From 4c81600fc9ea5938a11b0df9c6ff3a97d1bda50b Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Sat, 5 Dec 2020 14:20:17 -0500
Subject: [PATCH] Special-case rects for strokes

In many cases, the outline of a rectangle is just
two rectangles.
---
 gsk/gskcontour.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/gsk/gskcontour.c b/gsk/gskcontour.c
index cdd9adc754..29f50f50fd 100644
--- a/gsk/gskcontour.c
+++ b/gsk/gskcontour.c
@@ -495,11 +495,43 @@ gsk_rect_contour_get_stroke_bounds (const GskContour       *contour,
   return TRUE;
 }
 
+static gboolean
+stroke_is_simple (GskStroke *stroke)
+{
+  if (stroke->line_join != GSK_LINE_JOIN_MITER &&
+      stroke->line_join != GSK_LINE_JOIN_MITER_CLIP)
+    return FALSE;
+
+  if (stroke->miter_limit < 1.5)
+    return FALSE;
+
+  if (stroke->dash_length != 0)
+    return FALSE;
+
+  return TRUE;
+}
+
 static void
 gsk_rect_contour_add_stroke (const GskContour *contour,
                              GskPathBuilder   *builder,
                              GskStroke        *stroke)
 {
+  const GskRectContour *self = (const GskRectContour *) contour;
+
+  if (stroke_is_simple (stroke))
+    {
+      graphene_rect_t rect;
+
+      graphene_rect_init (&rect, self->x, self->y, self->width, self->height);
+
+      graphene_rect_inset (&rect, stroke->line_width / 2, stroke->line_width / 2);
+      gsk_path_builder_add_rect (builder, &rect);
+
+      graphene_rect_inset (&rect, - stroke->line_width, - stroke->line_width);
+      rect.origin.x += rect.size.width;
+      rect.size.width = - rect.size.width;
+      gsk_path_builder_add_rect (builder, &rect);
+    }
 }
 
 static const GskContourClass GSK_RECT_CONTOUR_CLASS =