usvg/parser/
clippath.rs

1// Copyright 2018 the Resvg Authors
2// SPDX-License-Identifier: Apache-2.0 OR MIT
3
4use std::str::FromStr;
5use std::sync::Arc;
6
7use super::converter;
8use super::svgtree::{AId, EId, SvgNode};
9use crate::{ClipPath, Group, NonEmptyString, NonZeroRect, Transform, Units};
10
11pub(crate) fn convert(
12    node: SvgNode,
13    state: &converter::State,
14    object_bbox: Option<NonZeroRect>,
15    cache: &mut converter::Cache,
16) -> Option<Arc<ClipPath>> {
17    // A `clip-path` attribute must reference a `clipPath` element.
18    if node.tag_name() != Some(EId::ClipPath) {
19        return None;
20    }
21
22    // The whole clip path should be ignored when a transform is invalid.
23    let mut transform = resolve_clip_path_transform(node, state)?;
24
25    let units = node
26        .attribute(AId::ClipPathUnits)
27        .unwrap_or(Units::UserSpaceOnUse);
28
29    // Check if this element was already converted.
30    //
31    // Only `userSpaceOnUse` clipPaths can be shared,
32    // because `objectBoundingBox` one will be converted into user one
33    // and will become node-specific.
34    let cacheable = units == Units::UserSpaceOnUse;
35    if cacheable {
36        if let Some(clip) = cache.clip_paths.get(node.element_id()) {
37            return Some(clip.clone());
38        }
39    }
40
41    if units == Units::ObjectBoundingBox {
42        let object_bbox = match object_bbox {
43            Some(v) => v,
44            None => {
45                log::warn!("Clipping of zero-sized shapes is not allowed.");
46                return None;
47            }
48        };
49
50        let ts = Transform::from_bbox(object_bbox);
51        transform = transform.pre_concat(ts);
52    }
53
54    // Resolve linked clip path.
55    let mut clip_path = None;
56    if let Some(link) = node.attribute::<SvgNode>(AId::ClipPath) {
57        clip_path = convert(link, state, object_bbox, cache);
58
59        // Linked `clipPath` must be valid.
60        if clip_path.is_none() {
61            return None;
62        }
63    }
64
65    let mut id = NonEmptyString::new(node.element_id().to_string())?;
66    // Generate ID only when we're parsing `objectBoundingBox` clip for the second time.
67    if !cacheable && cache.clip_paths.contains_key(id.get()) {
68        id = cache.gen_clip_path_id();
69    }
70    let id_copy = id.get().to_string();
71
72    let mut clip = ClipPath {
73        id,
74        transform,
75        clip_path,
76        root: Group::empty(),
77    };
78
79    let mut clip_state = state.clone();
80    clip_state.parent_clip_path = Some(node);
81    converter::convert_clip_path_elements(node, &clip_state, cache, &mut clip.root);
82
83    if clip.root.has_children() {
84        clip.root.calculate_bounding_boxes();
85        let clip = Arc::new(clip);
86        cache.clip_paths.insert(id_copy, clip.clone());
87        Some(clip)
88    } else {
89        // A clip path without children is invalid.
90        None
91    }
92}
93
94fn resolve_clip_path_transform(node: SvgNode, state: &converter::State) -> Option<Transform> {
95    // Do not use Node::attribute::<Transform>, because it will always
96    // return a valid transform.
97
98    let value: &str = match node.attribute(AId::Transform) {
99        Some(v) => v,
100        None => return Some(Transform::default()),
101    };
102
103    let ts = match svgtypes::Transform::from_str(value) {
104        Ok(v) => v,
105        Err(_) => {
106            log::warn!("Failed to parse {} value: '{}'.", AId::Transform, value);
107            return None;
108        }
109    };
110
111    let ts = Transform::from_row(
112        ts.a as f32,
113        ts.b as f32,
114        ts.c as f32,
115        ts.d as f32,
116        ts.e as f32,
117        ts.f as f32,
118    );
119
120    if ts.is_valid() {
121        Some(node.resolve_transform(AId::Transform, state))
122    } else {
123        None
124    }
125}
usvg/parser/clippath.rs

usvg/parser/
clippath.rs
