[frameworks/kirigami] src/platform: PlatformTheme: Only emit color changes if color actually changes

Git commit b4eafdefe421c5c994940774c6f8f62145b5576f by Devin Lin.
Committed on 20/07/2026 at 18:43.
Pushed by devinlin into branch 'master'.

PlatformTheme: Only emit color changes if color actually changes

In the Plasma Mobile homescreen, we have a bunch of icons drawn on the
screen. When the shell becomes unfocused, we get a gigantic spike in lag
that appears to be caused due to Kirigami.PlatformTheme emitting
colorsChanged (due to inactive color getting set), which causes Icon to
call polish().

M  +5    -3    src/platform/platformtheme.cpp

https://invent.kde.org/frameworks/kirigami/-/commit/b4eafdefe421c5c994940774c6f8f62145b5576f

diff --git a/src/platform/platformtheme.cpp b/src/platform/platformtheme.cpp
index 8bbfce0b2..2c707a895 100644
--- a/src/platform/platformtheme.cpp
+++ b/src/platform/platformtheme.cpp
@@ -380,9 +380,11 @@ public:
             }
         }
 
-        PlatformThemeChangeTracker tracker(theme, PlatformThemeChangeTracker::PropertyChange::Color);
-
-        if (data) {
+        // Only mark colors as changed if the value will actually change; the
+        // subclasses reset all colors when e.g. the window's active state
+        // changes.
+        if (data && data->owner == theme && data->colors[color] != value) {
+            PlatformThemeChangeTracker tracker(theme, PlatformThemeChangeTracker::PropertyChange::Color);
             data->setColor(theme, color, value);
         }
     }