test: Add extended-blend-solid tests

Unify extended-blend* tests and add a solid pattern version, which
crashes on the win32 backend.

Bug pointed out by Peter Frentrup <peter_frentrup@gmx.de> in
http://lists.cairographics.org/archives/cairo/2011-April/021908.html

1 files changed, 132 insertions, 38 deletions

diff --git a/test/extended-blend.c b/test/extended-blend.c
index cd2b06b99..45e0e4804 100644
--- a/test/extended-blend.c
+++ b/test/extended-blend.c
@@ -35,29 +35,97 @@
 #define START_OPERATOR	CAIRO_OPERATOR_MULTIPLY
 #define STOP_OPERATOR	CAIRO_OPERATOR_HSL_LUMINOSITY
 
+#define SIZE 5
+#define COUNT 4
+#define FULL_WIDTH  ((STEPS + 1) * COUNT - 1)
+#define FULL_HEIGHT ((COUNT + STOP_OPERATOR - START_OPERATOR) / COUNT) * (STEPS + 1)
+
+static void
+set_solid_pattern (cairo_t *cr,
+		   int step,
+		   cairo_bool_t bg,
+		   cairo_bool_t alpha)
+{
+    double c, a;
+
+    a = ((double) step) / (STEPS - 1);
+    if (alpha) {
+	c = 1;
+    } else {
+	c = a;
+	a = 1;
+    }
+
+    if (bg) /* draw a yellow background fading in using discrete steps */
+	cairo_set_source_rgba (cr, c, c, 0, a);
+    else /* draw a teal foreground pattern fading in using discrete steps */
+	cairo_set_source_rgba (cr, 0, c, c, a);
+}
+
+/* expects a STEP*STEP pixel rectangle */
 static void
-create_patterns (cairo_t *bg, cairo_t *fg)
+do_blend_solid (cairo_t *cr, cairo_operator_t op, cairo_bool_t alpha)
 {
     int x;
 
+    cairo_save (cr);
+    cairo_scale (cr, SIZE, SIZE);
+
+    /* not using CAIRO_OPERATOR_SOURCE here, it triggers a librsvg bug */
+    cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
+    for (x = 0; x < STEPS; x++) {
+	/* draw the background using discrete steps */
+	set_solid_pattern (cr, x, TRUE, alpha);
+	cairo_rectangle (cr, x, 0, 1, STEPS);
+	cairo_fill (cr);
+    }
+
+    cairo_set_operator (cr, op);
     for (x = 0; x < STEPS; x++) {
-	double i = (double) x / (STEPS - 1);
-	/* draw a yellow background fading in using discrete steps */
-	cairo_set_source_rgba (bg, i, i, 0, 1);
-	cairo_rectangle (bg, x, 0, 1, STEPS);
-	cairo_fill (bg);
-
-	/* draw an orthogonal teal pattern fading in using discrete steps */
-	cairo_set_source_rgba (fg, 0, i, i, 1);
-	cairo_rectangle (fg, 0, x, STEPS, 1);
-	cairo_fill (fg);
+	/* draw an orthogonal foreground pattern using discrete steps */
+	set_solid_pattern (cr, x, FALSE, alpha);
+	cairo_rectangle (cr, 0, x, STEPS, 1);
+	cairo_fill (cr);
     }
+
+    cairo_restore (cr);
+}
+
+static void
+create_patterns (cairo_t *cr,
+		 cairo_surface_t **bg,
+		 cairo_surface_t **fg,
+		 cairo_bool_t alpha)
+{
+    cairo_t *bgcr, *fgcr;
+
+    *bg = cairo_surface_create_similar (cairo_get_target (cr),
+					CAIRO_CONTENT_COLOR_ALPHA,
+					SIZE * STEPS,
+					SIZE * STEPS);
+    *fg = cairo_surface_create_similar (cairo_get_target (cr),
+					CAIRO_CONTENT_COLOR_ALPHA,
+					SIZE * STEPS,
+					SIZE * STEPS);
+
+    bgcr = cairo_create (*bg);
+    fgcr = cairo_create (*fg);
+
+    do_blend_solid (bgcr, CAIRO_OPERATOR_DEST, alpha);
+    do_blend_solid (fgcr, CAIRO_OPERATOR_SOURCE, alpha);
+
+    cairo_destroy (bgcr);
+    cairo_destroy (fgcr);
 }
 
