[Pixman] [PATCH 2/3] gradient-walker: Fix wraparound when using NONE/PAD

[Andrea Canciani]

When the pos parameter cannot be represented as int32_t (i.e. it is
outside [INT32_MIN, INT32_MAX]), truncating it to 32 bits can make it
belong to the [0,1] range.

For the NONE and PAD repeat modes, this can result in an incorrect
color.
---
 pixman/pixman-gradient-walker.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/pixman/pixman-gradient-walker.c b/pixman/pixman-gradient-walker.c
index ae917e6..e0aa3a4 100644
--- a/pixman/pixman-gradient-walker.c
+++ b/pixman/pixman-gradient-walker.c
@@ -65,7 +65,14 @@ gradient_walker_reset (pixman_gradient_walker_t *walker,
     }
     else
     {
-	x = pos;
+	/* Clamp to [-1,2] to make sure that the position can be
+	 * represented as int32_t without affecting the result. */
+	if (pos < -pixman_fixed_1)
+	    x = -pixman_fixed_1;
+	else if (pos > pixman_int_to_fixed (2))
+	    x = pixman_int_to_fixed (2);
+	else
+	    x = pos;
     }
     
     for (n = 0; n < count; n++)
-- 
1.7.5.4