vectorcraft/crates/engine/src/tests_pdfraster.rs

//! Raster effects in PDF on every kind of object: groups, layers, type, images, symbol instances,
//! live objects and single fills and strokes are written with images of their shadows, glows and
//! blurs (no "left out" warning), and the PDF reads back looking like the canvas.

use std::io::Cursor;
use std::sync::Arc;

use serde_json::json;
use vectorcraft_color::{Color, Paint};
use vectorcraft_doc::{Appearance, CharStyle, Document, Effect, ImageBlob, ImageObject, Node, NodeKind, Symbol, TextObject};
use vectorcraft_geom::{Affine, Point, Rect, shapes};
use vectorcraft_render::{Rendered, Renderer};

use super::*;

fn shadow() -> Effect {
    Effect { id: "stylize.dropShadow".into(), params: json!({"x": 6.0, "y": 6.0, "blur": 3.0, "opacity": 75.0}), visible: true }
}

fn blur() -> Effect {
    Effect { id: "blur.gaussian".into(), params: json!({"radius": 3.0}), visible: true }
}

fn rect(d: &mut Document, r: Rect, fill: Color) -> Node {
    Node::path(d.alloc_id(), shapes::rectangle(r), Appearance::basic(Paint::solid(fill), Paint::None, 0.0))
}

fn add(d: &mut Document, n: Node) {
    let l = d.layers[0].id;
    d.insert(Some(l), usize::MAX, n).unwrap();
}

fn with(mut n: Node, fx: Effect) -> Node {
    n.appearance.effects.push(fx);
    n
}

fn png(w: u32, h: u32) -> Vec<u8> {
    let img = image::RgbaImage::from_fn(w, h, |x, _| image::Rgba([(x * 255 / w) as u8, 60, 160, 255]));
    let mut out = Vec::new();
    image::DynamicImage::from(img).write_to(&mut Cursor::new(&mut out), image::ImageFormat::Png).unwrap();
    out
}

fn render(d: &Document) -> Rendered {
    Renderer::new().render_region(d, Rect::new(0.0, 0.0, 200.0, 200.0), 1.0, true)
}

/// Mean difference of the colour channels of two renders, as a share of full scale.
fn mean_diff(a: &Rendered, b: &Rendered) -> f64 {
    let sum: u64 = a.pixels.iter().zip(&b.pixels).map(|(x, y)| x.abs_diff(*y) as u64).sum();
    sum as f64 / a.pixels.len() as f64 / 255.0
}

/// The PDF of `d` embeds images, warns about nothing and reads back within 2% of the canvas, much
/// closer than the art without its raster effects.
fn assert_written(what: &str, d: &Document) {
    let r = crate::cmd::rasterfx::export_pdf_with_report(d, &Default::default()).unwrap();
    assert!(r.warnings.is_empty(), "{what}: {:?}", r.warnings);
    assert!(String::from_utf8_lossy(&r.bytes).contains("/Subtype/Image"), "{what}: an image XObject");
    let canvas = render(d);
    let diff = mean_diff(&canvas, &render(&vectorcraft_pdf::import(&r.bytes).unwrap()));
    let mut plain = d.clone();
    for l in &mut plain.layers {
        crate::cmd::rasterfx::strip_raster(Arc::make_mut(l), true);
    }
    for s in &mut plain.symbols {
        crate::cmd::rasterfx::strip_raster(Arc::make_mut(&mut s.art), true);
    }
    let without = mean_diff(&canvas, &render(&plain));
    assert!(diff < 0.02 && diff < without / 4.0, "{what}: read back {:.2}% off ({:.2}% without the effects)", diff * 100.0, without * 100.0);
}

#[test]
fn groups_layers_type_images_and_symbols_keep_their_raster_effects() {
    // A group's shadow (one shadow of both members).
    let mut d = Document::new(200.0, 200.0);
    let (a, b) = (
        rect(&mut d, Rect::new(30.0, 30.0, 90.0, 90.0), Color::rgb(1.0, 0.0, 0.0)),
        rect(&mut d, Rect::new(70.0, 70.0, 150.0, 150.0), Color::rgb(0.0, 0.0, 1.0)),
    );
    let g = Node::group(d.alloc_id(), vec![Arc::new(a), Arc::new(b)]);
    add(&mut d, with(g, shadow()));
    assert_written("group", &d);

