diff options
Diffstat (limited to 'servo/components/style/values/specified/svg_path.rs')
| -rw-r--r-- | servo/components/style/values/specified/svg_path.rs | 1029 |
1 files changed, 1029 insertions, 0 deletions
diff --git a/servo/components/style/values/specified/svg_path.rs b/servo/components/style/values/specified/svg_path.rs new file mode 100644 index 0000000000..1eb9866dd1 --- /dev/null +++ b/servo/components/style/values/specified/svg_path.rs @@ -0,0 +1,1029 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at https://mozilla.org/MPL/2.0/. */ + +//! Specified types for SVG Path. + +use crate::parser::{Parse, ParserContext}; +use crate::values::animated::{lists, Animate, Procedure, ToAnimatedZero}; +use crate::values::distance::{ComputeSquaredDistance, SquaredDistance}; +use crate::values::CSSFloat; +use cssparser::Parser; +use std::fmt::{self, Write}; +use std::iter::{Cloned, Peekable}; +use std::slice; +use style_traits::values::SequenceWriter; +use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss}; + +/// Whether to allow empty string in the parser. +#[derive(Clone, Debug, Eq, PartialEq)] +#[allow(missing_docs)] +pub enum AllowEmpty { + Yes, + No, +} + +/// The SVG path data. +/// +/// https://www.w3.org/TR/SVG11/paths.html#PathData +#[derive( + Clone, + Debug, + Deserialize, + MallocSizeOf, + PartialEq, + Serialize, + SpecifiedValueInfo, + ToAnimatedZero, + ToComputedValue, + ToResolvedValue, + ToShmem, +)] +#[repr(C)] +pub struct SVGPathData( + // TODO(emilio): Should probably measure this somehow only from the + // specified values. + #[ignore_malloc_size_of = "Arc"] pub crate::ArcSlice<PathCommand>, +); + +impl SVGPathData { + /// Get the array of PathCommand. + #[inline] + pub fn commands(&self) -> &[PathCommand] { + &self.0 + } + + /// Create a normalized copy of this path by converting each relative + /// command to an absolute command. + pub fn normalize(&self) -> Self { + let mut state = PathTraversalState { + subpath_start: CoordPair::new(0.0, 0.0), + pos: CoordPair::new(0.0, 0.0), + }; + let iter = self.0.iter().map(|seg| seg.normalize(&mut state)); + SVGPathData(crate::ArcSlice::from_iter(iter)) + } + + // FIXME: Bug 1714238, we may drop this once we use the same data structure for both SVG and + // CSS. + /// Decode the svg path raw data from Gecko. + #[cfg(feature = "gecko")] + pub fn decode_from_f32_array(path: &[f32]) -> Result<Self, ()> { + use crate::gecko_bindings::structs::dom::SVGPathSeg_Binding::*; + + let mut result: Vec<PathCommand> = Vec::new(); + let mut i: usize = 0; + while i < path.len() { + // See EncodeType() and DecodeType() in SVGPathSegUtils.h. + // We are using reinterpret_cast<> to encode and decode between u32 and f32, so here we + // use to_bits() to decode the type. + let seg_type = path[i].to_bits() as u16; + i = i + 1; + match seg_type { + PATHSEG_CLOSEPATH => result.push(PathCommand::ClosePath), + PATHSEG_MOVETO_ABS | PATHSEG_MOVETO_REL => { + debug_assert!(i + 1 < path.len()); + result.push(PathCommand::MoveTo { + point: CoordPair::new(path[i], path[i + 1]), + absolute: IsAbsolute::new(seg_type == PATHSEG_MOVETO_ABS), + }); + i = i + 2; + }, + PATHSEG_LINETO_ABS | PATHSEG_LINETO_REL => { + debug_assert!(i + 1 < path.len()); + result.push(PathCommand::LineTo { + point: CoordPair::new(path[i], path[i + 1]), + absolute: IsAbsolute::new(seg_type == PATHSEG_LINETO_ABS), + }); + i = i + 2; + }, + PATHSEG_CURVETO_CUBIC_ABS | PATHSEG_CURVETO_CUBIC_REL => { + debug_assert!