style.rs

   1use std::{
   2    hash::{Hash, Hasher},
   3    iter, mem,
   4    ops::Range,
   5};
   6
   7use crate::{
   8    AbsoluteLength, App, Background, BackgroundTag, BorderStyle, Bounds, ContentMask, Corners,
   9    CornersRefinement, CursorStyle, DefiniteLength, DevicePixels, Edges, EdgesRefinement, Font,
  10    FontFallbacks, FontFeatures, FontStyle, FontWeight, GridLocation, Hsla, Length, Pixels, Point,
  11    PointRefinement, Rgba, SharedString, Size, SizeRefinement, Styled, TextRun, Window, black, phi,
  12    point, quad, rems, size,
  13};
  14use collections::HashSet;
  15use refineable::Refineable;
  16use schemars::JsonSchema;
  17use serde::{Deserialize, Serialize};
  18
  19/// Use this struct for interfacing with the 'debug_below' styling from your own elements.
  20/// If a parent element has this style set on it, then this struct will be set as a global in
  21/// GPUI.
  22#[cfg(debug_assertions)]
  23pub struct DebugBelow;
  24
  25#[cfg(debug_assertions)]
  26impl crate::Global for DebugBelow {}
  27
  28/// How to fit the image into the bounds of the element.
  29pub enum ObjectFit {
  30    /// The image will be stretched to fill the bounds of the element.
  31    Fill,
  32    /// The image will be scaled to fit within the bounds of the element.
  33    Contain,
  34    /// The image will be scaled to cover the bounds of the element.
  35    Cover,
  36    /// The image will be scaled down to fit within the bounds of the element.
  37    ScaleDown,
  38    /// The image will maintain its original size.
  39    None,
  40}
  41
  42impl ObjectFit {
  43    /// Get the bounds of the image within the given bounds.
  44    pub fn get_bounds(
  45        &self,
  46        bounds: Bounds<Pixels>,
  47        image_size: Size<DevicePixels>,
  48    ) -> Bounds<Pixels> {
  49        let image_size = image_size.map(|dimension| Pixels::from(u32::from(dimension)));
  50        let image_ratio = image_size.width / image_size.height;
  51        let bounds_ratio = bounds.size.width / bounds.size.height;
  52
  53        match self {
  54            ObjectFit::Fill => bounds,
  55            ObjectFit::Contain => {
  56                let new_size = if bounds_ratio > image_ratio {
  57                    size(
  58                        image_size.width * (bounds.size.height / image_size.height),
  59                        bounds.size.height,
  60                    )
  61                } else {
  62                    size(
  63                        bounds.size.width,
  64                        image_size.height * (bounds.size.width / image_size.width),
  65                    )
  66                };
  67
  68                Bounds {
  69                    origin: point(
  70                        bounds.origin.x + (bounds.size.width - new_size.width) / 2.0,
  71                        bounds.origin.y + (bounds.size.height - new_size.height) / 2.0,
  72                    ),
  73                    size: new_size,
  74                }
  75            }
  76            ObjectFit::ScaleDown => {
  77                // Check if the image is larger than the bounds in either dimension.
  78                if image_size.width > bounds.size.width || image_size.height > bounds.size.height {
  79                    // If the image is larger, use the same logic as Contain to scale it down.
  80                    let new_size = if bounds_ratio > image_ratio {
  81                        size(
  82                            image_size.width * (bounds.size.height / image_size.height),
  83                            bounds.size.height,
  84                        )
  85                    } else {
  86                        size(
  87                            bounds.size.width,
  88                            image_size.height * (bounds.size.width / image_size.width),
  89                        )
  90                    };
  91
  92                    Bounds {
  93                        origin: point(
  94                            bounds.origin.x + (bounds.size.width - new_size.width) / 2.0,
  95                            bounds.origin.y + (bounds.size.height - new_size.height) / 2.0,
  96                        ),
  97                        size: new_size,
  98                    }
  99                } else {
 100                    // If the image is smaller than or equal to the container, display it at its original size,
 101                    // centered within the container.
 102                    let original_size = size(image_size.width, image_size.height);
 103                    Bounds {
 104                        origin: point(
 105                            bounds.origin.x + (bounds.size.width - original_size.width) / 2.0,
 106                            bounds.origin.y + (bounds.size.height - original_size.height) / 2.0,
 107                        ),
 108                        size: original_size,
 109                    }
 110                }
 111            }
 112            ObjectFit::Cover => {
 113                let new_size = if bounds_ratio > image_ratio {
 114                    size(
 115                        bounds.size.width,
 116                        image_size.height * (bounds.size.width / image_size.width),
 117                    )
 118                } else {
 119                    size(
 120                        image_size.width * (bounds.size.height / image_size.height),
 121                        bounds.size.height,
 122                    )
 123                };
 124
 125                Bounds {
 126                    origin: point(
 127                        bounds.origin.x + (bounds.size.width - new_size.width) / 2.0,
 128                        bounds.origin.y + (bounds.size.height - new_size.height) / 2.0,
 129                    ),
 130                    size: new_size,
 131                }
 132            }
 133            ObjectFit::None => Bounds {
 134                origin: bounds.origin,
 135                size: image_size,
 136            },
 137        }
 138    }
 139}
 140
 141/// The CSS styling that can be applied to an element via the `Styled` trait
 142#[derive(Clone, Refineable, Debug)]
 143#[refineable(Debug, PartialEq, Serialize, Deserialize, JsonSchema)]
 144pub struct Style {
 145    /// What layout strategy should be used?
 146    pub display: Display,
 147
 148    /// Should the element be painted on screen?
 149    pub visibility: Visibility,
 150
 151    // Overflow properties
 152    /// How children overflowing their container should affect layout
 153    #[refineable]
 154    pub overflow: Point<Overflow>,
 155    /// How much space (in points) should be reserved for the scrollbars of `Overflow::Scroll` and `Overflow::Auto` nodes.
 156    pub scrollbar_width: AbsoluteLength,
 157    /// Whether both x and y axis should be scrollable at the same time.
 158    pub allow_concurrent_scroll: bool,
 159    /// Whether scrolling should be restricted to the axis indicated by the mouse wheel.
 160    ///
 161    /// This means that:
 162    /// - The mouse wheel alone will only ever scroll the Y axis.
 163    /// - Holding `Shift` and using the mouse wheel will scroll the X axis.
 164    ///
 165    /// ## Motivation
 166    ///
 167    /// On the web when scrolling with the mouse wheel, scrolling up and down will always scroll the Y axis, even when
 168    /// the mouse is over a horizontally-scrollable element.
 169    ///
 170    /// The only way to scroll horizontally is to hold down `Shift` while scrolling, which then changes the scroll axis
 171    /// to the X axis.
