get_target (cr->gstate), &extents);
+ status = _cairo_clip_intersect_to_rectangle (_cairo_gstate_get_clip (cr->gstate), &extents);
+ if (status != CAIRO_STATUS_SUCCESS)
+ goto bail;
+
+ group_surface = cairo_surface_create_similar (_cairo_gstate_get_target (cr->gstate),
+ content,
+ extents.width,
+ extents.height);
+ status = cairo_surface_status (group_surface);
+ if (status)
+ goto bail;
+
+ /* Set device offsets on the new surface so that logically it appears at
+ * the same location on the parent surface. */
+ cairo_surface_set_device_offset (group_surface, -extents.x, -extents.y);
+
+ /* create a new gstate for the redirect */
+ cairo_save (cr);
+ if (cr->status)
+ goto bail;
+
+ _cairo_gstate_redirect_target (cr->gstate, group_surface);
+
+bail:
+ cairo_surface_destroy (group_surface);
+ if (status)
+ _cairo_set_error (cr, status);
}
+slim_hidden_def(cairo_push_group_with_content);
-void
+cairo_pattern_t *
cairo_pop_group (cairo_t *cr)
{
- if (cr->status)
- return;
+ cairo_surface_t *group_surface, *parent_target;
+ cairo_pattern_t *group_pattern = NULL;
+ cairo_matrix_t group_matrix;
+
+ /* Grab the active surfaces */
+ group_surface = _cairo_gstate_get_target (cr->gstate);
+ parent_target = _cairo_gstate_get_parent_target (cr->gstate);
+
+ /* Verify that we are at the right nesting level */
+ if (parent_target == NULL) {
+ _cairo_set_error (cr, CAIRO_STATUS_INVALID_POP_GROUP);
+ return NULL;
+ }
+
+ /* We need to save group_surface before we restore; we don't need
+ * to reference parent_target and original_target, since the
+ * gstate will still hold refs to them once we restore. */
+ cairo_surface_reference (group_surface);
+
+ cairo_restore (cr);
- cr->status = _cairo_gstate_end_group (cr->gstate);
if (cr->status)
- return;
+ goto done;
+
+ group_pattern = cairo_pattern_create_for_surface (group_surface);
+ if (!group_pattern) {
+ cr->status = CAIRO_STATUS_NO_MEMORY;
+ goto done;
+ }
+
+ _cairo_gstate_get_matrix (cr->gstate, &group_matrix);
+ cairo_pattern_set_matrix (group_pattern, &group_matrix);
+done:
+ cairo_surface_destroy (group_surface);
- cr->status = cairoPop (cr);
+ return group_pattern;
}
-*/
+slim_hidden_def(cairo_pop_group);
+
+void
+cairo_pop_group_to_source (cairo_t *cr)
+{
+ cairo_pattern_t *group_pattern;
+
+ group_pattern = cairo_pop_group (cr);
+ if (!group_pattern)
+ return;
+
+ cairo_set_source (cr, group_pattern);
+ cairo_pattern_destroy (group_pattern);
+}
+slim_hidden_def(cairo_pop_group_to_source);
/**
* cairo_set_operator:
@@ -2421,6 +2521,30 @@
if (cr->status)
return (cairo_surface_t*) &_cairo_surface_nil;
+ return _cairo_gstate_get_original_target (cr->gstate);
+}
+
+/**
+ * cairo_get_group_target:
+ * @cr: a cairo context
+ *
+ * Gets the target surface for the current transparency group
+ * started by the last cairo_push_group() call on the cairo
+ * context.
+ *
+ * This function may return NULL if there is no transparency
+ * group on the target.
+ *
+ * Return value: the target group surface, or NULL if none. This
+ * object is owned by cairo. To keep a reference to it, you must call
+ * cairo_surface_reference().
+ **/
+cairo_surface_t *
+cairo_get_group_target (cairo_t *cr)
+{
+ if (cr->status)
+ return (cairo_surface_t*) &_cairo_surface_nil;
+
return _cairo_gstate_get_target (cr->gstate);
}
Index: src/cairo.h
===================================================================
--- src/cairo.h.orig 2006-02-09 17:51:53.847750000 -0800
+++ src/cairo.h 2006-02-09 18:04:02.390625000 -0800
@@ -197,6 +197,26 @@
} cairo_status_t;
/**
+ * cairo_content_t
+ * @CAIRO_CONTENT_COLOR: The surface will hold color content only.
+ * @CAIRO_CONTENT_ALPHA: The surface will hold alpha content only.
+ * @CAIRO_CONTENT_COLOR_ALPHA: The surface will hold color and alpha content.