(i + 5 < path.len()); + result.push(PathCommand::CurveTo { + control1: CoordPair::new(path[i], path[i + 1]), + control2: CoordPair::new(path[i + 2], path[i + 3]), + point: CoordPair::new(path[i + 4], path[i + 5]), + absolute: IsAbsolute::new(seg_type == PATHSEG_CURVETO_CUBIC_ABS), + }); + i = i + 6; + }, + PATHSEG_CURVETO_QUADRATIC_ABS | PATHSEG_CURVETO_QUADRATIC_REL => { + debug_assert!(i + 3 < path.len()); + result.push(PathCommand::QuadBezierCurveTo { + control1: CoordPair::new(path[i], path[i + 1]), + point: CoordPair::new(path[i + 2], path[i + 3]), + absolute: IsAbsolute::new(seg_type == PATHSEG_CURVETO_QUADRATIC_ABS), + }); + i = i + 4; + }, + PATHSEG_ARC_ABS | PATHSEG_ARC_REL => { + debug_assert!(i + 6 < path.len()); + result.push(PathCommand::EllipticalArc { + rx: path[i], + ry: path[i + 1], + angle: path[i + 2], + large_arc_flag: ArcFlag(path[i + 3] != 0.0f32), + sweep_flag: ArcFlag(path[i + 4] != 0.0f32), + point: CoordPair::new(path[i + 5], path[i + 6]), + absolute: IsAbsolute::new(seg_type == PATHSEG_ARC_ABS), + }); + i = i + 7; + }, + PATHSEG_LINETO_HORIZONTAL_ABS | PATHSEG_LINETO_HORIZONTAL_REL => { + debug_assert!(i < path.len()); + result.push(PathCommand::HorizontalLineTo { + x: path[i], + absolute: IsAbsolute::new(seg_type == PATHSEG_LINETO_HORIZONTAL_ABS), + }); + i = i + 1; + }, + PATHSEG_LINETO_VERTICAL_ABS | PATHSEG_LINETO_VERTICAL_REL => { + debug_assert!(i < path.len()); + result.push(PathCommand::VerticalLineTo { + y: path[i], + absolute: IsAbsolute::new(seg_type == PATHSEG_LINETO_VERTICAL_ABS), + }); + i = i + 1; + }, + PATHSEG_CURVETO_CUBIC_SMOOTH_ABS | PATHSEG_CURVETO_CUBIC_SMOOTH_REL => { + debug_assert!(i + 3 < path.len()); + result.push(PathCommand::SmoothCurveTo { + control2: CoordPair::new(path[i], path[i + 1]), + point: CoordPair::new(path[i + 2], path[i + 3]), + absolute: IsAbsolute::new(seg_type == PATHSEG_CURVETO_CUBIC_SMOOTH_ABS), + }); + i = i + 4; + }, + PATHSEG_CURVETO_QUADRATIC_SMOOTH_ABS | PATHSEG_CURVETO_QUADRATIC_SMOOTH_REL => { + debug_assert!(i + 1 < path.len()); + result.push(PathCommand::SmoothQuadBezierCurveTo { + point: CoordPair::new(path[i], path[i + 1]), + absolute: IsAbsolute::new(seg_type == PATHSEG_CURVETO_QUADRATIC_SMOOTH_ABS), + }); + i = i + 2; + }, + PATHSEG_UNKNOWN | _ => return Err(()), + } + } + + Ok(SVGPathData(crate::ArcSlice::from_iter(result.into_iter()))) + } + + /// Parse this SVG path string with the argument that indicates whether we should allow the + /// empty string. + // We cannot use cssparser::Parser to parse a SVG path string because the spec wants to make + // the SVG path string as compact as possible. (i.e. The whitespaces may be dropped.) + // e.g. "M100 200L100 200" is a valid SVG path string. If we use tokenizer, the first ident + // is "M100", instead of "M", and this is not correct. Therefore, we use a Peekable + // str::Char iterator to check each character. + pub fn parse<'i, 't>( + input: &mut Parser<'i, 't>, + allow_empty: AllowEmpty, + ) -> Result<Self, ParseError<'i>> { + let location = input.current_source_location(); + let path_string = input.expect_string()?.as_ref(); + + // Parse the svg path string as multiple sub-paths. + let mut path_parser = PathParser::new(path_string); + while skip_wsp(&mut path_parser.chars) { + if path_parser.parse_subpath().is_err() { + return Err(location.new_custom_error(StyleParseErrorKind::UnspecifiedError)); + } + } + + // The css-shapes-1 says a path data string that does conform but defines an empty path is + // invalid and causes the entire path() to be invalid, so we use the argement to decide + // whether we should allow the empty string. + // https://drafts.csswg.org/css-shapes-1/#typedef-basic-shape + if matches!