Adjust the number of color components written to the pdf according to the color space (#4568)

Cargo.lock

@@ -2774,6 +2774,7 @@ dependencies = [
 name = "typst-pdf"
 version = "0.11.0"
 dependencies = [
+ "arrayvec",
  "base64",
  "bytemuck",
  "comemo",

Cargo.toml

@@ -28,6 +28,7 @@ typst-timing = { path = "crates/typst-timing", version = "0.11.0" }
 typst-utils = { path = "crates/typst-utils", version = "0.11.0" }
 typst-assets = { git = "https://github.com/typst/typst-assets", rev = "4ee794c" }
 typst-dev-assets = { git = "https://github.com/typst/typst-dev-assets", rev = "48a924d" }
+arrayvec = "0.7.4"
 az = "1.2"
 base64 = "0.22"
 bitflags = { version = "2", features = ["serde"] }

crates/typst-pdf/Cargo.toml

@@ -26,6 +26,7 @@ indexmap = { workspace = true }
 miniz_oxide = { workspace = true }
 once_cell = { workspace = true }
 pdf-writer = { workspace = true }
+arrayvec = { workspace = true }
 subsetter = { workspace = true }
 svg2pdf = { workspace = true }
 ttf-parser = { workspace = true }

crates/typst-pdf/src/color.rs

@@ -1,3 +1,4 @@
+use arrayvec::ArrayVec;
 use once_cell::sync::Lazy;
 use pdf_writer::{types::DeviceNSubtype, writers, Chunk, Dict, Filter, Name, Ref};
 use typst::visualize::{Color, ColorSpace, Paint};
@@ -377,26 +378,34 @@ impl PaintEncode for Color {
 /// Extra color space functions.
 pub(super) trait ColorSpaceExt {
     /// Returns the range of the color space.
-    fn range(self) -> [f32; 6];
+    fn range(self) -> &'static [f32];
 
     /// Converts a color to the color space.
-    fn convert<U: QuantizedColor>(self, color: Color) -> [U; 3];
+    fn convert<U: QuantizedColor>(self, color: Color) -> ArrayVec<U, 4>;
 }
 
 impl ColorSpaceExt for ColorSpace {
-    fn range(self) -> [f32; 6] {
+    fn range(self) -> &'static [f32] {
-        [0.0, 1.0, 0.0, 1.0, 0.0, 1.0]
+        match self {
+            ColorSpace::D65Gray => &[0.0, 1.0],
+            ColorSpace::Oklab => &[0.0, 1.0, 0.0, 1.0, 0.0, 1.0],
+            ColorSpace::Oklch => &[0.0, 1.0, 0.0, 1.0, 0.0, 1.0],
+            ColorSpace::LinearRgb => &[0.0, 1.0, 0.0, 1.0, 0.0, 1.0],
+            ColorSpace::Srgb => &[0.0, 1.0, 0.0, 1.0, 0.0, 1.0],
+            ColorSpace::Cmyk => &[0.0, 1.0, 0.0, 1.0, 0.0, 1.0, 0.0, 1.0],
+            ColorSpace::Hsl => &[0.0, 1.0, 0.0, 1.0, 0.0, 1.0],
+            ColorSpace::Hsv => &[0.0, 1.0, 0.0, 1.0, 0.0, 1.0],
+        }
     }
 
-    fn convert<U: QuantizedColor>(self, color: Color) -> [U; 3] {
+    fn convert<U: QuantizedColor>(self, color: Color) -> ArrayVec<U, 4> {
-        let range = self.range();
+        let components = self.encode(color);
-        let [x, y, z, _] = self.encode(color);
 
-        [
+        self.range()
-            U::quantize(x, [range[0], range[1]]),
+            .chunks(2)
-            U::quantize(y, [range[2], range[3]]),
+            .zip(components)
-            U::quantize(z, [range[4], range[5]]),
+            .map(|(range, component)| U::quantize(component, [range[0], range[1]]))
-        ]
+            .collect()
     }
 }
 

crates/typst-pdf/src/gradient.rs

@@ -145,10 +145,9 @@ pub fn write_gradients(
                         .bits_per_component(16)
                         .bits_per_flag(8)
                         .shading_type(StreamShadingType::CoonsPatch)
-                        .decode([
+                        .decode(
-                            0.0, 1.0, 0.0, 1.0, range[0], range[1], range[2], range[3],
+                            [0.0, 1.0, 0.0, 1.0].into_iter().chain(range.iter().copied()),
-                            range[4], range[5],
+                        )
-                        ])
                         .anti_alias(gradient.anti_alias())
                         .filter(Filter::FlateDecode);
 
@@ -216,7 +215,7 @@ fn shading_function(
     chunk
         .stitching_function(function)
         .domain([0.0, 1.0])
-        .range(color_space.range())
+        .range(color_space.range().iter().copied())
         .functions(functions)
         .bounds(bounds)
         .encode(encode);
@@ -235,7 +234,7 @@ fn single_gradient(
     let reference = chunk.alloc();
     chunk
         .exponential_function(reference)
-        .range(color_space.range())
+        .range(color_space.range().iter().copied())
         .c0(color_space.convert(first_color))
         .c1(color_space.convert(second_color))
         .domain([0.0, 1.0])
@@ -344,13 +343,13 @@ fn register_gradient(
 /// Structure:
 ///  - flag: `u8`
 ///  - points: `[u16; 24]`
-///  - colors: `[u16; 12]`
+///  - colors: `[u16; 4*N]` (N = number of components)
 fn write_patch(
     target: &mut Vec<u8>,
     t: f32,
     t1: f32,
-    c0: [u16; 3],
+    c0: &[u16],
-    c1: [u16; 3],
+    c1: &[u16],
     angle: Angle,
 ) {
     let theta = -TAU * t + angle.to_rad() as f32 + PI;
@@ -390,11 +389,13 @@ fn write_patch(
         p1, p1, p2, p2, cp1, cp2, p3, p3, p1, p1, p1, p1,
     ]));
 
-    let colors =
-        [c0.map(u16::to_be), c0.map(u16::to_be), c1.map(u16::to_be), c1.map(u16::to_be)];
-
     // Push the colors.
-    target.extend_from_slice(bytemuck::cast_slice(&colors));
+    let colors = [c0, c0, c1, c1]
+        .into_iter()
+        .flat_map(|c| c.iter().copied().map(u16::to_be_bytes))
+        .flatten();
+
+    target.extend(colors);
 }
 
 fn control_point(c: Point, r: f32, angle_start: f32, angle_end: f32) -> (Point, Point) {
@@ -452,8 +453,8 @@ fn compute_vertex_stream(gradient: &Gradient, aspect_ratio: Ratio) -> Arc<Vec<u8
                 &mut vertices,
                 t0.get() as f32,
                 t1.get() as f32,
-                encode_space.convert(c0),
+                &encode_space.convert(c0),
-                encode_space.convert(c1),
+                &encode_space.convert(c1),
                 angle,
             );
             continue;
@@ -483,8 +484,8 @@ fn compute_vertex_stream(gradient: &Gradient, aspect_ratio: Ratio) -> Arc<Vec<u8
                 &mut vertices,
                 t_x as f32,
                 t_next as f32,
-                encode_space.convert(c),
+                &encode_space.convert(c),
-                encode_space.convert(c_next),
+                &encode_space.convert(c_next),
                 angle,
             );