 172    ///
 173    /// Currently, GPUI operates differently from the web in that it will scroll an element in either the X or Y axis
 174    /// when scrolling with just the mouse wheel. This causes problems when scrolling in a vertical list that contains
 175    /// horizontally-scrollable elements, as when you get to the horizontally-scrollable elements the scroll will be
 176    /// hijacked.
 177    ///
 178    /// Ideally we would match the web's behavior and not have a need for this, but right now we're adding this opt-in
 179    /// style property to limit the potential blast radius.
 180    pub restrict_scroll_to_axis: bool,
 181
 182    // Position properties
 183    /// What should the `position` value of this struct use as a base offset?
 184    pub position: Position,
 185    /// How should the position of this element be tweaked relative to the layout defined?
 186    #[refineable]
 187    pub inset: Edges<Length>,
 188
 189    // Size properties
 190    /// Sets the initial size of the item
 191    #[refineable]
 192    pub size: Size<Length>,
 193    /// Controls the minimum size of the item
 194    #[refineable]
 195    pub min_size: Size<Length>,
 196    /// Controls the maximum size of the item
 197    #[refineable]
 198    pub max_size: Size<Length>,
 199    /// Sets the preferred aspect ratio for the item. The ratio is calculated as width divided by height.
 200    pub aspect_ratio: Option<f32>,
 201
 202    // Spacing Properties
 203    /// How large should the margin be on each side?
 204    #[refineable]
 205    pub margin: Edges<Length>,
 206    /// How large should the padding be on each side?
 207    #[refineable]
 208    pub padding: Edges<DefiniteLength>,
 209    /// How large should the border be on each side?
 210    #[refineable]
 211    pub border_widths: Edges<AbsoluteLength>,
 212
 213    // Alignment properties
 214    /// How this node's children aligned in the cross/block axis?
 215    pub align_items: Option<AlignItems>,
 216    /// How this node should be aligned in the cross/block axis. Falls back to the parents [`AlignItems`] if not set
 217    pub align_self: Option<AlignSelf>,
 218    /// How should content contained within this item be aligned in the cross/block axis
 219    pub align_content: Option<AlignContent>,
 220    /// How should contained within this item be aligned in the main/inline axis
 221    pub justify_content: Option<JustifyContent>,
 222    /// How large should the gaps between items in a flex container be?
 223    #[refineable]
 224    pub gap: Size<DefiniteLength>,
 225
 226    // Flexbox properties
 227    /// Which direction does the main axis flow in?
 228    pub flex_direction: FlexDirection,
 229    /// Should elements wrap, or stay in a single line?
 230    pub flex_wrap: FlexWrap,
 231    /// Sets the initial main axis size of the item
 232    pub flex_basis: Length,
 233    /// The relative rate at which this item grows when it is expanding to fill space, 0.0 is the default value, and this value must be positive.
 234    pub flex_grow: f32,
 235    /// The relative rate at which this item shrinks when it is contracting to fit into space, 1.0 is the default value, and this value must be positive.
 236    pub flex_shrink: f32,
 237
 238    /// The fill color of this element
 239    pub background: Option<Fill>,
 240
 241    /// The border color of this element
 242    pub border_color: Option<Hsla>,
 243
 244    /// The border style of this element
 245    pub border_style: BorderStyle,
 246
 247    /// The radius of the corners of this element
 248    #[refineable]
 249    pub corner_radii: Corners<AbsoluteLength>,
 250
 251    /// Box shadow of the element
 252    pub box_shadow: Vec<BoxShadow>,
 253
 254    /// The text style of this element
 255    #[refineable]
 256    pub text: TextStyleRefinement,
 257
 258    /// The mouse cursor style shown when the mouse pointer is over an element.
 259    pub mouse_cursor: Option<CursorStyle>,
 260
 261    /// The opacity of this element
 262    pub opacity: Option<f32>,
 263
 264    /// The grid columns of this element
 265    /// Equivalent to the Tailwind `grid-cols-<number>`
 266    pub grid_cols: Option<u16>,
 267
 268    /// The grid columns with min-content minimum sizing.
 269    /// Unlike grid_cols, it won't shrink to width 0 in AvailableSpace::MinContent constraints.
 270    pub grid_cols_min_content: Option<u16>,
 271
 272    /// The row span of this element
 273    /// Equivalent to the Tailwind `grid-rows-<number>`
 274    pub grid_rows: Option<u16>,
 275
 276    /// The grid location of this element
 277    pub grid_location: Option<GridLocation>,
 278
 279    /// Whether to draw a red debugging outline around this element
 280    #[cfg(debug_assertions)]
 281    pub debug: bool,
 282
 283    /// Whether to draw a red debugging outline around this element and all of its conforming children
 284    #[cfg(debug_assertions)]
 285    pub debug_below: bool,
 286}
 287
 288impl Styled for StyleRefinement {
 289    fn style(&mut self) -> &mut StyleRefinement {
 290        self
 291    }
 292}
 293
 294impl StyleRefinement {
 295    /// The grid location of this element
 296    pub fn grid_location_mut(&mut self) -> &mut GridLocation {
 297        self.grid_location.get_or_insert_default()
 298    }
 299}
 300
 301/// The value of the visibility property, similar to the CSS property `visibility`
 302#[derive(Default, Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize, JsonSchema)]
 303pub enum Visibility {
 304    /// The element should be drawn as normal.
 305    #[default]
 306    Visible,
 307    /// The element should not be drawn, but should still take up space in the layout.
 308    Hidden,
 309}
 310
 311/// The possible values of the box-shadow property
 312#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, JsonSchema)]
 313pub struct BoxShadow {
 314    /// What color should the shadow have?
 315    pub color: Hsla,
 316    /// How should it be offset from its element?
 317    pub offset: Point<Pixels>,
 318    /// How much should the shadow be blurred?
 319    pub blur_radius: Pixels,
 320    /// How much should the shadow spread?
 321    pub spread_radius: Pixels,
 322}
 323
 324/// How to handle whitespace in text
 325#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 326pub enum WhiteSpace {
 327    /// Normal line wrapping when text overflows the width of the element
 328    #[default]
 329    Normal,
 330    /// No line wrapping, text will overflow the width of the element
 331    Nowrap,
 332}
 333
 334/// How to truncate text that overflows the width of the element
 335#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 336pub enum TextOverflow {
 337    /// Truncate the text at the end when it doesn't fit, and represent this truncation by
 338    /// displaying the provided string (e.g., "very long te…").
 339    Truncate(SharedString),
 340    /// Truncate the text at the start when it doesn't fit, and represent this truncation by
 341    /// displaying the provided string at the beginning (e.g., "…ong text here").
 342    /// Typically more adequate for file paths where the end is more important than the beginning.
