[librsvg/librsvg-2.48] generate_cairo_mask - Create the bounding box transform as per the rest of the code

[Federico Mena Quintero <federico src gnome org>]

commit dad64ee133483450b2a3194f89c5d8297e049f03
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Apr 29 18:18:13 2020 -0500

    generate_cairo_mask - Create the bounding box transform as per the rest of the code
    
    Without using temporary variables for the individual
    x/y/width/height.  We'll replace this with something else.

 rsvg_internals/src/drawing_ctx.rs | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)
---
diff --git a/rsvg_internals/src/drawing_ctx.rs b/rsvg_internals/src/drawing_ctx.rs
index 7e89f64d..9b14f4b6 100644
--- a/rsvg_internals/src/drawing_ctx.rs
+++ b/rsvg_internals/src/drawing_ctx.rs
@@ -395,8 +395,6 @@ impl DrawingCtx {
         }
 
         let bbox_rect = bbox.rect.as_ref().unwrap();
-        let (bb_x, bb_y) = (bbox_rect.x0, bbox_rect.y0);
-        let (bb_w, bb_h) = bbox_rect.size();
 
         let cascaded = CascadedValues::new_from_node(mask_node);
         let values = cascaded.get();
@@ -426,7 +424,14 @@ impl DrawingCtx {
             let mask_cr = cairo::Context::new(&mask_content_surface);
             mask_cr.set_matrix(mask_transform.into());
 
-            let bbtransform = Transform::new(bb_w, 0.0, 0.0, bb_h, bb_x, bb_y);
+            let bbtransform = Transform::new(
+               bbox_rect.width(),
+               0.0,
+               0.0,
+               bbox_rect.height(),
+               bbox_rect.x0,
+               bbox_rect.y0
+           );
 
             let clip_rect = if mask_units == CoordUnits::ObjectBoundingBox {
                 bbtransform.transform_rect(&mask_rect)