[PATCH 0/1] MR6662: win32u/zibdrv: Round get_arc_max_points() value to a multiple of 4.

[Aida Jonikienė]

This seems like a weird solution to me (so I'm not sure if the tests pass)

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/6662

[PATCH 1/1] win32u/dibdrv: Round get_arc_max_points() value to a multiple of 4.

[Aida Jonikienė]

From: Aida Jonikienė <aidas957(a)gmail.com>

Fixes: 5924ab4c515 ("win32u: Implement drawing transformed round rectangles.")
Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=57306
---
 dlls/win32u/dibdrv/graphics.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/dlls/win32u/dibdrv/graphics.c b/dlls/win32u/dibdrv/graphics.c
index 414737fa8ca..933ecc2bacb 100644
--- a/dlls/win32u/dibdrv/graphics.c
+++ b/dlls/win32u/dibdrv/graphics.c
@@ -367,12 +367,13 @@ static unsigned int get_arc_max_points( DC *dc, const RECT *rect )
         {rect->right, rect->bottom},
         {rect->right, rect->top}
     };
-    unsigned int width, height;
+    unsigned int width, height, points;
 
     lp_to_dp( dc, pts, 4 );
     width = max( abs( pts[2].x - pts[0].x ), abs( pts[3].x - pts[1].x ));
     height = max( abs( pts[2].y - pts[0].y ), abs( pts[3].y - pts[1].y ));
-    return (width + height) * 3;
+    points = (width * height) * 3;
+    return (points % 4) == 0 ? points : points + (4 - ( points % 4 ));
 }
 
 /* backend for arc functions; extra_lines is -1 for ArcTo, 0 for Arc, 1 for Chord, 2 for Pie */
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/6662

[Piotr Caban (＠piotr)]

Piotr Caban (@piotr) commented about dlls/win32u/dibdrv/graphics.c:
> {rect->right, rect->bottom},
>          {rect->right, rect->top}
>      };
> -    unsigned int width, height;
> +    unsigned int width, height, points;
>
> lp_to_dp( dc, pts, 4 );
>      width = max( abs( pts[2].x - pts[0].x ), abs( pts[3].x - pts[1].x ));
>      height = max( abs( pts[2].y - pts[0].y ), abs( pts[3].y - pts[1].y ));
> -    return (width + height) * 3;
> +    points = (width * height) * 3;
> +    return (points % 4) == 0 ? points : points + (4 - ( points % 4 ));

`(points + 3) & ~3` is probably easier to read.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/6662#note_84866

[Piotr Caban (＠piotr)]

Piotr Caban (@piotr) commented about dlls/win32u/dibdrv/graphics.c:
> {rect->right, rect->bottom},
>          {rect->right, rect->top}
>      };
> -    unsigned int width, height;
> +    unsigned int width, height, points;
>
> lp_to_dp( dc, pts, 4 );
>      width = max( abs( pts[2].x - pts[0].x ), abs( pts[3].x - pts[1].x ));
>      height = max( abs( pts[2].y - pts[0].y ), abs( pts[3].y - pts[1].y ));
> -    return (width + height) * 3;
> +    points = (width * height) * 3;

You're changing `width + height` to `width * height`, is it intentional?

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/6662#note_84865