From f77d8e2a12a07ef6abe9c9bdfe33bd9d1e1a7ce8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20=C3=85dahl?= <jadahl@gmail.com>
Date: Thu, 21 Nov 2024 17:14:12 +0100
Subject: [PATCH] display: Fix cursor sprite sizes with fractional scales

This makes the cursor size match the expectation given by the theme
size. It also means the sprite size now matches GTK4 provided cursor
surfaces using wp_viewport.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3859>
---
 src/backends/meta-cursor-sprite-xcursor.c | 25 +++++++++++++++++++++--
 src/backends/meta-cursor-sprite-xcursor.h |  4 ++++
 src/core/display.c                        | 11 ++++++++--
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/src/backends/meta-cursor-sprite-xcursor.c b/src/backends/meta-cursor-sprite-xcursor.c
index aa310316c..6dac285ba 100644
--- a/src/backends/meta-cursor-sprite-xcursor.c
+++ b/src/backends/meta-cursor-sprite-xcursor.c
@@ -247,9 +247,11 @@ load_from_current_xcursor_image (MetaCursorSpriteXcursor *sprite_xcursor)
 
   if (meta_is_wayland_compositor ())
     {
-      hotspot_x = ((int) (xc_image->xhot / sprite_xcursor->theme_scale) *
+      hotspot_x = ((int) roundf ((float) xc_image->xhot /
+                                 sprite_xcursor->theme_scale) *
                    sprite_xcursor->theme_scale);
-      hotspot_y = ((int) (xc_image->yhot / sprite_xcursor->theme_scale) *
+      hotspot_y = ((int) roundf ((float) xc_image->yhot /
+                                 sprite_xcursor->theme_scale) *
                    sprite_xcursor->theme_scale);
     }
   else
@@ -273,6 +275,25 @@ meta_cursor_sprite_xcursor_set_theme_scale (MetaCursorSpriteXcursor *sprite_xcur
   sprite_xcursor->theme_scale = theme_scale;
 }
 
+void
+meta_cursor_sprite_xcursor_get_scaled_image_size (MetaCursorSpriteXcursor *sprite_xcursor,
+                                                  int                     *width,
+                                                  int                     *height)
+{
+  XcursorImage *current_image;
+  int theme_size;
+  int image_size;
+  float effective_theme_scale;
+
+  current_image = meta_cursor_sprite_xcursor_get_current_image (sprite_xcursor);
+  theme_size = meta_prefs_get_cursor_size ();
+  image_size = current_image->size;
+  effective_theme_scale = (float) theme_size / image_size;
+
+  *width = (int) ceilf (current_image->width * effective_theme_scale);
+  *height = (int) ceilf (current_image->width * effective_theme_scale);
+}
+
 static gboolean
 meta_cursor_sprite_xcursor_is_animated (MetaCursorSprite *sprite)
 {
diff --git a/src/backends/meta-cursor-sprite-xcursor.h b/src/backends/meta-cursor-sprite-xcursor.h
index 33f112ba2..3721b0fbe 100644
--- a/src/backends/meta-cursor-sprite-xcursor.h
+++ b/src/backends/meta-cursor-sprite-xcursor.h
@@ -38,6 +38,10 @@ MetaCursor meta_cursor_sprite_xcursor_get_cursor (MetaCursorSpriteXcursor *sprit
 
 XcursorImage * meta_cursor_sprite_xcursor_get_current_image (MetaCursorSpriteXcursor *sprite_xcursor);
 
+void meta_cursor_sprite_xcursor_get_scaled_image_size (MetaCursorSpriteXcursor *sprite_xcursor,
+                                                       int                     *width,
+                                                       int                     *height);
+
 META_EXPORT_TEST
 const char * meta_cursor_get_name (MetaCursor cursor);
 
diff --git a/src/core/display.c b/src/core/display.c
index 960d071da..2c02dc824 100644
--- a/src/core/display.c
+++ b/src/core/display.c
@@ -1697,12 +1697,19 @@ root_cursor_prepare_at (MetaCursorSpriteXcursor *sprite_xcursor,
       if (best_scale != 0.0f)
         {
           float ceiled_scale;
+          int cursor_width, cursor_height;
 
           ceiled_scale = ceilf (best_scale);
           meta_cursor_sprite_xcursor_set_theme_scale (sprite_xcursor,
                                                       (int) ceiled_scale);
-          meta_cursor_sprite_set_texture_scale (cursor_sprite,
-                                                1.0f / ceiled_scale);
+
+          meta_cursor_sprite_realize_texture (cursor_sprite);
+          meta_cursor_sprite_xcursor_get_scaled_image_size (sprite_xcursor,
+                                                            &cursor_width,
+                                                            &cursor_height);
+          meta_cursor_sprite_set_viewport_dst_size (cursor_sprite,
+                                                    cursor_width,
+                                                    cursor_height);
         }
     }
   else