diff options
| -rw-r--r-- | crates/typst-library/src/math/cancel.rs | 142 | ||||
| -rw-r--r-- | tests/ref/math/cancel.png | bin | 24765 -> 24825 bytes | |||
| -rw-r--r-- | tests/ref/math/spacing.png | bin | 21090 -> 20645 bytes | |||
| -rw-r--r-- | tests/typ/math/cancel.typ | 14 |
4 files changed, 103 insertions, 53 deletions
diff --git a/crates/typst-library/src/math/cancel.rs b/crates/typst-library/src/math/cancel.rs index 4b87117c..8add7bcd 100644 --- a/crates/typst-library/src/math/cancel.rs +++ b/crates/typst-library/src/math/cancel.rs @@ -29,8 +29,9 @@ pub struct CancelElem { #[default(Rel::new(Ratio::one(), Abs::pt(3.0).into()))] pub length: Rel<Length>, - /// If the cancel line should be inverted (pointing to the top left instead - /// of top right). + /// Whether the cancel line should be inverted (flipped along the y-axis). + /// For the default angle setting, inverted means the cancel line + /// points to the top left instead of top right. /// /// ```example /// >>> #set page(width: 140pt) @@ -40,8 +41,8 @@ pub struct CancelElem { #[default(false)] pub inverted: bool, - /// If two opposing cancel lines should be drawn, forming a cross over the - /// element. Overrides `inverted`. + /// Whether two opposing cancel lines should be drawn, forming a cross over + /// the element. Overrides `inverted`. /// /// ```example /// >>> #set page(width: 140pt) @@ -50,15 +51,26 @@ pub struct CancelElem { #[default(false)] pub cross: bool, - /// How to rotate the cancel line. See the - /// [line's documentation]($line.angle) for more details. + /// How much to rotate the cancel line. + /// + /// - If `{auto}`, the line assumes the default angle; that is, along the + /// diagonal line of the content box. + /// - If given an angle, the line is rotated by that angle clockwise w.r.t + /// the y-axis. + /// - It given a function `angle => angle`, the line is rotated by the angle + /// returned by that function. The function receives the default angle as + /// its input. /// /// ```example /// >>> #set page(width: 140pt) - /// $ cancel(Pi, rotation: #30deg) $ + /// $ cancel(Pi) + /// cancel(Pi, angle: #0deg) + /// cancel(Pi, angle: #45deg) + /// cancel(Pi, angle: #90deg) + /// cancel(1/(1+x), angle: #(a => a + 45deg)) + /// cancel(1/(1+x), angle: #(a => a + 90deg)) $ /// ``` - #[default(Angle::zero())] - pub rotation: Angle, + pub angle: Smart<CancelAngle>, /// How to [stroke]($stroke) the cancel line. /// @@ -102,17 +114,18 @@ impl LayoutMath for CancelElem { let invert = self.inverted(styles); let cross = self.cross(styles); - let angle = self.rotation(styles); + let angle = self.angle(styles); let invert_first_line = !cross && invert; let first_line = draw_cancel_line( + ctx, length, stroke.clone(), invert_first_line, - angle, + &angle, body_size, span, - ); + )?; // The origin of our line is the very middle of the element. let center = body_size.to_point() / 2.0; @@ -121,7 +134,7 @@ impl LayoutMath for CancelElem { if cross { // Draw the second line. let second_line = - draw_cancel_line(length, stroke, true, angle, body_size, span); + draw_cancel_line(ctx, length, stroke, true, &angle, body_size, span)?; body.push_frame(center, second_line); } @@ -132,15 +145,77 @@ impl LayoutMath for CancelElem { } } +/// Defines the cancel line. +pub enum CancelAngle { + Angle(Angle), + Func(Func), +} + +cast! { + CancelAngle, + self => match self { + Self::Angle(v) => v.into_value(), + Self::Func(v) => v.into_value() + }, + v: Angle => CancelAngle::Angle(v), + v: Func => CancelAngle::Func(v), +} + /// Draws a cancel line. fn draw_cancel_line( - length: Rel<Abs>, + ctx: &mut MathContext, + length_scale: Rel<Abs>, stroke: FixedStroke, invert: bool, - angle: Angle, + angle: &Smart<CancelAngle>, body_size: Size, span: Span, -) -> Frame { +) -> SourceResult<Frame> { + let default = default_angle(body_size); + let mut angle = match angle { + // Non specified angle defaults to the diagonal + Smart::Auto => default, + Smart::Custom(angle) => match angle { + // This specifies the absolute angle w.r.t y-axis clockwise. + CancelAngle::Angle(v) => *v, + // This specifies a function that takes the default angle as input. + CancelAngle::Func(func) => { + func.call_vt(ctx.vt, [default])?.cast().at(span)? + } + }, + }; + + // invert