[librsvg: 8/15] Svg - extract method to push the new viewport

[Federico Mena Quintero <federico src gnome org>]

commit f9bf169b11e8c0eaaaf94a187fb916eea8017421
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Nov 17 18:54:07 2020 -0600

    Svg - extract method to push the new viewport
    
    We'll use this to implement the recursion in draw_node_from_stack by hand.

 src/structure.rs | 81 +++++++++++++++++++++++++++++++-------------------------
 1 file changed, 45 insertions(+), 36 deletions(-)
---
diff --git a/src/structure.rs b/src/structure.rs
index 2198f56b..2e0dfa89 100644
--- a/src/structure.rs
+++ b/src/structure.rs
@@ -157,44 +157,13 @@ impl Svg {
 
         Rect::new(nx, ny, nx + nw, ny + nh)
     }
-}
-
-impl SetAttributes for Svg {
-    fn set_attributes(&mut self, attrs: &Attributes) -> ElementResult {
-        for (attr, value) in attrs.iter() {
-            match attr.expanded() {
-                expanded_name!("", "preserveAspectRatio") => {
-                    self.preserve_aspect_ratio = attr.parse(value)?
-                }
-                expanded_name!("", "x") => self.x = Some(attr.parse(value)?),
-                expanded_name!("", "y") => self.y = Some(attr.parse(value)?),
-                expanded_name!("", "width") => {
-                    self.w = Some(
-                        attr.parse_and_validate(value, Length::<Horizontal>::check_nonnegative)?,
-                    )
-                }
-                expanded_name!("", "height") => {
-                    self.h =
-                        Some(attr.parse_and_validate(value, Length::<Vertical>::check_nonnegative)?)
-                }
-                expanded_name!("", "viewBox") => self.vbox = attr.parse(value).map(Some)?,
-                _ => (),
-            }
-        }
 
-        Ok(())
-    }
-}
-
-impl Draw for Svg {
-    fn draw(
+    pub fn push_viewport(
         &self,
         node: &Node,
-        acquired_nodes: &mut AcquiredNodes<'_>,
         cascaded: &CascadedValues<'_>,
         draw_ctx: &mut DrawingCtx,
-        clipping: bool,
-    ) -> Result<BoundingBox, RenderingError> {
+    ) -> Option<ViewParams> {
         let values = cascaded.get();
 
         let params = draw_ctx.get_view_params();
@@ -231,10 +200,50 @@ impl Draw for Svg {
             )
         };
 
-        draw_ctx.with_discrete_layer(node, acquired_nodes, values, clipping, &mut |an, dc| {
-            let _params =
-                dc.push_new_viewport(vbox, viewport, self.preserve_aspect_ratio, clip_mode);
+        draw_ctx.push_new_viewport(vbox, viewport, self.preserve_aspect_ratio, clip_mode)
+    }
+}
 
+impl SetAttributes for Svg {
+    fn set_attributes(&mut self, attrs: &Attributes) -> ElementResult {
+        for (attr, value) in attrs.iter() {
+            match attr.expanded() {
+                expanded_name!("", "preserveAspectRatio") => {
+                    self.preserve_aspect_ratio = attr.parse(value)?
+                }
+                expanded_name!("", "x") => self.x = Some(attr.parse(value)?),
+                expanded_name!("", "y") => self.y = Some(attr.parse(value)?),
+                expanded_name!("", "width") => {
+                    self.w = Some(
+                        attr.parse_and_validate(value, Length::<Horizontal>::check_nonnegative)?,
+                    )
+                }
+                expanded_name!("", "height") => {
+                    self.h =
+                        Some(attr.parse_and_validate(value, Length::<Vertical>::check_nonnegative)?)
+                }
+                expanded_name!("", "viewBox") => self.vbox = attr.parse(value).map(Some)?,
+                _ => (),
+            }
+        }
+
+        Ok(())
+    }
+}
+
+impl Draw for Svg {
+    fn draw(
+        &self,
+        node: &Node,
+        acquired_nodes: &mut AcquiredNodes<'_>,
+        cascaded: &CascadedValues<'_>,
+        draw_ctx: &mut DrawingCtx,
+        clipping: bool,
+    ) -> Result<BoundingBox, RenderingError> {
+        let values = cascaded.get();
+
+        draw_ctx.with_discrete_layer(node, acquired_nodes, values, clipping, &mut |an, dc| {
+            let _params = self.push_viewport(node, cascaded, dc);
             node.draw_children(an, cascaded, dc, clipping)
         })
     }