src/cairo-surface.c src/cairoint.h: Add _cairo_surface_begin/end to save and restore the clip state of a surface. Copy and store clip regions set on a surface so that we can save and restore them.

Add a CAIRO_STATUS_BAD_NESTING error for interleaved use of two cairo_t's on the same surface. Also, add a skeleton doc comment for cairo_status_t.
src/cairo.c src/cairo-gstate.c src/cairoint.h: Use _cairo_surface_begin/end to replace _cairo_gstate_restore_external_state.
Use _cairo_surface_begin/end to save the state of a surface when we start drawing at it and restore it at the end. Check that the save level of the surface is what we expect on drawing operations and fail with CAIRO_STATUS_BAD_NESTING otherwise.
src/cairo-pattern.c src/cairoint.h (_cairo_pattern_acquire_surface_for_surface) (_cairo_pattern_release_surface): Surround use of pattern->surface with _cairo_surface->begin/end so we don't clip surfaces used as sources.
test/clip-nesting.c test/Makefile.am: Test of destinatin clipping with the nested creation of cairo_t's for the same context.
test/source-clip.c test/Makefile.am: Test that clipping on a source as a destination doesn't affect use of it as a source.
XFAIL test for copying from a surface as a source to itself as a destination with a clip.

7 files changed, 287 insertions, 0 deletions

diff --git a/test/Makefile.am b/test/Makefile.am
index 531f9b377..b1a90290c 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -1,6 +1,7 @@
 # All test cases go here
 TESTS = 		\
 clip-twice		\
+clip-nesting		\
 coverage		\
 create-for-png		\
 fill-and-stroke		\
@@ -17,7 +18,9 @@ path-data		\
 pdf-surface		\
 pixman-rotate		\
 select-font-no-show-text\
+self-copy		\
 set-source		\
+source-clip		\
 surface-finish-twice	\
 surface-pattern		\
 text-cache-crash	\
@@ -32,6 +35,7 @@ rel-path
 # I really don't like having to repeat this list. Anyone know a good
 # way to avoid it? Can I use a wildcard here?
 EXTRA_DIST =			\
+clip-nesting-ref.png		\
 create-for-png-ref.png		\
 fill-and-stroke-ref.png		\
 fill-rule-ref.png		\
@@ -43,11 +47,14 @@ mask-ref.png			\
 move-to-show-surface-ref.png	\
 coverage-ref.png		\
 clip-twice-ref.png		\
+mask-ref.png			\
 paint-ref.png			\
 path-data-ref.png		\
 pixman-rotate-ref.png		\
 romedalen.png			\
+self-copy-ref.png		\
 set-source-ref.png		\
+source-clip-ref.png		\
 surface-pattern-ref.png		\
 transforms-ref.png		\
 translate-show-surface-ref.png	\
@@ -70,6 +77,7 @@ rel-path-ref.png
 XFAIL_TESTS =		\
 coverage		\
 pixman-rotate		\
+self-copy		\
 text-rotate
 
 check_PROGRAMS = $(TESTS)
@@ -99,6 +107,7 @@ LDADDS = libcairotest.la $(top_builddir)/src/libcairo.la
 # ARGH! I have to repeat the list of tests a third time. Maybe it's
 # time to break down and auto-generate the Makefile.am or something
 # from autogen.sh. My, but this is painful...
+clip_nesting_LDADD = $(LDADDS)
 clip_twice_LDADD = $(LDADDS)
 coverage_LDADD = $(LDADDS)
 create_for_png_LDADD = $(LDADDS)
@@ -116,7 +125,9 @@ path_data_LDADD = $(LDADDS)
 pdf_surface_LDADD = $(LDADDS)
 pixman_rotate_LDADD = $(LDADDS)
 select_font_no_show_text_LDADD = $(LDADDS)
+self_copy_LDADD = $(LDADDS)
 set_source_LDADD = $(LDADDS)
+source_clip_LDADD = $(LDADDS)
 surface_finish_twice_LDADD = $(LDADDS)
 surface_pattern_LDADD = $(LDADDS)
 text_cache_crash_LDADD = $(LDADDS)
diff --git a/test/clip-nesting-ref.png b/test/clip-nesting-ref.png
new file mode 100644
index 000000000..6b7e1cd50
--- /dev/null
+++ b/test/clip-nesting-ref.png
diff --git a/test/clip-nesting.c b/test/clip-nesting.c
new file mode 100644
index 000000000..03760b017
--- /dev/null
+++ b/test/clip-nesting.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright © 2005 Red Hat, Inc.
