Use floating-point offsets for color stops

Previously we were using the cairo_fixed_t type which meant we've
historically only been using 16 bits of precision for these offsets,
and recently only 8 bits. Meanwhile, all manipulatons of offsets
have been in floating-point anyway, so we might as well store them
that way.

This change also prevents a rendering regression introduced with the
24.8->16.16 change betwen snapshots 1.5.10 and 1.5.12 .

This change affected gradient-rendering details for the clip-operator
and operator-source tests, so the corresponding reference images are
updated here.

1 files changed, 0 insertions, 0 deletions

diff --git a/test/operator-source-ref.png b/test/operator-source-ref.png
index ccd9be3d..8e2f5e61 100644
--- a/test/operator-source-ref.png
+++ b/test/operator-source-ref.png