layout::Filter: new struct; move some of the filter-related fields here

Let's try to avoid passing so many arguments to the functions in
drawing_ctx.rs.  In the end this will also encapsulate all the gunk needed for
resolving filters.

Part-of: <https://gitlab.gnome.org/GNOME/librsvg/-/merge_requests/816>

2 files changed, 26 insertions, 14 deletions

diff --git a/src/drawing_ctx.rs b/src/drawing_ctx.rs
index 5c5bc6fc..8ef328a6 100644
--- a/src/drawing_ctx.rs
+++ b/src/drawing_ctx.rs
@@ -765,7 +765,7 @@ impl DrawingCtx {
 
                     // Create temporary surface and its cr
 
-                    let cr = match stacking_ctx.filter {
+                    let cr = match stacking_ctx.filter.filter {
                         Filter::None => cairo::Context::new(
                             &self
                                 .create_similar_surface_for_toplevel_viewport(&self.cr.target())?,
@@ -790,7 +790,7 @@ impl DrawingCtx {
                             BoundingBox::new().with_transform(affines.for_temporary_surface)
                         };
 
-                        if let Filter::List(ref filter_list) = stacking_ctx.filter {
+                        if let Filter::List(ref filter_list) = stacking_ctx.filter.filter {
                             let surface_to_filter = SharedImageSurface::copy_from_surface(
                                 &cairo::ImageSurface::try_from(temporary_draw_ctx.cr.target())
                                     .unwrap(),
@@ -808,7 +808,7 @@ impl DrawingCtx {
                                     .resolve(
                                         acquired_nodes,
                                         values.stroke_opacity().0,
-                                        stacking_ctx.current_color,
+                                        stacking_ctx.filter.current_color,
                                         None,
                                         None,
                                         self.session(),
@@ -823,7 +823,7 @@ impl DrawingCtx {
                                     .resolve(
                                         acquired_nodes,
                                         values.fill_opacity().0,
-                                        stacking_ctx.current_color,
+                                        stacking_ctx.filter.current_color,
                                         None,
                                         None,
                                         self.session(),
@@ -849,7 +849,7 @@ impl DrawingCtx {
                                     &user_space_params,
                                     stroke_paint_source,
                                     fill_paint_source,
-                                    stacking_ctx.current_color,
+                                    stacking_ctx.filter.current_color,
                                     bbox,
                                 )?
                                 .into_image_surface()?;
@@ -1296,10 +1296,14 @@ impl DrawingCtx {
             ),
             LayerKind::Text(text) => {
                 self.draw_text(&text, &layer.stacking_ctx, acquired_nodes, values, clipping)
-            },
-            LayerKind::Image(image) => {
-                self.draw_image(&image, &layer.stacking_ctx, acquired_nodes, values, clipping)
-            },
+            }
+            LayerKind::Image(image) => self.draw_image(
+                &image,
+                &layer.stacking_ctx,
+                acquired_nodes,
+                values,
+                clipping,
+            ),
         }
     }
 
diff --git a/src/layout.rs b/src/layout.rs
index 7f55b275..a65bc1cf 100644
--- a/src/layout.rs
+++ b/src/layout.rs
@@ -19,7 +19,7 @@ use crate::node::*;
 use crate::paint_server::{PaintSource, UserSpacePaintSource};
 use crate::path_builder::Path;
 use crate::properties::{
-    ClipRule, ComputedValues, Direction, FillRule, Filter, FontFamily, FontStretch, FontStyle,
+    self, ClipRule, ComputedValues, Direction, FillRule, FontFamily, FontStretch, FontStyle,
     FontVariant, FontWeight, Isolation, MixBlendMode, Opacity, Overflow, PaintOrder,
     ShapeRendering, StrokeDasharray, StrokeLinecap, StrokeLinejoin, StrokeMiterlimit,
     TextDecoration, TextRendering, UnicodeBidi, VectorEffect, XmlLang,
@@ -48,7 +48,6 @@ pub struct StackingContext {
     pub transform: Transform,
     pub opacity: Opacity,
     pub filter: Filter,
-    pub current_color: RGBA,
     pub clip_in_user_space: Option<Node>,
     pub clip_in_object_space: Option<Node>,
     pub mask: Option<Node>,
@@ -150,6 +149,11 @@ pub struct FontProperties {
     pub text_decoration: TextDecoration,
 }
 
+pub struct Filter {
+    pub filter: properties::Filter,
+    pub current_color: RGBA,
+}
+
 impl StackingContext {
     pub fn new(
         session: &Session,
@@ -170,7 +174,7 @@ impl StackingContext {
             // https://drafts.fxtf.org/css-masking-1/#MaskElement
             ElementData::Mask(_) => {
                 opacity = Opacity(UnitInterval::clamp(1.0));
-                filter = Filter::None;
+                filter = properties::Filter::None;
             }
 
             _ => {
@@ -179,6 +183,11 @@ impl StackingContext {
             }
         }
 
+        let filter = Filter {
+            filter,
+            current_color,
+        };
+
         let clip_path = values.clip_path();
         let clip_uri = clip_path.0.get();
         let (clip_in_user_space, clip_in_object_space) = clip_uri
@@ -237,7 +246,6 @@ impl StackingContext {
             transform,
             opacity,
             filter,
-            current_color,
             clip_in_user_space,
             clip_in_object_space,
             mask,
@@ -266,7 +274,7 @@ impl StackingContext {
             Isolation::Auto => {
                 let is_opaque = approx_eq!(f64, opacity, 1.0);
                 !(is_opaque
-                    && self.filter == Filter::None
+                    && self.filter.filter == properties::Filter::None
                     && self.mask.is_none()
                     && self.mix_blend_mode == MixBlendMode::Normal
                     && self.clip_in_object_space.is_none())