Linear: Optimize for horizontal gradients

If the gradient is horizontal, we can reuse the same scanline over and
over. Add support for this optimization to
_pixman_linear_gradient_iter_init().

diff --git a/pixman/pixman-linear-gradient.c b/pixman/pixman-linear-gradient.c
index c657243..66d37ab 100644 (file)
--- a/pixman/pixman-linear-gradient.c
+++ b/pixman/pixman-linear-gradient.c
@@ -245,10 +245,23 @@ _pixman_linear_gradient_iter_init (pixman_image_t *image,
                                   uint8_t        *buffer,
                                   iter_flags_t    flags)
 {
-    if (flags & ITER_NARROW)
-       iter->get_scanline = linear_get_scanline_narrow;
+    if (linear_gradient_classify (image, x, y, width, height) ==
+       SOURCE_IMAGE_CLASS_HORIZONTAL)
+    {
+       if (flags & ITER_NARROW)
+           linear_get_scanline_narrow (iter, NULL);
+       else
+           linear_get_scanline_wide (iter, NULL);
+
+       iter->get_scanline = _pixman_iter_get_scanline_noop;
+    }
     else
-       iter->get_scanline = linear_get_scanline_wide;
+    {
+       if (flags & ITER_NARROW)
+           iter->get_scanline = linear_get_scanline_narrow;
+       else
+           iter->get_scanline = linear_get_scanline_wide;
+    }
 }
 
 PIXMAN_EXPORT pixman_image_t *