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moppeeerandClaude Opus 5.5
7a30e5427e
InDesign draws a radial gradient in the object's bounding box: on a non-square frame it's an ellipse reaching the frame's sides, and a Gradient Swatch tool drag keeps those proportions. LYH Studio episode 6 (3:16) gives the left page's background a radial gradient: magenta in the middle, cyan out to every edge. DesignCraft drew a circle reaching only the longer side, so a portrait page stayed purple at its sides. - doc: `Fill::radial_ellipse(bounds)`: centre and radii (default: the box's centre and half its width and height; with a tool vector, its start, and its length measured with the box made square). - render: the radial paint is that circle, stretched by the paint transform; PDF: the shading's transform does the same. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
56 lines
2.7 KiB
Rust
56 lines
2.7 KiB
Rust
//! Gradient fills: InDesign stretches a radial gradient with the object's box.
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use designcraft_color::swatch::{Swatch, SwatchValue};
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use designcraft_color::{Color, Gradient, GradientKind, GradientStop};
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use designcraft_compose::Cache;
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use designcraft_doc::build::NewDocument;
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use designcraft_doc::{Document, Fill, Item, ItemId, Shape, SpreadRef};
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use designcraft_geom::{Affine, Rect, Vec2, shapes};
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use designcraft_render::{Placed, RenderOptions, Rendered, Renderer};
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/// A 100×200 rectangle at (50, 20) filled with a black-to-white radial gradient.
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fn portrait(vector: Option<[f64; 4]>) -> Document {
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let mut d = Document::new(&NewDocument { width: 200.0, height: 240.0, facing_pages: false, ..Default::default() });
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let stop = |offset: f32, color: Color| GradientStop { offset, color, opacity: 1.0, midpoint: 0.5 };
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d.swatches.push(Swatch {
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name: "Radial".into(),
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value: SwatchValue::Gradient {
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gradient: Gradient { kind: GradientKind::Radial, stops: vec![stop(0.0, Color::BLACK), stop(1.0, Color::WHITE)] },
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},
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locked: false,
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named: true,
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hidden: false,
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});
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let id = ItemId(d.alloc());
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let mut it = Item::new(id, d.default_layer(), Shape::Rectangle, shapes::rectangle(Rect::new(50.0, 20.0, 150.0, 220.0)));
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it.fill = Fill { swatch: "Radial".into(), gradient_vector: vector, ..Fill::none() };
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d.insert_item(SpreadRef::Doc(0), it, None).unwrap();
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d
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}
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fn render(d: &Document) -> Rendered {
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let mut r = Renderer::new();
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r.threads = 0;
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let opts = RenderOptions { background: Some([255, 255, 255, 255]), ..Default::default() };
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r.render(d, &Cache::new(), &[Placed { spread: SpreadRef::Doc(0), xf: Affine::translate(Vec2::ZERO) }], 200, 240, Affine::IDENTITY, &opts)
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}
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fn grey(img: &Rendered, x: u32, y: u32) -> u8 {
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img.pixel(x, y)[0]
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}
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#[test]
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fn a_radial_gradient_stretches_with_its_object() {
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// Centred, it reaches white at the sides and at the top and bottom alike (an ellipse).
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let img = render(&portrait(None));
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assert!(grey(&img, 100, 120) < 20, "black at the centre: {}", grey(&img, 100, 120));
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let (side, top) = (grey(&img, 52, 120), grey(&img, 100, 22));
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assert!(side > 225 && top > 225, "white at the side ({side}) and the top ({top})");
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// Half-way to the side and half-way to the top: the same grey.
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let (hs, ht) = (grey(&img, 75, 120), grey(&img, 100, 70));
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assert!(hs.abs_diff(ht) < 12, "half-way: side {hs}, top {ht}");
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// A Gradient Swatch tool vector to the right side: the same ellipse.
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let dragged = render(&portrait(Some([100.0, 120.0, 150.0, 120.0])));
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assert!(grey(&dragged, 100, 70).abs_diff(ht) < 12 && grey(&dragged, 75, 120).abs_diff(hs) < 12);
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}
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