st/theme-context: Invalidate texture cache when scaling changes

The CSS engine is scale-aware, whereas simply setting the
width and height properties directly isn't.

Use CSS to set the folder icon.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1176

js/ui/appDisplay.js

@@ -1376,12 +1376,12 @@ class FolderView extends BaseAppView {
         });
         layout.hookup_style(icon);
         let subSize = Math.floor(FOLDER_SUBICON_FRACTION * size);
-        let scale = St.ThemeContext.get_for_stage(global.stage).scale_factor;
 
         let numItems = this._orderedItems.length;
         let rtl = icon.get_text_direction() == Clutter.TextDirection.RTL;
         for (let i = 0; i < 4; i++) {
-            let bin = new St.Bin({ width: subSize * scale, height: subSize * scale });
+            const style = 'width: %dpx; height: %dpx;'.format(subSize, subSize);
+            let bin = new St.Bin({ style });
             if (i < numItems)
                 bin.child = this._orderedItems[i].app.create_icon_texture(subSize);
             layout.attach(bin, rtl ? (i + 1) % 2 : i % 2, Math.floor(i / 2), 1, 1);

src/st/st-texture-cache.c

@@ -1619,3 +1619,18 @@ st_texture_cache_rescan_icon_theme (StTextureCache *cache)
 
   return gtk_icon_theme_rescan_if_needed (priv->icon_theme);
 }
+
+
+/**
+ * st_texture_cache_invalidate:
+ * @cache: a #StTextureCache
+ *
+ * Invalidates the texture cache, and evicts all icons.
+ */
+void
+st_texture_cache_invalidate (StTextureCache *cache)
+{
+  g_return_if_fail (ST_IS_TEXTURE_CACHE (cache));
+
+  st_texture_cache_evict_icons (cache);
+}

src/st/st-texture-cache.h

@@ -115,4 +115,6 @@ CoglTexture * st_texture_cache_load (StTextureCache       *cache,
 
 gboolean st_texture_cache_rescan_icon_theme (StTextureCache *cache);
 
+void st_texture_cache_invalidate (StTextureCache *cache);
+
 #endif /* __ST_TEXTURE_CACHE_H__ */

src/st/st-theme-context.c

@@ -176,7 +176,11 @@ st_theme_context_set_property (GObject      *object,
         int scale_factor = g_value_get_int (value);
         if (scale_factor != context->scale_factor)
           {
+            StTextureCache *cache = st_texture_cache_get_default ();
+
             context->scale_factor = scale_factor;
+
+            st_texture_cache_invalidate (cache);
             st_theme_context_changed (context);
           }
 

src/st/st-theme-node-private.h

@@ -117,6 +117,8 @@ struct _StThemeNode {
   CoglPipeline *color_pipeline;
 
   StThemeNodePaintState cached_state;
+
+  int scale_factor;
 };
 
 void _st_theme_node_ensure_background (StThemeNode *node);

src/st/st-theme-node.c

@@ -219,6 +219,8 @@ st_theme_node_new (StThemeContext    *context,
   if (theme == NULL && parent_node != NULL)
     theme = parent_node->theme;
 
+  g_object_get (context, "scale-factor", &node->scale_factor, NULL);
+
   g_set_object (&node->theme, theme);
   node->element_type = element_type;
   node->element_id = g_strdup (element_id);
@@ -345,6 +347,7 @@ st_theme_node_equal (StThemeNode *node_a, StThemeNode *node_b)
       node_a->context != node_b->context ||
       node_a->theme != node_b->theme ||
       node_a->element_type != node_b->element_type ||
+      node_a->scale_factor != node_b->scale_factor ||
       g_strcmp0 (node_a->element_id, node_b->element_id) ||
       g_strcmp0 (node_a->inline_style, node_b->inline_style))
     return FALSE;
@@ -396,6 +399,7 @@ st_theme_node_hash (StThemeNode *node)
   hash = hash * 33 + GPOINTER_TO_UINT (node->context);
   hash = hash * 33 + GPOINTER_TO_UINT (node->theme);
   hash = hash * 33 + ((guint) node->element_type);
+  hash = hash * 33 + ((guint) node->scale_factor);
 
   if (node->element_id != NULL)
     hash = hash * 33 + g_str_hash (node->element_id);
@@ -975,9 +979,7 @@ get_length_from_term (StThemeNode *node,
   } type = ABSOLUTE;
 
   double multiplier = 1.0;
-  int scale_factor;
 
-  g_object_get (node->context, "scale-factor", &scale_factor, NULL);
 
   if (term->type != TERM_NUMBER)
     {
@@ -992,7 +994,7 @@ get_length_from_term (StThemeNode *node,
     {
     case NUM_LENGTH_PX:
       type = ABSOLUTE;
-      multiplier = 1 * scale_factor;
+      multiplier = 1 * node->scale_factor;
       break;
     case NUM_LENGTH_PT:
       type = POINTS;
@@ -1123,14 +1125,10 @@ get_length_from_term_int (StThemeNode *node,
 {
   double value;
   GetFromTermResult result;
-  int scale_factor;
 
   result = get_length_from_term (node, term, use_parent_font, &value);
   if (result == VALUE_FOUND)
-    {
+    *length = (int) ((value / node->scale_factor) + 0.5) * node->scale_factor;
-      g_object_get (node->context, "scale-factor", &scale_factor, NULL);
-      *length = (int) ((value / scale_factor) + 0.5) * scale_factor;
-    }
   return result;
 }
 
@@ -3012,7 +3010,6 @@ StBorderImage *
 st_theme_node_get_border_image (StThemeNode *node)
 {
   int i;
-  int scale_factor;
 
   if (node->border_image_computed)
     return node->border_image;
@@ -3021,7 +3018,6 @@ st_theme_node_get_border_image (StThemeNode *node)
   node->border_image_computed = TRUE;
 
   ensure_properties (node);
-  g_object_get (node->context, "scale-factor", &scale_factor, NULL);
 
   for (i = node->n_properties - 1; i >= 0; i--)
     {
@@ -3126,7 +3122,7 @@ st_theme_node_get_border_image (StThemeNode *node)
 
           node->border_image = st_border_image_new (file,
                                                     border_top, border_right, border_bottom, border_left,
-                                                    scale_factor);
+                                                    node->scale_factor);
 
           g_object_unref (file);
 
@@ -3967,6 +3963,9 @@ st_theme_node_geometry_equal (StThemeNode *node,
 
   g_return_val_if_fail (ST_IS_THEME_NODE (other), FALSE);
 
+  if (node->scale_factor != other->scale_factor)
+    return FALSE;
+
   _st_theme_node_ensure_geometry (node);
   _st_theme_node_ensure_geometry (other);