1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
//! Layout tree.
//!
//! The idea is to take the DOM tree and produce a layout tree with SVG concepts.

use std::rc::Rc;

use cssparser::Color;
use float_cmp::approx_eq;

use crate::aspect_ratio::AspectRatio;
use crate::bbox::BoundingBox;
use crate::coord_units::CoordUnits;
use crate::dasharray::Dasharray;
use crate::document::AcquiredNodes;
use crate::element::{Element, ElementData};
use crate::filter::FilterValueList;
use crate::length::*;
use crate::node::*;
use crate::paint_server::{PaintSource, UserSpacePaintSource};
use crate::path_builder::Path;
use crate::properties::{
    self, ClipRule, ComputedValues, Direction, FillRule, FontFamily, FontStretch, FontStyle,
    FontVariant, FontWeight, ImageRendering, Isolation, MixBlendMode, Opacity, Overflow,
    PaintOrder, ShapeRendering, StrokeDasharray, StrokeLinecap, StrokeLinejoin, StrokeMiterlimit,
    TextDecoration, TextRendering, UnicodeBidi, VectorEffect, XmlLang,
};
use crate::rect::Rect;
use crate::rsvg_log;
use crate::session::Session;
use crate::surface_utils::shared_surface::SharedImageSurface;
use crate::transform::Transform;
use crate::unit_interval::UnitInterval;
use crate::viewbox::ViewBox;
use crate::{borrow_element_as, is_element_of_type};

/// SVG Stacking context, an inner node in the layout tree.
///
/// <https://www.w3.org/TR/SVG2/render.html#EstablishingStackingContex>
///
/// This is not strictly speaking an SVG2 stacking context, but a
/// looser version of it.  For example. the SVG spec mentions that a
/// an element should establish a stacking context if the `filter`
/// property applies to the element and is not `none`.  In that case,
/// the element is rendered as an "isolated group" -
/// <https://www.w3.org/TR/2015/CR-compositing-1-20150113/#csscompositingrules_SVG>
///
/// Here we store all the parameters that may lead to the decision to actually
/// render an element as an isolated group.
pub struct StackingContext {
    pub element_name: String,
    pub transform: Transform,
    pub opacity: Opacity,
    pub filter: Option<Filter>,
    pub clip_rect: Option<Rect>,
    pub clip_in_user_space: Option<Node>,
    pub clip_in_object_space: Option<Node>,
    pub mask: Option<Node>,
    pub mix_blend_mode: MixBlendMode,
    pub isolation: Isolation,

    /// Target from an `<a>` element
    pub link_target: Option<String>,
}

/// The item being rendered inside a stacking context.
pub struct Layer {
    pub kind: LayerKind,
    pub stacking_ctx: StackingContext,
}
pub enum LayerKind {
    Shape(Box<Shape>),
    Text(Box<Text>),
    Image(Box<Image>),
    Group(Box<Group>),
}

pub struct Group {
    pub children: Vec<Layer>,
    pub is_visible: bool, // FIXME: move to Layer?  All of them have this...
    pub establish_viewport: Option<LayoutViewport>,
}

/// Used for elements that need to establish a new viewport, like `<svg>`.
pub struct LayoutViewport {
    // transform goes in the group's layer's StackingContext
    /// Position and size of the element, per its x/y/width/height properties.
    /// For markers, this is markerWidth/markerHeight.
    pub geometry: Rect,

    /// viewBox attribute
    pub vbox: Option<ViewBox>,

    /// preserveAspectRatio attribute
    pub preserve_aspect_ratio: AspectRatio,

    /// overflow property
    pub overflow: Overflow,
}

/// Stroke parameters in user-space coordinates.
pub struct Stroke {
    pub width: f64,
    pub miter_limit: StrokeMiterlimit,
    pub line_cap: StrokeLinecap,
    pub line_join: StrokeLinejoin,
    pub dash_offset: f64,
    pub dashes: Box<[f64]>,
    // https://svgwg.org/svg2-draft/painting.html#non-scaling-stroke
    pub non_scaling: bool,
}

