Add rectangle function 🎛

src/export/pdf.rs

@@ -13,9 +13,10 @@ use pdf_writer::{
 };
 use ttf_parser::{name_id, GlyphId};
 
+use crate::color::Color;
 use crate::env::{Env, ImageResource, ResourceId};
 use crate::geom::Length;
-use crate::layout::{Element, Frame};
+use crate::layout::{Element, Fill, Frame, Shape};
 
 /// Export a collection of frames into a _PDF_ document.
 ///
@@ -57,6 +58,7 @@ impl<'a> PdfExporter<'a> {
                         }
                         images.insert(image.res);
                     }
+                    Element::Geometry(_) => {}
                 }
             }
         }
@@ -127,6 +129,56 @@ impl<'a> PdfExporter<'a> {
     fn write_page(&mut self, id: Ref, page: &'a Frame) {
         let mut content = Content::new();
 
+        for (pos, element) in &page.elements {
+            match element {
+                Element::Image(image) => {
+                    let name = format!("Im{}", self.images.map(image.res));
+                    let size = image.size;
+                    let x = pos.x.to_pt() as f32;
+                    let y = (page.size.height - pos.y - size.height).to_pt() as f32;
+                    let w = size.width.to_pt() as f32;
+                    let h = size.height.to_pt() as f32;
+
+                    content.save_state();
+                    content.matrix(w, 0.0, 0.0, h, x, y);
+                    content.x_object(Name(name.as_bytes()));
+                    content.restore_state();
+                }
+
+                Element::Geometry(geometry) => {
+                    content.save_state();
+
+                    match geometry.fill {
+                        Fill::Color(Color::Rgba(c)) => {
+                            content.fill_rgb(
+                                c.r as f32 / 255.,
+                                c.g as f32 / 255.,
+                                c.b as f32 / 255.,
+                            );
+                        }
+                        Fill::Image(_) => unimplemented!(),
+                    }
+
+                    match &geometry.shape {
+                        Shape::Rect(r) => {
+                            content.rect(
+                                pos.x.to_pt() as f32,
+                                (page.size.height - pos.y - r.size.height).to_pt() as f32,
+                                r.size.width.to_pt() as f32,
+                                r.size.height.to_pt() as f32,
+                                false,
+                                true,
+                            );
+                        }
+                    }
+
+                    content.restore_state();
+                }
+
+                _ => {}
+            }
+        }
+
         // We only write font switching actions when the used face changes. To
         // do that, we need to remember the active face.
         let mut face = FaceId::MAX;
@@ -153,22 +205,6 @@ impl<'a> PdfExporter<'a> {
 
         drop(text);
 
-        for (pos, element) in &page.elements {
-            if let Element::Image(image) = element {
-                let name = format!("Im{}", self.images.map(image.res));
-                let size = image.size;
-                let x = pos.x.to_pt() as f32;
-                let y = (page.size.height - pos.y - size.height).to_pt() as f32;
-                let w = size.width.to_pt() as f32;
-                let h = size.height.to_pt() as f32;
-
-                content.save_state();
-                content.matrix(w, 0.0, 0.0, h, x, y);
-                content.x_object(Name(name.as_bytes()));
-                content.restore_state();
-            }
-        }
-
         self.writer.stream(id, &content.finish());
     }
 

src/layout/mod.rs

@@ -4,10 +4,12 @@ mod fixed;
 mod node;
 mod pad;
 mod par;
+mod rect;
 mod spacing;
 mod stack;
 mod text;
 
+use crate::color::Color;
 use crate::env::{Env, ResourceId};
 use crate::geom::*;
 use crate::shaping::Shaped;
@@ -16,6 +18,7 @@ pub use fixed::*;
 pub use node::*;
 pub use pad::*;
 pub use par::*;
+pub use rect::*;
 pub use spacing::*;
 pub use stack::*;
 pub use text::*;
@@ -54,7 +57,7 @@ impl NodePages {
     pub fn layout(&self, ctx: &mut LayoutContext) -> Vec<Frame> {
         let areas = Areas::repeat(self.size);
         let layouted = self.child.layout(ctx, &areas);
-        layouted.frames()
+        layouted.into_frames()
     }
 }
 
