drm/rect: Handle rounding errors in drm_rect_clip_scaled, v3.
Instead of relying on a scale which may increase rounding errors,
clip src by doing: src * (dst - clip) / dst and rounding the result
away from 1, so the new coordinates get closer to 1. We won't need
to fix up with a magic macro afterwards, because our scaling factor
will never go to the other side of 1.
Changes since v1:
- Adjust dst immediately, else drm_rect_width/height on dst gives bogus
results.
Change since v2:
- Get rid of macros and use 64-bits math.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[mlankhorst: Add Villes comment, and rename newsrc to tmp. (Ville)]
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180503112217.37292-3-maarten.lankhorst@linux.intel.com
diff --git a/include/drm/drm_rect.h b/include/drm/drm_rect.h
index 44bc122..6c54544 100644
--- a/include/drm/drm_rect.h
+++ b/include/drm/drm_rect.h
@@ -175,8 +175,7 @@ static inline bool drm_rect_equals(const struct drm_rect *r1,
bool drm_rect_intersect(struct drm_rect *r, const struct drm_rect *clip);
bool drm_rect_clip_scaled(struct drm_rect *src, struct drm_rect *dst,
- const struct drm_rect *clip,
- int hscale, int vscale);
+ const struct drm_rect *clip);
int drm_rect_calc_hscale(const struct drm_rect *src,
const struct drm_rect *dst,
int min_hscale, int max_hscale);