usvg/parser/
clippath.rs

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1// This Source Code Form is subject to the terms of the Mozilla Public
2// License, v. 2.0. If a copy of the MPL was not distributed with this
3// file, You can obtain one at http://mozilla.org/MPL/2.0/.
4
5use std::str::FromStr;
6use std::sync::Arc;
7
8use super::converter;
9use super::svgtree::{AId, EId, SvgNode};
10use crate::{ClipPath, Group, NonEmptyString, NonZeroRect, Transform, Units};
11
12pub(crate) fn convert(
13    node: SvgNode,
14    state: &converter::State,
15    object_bbox: Option<NonZeroRect>,
16    cache: &mut converter::Cache,
17) -> Option<Arc<ClipPath>> {
18    // A `clip-path` attribute must reference a `clipPath` element.
19    if node.tag_name() != Some(EId::ClipPath) {
20        return None;
21    }
22
23    // The whole clip path should be ignored when a transform is invalid.
24    let mut transform = resolve_clip_path_transform(node, state)?;
25
26    let units = node
27        .attribute(AId::ClipPathUnits)
28        .unwrap_or(Units::UserSpaceOnUse);
29
30    // Check if this element was already converted.
31    //
32    // Only `userSpaceOnUse` clipPaths can be shared,
33    // because `objectBoundingBox` one will be converted into user one
34    // and will become node-specific.
35    let cacheable = units == Units::UserSpaceOnUse;
36    if cacheable {
37        if let Some(clip) = cache.clip_paths.get(node.element_id()) {
38            return Some(clip.clone());
39        }
40    }
41
42    if units == Units::ObjectBoundingBox {
43        let object_bbox = match object_bbox {
44            Some(v) => v,
45            None => {
46                log::warn!("Clipping of zero-sized shapes is not allowed.");
47                return None;
48            }
49        };
50
51        let ts = Transform::from_bbox(object_bbox);
52        transform = transform.pre_concat(ts);
53    }
54
55    // Resolve linked clip path.
56    let mut clip_path = None;
57    if let Some(link) = node.attribute::<SvgNode>(AId::ClipPath) {
58        clip_path = convert(link, state, object_bbox, cache);
59
60        // Linked `clipPath` must be valid.
61        if clip_path.is_none() {
62            return None;
63        }
64    }
65
66    let mut id = NonEmptyString::new(node.element_id().to_string())?;
67    // Generate ID only when we're parsing `objectBoundingBox` clip for the second time.
68    if !cacheable && cache.clip_paths.contains_key(id.get()) {
69        id = cache.gen_clip_path_id();
70    }
71    let id_copy = id.get().to_string();
72
73    let mut clip = ClipPath {
74        id,
75        transform,
76        clip_path,
77        root: Group::empty(),
78    };
79
80    let mut clip_state = state.clone();
81    clip_state.parent_clip_path = Some(node);
82    converter::convert_clip_path_elements(node, &clip_state, cache, &mut clip.root);
83
84    if clip.root.has_children() {
85        clip.root.calculate_bounding_boxes();
86        let clip = Arc::new(clip);
87        cache.clip_paths.insert(id_copy, clip.clone());
88        Some(clip)
89    } else {
90        // A clip path without children is invalid.
91        None
92    }
93}
94
95fn resolve_clip_path_transform(node: SvgNode, state: &converter::State) -> Option<Transform> {
96    // Do not use Node::attribute::<Transform>, because it will always
97    // return a valid transform.
98
99    let value: &str = match node.attribute(AId::Transform) {
100        Some(v) => v,
101        None => return Some(Transform::default()),
102    };
103
104    let ts = match svgtypes::Transform::from_str(value) {
105        Ok(v) => v,
106        Err(_) => {
107            log::warn!("Failed to parse {} value: '{}'.", AId::Transform, value);
108            return None;
109        }
110    };
111
112    let ts = Transform::from_row(
113        ts.a as f32,
114        ts.b as f32,
115        ts.c as f32,
116        ts.d as f32,
117        ts.e as f32,
118        ts.f as f32,
119    );
120
121    if ts.is_valid() {
122        Some(node.resolve_transform(AId::Transform, state))
123    } else {
124        None
125    }
126}
usvg/parser/clippath.rs

usvg/parser/
clippath.rs
