[librsvg: 53/90] Reset back to the initial_affine before masking

[Federico Mena Quintero <federico src gnome org>]

commit 229f320b94ec92eff86a50483aa9aad06f727f5f
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Mar 19 19:15:32 2019 -0600

    Reset back to the initial_affine before masking

 rsvg_internals/src/drawing_ctx.rs | 4 ++++
 rsvg_internals/src/mask.rs        | 3 +--
 2 files changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/rsvg_internals/src/drawing_ctx.rs b/rsvg_internals/src/drawing_ctx.rs
index de73e51e..1e2c1d63 100644
--- a/rsvg_internals/src/drawing_ctx.rs
+++ b/rsvg_internals/src/drawing_ctx.rs
@@ -539,6 +539,10 @@ impl DrawingCtx {
         }
     }
 
+    pub fn set_initial_affine(&self, cr: &cairo::Context) {
+        cr.set_matrix(self.initial_affine);
+    }
+
     /// Saves the current Cairo matrix, runs the draw_fn, and restores the matrix
     ///
     /// This is slightly cheaper than a `cr.save()` / `cr.restore()`
diff --git a/rsvg_internals/src/mask.rs b/rsvg_internals/src/mask.rs
index 7072b6b0..78be20af 100644
--- a/rsvg_internals/src/mask.rs
+++ b/rsvg_internals/src/mask.rs
@@ -144,8 +144,7 @@ impl NodeMask {
         let mask_surface = compute_luminance_to_alpha(&mask_content_surface, opacity)?;
 
         let cr = draw_ctx.get_cairo_context();
-
-        cr.identity_matrix();
+        draw_ctx.set_initial_affine(&cr);
 
         cr.mask_surface(&mask_surface, 0.0, 0.0);