@@ -157,9 +160,27 @@ pub enum Layouted {
 }
 
 impl Layouted {
-    /// Return all frames contained in this variant (zero, one or arbitrarily
+    /// Return a reference to all frames contained in this variant (zero, one or
-    /// many).
+    /// arbitrarily many).
-    pub fn frames(self) -> Vec<Frame> {
+    pub fn frames(&self) -> &[Frame] {
+        match self {
+            Self::Spacing(_) => &[],
+            Self::Frame(frame, _) => std::slice::from_ref(frame),
+            Self::Frames(frames, _) => frames,
+        }
+    }
+
+    /// Return a mutable reference to all frames contained in this variant.
+    pub fn frames_mut(&mut self) -> &mut [Frame] {
+        match self {
+            Self::Spacing(_) => &mut [],
+            Self::Frame(frame, _) => std::slice::from_mut(frame),
+            Self::Frames(frames, _) => frames,
+        }
+    }
+
+    /// Return all frames contained in this varian.
+    pub fn into_frames(self) -> Vec<Frame> {
         match self {
             Self::Spacing(_) => vec![],
             Self::Frame(frame, _) => vec![frame],
@@ -204,6 +225,46 @@ pub enum Element {
     Text(Shaped),
     /// An image.
     Image(Image),
+    /// Some shape that could hold another frame.
+    Geometry(Geometry),
+}
+
+/// The kind of graphic fill to be applied to a [`Shape`].
+#[derive(Debug, Clone, PartialEq)]
+pub enum Fill {
+    /// The fill is a color.
+    Color(Color),
+    /// The fill is an image.
+    Image(Image),
+    // Gradient(Gradient),
+}
+
+/// A shape with some kind of fill.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Geometry {
+    /// The shape to draw.
+    pub shape: Shape,
+    /// How the shape looks on the inside.
+    ///
+    /// **TODO:** This could be made into a Vec<Fill> or something such that
+    ///           the user can compose multiple fills with alpha values less
+    ///           than one to achieve cool effects.
+    pub fill: Fill,
+}
+
+/// Some shape.
+#[derive(Debug, Clone, PartialEq)]
+pub enum Shape {
+    /// A rectangle.
+    Rect(Rect),
+    // Ellipse(Ellipse),
+}
+
+/// An rectangle.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Rect {
+    /// The dimensions of the rectangle.
+    pub size: Size,
 }
 
 /// An image element.

src/layout/pad.rs

@@ -15,15 +15,9 @@ impl Layout for NodePad {
         let areas = shrink(areas, self.padding);
 
         let mut layouted = self.child.layout(ctx, &areas);
-        match &mut layouted {
+        for frame in layouted.frames_mut() {
-            Layouted::Spacing(_) => {}
-            Layouted::Frame(frame, _) => pad(frame, self.padding),
-            Layouted::Frames(frames, _) => {
-                for frame in frames {
             pad(frame, self.padding);
         }
-            }
-        }
 
         layouted
     }

src/layout/rect.rs

@@ -0,0 +1,71 @@
+use std::cmp::Ordering;
+
+use super::*;
+use crate::{color::RgbaColor, geom::Linear};
+
+/// A node that represents a rectangular box.
+#[derive(Debug, Clone, PartialEq)]
+pub struct NodeRect {
+    /// The fixed width, if any.
+    pub width: Option<Linear>,
+    /// The fixed height, if any.
+    pub height: Option<Linear>,
+    /// The background color.
+    pub color: Option<Color>,
+    /// The child node whose sides to pad.
+    pub child: Node,
+}
+
+impl Layout for NodeRect {
+    fn layout(&self, ctx: &mut LayoutContext, areas: &Areas) -> Layouted {
+        let Areas { current, full, .. } = areas;
+
+        let height_opt = self.height.map(|h| h.resolve(full.height));
+        let mut size = Size::new(
+            self.width.map(|w| w.resolve(full.width)).unwrap_or(current.width),
+            height_opt.unwrap_or(current.height),
+        );
+
+        let areas = Areas::once(size);
+        let mut layouted = self.child.layout(ctx, &areas);
+
+        // If the children have some height, apply that,
+        // otherwise fall back to zero or the height property.
+        if let Some(max) = layouted
+            .frames()
+            .iter()
+            .map(|f| f.size.height)
+            .max_by(|x, y| x.partial_cmp(y).unwrap_or(Ordering::Equal))
+        {
+            size.height = max;
+        } else {
+            size.height = height_opt.unwrap_or(Length::ZERO)
+        }
+
+        if let Some(first) = layouted.frames_mut().first_mut() {
+            first.elements.insert(
+                0,
+                (
+                    Point::ZERO,
+                    Element::Geometry(Geometry {
+                        shape: Shape::Rect(Rect { size }),
+                        fill: Fill::Color(self.color.unwrap_or(Color::Rgba(RgbaColor {
+                            r: 255,
+                            g: 255,
+                            b: 255,
+                            a: 0,
+                        }))),
+                    }),
+                ),
+            )
+        }
+
+        layouted
+    }
+}
+
+impl From<NodeRect> for NodeAny {
+    fn from(pad: NodeRect) -> Self {
+        Self::new(pad)
+    }
+}

src/library/insert.rs

@@ -4,6 +4,43 @@ use crate::env::{ImageResource, ResourceId};
 use crate::layout::*;
 use crate::prelude::*;
 
