rsvg/
viewbox.rs

1//! Parser for the `viewBox` attribute.
2
3use cssparser::Parser;
4use std::ops::Deref;
5
6use crate::error::*;
7use crate::parsers::{CommaSeparatedList, Parse};
8use crate::rect::Rect;
9
10/// Newtype around a [`Rect`], used to represent the `viewBox` attribute.
11///
12/// A `ViewBox` is a new user-space coordinate system mapped onto the rectangle defined by
13/// the current viewport.  See <https://www.w3.org/TR/SVG2/coords.html#ViewBoxAttribute>
14///
15/// `ViewBox` derefs to [`Rect`], so you can use [`Rect`]'s methods and fields directly like
16/// `vbox.x0` or `vbox.width()`.
17#[derive(Debug, Copy, Clone, PartialEq)]
18pub struct ViewBox(Rect);
19
20impl Deref for ViewBox {
21    type Target = Rect;
22
23    fn deref(&self) -> &Rect {
24        &self.0
25    }
26}
27
28impl From<Rect> for ViewBox {
29    fn from(r: Rect) -> ViewBox {
30        ViewBox(r)
31    }
32}
33
34impl Parse for ViewBox {
35    // Parse a viewBox attribute
36    // https://www.w3.org/TR/SVG/coords.html#ViewBoxAttribute
37    //
38    // viewBox: double [,] double [,] double [,] double [,]
39    //
40    // x, y, w, h
41    //
42    // Where w and h must be nonnegative.
43    fn parse<'i>(parser: &mut Parser<'i, '_>) -> Result<ViewBox, ParseError<'i>> {
44        let loc = parser.current_source_location();
45
46        let CommaSeparatedList::<f64, 4, 4>(v) = CommaSeparatedList::parse(parser)?;
47        let (x, y, width, height) = (v[0], v[1], v[2], v[3]);
48
49        if width >= 0.0 && height >= 0.0 {
50            Ok(ViewBox(Rect::new(x, y, x + width, y + height)))
51        } else {
52            Err(loc.new_custom_error(ValueErrorKind::value_error(
53                "width and height must not be negative",
54            )))
55        }
56    }
57}
58
59#[cfg(test)]
60mod tests {
61    use super::*;
62
63    #[test]
64    fn parses_valid_viewboxes() {
65        assert_eq!(
66            ViewBox::parse_str("  1 2 3 4").unwrap(),
67            ViewBox(Rect::new(1.0, 2.0, 4.0, 6.0))
68        );
69
70        assert_eq!(
71            ViewBox::parse_str(" -1.5 -2.5e1,34,56e2  ").unwrap(),
72            ViewBox(Rect::new(-1.5, -25.0, 32.5, 5575.0))
73        );
74    }
75
76    #[test]
77    fn parsing_invalid_viewboxes_yields_error() {
78        assert!(ViewBox::parse_str("").is_err());
79        assert!(ViewBox::parse_str(" 1,2,-3,-4 ").is_err());
80        assert!(ViewBox::parse_str("qwerasdfzxcv").is_err());
81        assert!(ViewBox::parse_str(" 1 2 3 4   5").is_err());
82        assert!(ViewBox::parse_str(" 1 2 foo 3 4").is_err());
83
84        // https://gitlab.gnome.org/GNOME/librsvg/issues/344
85        assert!(ViewBox::parse_str("0 0 9E80.7").is_err());
86    }
87}
rsvg/viewbox.rs

rsvg/
viewbox.rs
