[gtk/wip/baedert/gl-rework: 1/3] GskTransform: Compute sin/deg of 90deg rotations manually
- From: Timm Bäder <baedert src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gtk/wip/baedert/gl-rework: 1/3] GskTransform: Compute sin/deg of 90deg rotations manually
- Date: Fri, 20 Dec 2019 10:07:30 +0000 (UTC)
commit 6803be0aaeb0e8f12baa03c75ec92b0c8ab140ea
Author: Timm Bäder <mail baedert org>
Date: Thu Dec 19 12:30:08 2019 +0100
GskTransform: Compute sin/deg of 90deg rotations manually
Otherwise we might end up with inaccuracies, e.g. when
gsk_transform_transform_bounds()'ing bounds.
gsk/gsktransform.c | 32 ++++++++++++++++++++++++++++----
1 file changed, 28 insertions(+), 4 deletions(-)
---
diff --git a/gsk/gsktransform.c b/gsk/gsktransform.c
index 330342b5e7..b8e0d681ff 100644
--- a/gsk/gsktransform.c
+++ b/gsk/gsktransform.c
@@ -690,11 +690,35 @@ gsk_rotate_transform_to_matrix (GskTransform *transform,
graphene_matrix_t *out_matrix)
{
GskRotateTransform *self = (GskRotateTransform *) transform;
- float rad, c, s;
+ float c, s;
+
+ if (self->angle == 90.0)
+ {
+ c = 0.0;
+ s = 1.0;
+ }
+ else if (self->angle == 180.0)
+ {
+ c = -1.0;
+ s = 0.0;
+ }
+ else if (self->angle == 270.0)
+ {
+ c = 0.0;
+ s = -1.0;
+ }
+ else if (self->angle == 0.0)
+ {
+ c = 1.0;
+ s = 0.0;
+ }
+ else
+ {
+ const float rad = self->angle * M_PI / 180.f;
+ c = cosf (rad);
+ s = sinf (rad);
+ }
- rad = self->angle * M_PI / 180.f;
- c = cosf (rad);
- s = sinf (rad);
graphene_matrix_init_from_2d (out_matrix,
c, s,
-s, c,
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