 /* expects a STEP*STEP pixel rectangle */
 static void
-do_blend (cairo_t *cr, cairo_operator_t op, cairo_surface_t *bg, cairo_surface_t *fg)
+do_blend (cairo_t *cr, cairo_operator_t op, cairo_bool_t alpha)
 {
+    cairo_surface_t *bg, *fg;
+
+    create_patterns (cr, &bg, &fg, alpha);
+
     /* not using CAIRO_OPERATOR_SOURCE here, it triggers a librsvg bug */
     cairo_set_operator (cr, CAIRO_OPERATOR_OVER);
     cairo_set_source_surface (cr, bg, 0, 0);
@@ -66,52 +134,78 @@ do_blend (cairo_t *cr, cairo_operator_t op, cairo_surface_t *bg, cairo_surface_t
     cairo_set_operator (cr, op);
     cairo_set_source_surface (cr, fg, 0, 0);
     cairo_paint (cr);
-}
 
-#define SIZE 5
-#define COUNT 4
-#define FULL_WIDTH  ((STEPS + 1) * COUNT - 1)
-#define FULL_HEIGHT ((COUNT + STOP_OPERATOR - START_OPERATOR) / COUNT) * (STEPS + 1)
+    cairo_surface_destroy (fg);
+    cairo_surface_destroy (bg);
+}
 
 static cairo_test_status_t
-draw (cairo_t *cr, int width, int height)
+draw (cairo_t *cr, cairo_bool_t alpha,
+      void (*blend)(cairo_t *, cairo_operator_t, cairo_bool_t))
 {
     size_t i = 0;
     cairo_operator_t op;
-    cairo_t *bgcr, *fgcr;
-    cairo_surface_t *bg, *fg;
-
-    bg = cairo_surface_create_similar (cairo_get_target (cr), 
-	    CAIRO_CONTENT_COLOR_ALPHA, SIZE * STEPS, SIZE * STEPS);
-    fg = cairo_surface_create_similar (cairo_get_target (cr), 
-	    CAIRO_CONTENT_COLOR_ALPHA, SIZE * STEPS, SIZE * STEPS);
-    bgcr = cairo_create (bg);
-    fgcr = cairo_create (fg);
-    cairo_scale (bgcr, SIZE, SIZE);
-    cairo_scale (fgcr, SIZE, SIZE);
-    create_patterns (bgcr, fgcr);
-    cairo_destroy (bgcr);
-    cairo_destroy (fgcr);
 
     for (op = START_OPERATOR; op <= STOP_OPERATOR; op++, i++) {
 	cairo_save (cr);
-	cairo_translate (cr, 
+	cairo_translate (cr,
 		SIZE * (STEPS + 1) * (i % COUNT),
 		SIZE * (STEPS + 1) * (i / COUNT));
-	do_blend (cr, op, bg, fg);
+	blend (cr, op, alpha);
 	cairo_restore (cr);
     }
 
-    cairo_surface_destroy (fg);
-    cairo_surface_destroy (bg);
-
     return CAIRO_TEST_SUCCESS;
 }
 
+static cairo_test_status_t
+draw_extended_blend (cairo_t *cr, int width, int height)
+{
+    return draw (cr, FALSE, do_blend);
+}
+
+static cairo_test_status_t
+draw_extended_blend_alpha (cairo_t *cr, int width, int height)
+{
+    return draw (cr, TRUE, do_blend);
+}
+
+static cairo_test_status_t
+draw_extended_blend_solid (cairo_t *cr, int width, int height)
+{
+    return draw (cr, FALSE, do_blend_solid);
+}
+
+static cairo_test_status_t
+draw_extended_blend_solid_alpha (cairo_t *cr, int width, int height)
+{
+    return draw (cr, TRUE, do_blend_solid);
+}
+
 CAIRO_TEST (extended_blend,
 	    "Tests extended blend modes without alpha",
 	    "operator", /* keywords */
 	    NULL, /* requirements */
 	    FULL_WIDTH * SIZE, FULL_HEIGHT * SIZE,
-	    NULL, draw)
+	    NULL, draw_extended_blend)
 
+CAIRO_TEST (extended_blend_alpha,
+	    "Tests extended blend modes with alpha",
+	    "operator", /* keywords */
+	    NULL, /* requirements */
+	    FULL_WIDTH * SIZE, FULL_HEIGHT * SIZE,
+	    NULL, draw_extended_blend_alpha)
+
+CAIRO_TEST (extended_blend_solid,
+	    "Tests extended blend modes on solid patterns without alpha",
+	    "operator", /* keywords */
+	    NULL, /* requirements */
+	    FULL_WIDTH * SIZE, FULL_HEIGHT * SIZE,
+	    NULL, draw_extended_blend_solid)
+
+CAIRO_TEST (extended_blend_solid_alpha,
+	    "Tests extended blend modes on solid patterns with alpha",
+	    "operator", /* keywords */
+	    NULL, /* requirements */
+	    FULL_WIDTH * SIZE, FULL_HEIGHT * SIZE,
+	    NULL, draw_extended_blend_solid_alpha)