From 7c357e7da5dbe873278a39e0aae9ce915b5a2d75 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Tue, 19 Mar 2024 23:06:24 -0400
Subject: [PATCH] cursor: Add private convenience api

Add function that either returns the texture, or converts
the paintable to a texture at its intrinsic size, and
returns that.

This allows for quick fallback implementations that minimally
handle the paintable cursor case.
---
 gdk/gdkcursor.c        | 74 ++++++++++++++++++++++++++++++++++++++++++
 gdk/gdkcursorprivate.h |  3 ++
 2 files changed, 77 insertions(+)

diff --git a/gdk/gdkcursor.c b/gdk/gdkcursor.c
index 2d4c021a4e..c3b6fe3c17 100644
--- a/gdk/gdkcursor.c
+++ b/gdk/gdkcursor.c
@@ -30,11 +30,14 @@
 #include "gdkcursor.h"
 #include "gdkcursorprivate.h"
 #include "gdktexture.h"
+#include "gdkdisplay.h"
 #include <glib/gi18n-lib.h>
 
 #include <math.h>
 #include <errno.h>
 
+#include <graphene.h>
+
 /**
  * GdkCursor:
  *
@@ -555,3 +558,74 @@ gdk_cursor_get_hotspot_y (GdkCursor *cursor)
 
   return cursor->hotspot_y;
 }
+
+/* Hack. We don't include gsk/gsk.h here to avoid a build order problem
+ * with the generated header gskenumtypes.h, so we need to hack around
+ * a bit to access the gsk and gtk api we need.
+ */
+
+typedef struct _GskRenderer GskRenderer;
+typedef struct _GskRenderNode GskRenderNode;
+typedef struct _GdkSnapshot GtkSnapshot;
+
+extern GskRenderer *   gsk_cairo_renderer_new           (void);
+extern gboolean        gsk_renderer_realize_for_display (GskRenderer            *renderer,
+                                                         GdkDisplay             *display,
+                                                         GError                **error);
+extern void            gsk_renderer_unrealize           (GskRenderer            *renderer);
+extern GdkTexture *    gsk_renderer_render_texture      (GskRenderer            *renderer,
+                                                         GskRenderNode          *root,
+                                                         const graphene_rect_t  *viewport);
+
+extern void            gsk_render_node_get_bounds       (GskRenderNode          *node,
+                                                         graphene_rect_t        *bounds);
+
+extern void            gsk_render_node_unref            (GskRenderNode          *node);
+
+extern GtkSnapshot *   gtk_snapshot_new                 (void);
+extern GskRenderNode * gtk_snapshot_free_to_node        (GtkSnapshot            *snapshot);
+
+static GdkTexture *
+paintable_to_texture (GdkPaintable *paintable,
+                      double        scale)
+{
+  GtkSnapshot *snapshot;
+  GskRenderNode *node;
+  GskRenderer *renderer;
+  int width, height;
+  GdkTexture *texture;
+  graphene_rect_t bounds;
+
+  width = gdk_paintable_get_intrinsic_width (paintable);
+  height = gdk_paintable_get_intrinsic_height (paintable);
+
+  snapshot = gtk_snapshot_new ();
+  gdk_paintable_snapshot (paintable, snapshot, width * scale, height * scale);
+  node = gtk_snapshot_free_to_node (snapshot);
+
+  /* FIXME: use a proper renderer, and cache it */
+  renderer = gsk_cairo_renderer_new ();
+  gsk_renderer_realize_for_display (renderer, gdk_display_get_default (), NULL);
+
+  gsk_render_node_get_bounds (node, &bounds);
+  texture = gsk_renderer_render_texture (renderer, node, &bounds);
+
+  gsk_renderer_unrealize (renderer);
+  g_object_unref (renderer);
+
+  gsk_render_node_unref (node);
+
+  return texture;
+}
+
+GdkTexture *
+gdk_cursor_create_texture (GdkCursor *cursor,
+                           double     scale)
+{
+  if (cursor->texture)
+    return g_object_ref (cursor->texture);
+  else if (cursor->paintable)
+    return paintable_to_texture (cursor->paintable, scale);
+  else
+    return NULL;
+}
diff --git a/gdk/gdkcursorprivate.h b/gdk/gdkcursorprivate.h
index 3b5cbde2d0..2caa96822d 100644
--- a/gdk/gdkcursorprivate.h
+++ b/gdk/gdkcursorprivate.h
@@ -56,5 +56,8 @@ guint                   gdk_cursor_hash                         (gconstpointer
 gboolean                gdk_cursor_equal                        (gconstpointer          a,
                                                                  gconstpointer          b);
 
+GdkTexture *            gdk_cursor_create_texture               (GdkCursor             *cursor,
+                                                                 double                 scale);
+
 G_END_DECLS