[Pixman] [PATCH] Fix bilinear filter computation in wide pipeline

[basile-pixman at clement.pm]

From: Basile Clement <basile-pixman at clement.pm>

The recently introduced wide pipeline for filters has a typo which
causes it to improperly compute bilinear interpolation positions,
causing various glitches when enabled.

This patch uses the proper computation for bilinear interpolation in the
wide pipeline.  It also makes related `if` statements conformant to the
CODING_STYLE:

* If a substatement spans multiple lines, then there must be braces
  around it.

* If one substatement of an if statement has braces, then the other
  must too.
---
 pixman/pixman-bits-image.c | 9 +++++++++
 pixman/pixman-inlines.h    | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/pixman/pixman-bits-image.c b/pixman/pixman-bits-image.c
index 564789e..7bc2ba8 100644
--- a/pixman/pixman-bits-image.c
+++ b/pixman/pixman-bits-image.c
@@ -432,29 +432,38 @@ bits_image_fetch_pixel_filtered (bits_image_t  *image,
 
     case PIXMAN_FILTER_CONVOLUTION:
 	if (wide)
+	{
 	    bits_image_fetch_pixel_convolution (image, x, y,
 						get_pixel, out,
 						accum_float,
 						reduce_float);
+	}
 	else
+	{
 	    bits_image_fetch_pixel_convolution (image, x, y,
 						get_pixel, out,
 						accum_32, reduce_32);
+	}
 	break;
 
     case PIXMAN_FILTER_SEPARABLE_CONVOLUTION:
 	if (wide)
+	{
 	    bits_image_fetch_pixel_separable_convolution (image, x, y,
 							  get_pixel, out,
 							  accum_float,
 							  reduce_float);
+	}
 	else
+	{
 	    bits_image_fetch_pixel_separable_convolution (image, x, y,
 							  get_pixel, out,
 							  accum_32, reduce_32);
+	}
         break;
 
     default:
+	assert (0);
         break;
     }
 }
diff --git a/pixman/pixman-inlines.h b/pixman/pixman-inlines.h
index 332e208..f785910 100644
--- a/pixman/pixman-inlines.h
+++ b/pixman/pixman-inlines.h
@@ -231,7 +231,7 @@ bilinear_interpolation_float (argb_t tl, argb_t tr,
     argb_t r;
 
     distxy = distx * disty;
-    distxiy = distx - (1.f - distxy);
+    distxiy = distx * (1.f - disty);
     distixy = (1.f - distx) * disty;
     distixiy = (1.f - distx) * (1.f - disty);
 
-- 
2.21.0