/// Paths and basic shapes resolved to a path.
pub struct Shape {
    pub path: Rc<Path>,
    pub extents: Option<Rect>,
    pub is_visible: bool,
    pub paint_order: PaintOrder,
    pub stroke: Stroke,
    pub stroke_paint: UserSpacePaintSource,
    pub fill_paint: UserSpacePaintSource,
    pub fill_rule: FillRule,
    pub clip_rule: ClipRule,
    pub shape_rendering: ShapeRendering,
    pub marker_start: Marker,
    pub marker_mid: Marker,
    pub marker_end: Marker,
}

pub struct Marker {
    pub node_ref: Option<Node>,
    pub context_stroke: Rc<PaintSource>,
    pub context_fill: Rc<PaintSource>,
}

/// Image in user-space coordinates.
pub struct Image {
    pub surface: SharedImageSurface,
    pub is_visible: bool,
    pub rect: Rect,
    pub aspect: AspectRatio,
    pub overflow: Overflow,
    pub image_rendering: ImageRendering,
}

/// A single text span in user-space coordinates.
pub struct TextSpan {
    pub layout: pango::Layout,
    pub gravity: pango::Gravity,
    pub bbox: Option<BoundingBox>,
    pub is_visible: bool,
    pub x: f64,
    pub y: f64,
    pub paint_order: PaintOrder,
    pub stroke: Stroke,
    pub stroke_paint: UserSpacePaintSource,
    pub fill_paint: UserSpacePaintSource,
    pub text_rendering: TextRendering,
    pub link_target: Option<String>,
}

/// Fully laid-out text in user-space coordinates.
pub struct Text {
    pub spans: Vec<TextSpan>,
}

/// Font-related properties extracted from `ComputedValues`.
pub struct FontProperties {
    pub xml_lang: XmlLang,
    pub unicode_bidi: UnicodeBidi,
    pub direction: Direction,
    pub font_family: FontFamily,
    pub font_style: FontStyle,
    pub font_variant: FontVariant,
    pub font_weight: FontWeight,
    pub font_stretch: FontStretch,
    pub font_size: f64,
    pub letter_spacing: f64,
    pub text_decoration: TextDecoration,
}

pub struct Filter {
    pub filter_list: FilterValueList,
    pub current_color: Color,
    pub stroke_paint_source: Rc<PaintSource>,
    pub fill_paint_source: Rc<PaintSource>,
    pub normalize_values: NormalizeValues,
}

fn get_filter(
    values: &ComputedValues,
    acquired_nodes: &mut AcquiredNodes<'_>,
    session: &Session,
) -> Option<Filter> {
    match values.filter() {
        properties::Filter::None => None,

        properties::Filter::List(filter_list) => Some(get_filter_from_filter_list(
            filter_list,
            acquired_nodes,
            values,
            session,
        )),
    }
}

fn get_filter_from_filter_list(
    filter_list: FilterValueList,
    acquired_nodes: &mut AcquiredNodes<'_>,
    values: &ComputedValues,
    session: &Session,
) -> Filter {
    let current_color = values.color().0;

    let stroke_paint_source = values.stroke().0.resolve(
        acquired_nodes,
        values.stroke_opacity().0,
        current_color,
        None,
        None,
        session,
    );

    let fill_paint_source = values.fill().0.resolve(
        acquired_nodes,
        values.fill_opacity().0,
        current_color,
        None,
        None,
        session,
    );

    let normalize_values = NormalizeValues::new(values);

    Filter {
        filter_list,
        current_color,
        stroke_paint_source,
        fill_paint_source,
        normalize_values,
    }
}

impl StackingContext {
    pub fn new(
        session: &Session,
        acquired_nodes: &mut AcquiredNodes<'_>,
        element: &Element,
        transform: Transform,
        clip_rect: Option<Rect>,
        values: &ComputedValues,
    ) -> StackingContext {
        let element_name = format!("{element}");

        let opacity;
        let filter;

        match element.element_data {
            // "The opacity, filter and display properties do not apply to the mask element"
            // https://drafts.fxtf.org/css-masking-1/#MaskElement
            ElementData::Mask(_) => {
                opacity = Opacity(UnitInterval::clamp(1.0));
                filter = None;
            }

