[cairo] [PATCH 2/3] test: Test a variety of scales when downscaling

[Bryce W. Harrington]

Downscaling from 96 to 24 is easy since it's an even multiple, so try
scaling by -1 pixel too.

This adds a 1:1 scaling test case as well, which should pass through the
image unchanged.

Signed-off-by: Bryce Harrington <b.harrington at samsung.com>
---
 test/pixman-downscale.c                    |   25 +++++++++++++++++++------
 test/reference/pixman-downscale-24.ref.png |  Bin 0 -> 191 bytes
 test/reference/pixman-downscale-95.ref.png |  Bin 0 -> 285 bytes
 test/reference/pixman-downscale-96.ref.png |  Bin 0 -> 301 bytes
 test/reference/pixman-downscale.ref.png    |  Bin 191 -> 0 bytes
 5 files changed, 19 insertions(+), 6 deletions(-)
 create mode 100644 test/reference/pixman-downscale-24.ref.png
 create mode 100644 test/reference/pixman-downscale-95.ref.png
 create mode 100644 test/reference/pixman-downscale-96.ref.png
 delete mode 100644 test/reference/pixman-downscale.ref.png

diff --git a/test/pixman-downscale.c b/test/pixman-downscale.c
index 0562015..1f8a9b4 100644
--- a/test/pixman-downscale.c
+++ b/test/pixman-downscale.c
@@ -44,13 +44,12 @@ draw (cairo_t *cr, int width, int height)
 
     cairo_set_source_rgb (cr, 1, 1, 1);
     image = cairo_test_create_surface_from_png (ctx, png_filename);
-    x_scale = WIDTH * 1.0 / cairo_image_surface_get_width (image);
-    y_scale = HEIGHT * 1.0 / cairo_image_surface_get_height (image);
+    x_scale = width * 1.0 / cairo_image_surface_get_width (image);
+    y_scale = height * 1.0 / cairo_image_surface_get_height (image);
     scale = fmin(x_scale, y_scale);
 
     cairo_save (cr);
-    cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
-    cairo_pattern_set_filter (cairo_get_source (cr), CAIRO_FILTER_NEAREST);
+    cairo_pattern_set_filter (cairo_get_source (cr), CAIRO_FILTER_FAST);
     cairo_scale (cr, scale, scale);
     cairo_set_source_surface (cr, image, 0, 0);
     cairo_paint (cr);
@@ -60,9 +59,23 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
-CAIRO_TEST (pixman_downscale,
-	    "Exposes errors when downscaling",
+CAIRO_TEST (pixman_downscale_96,
+	    "Tests scaling to equivalent size",
 	    "image, transform, raster", /* keywords */
 	    NULL, /* requirements */
 	    96, 96,
 	    NULL, draw)
+
+CAIRO_TEST (pixman_downscale_95,
+	    "Tests downscaling by a single pixel",
+	    "image, transform, raster", /* keywords */
+	    NULL, /* requirements */
+	    95, 95,
+	    NULL, draw)
+
+CAIRO_TEST (pixman_downscale_24,
+	    "Tests downscaling by an even multiple",
+	    "image, transform, raster", /* keywords */
+	    NULL, /* requirements */
+	    24, 24,
+	    NULL, draw)
diff --git a/test/reference/pixman-downscale-24.ref.png b/test/reference/pixman-downscale-24.ref.png
new file mode 100644
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diff --git a/test/reference/pixman-downscale-95.ref.png b/test/reference/pixman-downscale-95.ref.png
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diff --git a/test/reference/pixman-downscale-96.ref.png b/test/reference/pixman-downscale-96.ref.png
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diff --git a/test/reference/pixman-downscale.ref.png b/test/reference/pixman-downscale.ref.png
deleted file mode 100644
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GIT binary patch
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-- 
1.7.9.5


--
Bryce Harrington
Senior Open Source Developer  -  b.harrington at samsung.com
Open Source Group             -  Samsung Research America