 343    TruncateStart(SharedString),
 344}
 345
 346/// How to align text within the element
 347#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Serialize, Deserialize, JsonSchema)]
 348pub enum TextAlign {
 349    /// Align the text to the left of the element
 350    #[default]
 351    Left,
 352
 353    /// Center the text within the element
 354    Center,
 355
 356    /// Align the text to the right of the element
 357    Right,
 358}
 359
 360/// The properties that can be used to style text in GPUI
 361#[derive(Refineable, Clone, Debug, PartialEq)]
 362#[refineable(Debug, PartialEq, Serialize, Deserialize, JsonSchema)]
 363pub struct TextStyle {
 364    /// The color of the text
 365    pub color: Hsla,
 366
 367    /// The font family to use
 368    pub font_family: SharedString,
 369
 370    /// The font features to use
 371    pub font_features: FontFeatures,
 372
 373    /// The fallback fonts to use
 374    pub font_fallbacks: Option<FontFallbacks>,
 375
 376    /// The font size to use, in pixels or rems.
 377    pub font_size: AbsoluteLength,
 378
 379    /// The line height to use, in pixels or fractions
 380    pub line_height: DefiniteLength,
 381
 382    /// The font weight, e.g. bold
 383    pub font_weight: FontWeight,
 384
 385    /// The font style, e.g. italic
 386    pub font_style: FontStyle,
 387
 388    /// The background color of the text
 389    pub background_color: Option<Hsla>,
 390
 391    /// The underline style of the text
 392    pub underline: Option<UnderlineStyle>,
 393
 394    /// The strikethrough style of the text
 395    pub strikethrough: Option<StrikethroughStyle>,
 396
 397    /// How to handle whitespace in the text
 398    pub white_space: WhiteSpace,
 399
 400    /// The text should be truncated if it overflows the width of the element
 401    pub text_overflow: Option<TextOverflow>,
 402
 403    /// How the text should be aligned within the element
 404    pub text_align: TextAlign,
 405
 406    /// The number of lines to display before truncating the text
 407    pub line_clamp: Option<usize>,
 408}
 409
 410impl Default for TextStyle {
 411    fn default() -> Self {
 412        TextStyle {
 413            color: black(),
 414            // todo(linux) make this configurable or choose better default
 415            font_family: ".SystemUIFont".into(),
 416            font_features: FontFeatures::default(),
 417            font_fallbacks: None,
 418            font_size: rems(1.).into(),
 419            line_height: phi(),
 420            font_weight: FontWeight::default(),
 421            font_style: FontStyle::default(),
 422            background_color: None,
 423            underline: None,
 424            strikethrough: None,
 425            white_space: WhiteSpace::Normal,
 426            text_overflow: None,
 427            text_align: TextAlign::default(),
 428            line_clamp: None,
 429        }
 430    }
 431}
 432
 433impl TextStyle {
 434    /// Create a new text style with the given highlighting applied.
 435    pub fn highlight(mut self, style: impl Into<HighlightStyle>) -> Self {
 436        let style = style.into();
 437        if let Some(weight) = style.font_weight {
 438            self.font_weight = weight;
 439        }
 440        if let Some(style) = style.font_style {
 441            self.font_style = style;
 442        }
 443
 444        if let Some(color) = style.color {
 445            self.color = self.color.blend(color);
 446        }
 447
 448        if let Some(factor) = style.fade_out {
 449            self.color.fade_out(factor);
 450        }
 451
 452        if let Some(background_color) = style.background_color {
 453            self.background_color = Some(background_color);
 454        }
 455
 456        if let Some(underline) = style.underline {
 457            self.underline = Some(underline);
 458        }
 459
 460        if let Some(strikethrough) = style.strikethrough {
 461            self.strikethrough = Some(strikethrough);
 462        }
 463
 464        self
 465    }
 466
 467    /// Get the font configured for this text style.
 468    pub fn font(&self) -> Font {
 469        Font {
 470            family: self.font_family.clone(),
 471            features: self.font_features.clone(),
 472            fallbacks: self.font_fallbacks.clone(),
 473            weight: self.font_weight,
 474            style: self.font_style,
 475        }
 476    }
 477
 478    /// Returns the rounded line height in pixels.
 479    pub fn line_height_in_pixels(&self, rem_size: Pixels) -> Pixels {
 480        self.line_height.to_pixels(self.font_size, rem_size).round()
 481    }
 482
 483    /// Convert this text style into a [`TextRun`], for the given length of the text.
 484    pub fn to_run(&self, len: usize) -> TextRun {
 485        TextRun {
 486            len,
 487            font: Font {
 488                family: self.font_family.clone(),
 489                features: self.font_features.clone(),
 490                fallbacks: self.font_fallbacks.clone(),
 491                weight: self.font_weight,
 492                style: self.font_style,
 493            },
 494            color: self.color,
 495            background_color: self.background_color,
 496            underline: self.underline,
 497            strikethrough: self.strikethrough,
 498        }
 499    }
 500}
 501
 502/// A highlight style to apply, similar to a `TextStyle` except
 503/// for a single font, uniformly sized and spaced text.
 504#[derive(Copy, Clone, Debug, Default, PartialEq)]
 505pub struct HighlightStyle {
 506    /// The color of the text
 507    pub color: Option<Hsla>,
 508
 509    /// The font weight, e.g. bold
 510    pub font_weight: Option<FontWeight>,
 511
 512    /// The font style, e.g. italic
 513    pub font_style: Option<FontStyle>,
 514
 515    /// The background color of the text
 516    pub background_color: Option<Hsla>,
 517
 518    /// The underline style of the text
 519    pub underline: Option<UnderlineStyle>,
 520
 521    /// The underline style of the text
 522    pub strikethrough: Option<StrikethroughStyle>,
 523
 524    /// Similar to the CSS `opacity` property, this will cause the text to be less vibrant.
 525    pub fade_out: Option<f32>,
 526}
 527
 528impl Eq for HighlightStyle {}
 529
 530impl Hash for HighlightStyle {
 531    fn hash<H: Hasher>(&self, state: &mut H) {
 532        self.color.hash(state);
 533        self.font_weight.hash(state);
 534        self.font_style.hash(state);
 535        self.background_color.hash(state);
 536        self.underline.hash(state);
 537        self.strikethrough.hash(state);
 538        state.write_u32(u32::from_be_bytes(
 539            self.fade_out.map(|f| f.to_be_bytes()).unwrap_or_default(),
 540        ));
 541    }
 542}
 543
 544impl Style {
 545    /// Returns true if the style is visible and the background is opaque.
 546    pub fn has_opaque_background(&self) -> bool {
 547        self.background
 548            .as_ref()
 549            .is_some_and(|fill| fill.color().is_some_and(|color| !color.is_transparent()))
 550    }
 551
 552    /// Get the text style in this element style.
 553    pub fn text_style(&self) -> Option<&TextStyleRefinement> {
 554        if self.text.is_some() {
 555            Some(&self.text)
 556        } else {
 557            None
 558        }
 559    }
 560
 561    /// Get the content mask for this element style, based on the given bounds.
 562    /// If the element does not hide its overflow, this will return `None`.