(allow_empty, AllowEmpty::No) && path_parser.path.is_empty() { + return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError)); + } + + Ok(SVGPathData(crate::ArcSlice::from_iter( + path_parser.path.into_iter(), + ))) + } +} + +impl ToCss for SVGPathData { + #[inline] + fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result + where + W: fmt::Write, + { + dest.write_char('"')?; + { + let mut writer = SequenceWriter::new(dest, " "); + for command in self.commands() { + writer.item(command)?; + } + } + dest.write_char('"') + } +} + +impl Parse for SVGPathData { + fn parse<'i, 't>( + _context: &ParserContext, + input: &mut Parser<'i, 't>, + ) -> Result<Self, ParseError<'i>> { + // Note that the EBNF allows the path data string in the d property to be empty, so we + // don't reject empty SVG path data. + // https://svgwg.org/svg2-draft/single-page.html#paths-PathDataBNF + SVGPathData::parse(input, AllowEmpty::Yes) + } +} + +impl Animate for SVGPathData { + fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> { + if self.0.len() != other.0.len() { + return Err(()); + } + + // FIXME(emilio): This allocates three copies of the path, that's not + // great! Specially, once we're normalized once, we don't need to + // re-normalize again. + let left = self.normalize(); + let right = other.normalize(); + + let items: Vec<_> = lists::by_computed_value::animate(&left.0, &right.0, procedure)?; + Ok(SVGPathData(crate::ArcSlice::from_iter(items.into_iter()))) + } +} + +impl ComputeSquaredDistance for SVGPathData { + fn compute_squared_distance(&self, other: &Self) -> Result<SquaredDistance, ()> { + if self.0.len() != other.0.len() { + return Err(()); + } + let left = self.normalize(); + let right = other.normalize(); + lists::by_computed_value::squared_distance(&left.0, &right.0) + } +} + +/// The SVG path command. +/// The fields of these commands are self-explanatory, so we skip the documents. +/// Note: the index of the control points, e.g. control1, control2, are mapping to the control +/// points of the Bézier curve in the spec. +/// +/// https://www.w3.org/TR/SVG11/paths.html#PathData +#[derive( + Animate, + Clone, + ComputeSquaredDistance, + Copy, + Debug, + Deserialize, + MallocSizeOf, + PartialEq, + Serialize, + SpecifiedValueInfo, + ToAnimatedZero, + ToComputedValue, + ToResolvedValue, + ToShmem, +)] +#[allow(missing_docs)] +#[repr(C, u8)] +pub enum PathCommand { + /// The unknown type. + /// https://www.w3.org/TR/SVG/paths.html#__svg__SVGPathSeg__PATHSEG_UNKNOWN + Unknown, + /// The "moveto" command. + MoveTo { + point: CoordPair, + absolute: IsAbsolute, + }, + /// The "lineto" command. + LineTo { + point: CoordPair, + absolute: IsAbsolute, + }, + /// The horizontal "lineto" command. + HorizontalLineTo { x: CSSFloat, absolute: IsAbsolute }, + /// The vertical "lineto" command. + VerticalLineTo { y: CSSFloat, absolute: IsAbsolute }, + /// The