+ *
+ * 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
+ * Red Hat, Inc. not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Red Hat, Inc. makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL RED HAT, INC. 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: Owen Taylor <otaylor@redhat.com>
+ */
+
+#include <math.h>
+#include "cairo-test.h"
+#include <stdio.h>
+
+#define SIZE 100
+#define BORDER 10
+#define LINE_WIDTH 20
+
+cairo_test_t test = {
+    "clip-nesting",
+    "Test clipping with multiple contexts for the same surface",
+    SIZE, SIZE
+};
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_surface_t *target_surface;
+    cairo_t *cr2, *cr3;
+
+    target_surface = cairo_get_target_surface (cr);
+
+    cr2 = cairo_create ();
+    cairo_set_target_surface (cr2, target_surface);
+
+    /* Draw a diagonal line and clip to it */
+    
+    cairo_move_to (cr2, BORDER,                     BORDER);
+    cairo_line_to (cr2, BORDER + LINE_WIDTH,        BORDER);
+    cairo_line_to (cr2, SIZE - BORDER,              SIZE - BORDER);
+    cairo_line_to (cr2, SIZE - BORDER - LINE_WIDTH, SIZE - BORDER);
+
+    cairo_clip (cr2);
+    cairo_set_source_rgb (cr2, 0, 0, 1); /* Blue */
+    cairo_paint (cr2);
+
+    /* Clipping affects this cairo_t */
+
+    cairo_set_source_rgb (cr2, 1, 1, 1); /* White */
+    cairo_rectangle (cr2,
+		     SIZE / 2 - LINE_WIDTH / 2, BORDER,
+		     LINE_WIDTH,                SIZE - 2 * BORDER);
+    cairo_fill (cr2);
+
+    /* But doesn't affect another cairo_t that we create temporarily for
+     * the same surface
+     */
+    cr3 = cairo_create ();
+    
+    cairo_set_target_surface (cr3, target_surface);
+    cairo_set_source_rgb (cr3, 1, 1, 1); /* White */
+    cairo_rectangle (cr3,
+		     SIZE - BORDER - LINE_WIDTH, BORDER,
+		     LINE_WIDTH,                 SIZE - 2 * BORDER);
+    cairo_fill (cr3);
+
+    cairo_destroy (cr3);
+    cairo_destroy (cr2);
+
+    /* And doesn't affect anything after this cairo_t is destroyed */
+
+    cairo_set_source_rgb (cr, 1, 1, 1); /* White */
+    cairo_rectangle (cr,
+		     BORDER,     BORDER,
+		     LINE_WIDTH, SIZE - 2 * BORDER);
+    cairo_fill (cr);
+    
+    return CAIRO_TEST_SUCCESS;
+
+}
+
+int
+main (void)
+{
+    return cairo_test (&test, draw);
+}
diff --git a/test/self-copy-ref.png b/test/self-copy-ref.png
new file mode 100644
index 000000000..92a20db64
--- /dev/null
+++ b/test/self-copy-ref.png
diff --git a/test/self-copy.c b/test/self-copy.c
new file mode 100644
index 000000000..abb132711
--- /dev/null
+++ b/test/self-copy.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright © 2005 Red Hat, Inc.