 563    pub fn overflow_mask(
 564        &self,
 565        bounds: Bounds<Pixels>,
 566        rem_size: Pixels,
 567    ) -> Option<ContentMask<Pixels>> {
 568        match self.overflow {
 569            Point {
 570                x: Overflow::Visible,
 571                y: Overflow::Visible,
 572            } => None,
 573            _ => {
 574                let mut min = bounds.origin;
 575                let mut max = bounds.bottom_right();
 576
 577                if self
 578                    .border_color
 579                    .is_some_and(|color| !color.is_transparent())
 580                {
 581                    min.x += self.border_widths.left.to_pixels(rem_size);
 582                    max.x -= self.border_widths.right.to_pixels(rem_size);
 583                    min.y += self.border_widths.top.to_pixels(rem_size);
 584                    max.y -= self.border_widths.bottom.to_pixels(rem_size);
 585                }
 586
 587                let bounds = match (
 588                    self.overflow.x == Overflow::Visible,
 589                    self.overflow.y == Overflow::Visible,
 590                ) {
 591                    // x and y both visible
 592                    (true, true) => return None,
 593                    // x visible, y hidden
 594                    (true, false) => Bounds::from_corners(
 595                        point(min.x, bounds.origin.y),
 596                        point(max.x, bounds.bottom_right().y),
 597                    ),
 598                    // x hidden, y visible
 599                    (false, true) => Bounds::from_corners(
 600                        point(bounds.origin.x, min.y),
 601                        point(bounds.bottom_right().x, max.y),
 602                    ),
 603                    // both hidden
 604                    (false, false) => Bounds::from_corners(min, max),
 605                };
 606
 607                Some(ContentMask { bounds })
 608            }
 609        }
 610    }
 611
 612    /// Paints the background of an element styled with this style.
 613    pub fn paint(
 614        &self,
 615        bounds: Bounds<Pixels>,
 616        window: &mut Window,
 617        cx: &mut App,
 618        continuation: impl FnOnce(&mut Window, &mut App),
 619    ) {
 620        #[cfg(debug_assertions)]
 621        if self.debug_below {
 622            cx.set_global(DebugBelow)
 623        }
 624
 625        #[cfg(debug_assertions)]
 626        if self.debug || cx.has_global::<DebugBelow>() {
 627            window.paint_quad(crate::outline(bounds, crate::red(), BorderStyle::default()));
 628        }
 629
 630        let rem_size = window.rem_size();
 631        let corner_radii = self
 632            .corner_radii
 633            .to_pixels(rem_size)
 634            .clamp_radii_for_quad_size(bounds.size);
 635
 636        window.paint_shadows(bounds, corner_radii, &self.box_shadow);
 637
 638        let background_color = self.background.as_ref().and_then(Fill::color);
 639        if background_color.is_some_and(|color| !color.is_transparent()) {
 640            let mut border_color = match background_color {
 641                Some(color) => match color.tag {
 642                    BackgroundTag::Solid
 643                    | BackgroundTag::PatternSlash
 644                    | BackgroundTag::Checkerboard => color.solid,
 645
 646                    BackgroundTag::LinearGradient => color
 647                        .colors
 648                        .first()
 649                        .map(|stop| stop.color)
 650                        .unwrap_or_default(),
 651                },
 652                None => Hsla::default(),
 653            };
 654            border_color.a = 0.;
 655            window.paint_quad(quad(
 656                bounds,
 657                corner_radii,
 658                background_color.unwrap_or_default(),
 659                Edges::default(),
 660                border_color,
 661                self.border_style,
 662            ));
 663        }
 664
 665        continuation(window, cx);
 666
 667        if self.is_border_visible() {
 668            let border_widths = self.border_widths.to_pixels(rem_size);
 669            let max_border_width = border_widths.max();
 670            let max_corner_radius = corner_radii.max();
 671            let zero_size = Size {
 672                width: Pixels::ZERO,
 673                height: Pixels::ZERO,
 674            };
 675
 676            let mut top_bounds = Bounds::from_corners(
 677                bounds.origin,
 678                bounds.top_right() + point(Pixels::ZERO, max_border_width.max(max_corner_radius)),
 679            );
 680            top_bounds.size = top_bounds.size.max(&zero_size);
 681            let mut bottom_bounds = Bounds::from_corners(
 682                bounds.bottom_left() - point(Pixels::ZERO, max_border_width.max(max_corner_radius)),
 683                bounds.bottom_right(),
 684            );
 685            bottom_bounds.size = bottom_bounds.size.max(&zero_size);
 686            let mut left_bounds = Bounds::from_corners(
 687                top_bounds.bottom_left(),
 688                bottom_bounds.origin + point(max_border_width, Pixels::ZERO),
 689            );
 690            left_bounds.size = left_bounds.size.max(&zero_size);
 691            let mut right_bounds = Bounds::from_corners(
 692                top_bounds.bottom_right() - point(max_border_width, Pixels::ZERO),
 693                bottom_bounds.top_right(),
 694            );
 695            right_bounds.size = right_bounds.size.max(&zero_size);
 696
 697            let mut background = self.border_color.unwrap_or_default();
 698            background.a = 0.;
 699            let quad = quad(
 700                bounds,
 701                corner_radii,
 702                background,
 703                border_widths,
 704                self.border_color.unwrap_or_default(),
 705                self.border_style,
 706            );
 707
 708            window.with_content_mask(Some(ContentMask { bounds: top_bounds }), |window| {
 709                window.paint_quad(quad.clone());
 710            });
 711            window.with_content_mask(
 712                Some(ContentMask {
 713                    bounds: right_bounds,
 714                }),
 715                |window| {
 716                    window.paint_quad(quad.clone());
 717                },
 718            );
 719            window.with_content_mask(
 720                Some(ContentMask {
 721                    bounds: bottom_bounds,
 722                }),
 723                |window| {
 724                    window.paint_quad(quad.clone());
 725                },
 726            );
 727            window.with_content_mask(
 728                Some(ContentMask {
 729                    bounds: left_bounds,
 730                }),
 731                |window| {
 732                    window.paint_quad(quad);
 733                },
 734            );
 735        }
 736
 737        #[cfg(debug_assertions)]
 738        if self.debug_below {
 739            cx.remove_global::<DebugBelow>();
 740        }
 741    }
 742
 743    fn is_border_visible(&self) -> bool {
 744        self.border_color
 745            .is_some_and(|color| !color.is_transparent())
 746            && self.border_widths.any(|length| !length.is_zero())
 747    }
 748}
 749
 750impl Default for Style {
 751    fn default() -> Self {
 752        Style {
 753            display: Display::Block,
 754            visibility: Visibility::Visible,
 755            overflow: Point {
 756                x: Overflow::Visible,
 757                y: Overflow::Visible,
 758            },
 759            allow_concurrent_scroll: false,
 760            restrict_scroll_to_axis: false,
 761            scrollbar_width: AbsoluteLength::default(),
 762            position: Position::Relative,
 763            inset: Edges::auto(),
 764            margin: Edges::<Length>::zero(),
 765            padding: Edges::<DefiniteLength>::zero(),
 766            border_widths: Edges::<AbsoluteLength>::zero(),
 767            size: Size::auto(),
 768            min_size: Size::auto(),
 769            max_size: Size::auto(),
 770            aspect_ratio: None,
 771            gap: Size::default(),
 772            // Alignment
 773            align_items: None,
 774            align_self: None,
 775            align_content: None,
 776            justify_content: None,
 777            // Flexbox
 778            flex_direction: FlexDirection::Row,
 779            flex_wrap: FlexWrap::NoWrap,
 780            flex_grow: 0.0,
 781            flex_shrink: 1.0,
 782            flex_basis: Length::Auto,
 783            background: None,
 784            border_color: None,
 785            border_style: BorderStyle::default(),
 786            corner_radii: Corners::default(),
 787            box_shadow: Default::default(),
 788            text: TextStyleRefinement::default(),
 789            mouse_cursor: None,
 790            opacity: None,
 791            grid_rows: None,
 792            grid_cols: None,
 793            grid_cols_min_content: None,
 794            grid_location: None,
 795
 796            #[cfg(debug_assertions)]
 797            debug: false,
 798            #[cfg(debug_assertions)]
 799            debug_below: false,
 800        }
 801    }
 802}
 803
 804/// The properties that can be applied to an underline.