cubic Bézier curve command. + CurveTo { + control1: CoordPair, + control2: CoordPair, + point: CoordPair, + absolute: IsAbsolute, + }, + /// The smooth curve command. + SmoothCurveTo { + control2: CoordPair, + point: CoordPair, + absolute: IsAbsolute, + }, + /// The quadratic Bézier curve command. + QuadBezierCurveTo { + control1: CoordPair, + point: CoordPair, + absolute: IsAbsolute, + }, + /// The smooth quadratic Bézier curve command. + SmoothQuadBezierCurveTo { + point: CoordPair, + absolute: IsAbsolute, + }, + /// The elliptical arc curve command. + EllipticalArc { + rx: CSSFloat, + ry: CSSFloat, + angle: CSSFloat, + large_arc_flag: ArcFlag, + sweep_flag: ArcFlag, + point: CoordPair, + absolute: IsAbsolute, + }, + /// The "closepath" command. + ClosePath, +} + +/// For internal SVGPath normalization. +#[allow(missing_docs)] +struct PathTraversalState { + subpath_start: CoordPair, + pos: CoordPair, +} + +impl PathCommand { + /// Create a normalized copy of this PathCommand. Absolute commands will be copied as-is while + /// for relative commands an equivalent absolute command will be returned. + /// + /// See discussion: https://github.com/w3c/svgwg/issues/321 + fn normalize(&self, state: &mut PathTraversalState) -> Self { + use self::PathCommand::*; + match *self { + Unknown => Unknown, + ClosePath => { + state.pos = state.subpath_start; + ClosePath + }, + MoveTo { + mut point, + absolute, + } => { + if !absolute.is_yes() { + point += state.pos; + } + state.pos = point; + state.subpath_start = point; + MoveTo { + point, + absolute: IsAbsolute::Yes, + } + }, + LineTo { + mut point, + absolute, + } => { + if !absolute.is_yes() { + point += state.pos; + } + state.pos = point; + LineTo { + point, + absolute: IsAbsolute::Yes, + } + }, + HorizontalLineTo { mut x, absolute } => { + if !absolute.is_yes() { + x += state.pos.x; + } + state.pos.x = x; + HorizontalLineTo { + x, + absolute: IsAbsolute::Yes, + } + }, + VerticalLineTo { mut y, absolute } => { + if !absolute.is_yes() { + y += state.pos.y; + } + state.pos.y = y; + VerticalLineTo { + y, + absolute: IsAbsolute::Yes, + } + }, + CurveTo { + mut control1, + mut control2, + mut point, + absolute, + } => { + if !absolute.is_yes() { + control1 += state.pos; + control2 += state.pos; + point += state.pos; + } + state.pos = point; + CurveTo { + control1, + control2, + point, + absolute: IsAbsolute::Yes, + } + }, + SmoothCurveTo { + mut control2, + mut point, + absolute, + } => { + if !absolute.is_yes() { + control2 += state.pos; + point += state.pos; + } + state.pos = point; + SmoothCurveTo { + control2, + point, + absolute: IsAbsolute::Yes, + } + }, + QuadBezierCurveTo { + mut control1, + mut point, + absolute, + } => { + if !absolute.is_yes() { + control1 += state.pos; + point += state.pos; + } + state.pos = point; + QuadBezierCurveTo { + control1, + point, + absolute: IsAbsolute::Yes, + } + }, + SmoothQuadBezierCurveTo { + mut point, + absolute, + } => { + if !absolute.is_yes() { + point += state.pos; + } + state.pos = point; + SmoothQuadBezierCurveTo { + point, + absolute: IsAbsolute::Yes, + } + }, + EllipticalArc { + rx, + ry, + angle, + large_arc_flag, + sweep_flag, + mut point, + absolute, + } => { + if !absolute.is_yes() { + point += state.pos; + } + state.pos = point; + EllipticalArc { + rx, + ry, + angle, + large_arc_flag, + sweep_flag, + point, + absolute: