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Gradient Part 5c: Fix gradient rotation on text & math (#2606)

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Sébastien d'Herbais de Thun 2023-11-08 15:51:25 +01:00 committed by GitHub
parent ccbe901cb7
commit d7fea7077e
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5 changed files with 64 additions and 81 deletions
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15
crates/typst-pdf/src/color.rs
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@ -277,7 +277,7 @@ pub(super) trait PaintEncode {
fn set_as_fill(&self, ctx: &mut PageContext, on_text: bool, transforms: Transforms);
/// Set the paint as the stroke color.
fn set_as_stroke(&self, ctx: &mut PageContext, on_text: bool, transforms: Transforms);
fn set_as_stroke(&self, ctx: &mut PageContext, transforms: Transforms);
}
impl PaintEncode for Paint {
@ -288,15 +288,10 @@ impl PaintEncode for Paint {
}
}
fn set_as_stroke(
&self,
ctx: &mut PageContext,
on_text: bool,
transforms: Transforms,
) {
fn set_as_stroke(&self, ctx: &mut PageContext, transforms: Transforms) {
match self {
Self::Solid(c) => c.set_as_stroke(ctx, on_text, transforms),
Self::Gradient(gradient) => gradient.set_as_stroke(ctx, on_text, transforms),
Self::Solid(c) => c.set_as_stroke(ctx, transforms),
Self::Gradient(gradient) => gradient.set_as_stroke(ctx, transforms),
}
}
}
@ -355,7 +350,7 @@ impl PaintEncode for Color {
}
}
fn set_as_stroke(&self, ctx: &mut PageContext, _: bool, _: Transforms) {
fn set_as_stroke(&self, ctx: &mut PageContext, _: Transforms) {
match self {
Color::Luma(_) => {
ctx.parent.colors.d65_gray(&mut ctx.parent.alloc);

90
crates/typst-pdf/src/gradient.rs
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@ -26,21 +26,21 @@ pub struct PdfGradient {
pub aspect_ratio: Ratio,
/// The gradient.
pub gradient: Gradient,
/// Whether the gradient is applied to text.
pub on_text: bool,
/// The corrected angle of the gradient.
pub angle: Angle,
}
/// Writes the actual gradients (shading patterns) to the PDF.
/// This is performed once after writing all pages.
pub(crate) fn write_gradients(ctx: &mut PdfContext) {
for PdfGradient { transform, aspect_ratio, gradient, on_text } in
for PdfGradient { transform, aspect_ratio, gradient, angle } in
ctx.gradient_map.items().cloned().collect::<Vec<_>>()
{
let shading = ctx.alloc.bump();
ctx.gradient_refs.push(shading);
let mut shading_pattern = match &gradient {
Gradient::Linear(linear) => {
Gradient::Linear(_) => {
let shading_function = shading_function(ctx, &gradient);
let mut shading_pattern = ctx.pdf.shading_pattern(shading);
let mut shading = shading_pattern.function_shading();
@ -49,14 +49,24 @@ pub(crate) fn write_gradients(ctx: &mut PdfContext) {
ctx.colors
.write(gradient.space(), shading.color_space(), &mut ctx.alloc);
let angle = Gradient::correct_aspect_ratio(linear.angle, aspect_ratio);
let (sin, cos) = (angle.sin(), angle.cos());
let length = sin.abs() + cos.abs();
let (x1, y1, x2, y2): (f64, f64, f64, f64) = match angle.quadrant() {
Quadrant::First => (0.0, 0.0, cos, sin),