+ *
+ * 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
+ * Red Hat, Inc. not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Red Hat, Inc. makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL RED HAT, INC. 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: Owen Taylor <otaylor@redhat.com>
+ */
+
+#include <math.h>
+#include "cairo-test.h"
+#include <stdio.h>
+
+#define SIZE 40
+
+cairo_test_t test = {
+    "self-copy",
+    "Test copying from a surface to itself with a clip",
+    SIZE, SIZE
+};
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_pattern_t *pattern;
+    cairo_matrix_t matrix;
+    
+    /* Paint a diagonal division as a test image */
+    cairo_set_source_rgb (cr, 1, 1, 1);	/* White */
+    cairo_paint (cr);
+
+    cairo_move_to (cr, SIZE,    0);
+    cairo_line_to (cr, SIZE, SIZE);
+    cairo_line_to (cr, 0,    SIZE);
+
+    cairo_set_source_rgb (cr, 0, 0, 0);
+    cairo_fill (cr);
+
+    /* Create a pattern with the target surface as the source,
+     * offset by SIZE/2
+     */
+    pattern = cairo_pattern_create_for_surface (cairo_get_target_surface (cr));
+    
+    cairo_matrix_init_translate (&matrix, - SIZE / 2, - SIZE / 2);
+    cairo_pattern_set_matrix (pattern, &matrix);
+    
+    cairo_set_source (cr, pattern);
+    cairo_pattern_destroy (pattern);
+
+    /* Copy two rectangles from the upper-left quarter of the image to
+     * the lower right.  It will work if we use cairo_fill(), but the
+     * cairo_clip() cairo_paint() combination fails because the clip
+     * on the surface as a destination affects it as the source as
+     * well.
+     */
+    cairo_rectangle (cr,
+		     2 * SIZE / 4, 2 * SIZE / 4,
+		     SIZE / 4,     SIZE / 4);
+    cairo_rectangle (cr,
+		     3 * SIZE / 4, 3 * SIZE / 4,
+		     SIZE / 4,     SIZE / 4);
+    cairo_clip (cr);
+    cairo_paint (cr);
+
+    return CAIRO_TEST_SUCCESS;
+
+}
+
+int
+main (void)
+{
+    return cairo_test_expect_failure (&test, draw,
+				      "copying from a surface to itself doesn't handle clipping properly");
+}
diff --git a/test/source-clip-ref.png b/test/source-clip-ref.png
new file mode 100644
index 000000000..8df2bff97
--- /dev/null
+++ b/test/source-clip-ref.png
diff --git a/test/source-clip.c b/test/source-clip.c
new file mode 100644
index 000000000..ec4c68f6c
--- /dev/null
+++ b/test/source-clip.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright © 2005 Red Hat, Inc.
+ *
+ * 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
+ * Red Hat, Inc. not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Red Hat, Inc. makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL RED HAT, INC. 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: Owen Taylor <otaylor@redhat.com>
+ */
+
+#include <math.h>
+#include "cairo-test.h"
+#include <stdio.h>
+
+#define SIZE 50
+
+cairo_test_t test = {
+    "source-clip",
+    "Test using a surface with an active clip as a source",
+    SIZE, SIZE
+};
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_pattern_t *pattern;
+    cairo_surface_t *source_surface;
+    cairo_t *cr2;
+
+    source_surface = cairo_surface_create_similar (cairo_get_target_surface (cr),
+						   CAIRO_FORMAT_ARGB32,
+						   SIZE, SIZE);
+
+    cr2 = cairo_create ();
+    cairo_set_target_surface (cr2, source_surface);
+
+    /* Fill the source surface with solid black */
+    cairo_set_source_rgb (cr2, 0, 0, 0);
+    cairo_paint (cr2);
+
+    /* Now leave a clip in place */
+    cairo_rectangle (cr2,
+		     SIZE / 4, SIZE / 4,
+		     SIZE / 2, SIZE / 2);
+    cairo_clip (cr2);
+
+    /* Fill the destination surface with solid white */
+    cairo_set_source_rgb (cr, 1, 1, 1);
+    cairo_paint (cr);
+
+    /* Now draw the source surface onto the destination surface */
+    pattern = cairo_pattern_create_for_surface (source_surface);
+    cairo_set_source (cr, pattern);
+    cairo_paint (cr);
+
+    /* As the clip shouldn't matter, the result should be solid black */
+    
+    cairo_destroy (cr2);
+    cairo_pattern_destroy (pattern);
+    cairo_surface_destroy (source_surface);
+
+    return CAIRO_TEST_SUCCESS;
+
+}
+
+int
+main (void)
+{
+    return cairo_test (&test, draw);
+}