 805#[derive(
 806    Refineable, Copy, Clone, Default, Debug, PartialEq, Eq, Hash, Serialize, Deserialize, JsonSchema,
 807)]
 808pub struct UnderlineStyle {
 809    /// The thickness of the underline.
 810    pub thickness: Pixels,
 811
 812    /// The color of the underline.
 813    pub color: Option<Hsla>,
 814
 815    /// Whether the underline should be wavy, like in a spell checker.
 816    pub wavy: bool,
 817}
 818
 819/// The properties that can be applied to a strikethrough.
 820#[derive(
 821    Refineable, Copy, Clone, Default, Debug, PartialEq, Eq, Hash, Serialize, Deserialize, JsonSchema,
 822)]
 823pub struct StrikethroughStyle {
 824    /// The thickness of the strikethrough.
 825    pub thickness: Pixels,
 826
 827    /// The color of the strikethrough.
 828    pub color: Option<Hsla>,
 829}
 830
 831/// The kinds of fill that can be applied to a shape.
 832#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, JsonSchema)]
 833pub enum Fill {
 834    /// A solid color fill.
 835    Color(Background),
 836}
 837
 838impl Fill {
 839    /// Unwrap this fill into a solid color, if it is one.
 840    ///
 841    /// If the fill is not a solid color, this method returns `None`.
 842    pub fn color(&self) -> Option<Background> {
 843        match self {
 844            Fill::Color(color) => Some(*color),
 845        }
 846    }
 847}
 848
 849impl Default for Fill {
 850    fn default() -> Self {
 851        Self::Color(Background::default())
 852    }
 853}
 854
 855impl From<Hsla> for Fill {
 856    fn from(color: Hsla) -> Self {
 857        Self::Color(color.into())
 858    }
 859}
 860
 861impl From<Rgba> for Fill {
 862    fn from(color: Rgba) -> Self {
 863        Self::Color(color.into())
 864    }
 865}
 866
 867impl From<Background> for Fill {
 868    fn from(background: Background) -> Self {
 869        Self::Color(background)
 870    }
 871}
 872
 873impl From<TextStyle> for HighlightStyle {
 874    fn from(other: TextStyle) -> Self {
 875        Self::from(&other)
 876    }
 877}
 878
 879impl From<&TextStyle> for HighlightStyle {
 880    fn from(other: &TextStyle) -> Self {
 881        Self {
 882            color: Some(other.color),
 883            font_weight: Some(other.font_weight),
 884            font_style: Some(other.font_style),
 885            background_color: other.background_color,
 886            underline: other.underline,
 887            strikethrough: other.strikethrough,
 888            fade_out: None,
 889        }
 890    }
 891}
 892
 893impl HighlightStyle {
 894    /// Create a highlight style with just a color
 895    pub fn color(color: Hsla) -> Self {
 896        Self {
 897            color: Some(color),
 898            ..Default::default()
 899        }
 900    }
 901    /// Blend this highlight style with another.
 902    /// Non-continuous properties, like font_weight and font_style, are overwritten.
 903    #[must_use]
 904    pub fn highlight(self, other: HighlightStyle) -> Self {
 905        Self {
 906            color: other
 907                .color
 908                .map(|other_color| {
 909                    if let Some(color) = self.color {
 910                        color.blend(other_color)
 911                    } else {
 912                        other_color
 913                    }
 914                })
 915                .or(self.color),
 916            font_weight: other.font_weight.or(self.font_weight),
 917            font_style: other.font_style.or(self.font_style),
 918            background_color: other.background_color.or(self.background_color),
 919            underline: other.underline.or(self.underline),
 920            strikethrough: other.strikethrough.or(self.strikethrough),
 921            fade_out: other
 922                .fade_out
 923                .map(|source_fade| {
 924                    self.fade_out
 925                        .map(|dest_fade| (dest_fade * (1. + source_fade)).clamp(0., 1.))
 926                        .unwrap_or(source_fade)
 927                })
 928                .or(self.fade_out),
 929        }
 930    }
 931}
 932
 933impl From<Hsla> for HighlightStyle {
 934    fn from(color: Hsla) -> Self {
 935        Self {
 936            color: Some(color),
 937            ..Default::default()
 938        }
 939    }
 940}
 941
 942impl From<FontWeight> for HighlightStyle {
 943    fn from(font_weight: FontWeight) -> Self {
 944        Self {
 945            font_weight: Some(font_weight),
 946            ..Default::default()
 947        }
 948    }
 949}
 950
 951impl From<FontStyle> for HighlightStyle {
 952    fn from(font_style: FontStyle) -> Self {
 953        Self {
 954            font_style: Some(font_style),
 955            ..Default::default()
 956        }
 957    }
 958}
 959
 960impl From<Rgba> for HighlightStyle {
 961    fn from(color: Rgba) -> Self {
 962        Self {
 963            color: Some(color.into()),
 964            ..Default::default()
 965        }
 966    }
 967}
 968
 969/// Combine and merge the highlights and ranges in the two iterators.
