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wordcraft/crates/render/src/lib.rs
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//! WordCraft rasteriser: draws a page's display list with vello_cpu.
#![deny(clippy::unwrap_used, clippy::expect_used, clippy::panic, clippy::unimplemented, clippy::todo, clippy::unreachable)]
use std::collections::HashMap;
use std::sync::{Arc, Mutex, Weak};
use vello_cpu::kurbo::{self, Affine, BezPath, Shape};
use vello_cpu::peniko;
use vello_cpu::{Pixmap, RenderContext, Resources};
use wordcraft_doc::Document;
use wordcraft_doc::para::ShapeKind;
use wordcraft_doc::props::Rgb;
use wordcraft_fonts::FontDb;
use wordcraft_layout::Page;
use wordcraft_layout::display::Paint;
use wordcraft_layout::display::{DisplayOptions, Draw, Stroke, page_layers};
use wordcraft_metafile::{Item, Picture, PlacedItem, Seg};
mod color_glyph;
pub mod icon_lib;
/// Worker threads for rasterising (0 on the web, where there are no threads).
pub fn default_threads() -> u16 {
#[cfg(target_arch = "wasm32")]
{
0
}
#[cfg(not(target_arch = "wasm32"))]
{
std::thread::available_parallelism().map(|n| (n.get().saturating_sub(1)).clamp(1, 8) as u16).unwrap_or(2)
}
}
mod context_pool;
/// Largest raster side vello_cpu handles comfortably.
pub const MAX_SIDE: u32 = 16_000;
/// A rendered image (premultiplied RGBA8, row-major).
#[derive(Clone, Default)]
pub struct Rendered {
pub width: u32,
pub height: u32,
pub pixels: Vec<u8>,
}
impl Rendered {
pub fn to_straight(&self) -> Vec<u8> {
let mut out = self.pixels.clone();
for px in out.as_chunks_mut::<4>().0 {
let a = px[3] as u32;
if a != 0 && a != 255 {
for c in px.iter_mut().take(3) {
*c = ((*c as u32 * 255 + a / 2) / a).min(255) as u8;
}
}
}
out
}
/// Whether the pixels are exactly `width`×`height` RGBA, within a page raster's budget
/// ([`wordcraft_geom::MAX_RASTER_PIXELS`]): the fields are public, so an encoder is never asked
/// to pad a short buffer out to a huge claimed size (or, for JPEG, to assert on a mismatch).
fn encodable(&self) -> bool {
let budget = wordcraft_geom::MAX_RASTER_PIXELS.saturating_mul(4);
wordcraft_geom::rgba_fits(self.width, self.height, budget)
&& wordcraft_geom::rgba_bytes(self.width, self.height).is_some_and(|b| b == self.pixels.len() as u64)
}
/// PNG bytes (empty on failure, logged).
pub fn to_png(&self) -> Vec<u8> {
if !self.encodable() {
log::error!("PNG encode: {} bytes for {}×{} pixels", self.pixels.len(), self.width, self.height);
return Vec::new();
}
let Some(img) = image::RgbaImage::from_raw(self.width, self.height, self.to_straight()) else {
log::error!("PNG encode: bad size {}×{}", self.width, self.height);
return Vec::new();
};
let mut buf = Vec::new();
if let Err(e) = img.write_to(&mut std::io::Cursor::new(&mut buf), image::ImageFormat::Png) {
log::error!("PNG encode: {e}");
return Vec::new();
}
buf
}
/// JPEG bytes on white (empty on failure, logged).
pub fn to_jpeg(&self, quality: u8) -> Vec<u8> {
if !self.encodable() {
log::error!("JPEG encode: {} bytes for {}×{} pixels", self.pixels.len(), self.width, self.height);
return Vec::new();
}
let rgba = self.to_straight();
let rgb: Vec<u8> = rgba
.as_chunks::<4>()
.0
.iter()
.flat_map(|p| {
let a = p[3] as u32;
let mix = |c: u8| ((c as u32 * a + 255 * (255 - a)) / 255) as u8;
[mix(p[0]), mix(p[1]), mix(p[2])]
})
.collect();
let mut buf = Vec::new();
let enc = image::codecs::jpeg::JpegEncoder::new_with_quality(&mut buf, quality.clamp(1, 100));
let _ = image::ImageEncoder::write_image(enc, &rgb, self.width, self.height, image::ExtendedColorType::Rgb8);
buf
}
/// Straight RGBA at (x, y) (transparent outside).
pub fn pixel(&self, x: u32, y: u32) -> [u8; 4] {
if x >= self.width || y >= self.height {
return [0; 4];
}
let i = ((y as usize * self.width as usize) + x as usize) * 4;
let Some(p) = self.pixels.get(i..i + 4) else { return [0; 4] };
let a = p[3] as u32;
if a == 0 {
return [0; 4];
}
let un = |c: u8| ((c as u32 * 255 + a / 2) / a).min(255) as u8;
[un(p[0]), un(p[1]), un(p[2]), p[3]]
}
}
/// Paint `p` as the context's paint (gradients in page points, under the view transform).
fn set_paint(ctx: &mut RenderContext, p: &Paint, opts: &RenderOptions) {
set_paint_inked(ctx, p, |c| opts.ink(c));
}
/// [`set_paint`] with each colour passed through `ink` (a dark page's text inking, #1252).
