[cairo-commit] 3 commits - src/cairo-traps.c test/.gitignore
test/Makefile.am test/radial-gradient.c test/skew-extreme.c
test/skew-extreme-ref.png
Carl Worth
cworth at kemper.freedesktop.org
Wed Mar 14 15:07:07 PDT 2007
src/cairo-traps.c | 101 +++++++++++++++++++++---------------
test/.gitignore | 1
test/Makefile.am | 2
test/radial-gradient.c | 3 -
test/skew-extreme-ref.png |binary
test/skew-extreme.c | 126 ++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 188 insertions(+), 45 deletions(-)
New commits:
diff-tree 1f3a5b4e1283cc0e55f7ea6baca6d0fe67fd14b1 (from 0a6ae06c35d99e5e8397c58ee94291e7ee45eb4e)
Author: Carl Worth <cworth at cworth.org>
Date: Tue Mar 13 17:42:39 2007 -0700
Fix bugs in _cairo_traps_tessellate_convex_quad
The previous code was not handling all cases correctly, (yes,
even something as simple as a quadrilateral can exhibit a
remarkably large number of different cases when tessellation
is attempted).
This fix now introduces slope comparison which handles several
cases that were mis-handled with the previous implementation which
only used independent sorting of the X and Y values of the
coordinates.
This fixes the skew-extreme test case and the bug reported here:
Skew transforms were broken by the cairo update in December
https://bugzilla.mozilla.org/show_bug.cgi?id=373632
diff --git a/src/cairo-traps.c b/src/cairo-traps.c
index b767db8..33e6447 100644
--- a/src/cairo-traps.c
+++ b/src/cairo-traps.c
@@ -380,6 +380,8 @@ _cairo_traps_tessellate_convex_quad (cai
{
int a, b, c, d;
int i;
+ cairo_slope_t ab, ad;
+ cairo_bool_t b_left_of_d;
/* Choose a as a point with minimal y */
a = 0;
@@ -399,24 +401,39 @@ _cairo_traps_tessellate_convex_quad (cai
}
/* Without freedom left to choose anything else, we have four
- * cases to tessellate which we can distinguish by comparing c.y
- * to d.y and then by comparing b.x to d.x. And then for any of
- * these cases there is a trivial way to emit three
- * trapezoids. The 4 cases and their trapezoids are described and
- * implemented below:
- */
- if (q[c].y < q[d].y) {
- if (q[b].x < q[d].x) {
- /* c.y < d.y && b.x < d.x
+ * cases to tessellate.
+ *
+ * First, we have to determine the Y-axis sort of the four
+ * vertices, (either abcd or abdc). After that we need to detemine
+ * which edges will be "left" and which will be "right" in the
+ * resulting trapezoids. This can be determined by computing a
+ * slope comparison of ab and ad to determine if b is left of d or
+ * not.
+ *
+ * Note that "left of" here is in the sense of which edges should
+ * be the left vs. right edges of the trapezoid. In particular, b
+ * left of d does *not* mean that b.x is less than d.x.