 970pub fn combine_highlights(
 971    a: impl IntoIterator<Item = (Range<usize>, HighlightStyle)>,
 972    b: impl IntoIterator<Item = (Range<usize>, HighlightStyle)>,
 973) -> impl Iterator<Item = (Range<usize>, HighlightStyle)> {
 974    let mut endpoints = Vec::new();
 975    let mut highlights = Vec::new();
 976    for (range, highlight) in a.into_iter().chain(b) {
 977        if !range.is_empty() {
 978            let highlight_id = highlights.len();
 979            endpoints.push((range.start, highlight_id, true));
 980            endpoints.push((range.end, highlight_id, false));
 981            highlights.push(highlight);
 982        }
 983    }
 984    endpoints.sort_unstable_by_key(|(position, _, _)| *position);
 985    let mut endpoints = endpoints.into_iter().peekable();
 986
 987    let mut active_styles = HashSet::default();
 988    let mut ix = 0;
 989    iter::from_fn(move || {
 990        while let Some((endpoint_ix, highlight_id, is_start)) = endpoints.peek() {
 991            let prev_index = mem::replace(&mut ix, *endpoint_ix);
 992            if ix > prev_index && !active_styles.is_empty() {
 993                let current_style = active_styles
 994                    .iter()
 995                    .fold(HighlightStyle::default(), |acc, highlight_id| {
 996                        acc.highlight(highlights[*highlight_id])
 997                    });
 998                return Some((prev_index..ix, current_style));
 999            }
1000
1001            if *is_start {
1002                active_styles.insert(*highlight_id);
1003            } else {
1004                active_styles.remove(highlight_id);
1005            }
1006            endpoints.next();
1007        }
1008        None
1009    })
1010}
1011
1012/// Used to control how child nodes are aligned.
1013/// For Flexbox it controls alignment in the cross axis
1014/// For Grid it controls alignment in the block axis
1015///
1016/// [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/align-items)
1017#[derive(Copy, Clone, PartialEq, Eq, Debug, Serialize, Deserialize, JsonSchema)]
1018// Copy of taffy::style type of the same name, to derive JsonSchema.
1019pub enum AlignItems {
1020    /// Items are packed toward the start of the axis
1021    Start,
1022    /// Items are packed toward the end of the axis
1023    End,
1024    /// Items are packed towards the flex-relative start of the axis.
1025    ///
1026    /// For flex containers with flex_direction RowReverse or ColumnReverse this is equivalent
1027    /// to End. In all other cases it is equivalent to Start.
1028    FlexStart,
1029    /// Items are packed towards the flex-relative end of the axis.
1030    ///
1031    /// For flex containers with flex_direction RowReverse or ColumnReverse this is equivalent
1032    /// to Start. In all other cases it is equivalent to End.
1033    FlexEnd,
1034    /// Items are packed along the center of the cross axis
1035    Center,
1036    /// Items are aligned such as their baselines align
1037    Baseline,
1038    /// Stretch to fill the container
1039    Stretch,
1040}
1041/// Used to control how child nodes are aligned.
1042/// Does not apply to Flexbox, and will be ignored if specified on a flex container
1043/// For Grid it controls alignment in the inline axis
1044///
1045/// [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/justify-items)
1046pub type JustifyItems = AlignItems;
1047/// Used to control how the specified nodes is aligned.
1048/// Overrides the parent Node's `AlignItems` property.
1049/// For Flexbox it controls alignment in the cross axis
1050/// For Grid it controls alignment in the block axis
1051///
1052/// [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/align-self)
1053pub type AlignSelf = AlignItems;
1054/// Used to control how the specified nodes is aligned.
1055/// Overrides the parent Node's `JustifyItems` property.
1056/// Does not apply to Flexbox, and will be ignored if specified on a flex child
1057/// For Grid it controls alignment in the inline axis
1058///
1059/// [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/justify-self)
1060pub type JustifySelf = AlignItems;
1061
1062/// Sets the distribution of space between and around content items
1063/// For Flexbox it controls alignment in the cross axis
1064/// For Grid it controls alignment in the block axis
1065///
1066/// [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/align-content)
1067#[derive(Copy, Clone, PartialEq, Eq, Debug, Serialize, Deserialize, JsonSchema)]
1068// Copy of taffy::style type of the same name, to derive JsonSchema.
1069pub enum AlignContent {
1070    /// Items are packed toward the start of the axis
1071    Start,
1072    /// Items are packed toward the end of the axis
1073    End,
1074    /// Items are packed towards the flex-relative start of the axis.
1075    ///
1076    /// For flex containers with flex_direction RowReverse or ColumnReverse this is equivalent
1077    /// to End. In all other cases it is equivalent to Start.
1078    FlexStart,
1079    /// Items are packed towards the flex-relative end of the axis.
1080    ///
1081    /// For flex containers with flex_direction RowReverse or ColumnReverse this is equivalent
1082    /// to Start. In all other cases it is equivalent to End.
1083    FlexEnd,
1084    /// Items are centered around the middle of the axis
1085    Center,
1086    /// Items are stretched to fill the container
1087    Stretch,
1088    /// The first and last items are aligned flush with the edges of the container (no gap)
1089    /// The gap between items is distributed evenly.
1090    SpaceBetween,
1091    /// The gap between the first and last items is exactly THE SAME as the gap between items.
1092    /// The gaps are distributed evenly
1093    SpaceEvenly,
1094    /// The gap between the first and last items is exactly HALF the gap between items.
1095    /// The gaps are distributed evenly in proportion to these ratios.
1096    SpaceAround,
1097}
1098
1099/// Sets the distribution of space between and around content items
1100/// For Flexbox it controls alignment in the main axis
1101/// For Grid it controls alignment in the inline axis
1102///
1103/// [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/justify-content)
1104pub type JustifyContent = AlignContent;
1105
1106/// Sets the layout used for the children of this node
1107///
1108/// The default values depends on on which feature flags are enabled. The order of precedence is: Flex, Grid, Block, None.
1109#[derive(Copy, Clone, PartialEq, Eq, Debug, Default, Serialize, Deserialize, JsonSchema)]
1110// Copy of taffy::style type of the same name, to derive JsonSchema.
1111pub enum Display {
1112    /// The children will follow the block layout algorithm
1113    Block,
1114    /// The children will follow the flexbox layout algorithm
1115    #[default]
1116    Flex,
1117    /// The children will follow the CSS Grid layout algorithm
1118    Grid,
1119    /// The children will not be laid out, and will follow absolute positioning
1120    None,
1121}
1122
1123/// Controls whether flex items are forced onto one line or can wrap onto multiple lines.
1124///
1125/// Defaults to [`FlexWrap::NoWrap`]
1126///
1127/// [Specification](https://www.w3.org/TR/css-flexbox-1/#flex-wrap-property)
1128#[derive(Copy, Clone, PartialEq, Eq, Debug, Default, Serialize, Deserialize, JsonSchema)]
1129// Copy of taffy::style type of the same name, to derive JsonSchema.
1130pub enum FlexWrap {
1131    /// Items will not wrap and stay on a single line
1132    #[default]
1133    NoWrap,
1134    /// Items will wrap according to this item's [`FlexDirection`]
1135    Wrap,
1136    /// Items will wrap in the opposite direction to this item's [`FlexDirection`]
1137    WrapReverse,
1138}
1139
1140/// The direction of the flexbox layout main axis.
