render: Only render 4 different arrows

Instead of supporting every angle, just support top, right, bottom and
left and round the angle to one of those directions.

Adwaita overrides arrows anyway and doesn't even look at the angle, so
this should not be a problem.

3 files changed, 55 insertions, 7 deletions

diff --git a/gtk/gtkcssimagebuiltin.c b/gtk/gtkcssimagebuiltin.c
index 1ce28e2117..b80f5686fe 100644
--- a/gtk/gtkcssimagebuiltin.c
+++ b/gtk/gtkcssimagebuiltin.c
@@ -219,6 +219,7 @@ gtk_css_image_builtin_draw_arrow (GtkCssImage            *image,
                                   cairo_t                *cr,
                                   double                  width,
                                   double                  height,
+                                  GtkCssImageBuiltinType  image_type,
                                   const GdkRGBA *         color)
 {
   double line_width;
@@ -226,7 +227,25 @@ gtk_css_image_builtin_draw_arrow (GtkCssImage            *image,
 
   size = MIN (width, height);
 
-  cairo_translate (cr, width / 2.0 + size / 4.0, height / 2.0);
+  cairo_translate (cr, width / 2.0, height / 2.0);
+  switch (image_type)
+  {
+    case GTK_CSS_IMAGE_BUILTIN_ARROW_UP:
+      break;
+    case GTK_CSS_IMAGE_BUILTIN_ARROW_DOWN:
+      cairo_rotate (cr, G_PI);
+      break;
+    case GTK_CSS_IMAGE_BUILTIN_ARROW_LEFT:
+      cairo_rotate (cr, 3 * G_PI / 2);
+      break;
+    case GTK_CSS_IMAGE_BUILTIN_ARROW_RIGHT:
+      cairo_rotate (cr, G_PI / 2);
+      break;
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+  cairo_translate (cr, size / 4.0, 0);
 
   line_width = size / 3.0 / sqrt (2);
   cairo_set_line_width (cr, line_width);
@@ -867,9 +886,13 @@ gtk_css_image_builtin_draw (GtkCssImage            *image,
                                        fg_color, bg_color,
                                        border_color, border_width);
     break;
-  case GTK_CSS_IMAGE_BUILTIN_ARROW:
+  case GTK_CSS_IMAGE_BUILTIN_ARROW_UP:
+  case GTK_CSS_IMAGE_BUILTIN_ARROW_DOWN:
+  case GTK_CSS_IMAGE_BUILTIN_ARROW_LEFT:
+  case GTK_CSS_IMAGE_BUILTIN_ARROW_RIGHT:
     gtk_css_image_builtin_draw_arrow (image, cr,
                                       width, height,
+                                      image_type,
                                       fg_color);
     break;
   case GTK_CSS_IMAGE_BUILTIN_EXPANDER_HORIZONTAL_LEFT:
diff --git a/gtk/gtkcssimagebuiltinprivate.h b/gtk/gtkcssimagebuiltinprivate.h
index 3f11a79915..082a6e3111 100644
--- a/gtk/gtkcssimagebuiltinprivate.h
+++ b/gtk/gtkcssimagebuiltinprivate.h
@@ -33,7 +33,10 @@ typedef enum {
   GTK_CSS_IMAGE_BUILTIN_OPTION,
   GTK_CSS_IMAGE_BUILTIN_OPTION_CHECKED,
   GTK_CSS_IMAGE_BUILTIN_OPTION_INCONSISTENT,
-  GTK_CSS_IMAGE_BUILTIN_ARROW,
+  GTK_CSS_IMAGE_BUILTIN_ARROW_UP,
+  GTK_CSS_IMAGE_BUILTIN_ARROW_DOWN,
+  GTK_CSS_IMAGE_BUILTIN_ARROW_LEFT,
+  GTK_CSS_IMAGE_BUILTIN_ARROW_RIGHT,
   GTK_CSS_IMAGE_BUILTIN_EXPANDER_HORIZONTAL_LEFT,
   GTK_CSS_IMAGE_BUILTIN_EXPANDER_VERTICAL_LEFT,
   GTK_CSS_IMAGE_BUILTIN_EXPANDER_HORIZONTAL_RIGHT,
diff --git a/gtk/gtkrender.c b/gtk/gtkrender.c
index 542c4670e2..54bc410036 100644
--- a/gtk/gtkrender.c
+++ b/gtk/gtkrender.c
@@ -287,8 +287,32 @@ gtk_do_render_arrow (GtkStyleContext *context,
                      gdouble          size)
 {
   GtkBorderStyle border_style;
+  GtkCssImageBuiltinType image_type;
   gint border_width;
 
+  /* map [0, 2 * pi) to [0, 4) */
+  angle = round (2 * angle / G_PI);
+
+  switch (((int) angle) & 3)
+  {
+  case 0:
+    image_type = GTK_CSS_IMAGE_BUILTIN_ARROW_UP;
+    break;
+  case 1:
+    image_type = GTK_CSS_IMAGE_BUILTIN_ARROW_RIGHT;
+    break;
+  case 2:
+    image_type = GTK_CSS_IMAGE_BUILTIN_ARROW_DOWN;
+    break;
+  case 3:
+    image_type = GTK_CSS_IMAGE_BUILTIN_ARROW_LEFT;
+    break;
+  default:
+    g_assert_not_reached ();
+    image_type = GTK_CSS_IMAGE_BUILTIN_ARROW_UP;
+    break;
+  }
+
   if (render_icon_image (context, cr, x, y, size, size))
     return;
 
@@ -310,14 +334,12 @@ gtk_do_render_arrow (GtkStyleContext *context,
       border_width = 0;
     }
 
-  cairo_translate (cr, x + size / 2.0, y + size / 2.0);
-  cairo_rotate (cr, angle - G_PI_2);
-  cairo_translate (cr, - size / 2.0, - size / 2.0);
+  cairo_translate (cr, x, y);
 
   gtk_css_image_builtin_draw (_gtk_css_image_value_get_image (_gtk_style_context_peek_property (context, GTK_CSS_PROPERTY_ICON_SOURCE)),
                               cr,
                               size, size,
-                              GTK_CSS_IMAGE_BUILTIN_ARROW,
+                              image_type,
                               _gtk_css_rgba_value_get_rgba (_gtk_style_context_peek_property (context, GTK_CSS_PROPERTY_COLOR)),
                               _gtk_css_rgba_value_get_rgba (_gtk_style_context_peek_property (context, GTK_CSS_PROPERTY_BACKGROUND_COLOR)),
                               _gtk_css_rgba_value_get_rgba (_gtk_style_context_peek_property (context, GTK_CSS_PROPERTY_BORDER_TOP_COLOR)),