IsAbsolute::Yes, + } + }, + } + } +} + +impl ToCss for PathCommand { + fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result + where + W: fmt::Write, + { + use self::PathCommand::*; + match *self { + Unknown => dest.write_char('X'), + ClosePath => dest.write_char('Z'), + MoveTo { point, absolute } => { + dest.write_char(if absolute.is_yes() { 'M' } else { 'm' })?; + dest.write_char(' ')?; + point.to_css(dest) + }, + LineTo { point, absolute } => { + dest.write_char(if absolute.is_yes() { 'L' } else { 'l' })?; + dest.write_char(' ')?; + point.to_css(dest) + }, + CurveTo { + control1, + control2, + point, + absolute, + } => { + dest.write_char(if absolute.is_yes() { 'C' } else { 'c' })?; + dest.write_char(' ')?; + control1.to_css(dest)?; + dest.write_char(' ')?; + control2.to_css(dest)?; + dest.write_char(' ')?; + point.to_css(dest) + }, + QuadBezierCurveTo { + control1, + point, + absolute, + } => { + dest.write_char(if absolute.is_yes() { 'Q' } else { 'q' })?; + dest.write_char(' ')?; + control1.to_css(dest)?; + dest.write_char(' ')?; + point.to_css(dest) + }, + EllipticalArc { + rx, + ry, + angle, + large_arc_flag, + sweep_flag, + point, + absolute, + } => { + dest.write_char(if absolute.is_yes() { 'A' } else { 'a' })?; + dest.write_char(' ')?; + rx.to_css(dest)?; + dest.write_char(' ')?; + ry.to_css(dest)?; + dest.write_char(' ')?; + angle.to_css(dest)?; + dest.write_char(' ')?; + large_arc_flag.to_css(dest)?; + dest.write_char(' ')?; + sweep_flag.to_css(dest)?; + dest.write_char(' ')?; + point.to_css(dest) + }, + HorizontalLineTo { x, absolute } => { + dest.write_char(if absolute.is_yes() { 'H' } else { 'h' })?; + dest.write_char(' ')?; + x.to_css(dest) + }, + VerticalLineTo { y, absolute } => { + dest.write_char(if absolute.is_yes() { 'V' } else { 'v' })?; + dest.write_char(' ')?; + y.to_css(dest) + }, + SmoothCurveTo { + control2, + point, + absolute, + } => { + dest.write_char(if absolute.is_yes() { 'S' } else { 's' })?; + dest.write_char(' ')?; + control2.to_css(dest)?; + dest.write_char(' ')?; + point.to_css(dest) + }, + SmoothQuadBezierCurveTo { point, absolute } => { + dest.write_char(if absolute.is_yes() { 'T' } else { 't' })?; + dest.write_char(' ')?; + point.to_css(dest) + }, + } + } +} + +/// The path command absolute type. +#[allow(missing_docs)] +#[derive( + Animate, + Clone, + ComputeSquaredDistance, + Copy, + Debug, + Deserialize, + MallocSizeOf, + PartialEq, + Serialize, + SpecifiedValueInfo, + ToAnimatedZero, + ToComputedValue, + ToResolvedValue, + ToShmem, +)] +#[repr(u8)] +pub enum IsAbsolute { + Yes, + No, +} + +impl IsAbsolute { + /// Return true if this is IsAbsolute::Yes. + #[inline] + pub fn is_yes(&self) -> bool { + *self == IsAbsolute::Yes + } + + /// Return Yes if value is true. Otherwise, return No. + #[inline] + fn new(value: bool) -> Self { + if value { + IsAbsolute::Yes + } else { + IsAbsolute::No + } + } +} + +/// The path coord type. +#[allow(missing_docs)] +#[derive( + AddAssign, + Animate, + Clone, + ComputeSquaredDistance, + Copy, + Debug, + Deserialize, + MallocSizeOf, + PartialEq, + Serialize, + SpecifiedValueInfo, + ToAnimatedZero, + ToComputedValue, + ToCss, + ToResolvedValue, + ToShmem, +)] +#[repr(C)] +pub struct CoordPair { + x: CSSFloat, + y: CSSFloat, +} + +impl CoordPair { + /// Create a CoordPair. + #[inline] + pub fn new(x: CSSFloat, y: CSSFloat) -> Self { + CoordPair { x, y } + } +} + +/// The EllipticalArc flag type. +#[derive( + Clone, + Copy, + Debug, + Deserialize, + MallocSizeOf, + PartialEq, + Serialize, + SpecifiedValueInfo, + ToComputedValue, + ToResolvedValue, + ToShmem, +)] +#[repr(C)] +pub struct ArcFlag(bool); + +impl ToCss for ArcFlag { + #[inline] + fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result + where + W: fmt::Write, + { + (self.0 as i32).to_css(dest) + } +} + +impl Animate for ArcFlag { + #[inline] + fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> { + (self.0 as i32) + .animate(&(other.0 as i32), procedure) + .map(|v| ArcFlag(v > 0)) + } +} + +impl ComputeSquaredDistance for ArcFlag { + #[inline] + fn compute_squared_distance(&self, other: &Self) -> Result<SquaredDistance, ()> { + (self.0 as i32).compute_squared_distance(&(other.0 as i32)) + } +} + +impl ToAnimatedZero for ArcFlag { + #[inline] + fn to_animated_zero(&self) -> Result<Self, ()> { + // The 2 ArcFlags in EllipticalArc determine which one of the 4 different arcs will be + // used. (i.e. From 4 combinations). In other words, if we change the flag, we get a + // different arc. Therefore, we return *self. + // https://svgwg.org/svg2-draft/paths.html#PathDataEllipticalArcCommands + Ok(*self) + } +} + +/// SVG Path parser. +struct PathParser<'a> { + chars: Peekable<Cloned<slice::Iter<'a, u8>>>, + path: Vec<PathCommand>, +} + +macro_rules! parse_arguments { + ( + $parser:ident, + $abs:ident, + $enum:ident, + [ $para:ident => $func:ident $(, $other_para:ident => $other_func:ident)* ] + ) => { + { + loop { + let $para = $func(&mut $parser.chars)?; + $( + skip_comma_wsp(&mut $parser.chars); + let $other_para = $other_func(&mut $parser.chars)?; + )* + $parser.path.push(PathCommand::$enum { $para $(, $other_para)*, $abs }); + + // End of string or the next character is a possible new command. + if !skip_wsp(&mut $parser.chars) || + $parser.chars.peek().map_or(true, |c| c.is_ascii_alphabetic()) { + break; + } + skip_comma_wsp(&mut $parser.chars); + } + Ok(()) + } + } +} + +impl<'a> PathParser<'a> { + /// Return a PathParser. + #[inline] + fn new(string: &'a str) -> Self { + PathParser { + chars: string.as_bytes().iter().cloned().peekable(), + path: Vec::new(), + } + } + + /// Parse a sub-path. + fn parse_subpath(&mut self) -> Result<(), ()> { + // Handle "moveto" Command first. If there is no "moveto", this is not a valid sub-path + // (i.e. not a valid moveto-drawto-command-group). + self.parse_moveto()?; + + // Handle other commands. + loop { + skip_wsp(&mut self.chars); + if self.chars.peek().map_or(true, |&m| m == b'M' || m == b'm') { + break; + } + + let command = self.chars.next().unwrap(); + let abs = if command.is_ascii_uppercase() { + IsAbsolute::Yes + } else { + IsAbsolute::No + }; + + skip_wsp(&mut self.chars); + match command { + b'Z' | b'z' => self.parse_closepath(), + b'L' | b'l' => self.parse_lineto(abs), + b'H' | b'h' => self.parse_h_lineto(abs), + b'V' | b'v' => self.parse_v_lineto(abs), + b'C' | b'c' => self.parse_curveto(abs), + b'S' | b's' => self.parse_smooth_curveto(abs), + b'Q' | b'q' => self.parse_quadratic_bezier_curveto(abs), + b'T' | b't' => self.parse_smooth_quadratic_bezier_curveto(abs), + b'A' | b'a' => self.parse_elliptical_arc(abs), + _ => return Err(()), + }?; + } + Ok(()) + } + + /// Parse "moveto" command. + fn