1141///
1142/// There are always two perpendicular layout axes: main (or primary) and cross (or secondary).
1143/// Adding items will cause them to be positioned adjacent to each other along the main axis.
1144/// By varying this value throughout your tree, you can create complex axis-aligned layouts.
1145///
1146/// Items are always aligned relative to the cross axis, and justified relative to the main axis.
1147///
1148/// The default behavior is [`FlexDirection::Row`].
1149///
1150/// [Specification](https://www.w3.org/TR/css-flexbox-1/#flex-direction-property)
1151#[derive(Copy, Clone, PartialEq, Eq, Debug, Default, Serialize, Deserialize, JsonSchema)]
1152// Copy of taffy::style type of the same name, to derive JsonSchema.
1153pub enum FlexDirection {
1154    /// Defines +x as the main axis
1155    ///
1156    /// Items will be added from left to right in a row.
1157    #[default]
1158    Row,
1159    /// Defines +y as the main axis
1160    ///
1161    /// Items will be added from top to bottom in a column.
1162    Column,
1163    /// Defines -x as the main axis
1164    ///
1165    /// Items will be added from right to left in a row.
1166    RowReverse,
1167    /// Defines -y as the main axis
1168    ///
1169    /// Items will be added from bottom to top in a column.
1170    ColumnReverse,
1171}
1172
1173/// How children overflowing their container should affect layout
1174///
1175/// In CSS the primary effect of this property is to control whether contents of a parent container that overflow that container should
1176/// be displayed anyway, be clipped, or trigger the container to become a scroll container. However it also has secondary effects on layout,
1177/// the main ones being:
1178///
1179///   - The automatic minimum size Flexbox/CSS Grid items with non-`Visible` overflow is `0` rather than being content based
1180///   - `Overflow::Scroll` nodes have space in the layout reserved for a scrollbar (width controlled by the `scrollbar_width` property)
1181///
1182/// In Taffy, we only implement the layout related secondary effects as we are not concerned with drawing/painting. The amount of space reserved for
1183/// a scrollbar is controlled by the `scrollbar_width` property. If this is `0` then `Scroll` behaves identically to `Hidden`.
1184///
1185/// <https://developer.mozilla.org/en-US/docs/Web/CSS/overflow>
1186#[derive(Copy, Clone, PartialEq, Eq, Debug, Default, Serialize, Deserialize, JsonSchema)]
1187// Copy of taffy::style type of the same name, to derive JsonSchema.
1188pub enum Overflow {
1189    /// The automatic minimum size of this node as a flexbox/grid item should be based on the size of its content.
1190    /// Content that overflows this node *should* contribute to the scroll region of its parent.
1191    #[default]
1192    Visible,
1193    /// The automatic minimum size of this node as a flexbox/grid item should be based on the size of its content.
1194    /// Content that overflows this node should *not* contribute to the scroll region of its parent.
1195    Clip,
1196    /// The automatic minimum size of this node as a flexbox/grid item should be `0`.
1197    /// Content that overflows this node should *not* contribute to the scroll region of its parent.
1198    Hidden,
1199    /// The automatic minimum size of this node as a flexbox/grid item should be `0`. Additionally, space should be reserved
1200    /// for a scrollbar. The amount of space reserved is controlled by the `scrollbar_width` property.
1201    /// Content that overflows this node should *not* contribute to the scroll region of its parent.
1202    Scroll,
1203}
1204
1205/// The positioning strategy for this item.
1206///
1207/// This controls both how the origin is determined for the [`Style::position`] field,
1208/// and whether or not the item will be controlled by flexbox's layout algorithm.
1209///
1210/// WARNING: this enum follows the behavior of [CSS's `position` property](https://developer.mozilla.org/en-US/docs/Web/CSS/position),
1211/// which can be unintuitive.
1212///
1213/// [`Position::Relative`] is the default value, in contrast to the default behavior in CSS.
1214#[derive(Copy, Clone, PartialEq, Eq, Debug, Default, Serialize, Deserialize, JsonSchema)]
1215// Copy of taffy::style type of the same name, to derive JsonSchema.
1216pub enum Position {
1217    /// The offset is computed relative to the final position given by the layout algorithm.
1218    /// Offsets do not affect the position of any other items; they are effectively a correction factor applied at the end.
1219    #[default]
1220    Relative,
1221    /// The offset is computed relative to this item's closest positioned ancestor, if any.
1222    /// Otherwise, it is placed relative to the origin.
1223    /// No space is created for the item in the page layout, and its size will not be altered.
1224    ///
1225    /// WARNING: to opt-out of layouting entirely, you must use [`Display::None`] instead on your [`Style`] object.
1226    Absolute,
1227}
1228
1229impl From<AlignItems> for taffy::style::AlignItems {
1230    fn from(value: AlignItems) -> Self {
1231        match value {
1232            AlignItems::Start => Self::Start,
1233            AlignItems::End => Self::End,
1234            AlignItems::FlexStart => Self::FlexStart,
1235            AlignItems::FlexEnd => Self::FlexEnd,
1236            AlignItems::Center => Self::Center,
1237            AlignItems::Baseline => Self::Baseline,
1238            AlignItems::Stretch => Self::Stretch,
1239        }
1240    }
1241}
1242
1243impl From<AlignContent> for taffy::style::AlignContent {
1244    fn from(value: AlignContent) -> Self {
1245        match value {
1246            AlignContent::Start => Self::Start,
1247            AlignContent::End => Self::End,
1248            AlignContent::FlexStart => Self::FlexStart,
1249            AlignContent::FlexEnd => Self::FlexEnd,
1250            AlignContent::Center => Self::Center,
1251            AlignContent::Stretch => Self::Stretch,
1252            AlignContent::SpaceBetween => Self::SpaceBetween,
1253            AlignContent::SpaceEvenly => Self::SpaceEvenly,
1254            AlignContent::SpaceAround => Self::SpaceAround,
1255        }
1256    }
1257}
1258
1259impl From<Display> for taffy::style::Display {
1260    fn from(value: Display) -> Self {
1261        match value {
1262            Display::Block => Self::Block,
1263            Display::Flex => Self::Flex,
1264            Display::Grid => Self::Grid,
1265            Display::None => Self::None,
1266        }
1267    }
1268}
1269
1270impl From<FlexWrap> for taffy::style::FlexWrap {
1271    fn from(value: FlexWrap) -> Self {
1272        match value {
1273            FlexWrap::NoWrap => Self::NoWrap,
1274            FlexWrap::Wrap => Self::Wrap,
1275            FlexWrap::WrapReverse => Self::WrapReverse,
1276        }
1277    }
1278}
1279
1280impl From<FlexDirection> for taffy::style::FlexDirection {
1281    fn from(value: FlexDirection) -> Self {
1282        match value {
1283            FlexDirection::Row => Self::Row,
1284            FlexDirection::Column => Self::Column,
1285            FlexDirection::RowReverse => Self::RowReverse,
1286            FlexDirection::ColumnReverse => Self::ColumnReverse,
1287        }
1288    }
1289}
1290
1291impl From<Overflow> for taffy::style::Overflow {
1292    fn from(value: Overflow) -> Self {
1293        match value {
1294            Overflow::Visible => Self::Visible,
1295            Overflow::Clip => Self::Clip,
1296            Overflow::Hidden => Self::Hidden,
1297            Overflow::Scroll => Self::Scroll,
1298        }
1299    }
1300}
1301
1302impl From<Position> for taffy::style::Position {
1303    fn from(value: Position) -> Self {
1304        match value {
1305            Position::Relative => Self::Relative,
1306            Position::Absolute => Self::Absolute,
1307        }
1308    }
1309}
1310
1311#[cfg(test)]
1312mod tests {
1313    use crate::{blue, green, px, red, yellow};
1314
1315    use super::*;
1316
1317    use util_macros::perf;
1318
1319    #[perf]
1320    fn test_basic_highlight_style_combination() {
1321        let style_a = HighlightStyle::default();
1322        let style_b = HighlightStyle::default();
1323        let style_a = style_a.highlight(style_b);
1324        assert_eq!(
1325            style_a,
1326            HighlightStyle::default(),
1327            "Combining empty styles should not produce a non-empty style."
