[test] Overlapping glyphs

Add a test case to explicitly check handling of overlapping glyphs.

1 files changed, 123 insertions, 0 deletions

diff --git a/test/overlapping-glyphs.c b/test/overlapping-glyphs.c
new file mode 100644
index 00000000..690a6dd2
--- /dev/null
+++ b/test/overlapping-glyphs.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright © 2009 Chris Wilson
+ *
+ * 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
+ * Chris Wilson not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Chris Wilson makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * CHRIS WILSON DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL CHRIS WILSON 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: Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#include "cairo-test.h"
+
+#include <assert.h>
+
+#define TEXT_SIZE 12
+#define HEIGHT (TEXT_SIZE + 4)
+#define WIDTH 50
+
+#define MAX_GLYPHS 80
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_glyph_t glyphs_stack[MAX_GLYPHS], *glyphs;
+    const char *cairo = "Cairo";
+    const char *giza = "Giza";
+    cairo_text_extents_t cairo_extents;
+    cairo_text_extents_t giza_extents;
+    int count, num_glyphs;
+    double x0, y0;
+
+    /* We draw in the default black, so paint white first. */
+    cairo_set_source_rgb (cr, 1.0, 1.0, 1.0); /* white */
+    cairo_paint (cr);
+
+    cairo_select_font_face (cr, "Bitstream Vera Sans",
+			    CAIRO_FONT_SLANT_NORMAL,
+			    CAIRO_FONT_WEIGHT_NORMAL);
+    cairo_set_font_size (cr, TEXT_SIZE);
+
+    /* We want to overlap two strings, so compute overlapping glyphs.  */
+
+    cairo_text_extents (cr, cairo, &cairo_extents);
+    cairo_text_extents (cr, giza, &giza_extents);
+
+    x0 = WIDTH/2. - (cairo_extents.width/2. + cairo_extents.x_bearing);
+    y0 = HEIGHT/2. - (cairo_extents.height/2. + cairo_extents.y_bearing);
+    glyphs = glyphs_stack;
+    count = MAX_GLYPHS;
+    cairo_scaled_font_text_to_glyphs (cairo_get_scaled_font (cr),
+				      x0, y0,
+				      cairo, strlen (cairo),
+				      &glyphs, &count,
+				      NULL, NULL,
+				      NULL);
+    assert (glyphs == glyphs_stack);
+    num_glyphs = count;
+
+    x0 = WIDTH/2. - (giza_extents.width/2. + giza_extents.x_bearing);
+    y0 = HEIGHT/2. - (giza_extents.height/2. + giza_extents.y_bearing);
+    glyphs = glyphs_stack + count;
+    count = MAX_GLYPHS - count;
+    cairo_scaled_font_text_to_glyphs (cairo_get_scaled_font (cr),
+				      x0, y0,
+				      giza, strlen (giza),
+				      &glyphs, &count,
+				      NULL, NULL,
+				      NULL);
+    assert (glyphs == glyphs_stack + num_glyphs);
+    glyphs = glyphs_stack;
+    num_glyphs += count;
+
+    cairo_set_source_rgba (cr, 0, 0, 0, .5); /* translucent black, gray! */
+    cairo_show_glyphs (cr, glyphs, num_glyphs);
+
+    /* and compare with filling */
+    cairo_translate (cr, 0, HEIGHT);
+    cairo_glyph_path (cr, glyphs, num_glyphs);
+    cairo_fill (cr);
+
+    /* switch to using an unbounded operator for added complexity */
+    cairo_set_operator (cr, CAIRO_OPERATOR_IN);
+
+    cairo_translate (cr, WIDTH, -HEIGHT);
+    cairo_save (cr);
+    cairo_rectangle (cr, 0, 0, WIDTH, HEIGHT);
+    cairo_clip (cr);
+    cairo_show_glyphs (cr, glyphs, num_glyphs);
+    cairo_restore (cr);
+
+    cairo_translate (cr, 0, HEIGHT);
+    cairo_save (cr);
+    cairo_rectangle (cr, 0, 0, WIDTH, HEIGHT);
+    cairo_clip (cr);
+    cairo_glyph_path (cr, glyphs, num_glyphs);
+    cairo_fill (cr);
+    cairo_restore (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (overlapping_glyphs,
+	    "Test handing of overlapping glyphs",
+	    "text, glyphs", /* keywords */
+	    NULL, /* requirements */
+	    2 * WIDTH, 2 * HEIGHT,
+	    NULL, draw)
+