Quadrant::Second => (1.0, 0.0, cos + 1.0, sin),
Quadrant::Third => (1.0, 1.0, cos + 1.0, sin + 1.0),
Quadrant::Fourth => (0.0, 1.0, cos, sin + 1.0),
};
let clamp = |i: f64| if i < 1e-4 { 0.0 } else { i.clamp(0.0, 1.0) };
let x1 = clamp(x1);
let y1 = clamp(y1);
let x2 = clamp(x2);
let y2 = clamp(y2);
shading
.anti_alias(gradient.anti_alias())
.function(shading_function)
.coords([0.0, 0.0, length as f32, 0.0])
.coords([x1 as f32, y1 as f32, x2 as f32, y2 as f32])
.extend([true; 2]);
shading.finish();
@ -90,7 +100,7 @@ pub(crate) fn write_gradients(ctx: &mut PdfContext) {
shading_pattern
}
Gradient::Conic(conic) => {
let vertices = compute_vertex_stream(conic, aspect_ratio, on_text);
let vertices = compute_vertex_stream(conic, aspect_ratio);
let stream_shading_id = ctx.alloc.bump();
let mut stream_shading =
@ -265,15 +275,10 @@ impl PaintEncode for Gradient {
ctx.content.set_fill_pattern(None, name);
}
fn set_as_stroke(
&self,
ctx: &mut PageContext,
on_text: bool,
transforms: Transforms,
) {
fn set_as_stroke(&self, ctx: &mut PageContext, transforms: Transforms) {
ctx.reset_stroke_color_space();
let id = register_gradient(ctx, self, on_text, transforms);
let id = register_gradient(ctx, self, false, transforms);
let name = Name(id.as_bytes());
ctx.content.set_stroke_color_space(ColorSpaceOperand::Pattern);
@ -296,33 +301,20 @@ fn register_gradient(
if transforms.size.y.is_zero() {
transforms.size.y = Abs::pt(1.0);
}
let size = match gradient.unwrap_relative(on_text) {
Relative::Self_ => transforms.size,
Relative::Parent => transforms.container_size,
};
// Correction for y-axis flipping on text.
let angle = gradient.angle().unwrap_or_else(Angle::zero);
let angle = if on_text { Angle::rad(TAU as f64) - angle } else { angle };
let (offset_x, offset_y) = match gradient {
Gradient::Conic(conic) => (
-size.x * (1.0 - conic.center.x.get() / 2.0) / 2.0,
-size.y * (1.0 - conic.center.y.get() / 2.0) / 2.0,
),
_ => match angle.quadrant() {
Quadrant::First => (Abs::zero(), Abs::zero()),
Quadrant::Second => (size.x, Abs::zero()),
Quadrant::Third => (size.x, size.y),
Quadrant::Fourth => (Abs::zero(), size.y),
},
_ => (Abs::zero(), Abs::zero()),
};
let rotation = match gradient {
Gradient::Conic(_) => Angle::zero(),
_ => angle,
};
let rotation = gradient.angle().unwrap_or_else(Angle::zero);
let transform = match gradient.unwrap_relative(on_text) {
Relative::Self_ => transforms.transform,
@ -344,13 +336,9 @@ fn register_gradient(
.pre_concat(Transform::scale(
Ratio::new(size.x.to_pt() * scale_offset),
Ratio::new(size.y.to_pt() * scale_offset),
))
.pre_concat(Transform::rotate(Gradient::correct_aspect_ratio(
rotation,
size.aspect_ratio(),
))),
)),
gradient: gradient.clone(),
on_text,
angle: Gradient::correct_aspect_ratio(rotation, size.aspect_ratio()),
};
let index = ctx.parent.gradient_map.insert(pdf_gradient);
@ -383,16 +371,9 @@ fn write_patch(
c0: [u16; 3],
c1: [u16; 3],
angle: Angle,
on_text: bool,
) {
let mut theta = -TAU * t + angle.to_rad() as f32 + PI;
let mut theta1 = -TAU * t1 + angle.to_rad() as f32 + PI;
// Correction for y-axis flipping on text.
