Add support for markers in-between fills/strokes.

Closes #550

crates/usvg-parser/src/converter.rs

@@ -7,7 +7,7 @@ use std::hash::{Hash, Hasher};
 use std::rc::Rc;
 use std::str::FromStr;
 
-use svgtypes::{Length, LengthUnit as Unit};
+use svgtypes::{Length, LengthUnit as Unit, PaintOrderKind};
 use usvg_tree::*;
 
 use crate::svgtree::{self, AId, EId, FromValue, SvgNode};
@@ -665,17 +665,17 @@ fn convert_path(
         node.find_attribute(AId::PaintOrder).unwrap_or_default();
     let paint_order = svg_paint_order_to_usvg(raw_paint_order);
 
-    // If a path doesn't have a fill or a stroke than it's invisible.
+    // If a path doesn't have a fill or a stroke then it's invisible.
     // By setting `visibility` to `hidden` we are disabling rendering of this path.
     if fill.is_none() && stroke.is_none() {
         visibility = Visibility::Hidden;
     }
 
-    let mut markers_group = None;
+    let mut markers_node = None;
     if crate::marker::is_valid(node) && visibility == Visibility::Visible {
-        let mut g = parent.append_kind(NodeKind::Group(Group::default()));
-        crate::marker::convert(node, &path, state, cache, &mut g);
-        markers_group = Some(g);
+        let mut marker = Node::new(NodeKind::Group(Group::default()));
+        crate::marker::convert(node, &path, state, cache, &mut marker);
+        markers_node = Some(marker);
     }
 
     // Nodes generated by markers must not have an ID. Otherwise we would have duplicates.
@@ -685,7 +685,7 @@ fn convert_path(
         String::new()
     };
 
-    parent.append_kind(NodeKind::Path(Path {
+    let path = Path {
         id,
         visibility,
         fill,
@@ -694,14 +694,54 @@ fn convert_path(
         rendering_mode,
         text_bbox: None,
         data: path,
-    }));
+    };
+
+    let append_marker = || {
+        if let Some(markers_node) = markers_node {
+            parent.append(markers_node);
+        }
+    };
+
+    let append_path = || {
+        parent.append(Node::new(NodeKind::Path(path.clone())));
+    };
 
-    if raw_paint_order.order[2] == svgtypes::PaintOrderKind::Markers {
-        // Insert markers group after `path`.
-        if let Some(g) = markers_group {
-            g.detach();
-            parent.append(g);
+    match raw_paint_order.order {
+        [PaintOrderKind::Markers, _, _] => {
+            append_marker();
+            append_path();
+        }
+        [first, PaintOrderKind::Markers, last] => {
+            let append_single_paint_path = |paint_order_kind: PaintOrderKind| match paint_order_kind
+            {
+                PaintOrderKind::Fill => {
+                    if !path.fill.is_none() {
+                        let mut fill_path = path.clone();
+                        fill_path.stroke = None;
+                        fill_path.id = String::new();
+                        parent.append(Node::new(NodeKind::Path(fill_path)));
+                    }
+                }
+                PaintOrderKind::Stroke => {
+                    if !path.stroke.is_none() {
+                        let mut stroke_path = path.clone();
+                        stroke_path.fill = None;
+                        stroke_path.id = String::new();
+                        parent.append(Node::new(NodeKind::Path(stroke_path)));
+                    }
+                }
+                _ => {}
+            };
+
+            append_single_paint_path(first);
+            append_marker();
+            append_single_paint_path(last)
+        }
+        [_, _, PaintOrderKind::Markers] => {
+            append_path();
+            append_marker();
         }
+        _ => append_path(),
     }
 }