[gtk] rendernode: Compute border node colors properly

[Benjamin Otte <otte src gnome org>]

commit 19227d978954fb0d1e19503bd1ab59a6c8731f41
Author: Benjamin Otte <otte redhat com>
Date:   Thu May 2 19:22:43 2019 +0200

    rendernode: Compute border node colors properly
    
    Change the way we compute border color cutoffs to the same method that
    browsers use. This method does not consider the corner sizes at all and
    only looks at border-width.

 gsk/gskrendernodeimpl.c | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)
---
diff --git a/gsk/gskrendernodeimpl.c b/gsk/gskrendernodeimpl.c
index d76c6b6609..f612e3613a 100644
--- a/gsk/gskrendernodeimpl.c
+++ b/gsk/gskrendernodeimpl.c
@@ -580,22 +580,32 @@ gsk_border_node_draw (GskRenderNode *node,
        * Note that the call to cairo_fill() will add the potential final
        * segment by closing the path, so we don't have to care.
        */
-      float dst = MIN (bounds->size.width, bounds->size.height) / 2.0;
       cairo_pattern_t *mesh;
       cairo_matrix_t mat;
+      graphene_point_t tl, br;
+      float scale;
 
       mesh = cairo_pattern_create_mesh ();
       cairo_matrix_init_translate (&mat, -bounds->origin.x, -bounds->origin.y);
       cairo_pattern_set_matrix (mesh, &mat);
 
+      scale = MIN (bounds->size.width / (self->border_width[1] + self->border_width[3]),
+                   bounds->size.height / (self->border_width[0] + self->border_width[2]));
+      graphene_point_init (&tl,
+                           self->border_width[3] * scale,
+                           self->border_width[0] * scale);
+      graphene_point_init (&br,
+                           bounds->size.width - self->border_width[1] * scale,
+                           bounds->size.height - self->border_width[2] * scale);
+
       /* Top */
       if (self->border_width[0] > 0)
         {
           gsk_border_node_mesh_add_patch (mesh,
                                           &self->border_color[0],
                                           0, 0,
-                                          dst * self->border_width[3] / self->border_width[0], dst,
-                                          bounds->size.width - dst * self->border_width[1] / 
self->border_width[0], dst,
+                                          tl.x, tl.y,
+                                          br.x, tl.y,
                                           bounds->size.width, 0);
         }
 
@@ -605,8 +615,8 @@ gsk_border_node_draw (GskRenderNode *node,
           gsk_border_node_mesh_add_patch (mesh,
                                           &self->border_color[1],
                                           bounds->size.width, 0,
-                                          bounds->size.width - dst, dst * self->border_width[0] / 
self->border_width[1],
-                                          bounds->size.width - dst, bounds->size.height - dst * 
self->border_width[2] / self->border_width[1],
+                                          br.x, tl.y,
+                                          br.x, br.y,
                                           bounds->size.width, bounds->size.height);
         }
 
@@ -616,8 +626,8 @@ gsk_border_node_draw (GskRenderNode *node,
           gsk_border_node_mesh_add_patch (mesh,
                                           &self->border_color[2],
                                           0, bounds->size.height,
-                                          dst * self->border_width[3] / self->border_width[2], 
bounds->size.height - dst,
-                                          bounds->size.width - dst * self->border_width[1] / 
self->border_width[2], bounds->size.height - dst,
+                                          tl.x, br.y,
+                                          br.x, br.y,
                                           bounds->size.width, bounds->size.height);
         }
 
@@ -627,8 +637,8 @@ gsk_border_node_draw (GskRenderNode *node,
           gsk_border_node_mesh_add_patch (mesh,
                                           &self->border_color[3],
                                           0, 0,
-                                          dst, dst * self->border_width[0] / self->border_width[3],
-                                          dst, bounds->size.height - dst * self->border_width[2] / 
self->border_width[3],
+                                          tl.x, tl.y,
+                                          tl.x, br.y,
                                           0, bounds->size.height);
         }