if on_text {
theta = (TAU - theta).rem_euclid(TAU);
theta1 = (TAU - theta1).rem_euclid(TAU);
}
let theta = -TAU * t + angle.to_rad() as f32 + PI;
let theta1 = -TAU * t1 + angle.to_rad() as f32 + PI;
let (cp1, cp2) =
control_point(Point::new(Abs::pt(0.5), Abs::pt(0.5)), 0.5, theta, theta1);
@ -453,11 +434,7 @@ fn control_point(c: Point, r: f32, angle_start: f32, angle_end: f32) -> (Point,
}
#[comemo::memoize]
fn compute_vertex_stream(
conic: &ConicGradient,
aspect_ratio: Ratio,
on_text: bool,
) -> Arc<Vec<u8>> {
fn compute_vertex_stream(conic: &ConicGradient, aspect_ratio: Ratio) -> Arc<Vec<u8>> {
// Generated vertices for the Coons patches
let mut vertices = Vec::new();
@ -534,18 +511,9 @@ fn compute_vertex_stream(
conic.space.convert(c),
c0,
angle,
on_text,
);
write_patch(
&mut vertices,
t_prime,
t_prime,
c0,
c1,
angle,
on_text,
);
write_patch(&mut vertices, t_prime, t_prime, c0, c1, angle);
write_patch(
&mut vertices,
@ -554,7 +522,6 @@ fn compute_vertex_stream(
c1,
conic.space.convert(c_next),
angle,
on_text,
);
t_x = t_next;
@ -570,7 +537,6 @@ fn compute_vertex_stream(
conic.space.convert(c),
conic.space.convert(c_next),
angle,
on_text,
);
t_x = t_next;

17
crates/typst-pdf/src/page.rs
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@ -322,7 +322,7 @@ impl State {
}
/// Subset of the state used to calculate the transform of gradients and patterns.
#[derive(Clone, Copy)]
#[derive(Debug, Clone, Copy)]
pub(super) struct Transforms {
/// The transform of the current item.
pub transform: Transform,
@ -385,6 +385,9 @@ impl PageContext<'_, '_> {
fn transform(&mut self, transform: Transform) {
let Transform { sx, ky, kx, sy, tx, ty } = transform;
self.state.transform = self.state.transform.pre_concat(transform);
if self.state.container_transform.is_identity() {
self.state.container_transform = self.state.transform;
}
self.content.transform([
sx.get() as _,
ky.get() as _,
@ -449,7 +452,7 @@ impl PageContext<'_, '_> {
miter_limit,
} = stroke;
paint.set_as_stroke(self, false, transforms);
paint.set_as_stroke(self, transforms);
self.content.set_line_width(thickness.to_f32());
if self.state.stroke.as_ref().map(|s| &s.line_cap) != Some(line_cap) {
@ -517,12 +520,10 @@ fn write_group(ctx: &mut PageContext, pos: Point, group: &GroupItem) {
if group.frame.kind().is_hard() {
ctx.group_transform(
translation
.pre_concat(
ctx.state
.transform
.post_concat(ctx.state.container_transform.invert().unwrap()),
)
ctx.state
.transform
.post_concat(ctx.state.container_transform.invert().unwrap())
.pre_concat(translation)
.pre_concat(group.transform),
);
ctx.size(group.frame.size());

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tests/ref/visualize/gradient-math.png
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23
tests/typ/visualize/gradient-math.typ
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@ -55,7 +55,6 @@ $ x_"1,2" = frac(-b +- sqrt(b^2 - 4 a c), 2 a) $
---
// Test miscelaneous
#show math.equation: set text(fill: gradient.linear(..color.map.rainbow))
#show math.equation: box
@ -66,3 +65,25 @@ $ attach(
Pi, t: alpha, b: beta,
tl: 1, tr: 2+3, bl: 4+5, br: 6,
) $
---
// Test radial gradient
#show math.equation: set text(fill: gradient.radial(..color.map.rainbow, center: (30%, 30%)))
#show math.equation: box
$ A = mat(
1, 2, 3;
4, 5, 6;
7, 8, 9
) $
---
// Test conic gradient
#show math.equation: set text(fill: gradient.conic(red, blue, angle: 45deg))
#show math.equation: box
$ A = mat(
1, 2, 3;
4, 5, 6;
7, 8, 9
) $