+ *
+ * @cairo_content_t is used to describe the content that a surface will
+ * contain, whether color information, alpha information (translucence
+ * vs. opacity), or both.
+ *
+ * Note: The large values here are designed to keep cairo_content_t
+ * values distinct from cairo_format_t values so that the
+ * implementation can detect the error if users confuse the two types.
+ */
+typedef enum _cairo_content {
+ CAIRO_CONTENT_COLOR = 0x1000,
+ CAIRO_CONTENT_ALPHA = 0x2000,
+ CAIRO_CONTENT_COLOR_ALPHA = 0x3000
+} cairo_content_t;
+
+/**
* cairo_write_func_t:
* @closure: the output closure
* @data: the buffer containing the data to write
@@ -255,13 +275,17 @@
cairo_public void
moz_cairo_set_target (cairo_t *cr, cairo_surface_t *target);
-/* XXX: I want to rethink this API
cairo_public void
cairo_push_group (cairo_t *cr);
cairo_public void
+cairo_push_group_with_content (cairo_t *cr, cairo_content_t content);
+
+cairo_public cairo_pattern_t *
cairo_pop_group (cairo_t *cr);
-*/
+
+cairo_public void
+cairo_pop_group_to_source (cairo_t *cr);
/* Modify state */
@@ -996,6 +1020,9 @@
cairo_public cairo_surface_t *
cairo_get_target (cairo_t *cr);
+cairo_public cairo_surface_t *
+cairo_get_group_target (cairo_t *cr);
+
typedef enum _cairo_path_data_type {
CAIRO_PATH_MOVE_TO,
CAIRO_PATH_LINE_TO,
@@ -1121,26 +1148,6 @@
/* Surface manipulation */
-/**
- * cairo_content_t
- * @CAIRO_CONTENT_COLOR: The surface will hold color content only.
- * @CAIRO_CONTENT_ALPHA: The surface will hold alpha content only.
- * @CAIRO_CONTENT_COLOR_ALPHA: The surface will hold color and alpha content.
- *
- * @cairo_content_t is used to describe the content that a surface will
- * contain, whether color information, alpha information (translucence
- * vs. opacity), or both.
- *
- * Note: The large values here are designed to keep cairo_content_t
- * values distinct from cairo_format_t values so that the
- * implementation can detect the error if users confuse the two types.
- */
-typedef enum _cairo_content {
- CAIRO_CONTENT_COLOR = 0x1000,
- CAIRO_CONTENT_ALPHA = 0x2000,
- CAIRO_CONTENT_COLOR_ALPHA = 0x3000
-} cairo_content_t;
-
cairo_public cairo_surface_t *
cairo_surface_create_similar (cairo_surface_t *other,
cairo_content_t content,
Index: src/cairoint.h
===================================================================
--- src/cairoint.h.orig 2006-02-09 18:01:01.890625000 -0800
+++ src/cairoint.h 2006-02-09 18:51:23.265625000 -0800
@@ -1077,9 +1077,24 @@
cairo_private void
_moz_cairo_gstate_set_target (cairo_gstate_t *gstate, cairo_surface_t *target);
+cairo_private cairo_bool_t
+_cairo_gstate_is_redirected (cairo_gstate_t *gstate);
+
+cairo_private void
+_cairo_gstate_redirect_target (cairo_gstate_t *gstate, cairo_surface_t *child);
+
cairo_private cairo_surface_t *
_cairo_gstate_get_target (cairo_gstate_t *gstate);
+cairo_private cairo_surface_t *
+_cairo_gstate_get_parent_target (cairo_gstate_t *gstate);
+
+cairo_private cairo_surface_t *
+_cairo_gstate_get_original_target (cairo_gstate_t *gstate);
+
+cairo_private cairo_clip_t *
+_cairo_gstate_get_clip (cairo_gstate_t *gstate);
+
cairo_private cairo_status_t
_cairo_gstate_set_source (cairo_gstate_t *gstate, cairo_pattern_t *source);
@@ -2189,6 +2204,10 @@
slim_hidden_proto(cairo_save)
slim_hidden_proto(cairo_stroke_preserve)
slim_hidden_proto(cairo_surface_destroy)
+slim_hidden_proto(cairo_push_group)
+slim_hidden_proto(cairo_push_group_with_content)
+slim_hidden_proto(cairo_pop_group)
+slim_hidden_proto(cairo_pop_group_to_source)
slim_hidden_proto(moz_cairo_set_target)
CAIRO_END_DECLS
Index: test/Makefile.am
===================================================================
--- test/Makefile.am.orig 2006-02-09 17:51:53.912750000 -0800
+++ test/Makefile.am 2006-02-09 18:03:23.671875000 -0800
@@ -59,7 +59,8 @@
unantialiased-shapes \
unbounded-operator \
user-data \
-rel-path
+rel-path \
+push-group
if HAVE_PTHREAD
TESTS += pthread-show-text
@@ -346,6 +347,7 @@
user_data_LDADD = $(LDADDS)
rel_path_LDADD = $(LDADDS)
xlib_surface_LDADD = $(LDADDS)
+push_group_LDADD = $(LDADDS)
noinst_PROGRAMS = imagediff png-flatten
imagediff_LDADD = $(LDADDS)
Index: test/push-group.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ test/push-group.c 2006-02-09 18:03:23.671875000 -0800
@@ -0,0 +1,119 @@
+/*
+ * Copyright © 2005 Mozilla Corporation
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of
+ * Mozilla Corporation not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Mozilla Corporation makes no representations about the
+ * suitability of this software for any purpose. It is provided "as
+ * is" without express or implied warranty.