1328        );
1329
1330        let mut style_b = HighlightStyle {
1331            color: Some(red()),
1332            strikethrough: Some(StrikethroughStyle {
1333                thickness: px(2.),
1334                color: Some(blue()),
1335            }),
1336            fade_out: Some(0.),
1337            font_style: Some(FontStyle::Italic),
1338            font_weight: Some(FontWeight(300.)),
1339            background_color: Some(yellow()),
1340            underline: Some(UnderlineStyle {
1341                thickness: px(2.),
1342                color: Some(red()),
1343                wavy: true,
1344            }),
1345        };
1346        let expected_style = style_b;
1347
1348        let style_a = style_a.highlight(style_b);
1349        assert_eq!(
1350            style_a, expected_style,
1351            "Blending an empty style with another style should return the other style"
1352        );
1353
1354        let style_b = style_b.highlight(Default::default());
1355        assert_eq!(
1356            style_b, expected_style,
1357            "Blending a style with an empty style should not change the style."
1358        );
1359
1360        let mut style_c = expected_style;
1361
1362        let style_d = HighlightStyle {
1363            color: Some(blue().alpha(0.7)),
1364            strikethrough: Some(StrikethroughStyle {
1365                thickness: px(4.),
1366                color: Some(crate::red()),
1367            }),
1368            fade_out: Some(0.),
1369            font_style: Some(FontStyle::Oblique),
1370            font_weight: Some(FontWeight(800.)),
1371            background_color: Some(green()),
1372            underline: Some(UnderlineStyle {
1373                thickness: px(4.),
1374                color: None,
1375                wavy: false,
1376            }),
1377        };
1378
1379        let expected_style = HighlightStyle {
1380            color: Some(red().blend(blue().alpha(0.7))),
1381            strikethrough: Some(StrikethroughStyle {
1382                thickness: px(4.),
1383                color: Some(red()),
1384            }),
1385            // TODO this does not seem right
1386            fade_out: Some(0.),
1387            font_style: Some(FontStyle::Oblique),
1388            font_weight: Some(FontWeight(800.)),
1389            background_color: Some(green()),
1390            underline: Some(UnderlineStyle {
1391                thickness: px(4.),
1392                color: None,
1393                wavy: false,
1394            }),
1395        };
1396
1397        let style_c = style_c.highlight(style_d);
1398        assert_eq!(
1399            style_c, expected_style,
1400            "Blending styles should blend properties where possible and override all others"
1401        );
1402    }
1403
1404    #[perf]
1405    fn test_combine_highlights() {
1406        assert_eq!(
1407            combine_highlights(
1408                [
1409                    (0..5, green().into()),
1410                    (4..10, FontWeight::BOLD.into()),
1411                    (15..20, yellow().into()),
1412                ],
1413                [
1414                    (2..6, FontStyle::Italic.into()),
1415                    (1..3, blue().into()),
1416                    (21..23, red().into()),
1417                ]
1418            )
1419            .collect::<Vec<_>>(),
1420            [
1421                (
1422                    0..1,
1423                    HighlightStyle {
1424                        color: Some(green()),
1425                        ..Default::default()
1426                    }
1427                ),
1428                (
1429                    1..2,
1430                    HighlightStyle {
1431                        color: Some(blue()),
1432                        ..Default::default()
1433                    }
1434                ),
1435                (
1436                    2..3,
1437                    HighlightStyle {
1438                        color: Some(blue()),
1439                        font_style: Some(FontStyle::Italic),
1440                        ..Default::default()
1441                    }
1442                ),
1443                (
1444                    3..4,
1445                    HighlightStyle {
1446                        color: Some(green()),
1447                        font_style: Some(FontStyle::Italic),
1448                        ..Default::default()
1449                    }
1450                ),
1451                (
1452                    4..5,
1453                    HighlightStyle {
1454                        color: Some(green()),
1455                        font_weight: Some(FontWeight::BOLD),
1456                        font_style: Some(FontStyle::Italic),
1457                        ..Default::default()
1458                    }
1459                ),
1460                (
1461                    5..6,
1462                    HighlightStyle {
1463                        font_weight: Some(FontWeight::BOLD),
1464                        font_style: Some(FontStyle::Italic),
1465                        ..Default::default()
1466                    }
1467                ),
1468                (
1469                    6..10,
1470                    HighlightStyle {
1471                        font_weight: Some(FontWeight::BOLD),
1472                        ..Default::default()
1473                    }
1474                ),
1475                (
1476                    15..20,
1477                    HighlightStyle {
1478                        color: Some(yellow()),
1479                        ..Default::default()
1480                    }
1481                ),
1482                (
1483                    21..23,
1484                    HighlightStyle {
1485                        color: Some(red()),
1486                        ..Default::default()
1487                    }
1488                )
1489            ]
1490        );
1491    }
1492
1493    #[perf]
1494    fn test_text_style_refinement() {
1495        let mut style = Style::default();
1496        style.refine(&StyleRefinement::default().text_size(px(20.0)));
1497        style.refine(&StyleRefinement::default().font_weight(FontWeight::SEMIBOLD));
1498
1499        assert_eq!(
1500            Some(AbsoluteLength::from(px(20.0))),
1501            style.text_style().unwrap().font_size
1502        );
1503
1504        assert_eq!(
1505            Some(FontWeight::SEMIBOLD),
1506            style.text_style().unwrap().font_weight
1507        );
1508    }
1509}