+ *
+ * This should hopefully be made clear in the lame ASCII art
+ * below. Since the same slope comparison is used in all cases, we
+ * compute it before testing for the Y-value sort. */
+ _cairo_slope_init (&ab, &q[a], &q[b]);
+ _cairo_slope_init (&ad, &q[a], &q[d]);
+
+ b_left_of_d = (_cairo_slope_compare (&ab, &ad) > 0);
+
+ if (q[c].y <= q[d].y) {
+ if (b_left_of_d) {
+ /* Y-sort is abcd and b is left of d, (slope(ab) > slope (ad))
*
- * top bot left right
- * a
- * / | a.y b.y ab ad
- * b |
- * | | b.y c.y bc ad
- * c |
- * \ | c.y d.y cd ad
- * d
+ * top bot left right
+ * _a a a
+ * / / /| |\ a.y b.y ab ad
+ * b / b | b \
+ * / / | | \ \ b.y c.y bc ad
+ * c / c | c \
+ * | / \| \ \ c.y d.y cd ad
+ * d d d
*/
_cairo_traps_add_trap_from_points (traps,
q[a].y, q[b].y,
@@ -428,15 +445,15 @@ _cairo_traps_tessellate_convex_quad (cai
q[c].y, q[d].y,
q[c], q[d], q[a], q[d]);
} else {
- /* c.y < d.y && b.x >= d.x
+ /* Y-sort is abcd and b is right of d, (slope(ab) <= slope (ad))
*
- * a
- * | \ a.y b.y ad ab
- * | b
- * | | b.y c.y ad bc
- * | c
- * | / c.y d.y ad cd
- * d
+ * a a a_
+ * /| |\ \ \ a.y b.y ad ab
+ * / b | b \ b
+ * / / | | \ \ b.y c.y ad bc
+ * / c | c \ c
+ * / / |/ \ | c.y d.y ad cd
+ * d d d
*/
_cairo_traps_add_trap_from_points (traps,
q[a].y, q[b].y,
@@ -449,16 +466,16 @@ _cairo_traps_tessellate_convex_quad (cai
q[a], q[d], q[c], q[d]);
}
} else {
- if (q[b].x < q[d].x) {
- /* c.y >= d.y && b.x < d.x
+ if (b_left_of_d) {
+ /* Y-sort is abdc and b is left of d, (slope (ab) > slope (ad))
*
- * a
- * / \ a.y b.y ab ad
- * b \
- * \ \ b.y d.y bc ad
- * \ d
- * \ / d.y c.y bc dc
- * c
+ * a a a
+ * // / \ |\ a.y b.y ab ad
+ * /b/ b \ b \
+ * / / \ \ \ \ b.y d.y bc ad
+ * /d/ \ d \ d
+ * // \ / \| d.y c.y bc dc
+ * c c c
*/
_cairo_traps_add_trap_from_points (traps,
q[a].y, q[b].y,
@@ -470,15 +487,15 @@ _cairo_traps_tessellate_convex_quad (cai
q[d].y, q[c].y,
q[b], q[c], q[d], q[c]);
} else {
- /* c.y >= d.y && b.x >= d.x
+ /* Y-sort is abdc and b is right of d, (slope (ab) <= slope (ad))
*
- * a
- * / \ a.y b.y ad ab
- * / b
- * / / b.y d.y ad bc
- * d /
- * \ / d.y c.y dc bc
- * c
+ * a a a
+ * /| / \ \\ a.y b.y ad ab
+ * / b / b \b\
+ * / / / / \ \ b.y d.y ad bc
+ * d / d / \d\
+ * |/ \ / \\ d.y c.y dc bc
+ * c c c
*/
_cairo_traps_add_trap_from_points (traps,
q[a].y, q[b].y,
diff-tree 0a6ae06c35d99e5e8397c58ee94291e7ee45eb4e (from 40b6d8842e1bcb5fbb3a7dffd0c05b7d3bf6cc6b)
Author: Carl Worth <cworth at cworth.org>
Date: Tue Mar 13 17:39:48 2007 -0700
Add new skew-extreme test case.
This test currently fails, demonstrating the bug reported here:
Skew transforms were broken by the cairo update in December
https://bugzilla.mozilla.org/show_bug.cgi?id=373632
diff --git a/test/.gitignore b/test/.gitignore
index e514f5d..6c4adfc 100644
--- a/test/.gitignore
+++ b/test/.gitignore
@@ -121,6 +121,7 @@ self-intersecting
set-source
show-glyphs-many
show-text-current-point
+skew-extreme
source-clip
source-clip-scale
source-surface-scale-paint
diff --git a/test/Makefile.am b/test/Makefile.am
index 05f3620..54928cf 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -85,6 +85,7 @@ self-copy \
self-intersecting \
set-source \
show-text-current-point \
+skew-extreme \
source-clip \
source-clip-scale \
source-surface-scale-paint \
diff --git a/test/skew-extreme-ref.png b/test/skew-extreme-ref.png
new file mode 100644
index 0000000..1408395
Binary files /dev/null and b/test/skew-extreme-ref.png differ
diff --git a/test/skew-extreme.c b/test/skew-extreme.c
new file mode 100644
index 0000000..919937b
--- /dev/null
+++ b/test/skew-extreme.c
@@ -0,0 +1,126 @@
+/*
+ * Copyright © 2007 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Author: Carl Worth <cworth at cworth.org>
+ */
+
+#include "cairo-test.h"
+
+/* This test case is designed to exercise the following bug:
+ *
+ * Skew transforms were broken by the cairo update in December
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=373632
+ *
+ * What's happening is that the rectangle is being skewed into the
+ * following shape:
+ *
+ * a__b
+ * \ \
+ * \ \
+ * \ \
+ * \ \
+ * \ \
+ * d\_\c
+ *
+ * and the bug is that _cairo_traps_tessellate_convex_quad is
+ * comparing b.x as less then d.x and therfore determining that the bc
+ * edge is left of the ad edge. The fix is simply to compare c.x to
+ * d.x instead of b.x to d.x .
