From 425e65049b398a85c5579d8b421d4fdbf0778984 Mon Sep 17 00:00:00 2001
From: Georges Basile Stavracas Neto <georges.stavracas@gmail.com>
Date: Thu, 27 Dec 2018 14:16:50 -0200
Subject: [PATCH] shaped-texture: Draw pipeline relative to alloc

By implementing ClutterContent, it is expected that
MetaShapedTexture can draw on any actor. However,
right now this is not possible, since it assumes
that the drawing coordinates and sizes of the actor
are synchronized with its own reported width and
height.

It mistakenly draws, for example, when setting an
actor's content to it. There is no way to trigger
this wrong behavior right now, but it will become
a problem in the future where we can collect the
paint nodes of MetaShapedTexture as part of other
ClutterContent implementations.

Use the allocation box passed by the actor to draw
the pipelines of MetaShapedTexture.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/409
---
 src/compositor/meta-shaped-texture.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/src/compositor/meta-shaped-texture.c b/src/compositor/meta-shaped-texture.c
index 667d43d56..308d9361a 100644
--- a/src/compositor/meta-shaped-texture.c
+++ b/src/compositor/meta-shaped-texture.c
@@ -447,17 +447,27 @@ paint_clipped_rectangle_node (MetaShapedTexture     *stex,
                               ClutterActorBox       *alloc)
 {
   g_autoptr (ClutterPaintNode) node = NULL;
+  float ratio_h, ratio_v;
+  float x1, y1, x2, y2;
   float coords[8];
   float alloc_width;
   float alloc_height;
 
+  ratio_h = clutter_actor_box_get_width (alloc) / (float) stex->dst_width;
+  ratio_v = clutter_actor_box_get_height (alloc) / (float) stex->dst_height;
+
+  x1 = alloc->x1 + rect->x * ratio_h;
+  y1 = alloc->y1 + rect->y * ratio_v;
+  x2 = alloc->x1 + (rect->x + rect->width) * ratio_h;
+  y2 = alloc->y1 + (rect->y + rect->height) * ratio_v;
+
   alloc_width = alloc->x2 - alloc->x1;
   alloc_height = alloc->y2 - alloc->y1;
 
-  coords[0] = rect->x / alloc_width;
-  coords[1] = rect->y / alloc_height;
-  coords[2] = (rect->x + rect->width) / alloc_width;
-  coords[3] = (rect->y + rect->height) / alloc_height;
+  coords[0] = rect->x / alloc_width * ratio_h;
+  coords[1] = rect->y / alloc_height * ratio_v;
+  coords[2] = (rect->x + rect->width) / alloc_width * ratio_h;
+  coords[3] = (rect->y + rect->height) / alloc_height * ratio_v;
 
   coords[4] = coords[0];
   coords[5] = coords[1];
@@ -470,10 +480,10 @@ paint_clipped_rectangle_node (MetaShapedTexture     *stex,
 
   clutter_paint_node_add_multitexture_rectangle (node,
                                                  &(ClutterActorBox) {
-                                                   .x1 = rect->x,
-                                                   .x2 = rect->x + rect->width,
-                                                   .y1 = rect->y,
-                                                   .y2 = rect->y + rect->height,
+                                                   .x1 = x1,
+                                                   .y1 = y1,
+                                                   .x2 = x2,
+                                                   .y2 = y2,
                                                  },
                                                  coords, 8);
 }