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Diffstat (limited to 'library/src/math/cancel.rs')
| -rw-r--r-- | library/src/math/cancel.rs | 187 |
1 files changed, 0 insertions, 187 deletions
diff --git a/library/src/math/cancel.rs b/library/src/math/cancel.rs deleted file mode 100644 index f576a727..00000000 --- a/library/src/math/cancel.rs +++ /dev/null @@ -1,187 +0,0 @@ -use super::*; - -/// Displays a diagonal line over a part of an equation. -/// -/// This is commonly used to show the elimination of a term. -/// -/// ## Example { #example } -/// ```example -/// >>> #set page(width: 140pt) -/// Here, we can simplify: -/// $ (a dot b dot cancel(x)) / -/// cancel(x) $ -/// ``` -/// -/// Display: Cancel -/// Category: math -#[element(LayoutMath)] -pub struct CancelElem { - /// The content over which the line should be placed. - #[required] - pub body: Content, - - /// The length of the line, relative to the length of the diagonal spanning - /// the whole element being "cancelled". A value of `{100%}` would then have - /// the line span precisely the element's diagonal. - /// - /// ```example - /// >>> #set page(width: 140pt) - /// $ a + cancel(x, length: #200%) - /// - cancel(x, length: #200%) $ - /// ``` - #[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). - /// - /// ```example - /// >>> #set page(width: 140pt) - /// $ (a cancel((b + c), inverted: #true)) / - /// cancel(b + c, inverted: #true) $ - /// ``` - #[default(false)] - pub inverted: bool, - - /// If two opposing cancel lines should be drawn, forming a cross over the - /// element. Overrides `inverted`. - /// - /// ```example - /// >>> #set page(width: 140pt) - /// $ cancel(Pi, cross: #true) $ - /// ``` - #[default(false)] - pub cross: bool, - - /// How to rotate the cancel line. See the [line's - /// documentation]($func/line.angle) for more details. - /// - /// ```example - /// >>> #set page(width: 140pt) - /// $ cancel(Pi, rotation: #30deg) $ - /// ``` - #[default(Angle::zero())] - pub rotation: Angle, - - /// How to stroke the cancel line. See the - /// [line's documentation]($func/line.stroke) for more details. - /// - /// ```example - /// >>> #set page(width: 140pt) - /// $ cancel( - /// sum x, - /// stroke: #( - /// paint: red, - /// thickness: 1.5pt, - /// dash: "dashed", - /// ), - /// ) $ - /// ``` - #[resolve] - #[fold] - #[default(PartialStroke { - // Default stroke has 0.5pt for better visuals. - thickness: Smart::Custom(Abs::pt(0.5)), - ..Default::default() - })] - pub stroke: PartialStroke, -} - -impl LayoutMath for CancelElem { - fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> { - let body = ctx.layout_fragment(&self.body())?; - // Use the same math class as the body, in order to preserve automatic spacing around it. - let body_class = body.class().unwrap_or(MathClass::Special); - let mut body = body.into_frame(); - - let styles = ctx.styles(); - let body_size = body.size(); - let span = self.span(); - let length = self.length(styles).resolve(styles); - - let stroke = self.stroke(styles).unwrap_or(Stroke { - paint: TextElem::fill_in(styles), - ..Default::default() - }); - - let invert = self.inverted(styles); - let cross = self.cross(styles); - let angle = self.rotation(styles); - - let invert_first_line = !cross && invert; - let first_line = draw_cancel_line( - length, - stroke.clone(), - invert_first_line, - angle, - body_size, - span, - ); - - // The origin of our line is the very middle of the element. - let center = body_size.to_point() / 2.0; - body.push_frame(center, first_line); - - if cross { - // Draw the second line. - let second_line = - draw_cancel_line(length, stroke, true, angle, body_size, span); - - body.push_frame(center, second_line); - } - - ctx.push(FrameFragment::new(ctx, body).with_class(body_class)); - - Ok(()) - } -} - -/// Draws a cancel line. -fn draw_cancel_line( - length: Rel<Abs>, - stroke: Stroke, - invert: bool, - angle: Angle, - body_size: Size, - span: Span, -) -> Frame { - // B - // /| - // diagonal / | height - // / | - // / | - // 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(scales).map(|(l, s)| l * s); - let delta = Axes::new(width, -height).zip(scales).map(|(l, s)| l * s); - - let mut frame = Frame::new(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 -} |