parse_moveto(&mut self) -> Result<(), ()> { + let command = match self.chars.next() { + Some(c) if c == b'M' || c == b'm' => c, + _ => return Err(()), + }; + + skip_wsp(&mut self.chars); + let point = parse_coord(&mut self.chars)?; + let absolute = if command == b'M' { + IsAbsolute::Yes + } else { + IsAbsolute::No + }; + self.path.push(PathCommand::MoveTo { point, absolute }); + + // End of string or the next character is a possible new command. + if !skip_wsp(&mut self.chars) || self.chars.peek().map_or(true, |c| c.is_ascii_alphabetic()) + { + return Ok(()); + } + skip_comma_wsp(&mut self.chars); + + // If a moveto is followed by multiple pairs of coordinates, the subsequent + // pairs are treated as implicit lineto commands. + self.parse_lineto(absolute) + } + + /// Parse "closepath" command. + fn parse_closepath(&mut self) -> Result<(), ()> { + self.path.push(PathCommand::ClosePath); + Ok(()) + } + + /// Parse "lineto" command. + fn parse_lineto(&mut self, absolute: IsAbsolute) -> Result<(), ()> { + parse_arguments!(self, absolute, LineTo, [ point => parse_coord ]) + } + + /// Parse horizontal "lineto" command. + fn parse_h_lineto(&mut self, absolute: IsAbsolute) -> Result<(), ()> { + parse_arguments!(self, absolute, HorizontalLineTo, [ x => parse_number ]) + } + + /// Parse vertical "lineto" command. + fn parse_v_lineto(&mut self, absolute: IsAbsolute) -> Result<(), ()> { + parse_arguments!(self, absolute, VerticalLineTo, [ y => parse_number ]) + } + + /// Parse cubic Bézier curve command. + fn parse_curveto(&mut self, absolute: IsAbsolute) -> Result<(), ()> { + parse_arguments!(self, absolute, CurveTo, [ + control1 => parse_coord, control2 => parse_coord, point => parse_coord + ]) + } + + /// Parse smooth "curveto" command. + fn parse_smooth_curveto(&mut self, absolute: IsAbsolute) -> Result<(), ()> { + parse_arguments!(self, absolute, SmoothCurveTo, [ + control2 => parse_coord, point => parse_coord + ]) + } + + /// Parse quadratic Bézier curve command. + fn parse_quadratic_bezier_curveto(&mut self, absolute: IsAbsolute) -> Result<(), ()> { + parse_arguments!(self, absolute, QuadBezierCurveTo, [ + control1 => parse_coord, point => parse_coord + ]) + } + + /// Parse smooth quadratic Bézier curveto command. + fn parse_smooth_quadratic_bezier_curveto(&mut self, absolute: IsAbsolute) -> Result<(), ()> { + parse_arguments!(self, absolute, SmoothQuadBezierCurveTo, [ point => parse_coord ]) + } + + /// Parse elliptical arc curve command. + fn parse_elliptical_arc(&mut self, absolute: IsAbsolute) -> Result<(), ()> { + // Parse a flag whose value is '0' or '1'; otherwise, return Err(()). + let parse_flag = |iter: &mut Peekable<Cloned<slice::Iter<u8>>>| match iter.next() { + Some(c) if c == b'0' || c == b'1' => Ok(ArcFlag(c == b'1')), + _ => Err(()), + }; + parse_arguments!(self, absolute, EllipticalArc, [ + rx => parse_number, + ry => parse_number, + angle => parse_number, + large_arc_flag => parse_flag, + sweep_flag => parse_flag, + point => parse_coord + ]) + } +} + +/// Parse a pair of numbers into CoordPair. +fn parse_coord(iter: &mut Peekable<Cloned<slice::Iter<u8>>>) -> Result<CoordPair, ()> { + let x = parse_number(iter)?; + skip_comma_wsp(iter); + let y = parse_number(iter)?; + Ok(CoordPair::new(x, y)) +} + +/// This is a special version which parses the number for SVG Path. e.g. "M 0.6.5" should be parsed +/// as MoveTo with a coordinate of ("0.6", ".5"), instead of treating 0.6.5 as a non-valid floating +/// point number. In other words, the logic here is similar with that of +/// tokenizer::consume_numeric, which also consumes the number as many as possible, but here the +/// input is a Peekable and we only accept an integer of a floating point number. +/// +/// The "number" syntax in https://www.w3.org/TR/SVG/paths.html#PathDataBNF +fn parse_number(iter: &mut Peekable<Cloned<slice::Iter<u8>>>) -> Result<CSSFloat, ()> { + // 1. Check optional sign. + let sign = if iter + .peek() + .map_or(false, |&sign| sign == b'+' || sign == b'-') + { + if iter.next().unwrap() == b'-' { + -1. + } else { + 1. + } + } else { + 1. + }; + + // 2. Check integer part. + let mut integral_part: f64 = 0.; + let got_dot = if !iter.peek().map_or(false, |&n| n == b'.') { + // If the first digit in integer part is neither a dot nor a digit, this is not a number. + if iter.peek().map_or(true, |n| !n.is_ascii_digit()) { + return Err(()); + } + + while iter.peek().map_or(false, |n| n.is_ascii_digit()) { + integral_part = integral_part * 10. + (iter.next().unwrap() - b'0') as f64; + } + + iter.peek().map_or(false, |&n| n == b'.') + } else { + true + }; + + // 3. Check fractional part. + let mut fractional_part: f64 = 0.; + if got_dot { + // Consume '.'. + iter.next(); + // If the first digit in fractional part is not a digit, this is not a number. + if iter.peek().map_or(true, |n| !n.is_ascii_digit()) { + return Err(()); + } + + let mut factor = 0.1; + while iter.peek().map_or(false, |n| n.is_ascii_digit()) { + fractional_part += (iter.next().unwrap() - b'0') as f64 * factor; + factor *= 0.1; + } + } + + let mut value = sign * (integral_part + fractional_part); + + // 4. Check exp part. The segment name of SVG Path doesn't include 'E' or 'e', so it's ok to + // treat the numbers after 'E' or 'e' are in the exponential part. + if iter.peek().map_or(false, |&exp| exp == b'E' || exp == b'e') { + // Consume 'E' or 'e'. + iter.next(); + let exp_sign = if iter + .peek() + .map_or(false, |&sign| sign == b'+' || sign == b'-') + { + if iter.next().unwrap() == b'-' { + -1. + } else { + 1. + } + } else { + 1. + }; + + let mut exp: f64 = 0.; + while iter.peek().map_or(false, |n| n.is_ascii_digit()) { + exp = exp * 10. + (iter.next().unwrap() - b'0') as f64; + } + + value *= f64::powf(10., exp * exp_sign); + } + + if value.is_finite() { + Ok(value.min(f32::MAX as f64).max(f32::MIN as f64) as CSSFloat) + } else { + Err(()) + } +} + +/// Skip all svg whitespaces, and return true if |iter| hasn't finished. +#[inline] +fn skip_wsp(iter: &mut Peekable<Cloned<slice::Iter<u8>>>) -> bool { + // Note: SVG 1.1 defines the whitespaces as \u{9}, \u{20}, \u{A}, \u{D}. + // However, SVG 2 has one extra whitespace: \u{C}. + // Therefore, we follow the newest spec for the definition of whitespace, + // i.e. \u{9}, \u{20}, \u{A}, \u{C}, \u{D}. + while iter.peek().map_or(false, |c| c.is_ascii_whitespace()) { + iter.next(); + } + iter.peek().is_some() +} + +/// Skip all svg whitespaces and one comma, and return true if |iter| hasn't finished. +#[inline] +fn skip_comma_wsp(iter: &mut Peekable<Cloned<slice::Iter<u8>>>) -> bool { + if !skip_wsp(iter) { + return false; + } + + if *iter.peek().unwrap() != b',' { + return true; + } + iter.next(); + + skip_wsp(iter) +} |