+/// `rect`: Layout content into a rectangle that also might have a fill.
+///
+/// # Named arguments
+/// - Width of the box:  `width`, of type `linear` relative to parent width.
+/// - Height of the box: `height`, of type `linear` relative to parent height.
+pub fn rect(ctx: &mut EvalContext, args: &mut Args) -> Value {
+    let snapshot = ctx.state.clone();
+
+    let width = args.get(ctx, "width");
+    let height = args.get(ctx, "height");
+    let color = args.get(ctx, "color");
+
+    let dirs = ctx.state.dirs;
+    let align = ctx.state.align;
+
+    ctx.start_content_group();
+
+    if let Some(body) = args.find::<ValueTemplate>(ctx) {
+        body.eval(ctx);
+    }
+
+    let children = ctx.end_content_group();
+
+    let fill_if = |c| if c { Expansion::Fill } else { Expansion::Fit };
+    let expand = Spec::new(fill_if(width.is_some()), fill_if(height.is_some()));
+
+    ctx.push(NodeRect {
+        width,
+        height,
+        color,
+        child: NodeStack { dirs, align, expand, children }.into(),
+    });
+
+    ctx.state = snapshot;
+    Value::None
+}
+
 /// `image`: Insert an image.
 ///
 /// Supports PNG and JPEG files.

src/library/mod.rs

@@ -38,6 +38,7 @@ pub fn new() -> Scope {
     set!(func: "image", image);
     set!(func: "page", page);
     set!(func: "pagebreak", pagebreak);
+    set!(func: "rect", rect);
     set!(func: "rgb", rgb);
     set!(func: "type", type_);
     set!(func: "v", v);

tests/library/typ/geom.typ

@@ -0,0 +1,23 @@
+#[page "a5", flip: true]
+
+// Rectangle with width, should have paragraph height
+#[rect width: 2cm, color: #9650D6][aa]
+
+Sometimes there is no box
+
+// Rectangle with height, should span line
+#[rect height: 2cm, color: #734CED][bb]
+
+// Empty rectangle with width and height
+#[rect width: 6cm, height: 12pt, color: #CB4CED]
+
+// This empty rectangle should not be displayed
+#[rect width: 2in, color: #ff0000]
+
+// This one should be
+#[rect height: 15mm, color: #494DE3]
+
+// These are in a row!
+#[rect width: 2in, height: 10pt, color: #D6CD67]
+#[rect width: 2in, height: 10pt, color: #EDD466]
+#[rect width: 2in, height: 10pt, color: #E3BE62]

tests/typeset.rs

@@ -20,7 +20,7 @@ use typst::eval::{Args, EvalContext, Scope, State, Value, ValueFunc};
 use typst::export::pdf;
 use typst::font::FsIndexExt;
 use typst::geom::{Length, Point, Sides, Size, Spec};
-use typst::layout::{Element, Expansion, Frame, Image};
+use typst::layout::{Element, Expansion, Fill, Frame, Geometry, Image, Shape};
 use typst::library;
 use typst::parse::{LineMap, Scanner};
 use typst::pretty::{Pretty, Printer};
@@ -409,6 +409,9 @@ fn draw(frames: &[Frame], env: &Env, pixel_per_pt: f32) -> Canvas {
                 Element::Image(image) => {
                     draw_image(&mut canvas, pos, env, image);
                 }
+                Element::Geometry(geom) => {
+                    draw_geometry(&mut canvas, pos, env, geom);
+                }
             }
         }
 
@@ -444,6 +447,28 @@ fn draw_text(canvas: &mut Canvas, pos: Point, env: &Env, shaped: &Shaped) {
     }
 }
 
+fn draw_geometry(canvas: &mut Canvas, pos: Point, _: &Env, element: &Geometry) {
+    let x = pos.x.to_pt() as f32;
+    let y = pos.y.to_pt() as f32;
+
+    let (w, h) = match &element.shape {
+        Shape::Rect(s) => (s.size.width.to_pt() as f32, s.size.height.to_pt() as f32),
+    };
+
+    let mut paint = Paint::default();
+
+    match &element.fill {
+        Fill::Color(c) => match c {
+            typst::color::Color::Rgba(c) => paint.set_color_rgba8(c.r, c.g, c.b, c.a),
+        },
+        Fill::Image(_) => todo!(),
+    };
+
+    if let Some(rect) = Rect::from_xywh(x, y, w, h) {
+        canvas.fill_rect(rect, &paint);
+    }
+}
+
 fn draw_image(canvas: &mut Canvas, pos: Point, env: &Env, element: &Image) {
     let img = &env.resources.loaded::<ImageResource>(element.res);