means flipping along the y-axis + if invert { + angle *= -1.0; + } + + // same as above, the default length is the diagonal of the body box. + let default_length = body_size.to_point().hypot(); + let length = length_scale.relative_to(default_length); + + // Draw a vertical line of length and rotate it by angle + let start = Point::new(Abs::zero(), length / 2.0); + let delta = Point::new(Abs::zero(), -length); + + let mut frame = Frame::soft(body_size); + frame.push(start, FrameItem::Shape(Geometry::Line(delta).stroked(stroke), span)); + + // Having the middle of the line at the origin is convenient here. + frame.transform(Transform::rotate(angle)); + Ok(frame) +} + +/// The default line angle for a body of the given size. +fn default_angle(body: Size) -> Angle { + // The default cancel line is the diagonal. + // We infer the default angle from + // the diagonal w.r.t to the body box. + // + // The returned angle is in the range of [0, Pi/2] + // + // Note that the angle is computed w.r.t to the y-axis + // // B // /| // diagonal / | height @@ -148,36 +223,7 @@ fn draw_cancel_line( // / | // O ---- // width - let diagonal = body_size.to_point().hypot(); - let length = length.relative_to(diagonal); - let (width, height) = (body_size.x, body_size.y); - let mid = body_size / 2.0; - - // Scale the amount needed such that the cancel line has the given 'length' - // (reference length, or 100%, is the whole diagonal). - // Scales from the center. - let scale = length.to_raw() / diagonal.to_raw(); - - // invert horizontally if 'invert' was given - let scale_x = scale * if invert { -1.0 } else { 1.0 }; - let scale_y = scale; - let scales = Axes::new(scale_x, scale_y); - - // Draw a line from bottom left to top right of the given element, where the - // origin represents the very middle of that element, that is, a line from - // (-width / 2, height / 2) with length components (width, -height) (sign is - // inverted in the y-axis). After applying the scale, the line will have the - // correct length and orientation (inverted if needed). - let start = Axes::new(-mid.x, mid.y).zip_map(scales, |l, s| l * s); - let delta = Axes::new(width, -height).zip_map(scales, |l, s| l * s); - - let mut frame = Frame::soft(body_size); - frame.push( - start.to_point(), - FrameItem::Shape(Geometry::Line(delta.to_point()).stroked(stroke), span), - ); - - // Having the middle of the line at the origin is convenient here. - frame.transform(Transform::rotate(angle)); - frame + let (width, height) = (body.x, body.y); + let default_angle = (width / height).atan(); // arctangent (in the range [0, Pi/2]) + Angle::rad(default_angle) } diff --git a/tests/ref/math/cancel.png b/tests/ref/math/cancel.png Binary files differindex 146bb855..b39d8d2d 100644 --- a/tests/ref/math/cancel.png +++ b/tests/ref/math/cancel.png diff --git a/tests/ref/math/spacing.png b/tests/ref/math/spacing.png Binary files differindex c9522b36..20faf665 100644 --- a/tests/ref/math/spacing.png +++ b/tests/ref/math/spacing.png diff --git a/tests/typ/math/cancel.typ b/tests/typ/math/cancel.typ index 315cc7d4..ac715154 100644 --- a/tests/typ/math/cancel.typ +++ b/tests/typ/math/cancel.typ @@ -25,10 +25,14 @@ $ a + cancel(b + c + d, cross: #true) + e $ --- // Resized and styled #set page(width: 200pt, height: auto) -$a + cancel(x, length: #200%) - cancel(x, length: #50%, stroke: #{red + 1.1pt})$ -$ b + cancel(x, length: #150%) - cancel(a + b + c, length: #50%, stroke: #{blue + 1.2pt}) $ +$a + cancel(x, length: #200%) - cancel(x, length: #50%, stroke: #(red + 1.1pt))$ +$ b + cancel(x, length: #150%) - cancel(a + b + c, length: #50%, stroke: #(blue + 1.2pt)) $ --- -// Rotated -$x + cancel(y, rotation: #90deg) - cancel(z, rotation: #135deg)$ -$ e + cancel((j + e)/(f + e)) - cancel((j + e)/(f + e), rotation: #30deg) $ +// Specifying cancel line angle with an absolute angle +$cancel(x, angle: #0deg) + cancel(x, angle: #45deg) + cancel(x, angle: #90deg) + cancel(x, angle: #135deg)$ + +--- +// Specifying cancel line angle with a function +$x + cancel(y, angle: #{angle => angle + 90deg}) - cancel(z, angle: #(angle => angle + 135deg))$ +$ e + cancel((j + e)/(f + e)) - cancel((j + e)/(f + e), angle: #(angle => angle + 30deg)) $ |