    // A layer's blur.
    let mut d = Document::new(200.0, 200.0);
    let r = rect(&mut d, Rect::new(40.0, 40.0, 160.0, 120.0), Color::rgb(0.1, 0.6, 0.2));
    add(&mut d, r);
    Arc::make_mut(&mut d.layers[0]).appearance.effects.push(blur());
    assert_written("layer", &d);

    // Type with a shadow.
    let mut d = Document::new(200.0, 200.0);
    let style = CharStyle { size: 60.0, fill: Paint::solid(Color::rgb(0.8, 0.1, 0.1)), ..Default::default() };
    let t = Node::new(d.alloc_id(), NodeKind::Text(Box::new(TextObject::point(Point::new(20.0, 120.0), "Ab", style))));
    add(&mut d, with(t, shadow()));
    assert_written("type", &d);

    // An image with a shadow.
    let mut d = Document::new(200.0, 200.0);
    d.images.insert("pic".into(), ImageBlob::new("image/png", png(40, 30)));
    let xf = Affine::translate((40.0, 50.0)) * Affine::scale(2.5);
    let im = Node::new(
        d.alloc_id(),
        NodeKind::Image(ImageObject { key: "pic".into(), width: 40, height: 30, xf, link: None, placement: Default::default() }),
    );
    add(&mut d, with(im, shadow()));
    assert_written("image", &d);

    // A symbol instance with a shadow, and a symbol whose art blurs.
    let mut d = Document::new(200.0, 200.0);
    let art = rect(&mut d, Rect::new(0.0, 0.0, 50.0, 50.0), Color::rgb(0.9, 0.6, 0.0));
    d.symbols.push(Symbol { name: "Tile".into(), art: Arc::new(art) });
    let blurred = with(rect(&mut d, Rect::new(0.0, 0.0, 40.0, 40.0), Color::rgb(0.2, 0.2, 0.8)), blur());
    d.symbols.push(Symbol { name: "Soft".into(), art: Arc::new(blurred) });
    let inst = Node::new(d.alloc_id(), NodeKind::SymbolInstance { symbol: "Tile".into(), xf: Affine::translate((30.0, 30.0)) });
    add(&mut d, with(inst, shadow()));
    let soft = Node::new(d.alloc_id(), NodeKind::SymbolInstance { symbol: "Soft".into(), xf: Affine::translate((120.0, 120.0)) });
    add(&mut d, soft);
    assert_written("symbols", &d);
}

#[test]
fn live_objects_and_single_fills_and_strokes_keep_their_raster_effects() {
    // A blend with a shadow.
    let mut s = Session::new();
    s.execute("file.new", &json!({"width": 200, "height": 200})).unwrap();
    let a = s.execute("shape.rectangle", &json!({"x": 20, "y": 40, "width": 30, "height": 30})).unwrap()["id"].clone();
    let b = s.execute("shape.rectangle", &json!({"x": 140, "y": 120, "width": 30, "height": 30})).unwrap()["id"].clone();
    s.execute("select.set", &json!({"ids": [a, b]})).unwrap();
    let g = s.execute("object.blend.make", &json!({"steps": 3})).unwrap()["id"].clone();
    s.execute("effect.apply", &json!({"effect": "stylize.dropShadow", "ids": [g]})).unwrap();
    assert_written("blend", &s.doc().unwrap().doc);

    // A stroke's shadow falls on the fill below it; a fill's blur stays under a sharp stroke.
    let wide_blur = Effect { params: json!({"radius": 12.0}), ..blur() };
    for (item, fx) in [(1, shadow()), (0, wide_blur)] {
        let mut d = Document::new(200.0, 200.0);
        let mut n = Node::path(
            d.alloc_id(),
            shapes::rectangle(Rect::new(40.0, 40.0, 160.0, 160.0)),
            Appearance::basic(Paint::solid(Color::rgb(1.0, 0.9, 0.2)), Paint::solid(Color::rgb(0.1, 0.1, 0.6)), 6.0),
        );
        n.appearance.effects_mut(Some(item)).unwrap().push(fx);
        add(&mut d, n);
        assert_written(&format!("item {item}"), &d);
        let flat = crate::flatten_raster_effects(&d).unwrap();
        let pieces = flat.layers[0].children().unwrap()[0].children().map_or(0, |c| c.len());
        assert_eq!(pieces, 2, "item {item}: one piece per fill and stroke");
    }
}