+ */
+
+#define PAD 2
+#define LINE_WIDTH 10
+#define LINE_LENGTH (2 * LINE_WIDTH)
+#define SKEW_FACTOR 5.0
+#define WIDTH (PAD + (LINE_LENGTH * SKEW_FACTOR) + LINE_WIDTH + PAD)
+#define HEIGHT (PAD + LINE_WIDTH + (LINE_LENGTH * SKEW_FACTOR) + LINE_WIDTH + PAD)
+
+static cairo_test_draw_function_t draw;
+
+cairo_test_t test = {
+ "skew-extreme",
+ "Test cases of extreme skew.",
+ WIDTH, HEIGHT,
+ draw
+};
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+ /* We draw in the default black, so paint white first. */
+ cairo_save (cr);
+ cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */
+ cairo_paint (cr);
+ cairo_restore (cr);
+
+ cairo_translate (cr, PAD, PAD);
+
+ cairo_set_line_width (cr, LINE_WIDTH);
+ cairo_set_line_cap (cr, CAIRO_LINE_CAP_BUTT);
+
+ cairo_save (cr);
+ {
+ cairo_matrix_t skew_x = {
+ 1.0, 0.0,
+ SKEW_FACTOR, 1.0,
+ 0.0, 0.0
+ };
+
+ cairo_translate (cr, LINE_WIDTH / 2.0, 0.0);
+
+ cairo_transform (cr, &skew_x);
+
+ cairo_move_to (cr, 0.0, 0.0);
+ cairo_line_to (cr, 0.0, LINE_LENGTH);
+ cairo_stroke (cr);
+ }
+ cairo_restore (cr);
+
+ cairo_translate (cr, 0.0, LINE_WIDTH);
+
+ cairo_save (cr);
+ {
+ cairo_matrix_t skew_y = {
+ 1.0, SKEW_FACTOR,
+ 0.0, 1.0,
+ 0.0, 0.0
+ };
+
+ cairo_translate (cr, 0.0, LINE_WIDTH / 2.0);
+
+ cairo_transform (cr, &skew_y);
+
+ cairo_move_to (cr, 0.0, 0.0);
+ cairo_line_to (cr, LINE_LENGTH, 0.0);
+ cairo_stroke (cr);
+ }
+ cairo_restore (cr);
+
+ return CAIRO_TEST_SUCCESS;
+}
+
+int
+main (void)
+{
+ return cairo_test (&test);
+}
diff-tree 40b6d8842e1bcb5fbb3a7dffd0c05b7d3bf6cc6b (from e803e2e69ba02a1db316c97eb9a8d386709380e2)
Author: Carl Worth <cworth at cworth.org>
Date: Tue Mar 13 13:07:42 2007 -0700
Remove radial-gradient test from XFAIL list
This test has not been failing since the fix in:
772edc9133d41dfd667ae5915dfa6ace0bcbfd0d
So get rid of the '1 unexpected passes' complaint.
diff --git a/test/Makefile.am b/test/Makefile.am
index ea4787c..05f3620 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -409,7 +409,6 @@ extend-pad \
filter-nearest-offset \
ft-text-vertical-layout-type1 \
long-lines \
-radial-gradient \
self-intersecting \
surface-pattern \
surface-pattern-scale-down \
diff --git a/test/radial-gradient.c b/test/radial-gradient.c
index d78c430..1207943 100644
--- a/test/radial-gradient.c
+++ b/test/radial-gradient.c
@@ -36,8 +36,7 @@ static cairo_test_draw_function_t draw;
cairo_test_t test = {
"radial-gradient",
- "Simple test of radial gradients"
- "\nCurrently failing EXTEND_REFLECT with non-zero inner radius for SVG backend",
+ "Simple test of radial gradients",
WIDTH, HEIGHT,
draw
};
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