+ *
+ * MOZILLA CORPORATION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL MOZILLA CORPORATION BE LIABLE FOR ANY SPECIAL,
+ * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Author: Vladimir Vukicevic <vladimir@pobox.com>
+ */
+
+
+#include "cairo-test.h"
+
+
+#define UNIT_SIZE 100
+#define PAD 5
+#define INNER_PAD 10
+
+#define WIDTH (UNIT_SIZE + PAD) + PAD
+#define HEIGHT (UNIT_SIZE + PAD) + PAD
+
+cairo_test_t test = {
+ "push-group",
+ "Verify that cairo_push_group works.",
+ WIDTH, HEIGHT
+};
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+ cairo_pattern_t *gradient;
+ int i, j;
+
+ gradient = cairo_pattern_create_linear (UNIT_SIZE - (INNER_PAD*2), 0,
+ UNIT_SIZE - (INNER_PAD*2), UNIT_SIZE - (INNER_PAD*2));
+ cairo_pattern_add_color_stop_rgba (gradient, 0.0, 0.3, 0.3, 0.3, 1.0);
+ cairo_pattern_add_color_stop_rgba (gradient, 1.0, 1.0, 1.0, 1.0, 1.0);
+
+ for (j = 0; j < 1; j++) {
+ for (i = 0; i < 1; i++) {
+ double x = (i * UNIT_SIZE) + (i + 1) * PAD;
+ double y = (j * UNIT_SIZE) + (j + 1) * PAD;
+
+ cairo_save (cr);
+
+ cairo_translate (cr, x, y);
+
+ /* draw a gradient background */
+ cairo_save (cr);
+ cairo_translate (cr, INNER_PAD, INNER_PAD);
+ cairo_new_path (cr);
+ cairo_rectangle (cr, 0, 0,
+ UNIT_SIZE - (INNER_PAD*2), UNIT_SIZE - (INNER_PAD*2));
+ cairo_set_source (cr, gradient);
+ cairo_fill (cr);
+ cairo_restore (cr);
+
+ /* clip to the unit size */
+ cairo_rectangle (cr, 0, 0,
+ UNIT_SIZE, UNIT_SIZE);
+ cairo_clip (cr);
+
+ cairo_rectangle (cr, 0, 0,
+ UNIT_SIZE, UNIT_SIZE);
+ cairo_set_source_rgba (cr, 0, 0, 0, 1);
+ cairo_set_line_width (cr, 2);
+ cairo_stroke (cr);
+
+ /* start a group */
+ cairo_push_group (cr);
+
+ /* draw diamond */
+ cairo_move_to (cr, UNIT_SIZE / 2, 0);
+ cairo_line_to (cr, UNIT_SIZE , UNIT_SIZE / 2);
+ cairo_line_to (cr, UNIT_SIZE / 2, UNIT_SIZE);
+ cairo_line_to (cr, 0 , UNIT_SIZE / 2);
+ cairo_close_path (cr);
+ cairo_set_source_rgba (cr, 0, 0, 1, 1);
+ cairo_fill (cr);
+
+ /* draw circle */
+ cairo_arc (cr,
+ UNIT_SIZE / 2, UNIT_SIZE / 2,
+ UNIT_SIZE / 3.5,
+ 0, M_PI * 2);
+ cairo_set_source_rgba (cr, 1, 0, 0, 1);
+ cairo_fill (cr);
+
+ /* end group and paint */
+ cairo_pop_group_to_source (cr);
+ cairo_paint_with_alpha (cr, 0.5);
+
+ cairo_restore (cr);
+ }
+ }
+
+ return CAIRO_TEST_SUCCESS;
+}
+
+int
+main (void)
+{
+ return cairo_test (&test, draw);
+}