            _ => {
                opacity = values.opacity();
                filter = get_filter(values, acquired_nodes, session);
            }
        }

        let clip_path = values.clip_path();
        let clip_uri = clip_path.0.get();
        let (clip_in_user_space, clip_in_object_space) = clip_uri
            .and_then(|node_id| {
                acquired_nodes
                    .acquire(node_id)
                    .ok()
                    .filter(|a| is_element_of_type!(*a.get(), ClipPath))
            })
            .map(|acquired| {
                let clip_node = acquired.get().clone();

                let units = borrow_element_as!(clip_node, ClipPath).get_units();

                match units {
                    CoordUnits::UserSpaceOnUse => (Some(clip_node), None),
                    CoordUnits::ObjectBoundingBox => (None, Some(clip_node)),
                }
            })
            .unwrap_or((None, None));

        let mask = values.mask().0.get().and_then(|mask_id| {
            if let Ok(acquired) = acquired_nodes.acquire(mask_id) {
                let node = acquired.get();
                match *node.borrow_element_data() {
                    ElementData::Mask(_) => Some(node.clone()),

                    _ => {
                        rsvg_log!(
                            session,
                            "element {} references \"{}\" which is not a mask",
                            element,
                            mask_id
                        );

                        None
                    }
                }
            } else {
                rsvg_log!(
                    session,
                    "element {} references nonexistent mask \"{}\"",
                    element,
                    mask_id
                );

                None
            }
        });

        let mix_blend_mode = values.mix_blend_mode();
        let isolation = values.isolation();

        StackingContext {
            element_name,
            transform,
            opacity,
            filter,
            clip_rect,
            clip_in_user_space,
            clip_in_object_space,
            mask,
            mix_blend_mode,
            isolation,
            link_target: None,
        }
    }

    pub fn new_with_link(
        session: &Session,
        acquired_nodes: &mut AcquiredNodes<'_>,
        element: &Element,
        transform: Transform,
        values: &ComputedValues,
        link_target: Option<String>,
    ) -> StackingContext {
        // Note that the clip_rect=Some(...) argument is only used by the markers code,
        // hence it is None here.  Something to refactor later.
        let mut ctx = Self::new(session, acquired_nodes, element, transform, None, values);
        ctx.link_target = link_target;
        ctx
    }

    pub fn should_isolate(&self) -> bool {
        let Opacity(UnitInterval(opacity)) = self.opacity;
        match self.isolation {
            Isolation::Auto => {
                let is_opaque = approx_eq!(f64, opacity, 1.0);
                !(is_opaque
                    && self.filter.is_none()
                    && self.mask.is_none()
                    && self.mix_blend_mode == MixBlendMode::Normal
                    && self.clip_in_object_space.is_none())
            }
            Isolation::Isolate => true,
        }
    }
}

impl Stroke {
    pub fn new(values: &ComputedValues, params: &NormalizeParams) -> Stroke {
        let width = values.stroke_width().0.to_user(params);
        let miter_limit = values.stroke_miterlimit();
        let line_cap = values.stroke_line_cap();
        let line_join = values.stroke_line_join();
        let dash_offset = values.stroke_dashoffset().0.to_user(params);
        let non_scaling = values.vector_effect() == VectorEffect::NonScalingStroke;

        let dashes = match values.stroke_dasharray() {
            StrokeDasharray(Dasharray::None) => Box::new([]),
            StrokeDasharray(Dasharray::Array(dashes)) => dashes
                .iter()
                .map(|l| l.to_user(params))
                .collect::<Box<[f64]>>(),
        };

        Stroke {
            width,
            miter_limit,
            line_cap,
            line_join,
            dash_offset,
            dashes,
            non_scaling,
        }
    }
}

impl FontProperties {
    /// Collects font properties from a `ComputedValues`.
    ///
    /// The `writing-mode` property is passed separately, as it must come from the `<text>` element,
    /// not the `<tspan>` whose computed values are being passed.
    pub fn new(values: &ComputedValues, params: &NormalizeParams) -> FontProperties {
        FontProperties {
            xml_lang: values.xml_lang(),
            unicode_bidi: values.unicode_bidi(),
            direction: values.direction(),
            font_family: values.font_family(),
            font_style: values.font_style(),
            font_variant: values.font_variant(),
            font_weight: values.font_weight(),
            font_stretch: values.font_stretch(),
            font_size: values.font_size().to_user(params),
            letter_spacing: values.letter_spacing().to_user(params),
            text_decoration: values.text_decoration(),
        }
    }
}