fn set_paint_inked(ctx: &mut RenderContext, p: &Paint, ink: impl Fn(Rgb) -> Rgb) {
let stops = |stops: &[(f32, Rgb, f32)]| -> Vec<peniko::ColorStop> {
stops.iter().map(|(o, c, a)| peniko::ColorStop::from((o.clamp(0.0, 1.0), color(ink(*c), *a)))).collect()
};
match p {
Paint::Solid(c, a) => ctx.set_paint(color(ink(*c), *a)),
Paint::Linear { p0, p1, stops: s } => ctx.set_paint(
peniko::Gradient::new_linear((f64::from(p0.0), f64::from(p0.1)), (f64::from(p1.0), f64::from(p1.1))).with_stops(stops(s).as_slice()),
),
Paint::Radial { c, r, stops: s } => {
ctx.set_paint(peniko::Gradient::new_radial((f64::from(c.0), f64::from(c.1)), *r).with_stops(stops(s).as_slice()))
}
}
}
fn color(c: Rgb, alpha: f32) -> peniko::Color {
peniko::Color::from_rgba8(c.0, c.1, c.2, (alpha.clamp(0.0, 1.0) * 255.0) as u8)
}
/// Upper bound on the bytes the two decoded-media caches keep together (about 256 MB), half each;
/// past its half a cache starts over.
const CACHE_BYTES: usize = 256 * 1024 * 1024 / 2;
/// Upper bound on cached entries per cache.
const CACHE_ENTRIES: usize = 256;
/// Decoded media by media key, shared across renders, with an approximate byte budget. An entry knows
/// its source allocation weakly: a hit needs the same allocation, whose address can't be reused while
/// the entry lives, and the source bytes are still freed with the document.
struct MediaCache<T> {
map: HashMap<String, Entry<T>>,
bytes: usize,
}
struct Entry<T> {
src: Weak<Vec<u8>>,
val: T,
size: usize,
}
impl<T: Clone> MediaCache<T> {
fn get(&self, key: &str, src: &Arc<Vec<u8>>) -> Option<T> {
let e = self.map.get(key)?;
std::ptr::eq(e.src.as_ptr(), Arc::as_ptr(src)).then(|| e.val.clone())
}
/// Stores `val` (about `size` bytes) for `src`. Clears the cache first when the budget or entry
/// cap is hit; an entry larger than the whole budget is not kept.
fn insert(&mut self, key: &str, src: &Arc<Vec<u8>>, val: T, size: usize) {
if size > CACHE_BYTES {
return;
}
if let Some(old) = self.map.remove(key) {
self.bytes = self.bytes.saturating_sub(old.size);
}
if self.map.len() >= CACHE_ENTRIES || self.bytes.saturating_add(size) > CACHE_BYTES {
self.map.clear();
self.bytes = 0;
}
self.map.insert(key.to_string(), Entry { src: Arc::downgrade(src), val, size });
self.bytes = self.bytes.saturating_add(size);
}
}
fn lock<T>(m: &Mutex<T>) -> std::sync::MutexGuard<'_, T> {
m.lock().unwrap_or_else(std::sync::PoisonError::into_inner)
}
fn images() -> &'static Mutex<MediaCache<Option<Arc<Pixmap>>>> {
static C: std::sync::OnceLock<Mutex<MediaCache<Option<Arc<Pixmap>>>>> = std::sync::OnceLock::new();
C.get_or_init(|| Mutex::new(MediaCache { map: HashMap::new(), bytes: 0 }))
}
fn vectors() -> &'static Mutex<MediaCache<Option<Arc<Vector>>>> {
static C: std::sync::OnceLock<Mutex<MediaCache<Option<Arc<Vector>>>>> = std::sync::OnceLock::new();
C.get_or_init(|| Mutex::new(MediaCache { map: HashMap::new(), bytes: 0 }))
}
/// Largest side (pixels) a document picture may decode to: what a `Pixmap` can hold (`u16`
/// sides, which [`premul_pixmap`] enforces after decoding). Applying it as a decode limit rejects
/// a small file that declares a bigger image at header time, before anything is allocated.
const MAX_DECODE_SIDE: u32 = u16::MAX as u32;
/// Decode an encoded image to a premultiplied pixmap. The dimension limit above and the default
/// allocation cap (512 MB, what `load_from_memory` applied) bound the decode during paint.
pub fn decode_pixmap(bytes: &[u8]) -> Option<Pixmap> {
// The shared probe also charges what the decoder holds beside its output (#3644).
if !wordcraft_geom::picture::probe(bytes).is_ok_and(|p| p.fits(wordcraft_geom::MAX_DECODED_BYTES)) {
return None;
}
decode_pixmap_within(bytes, wordcraft_geom::MAX_DECODED_BYTES)
}
/// [`decode_pixmap`] with an explicit RGBA byte budget (a small one in tests).
fn decode_pixmap_within(bytes: &[u8], budget: u64) -> Option<Pixmap> {
use image::ImageDecoder;
let mut limits = image::Limits::default();
limits.max_image_width = Some(MAX_DECODE_SIDE);
limits.max_image_height = Some(MAX_DECODE_SIDE);
let reader = || {
let mut r = image::ImageReader::new(std::io::Cursor::new(bytes)).with_guessed_format().ok()?;
r.limits(limits.clone());
Some(r)
};
// The header gives the size and the decoder's pixel format (16-bit RGBA takes 8 bytes a pixel
// before its RGBA8 copy); refuse before the decoder (and the RGBA copy) allocate anything.
let (hw, hh, native) = {
let d = reader()?.into_decoder().ok()?;
let (w, h) = d.dimensions();
(w, h, u64::from(d.color_type().bytes_per_pixel()))
};
if !wordcraft_geom::decode_peak_fits(hw, hh, native, budget) {
// Logged once a picture: its refusal is cached with it (`pixmap_for`).
log::warn!(
"a {hw}×{hh} picture of {native} bytes a pixel needs more than {budget} bytes to decode: it is not drawn (in the text, a grey box takes its place)"
);
return None;
}
let img = reader()?.decode().ok()?.into_rgba8();
let (w, h) = img.dimensions();
premul_pixmap(w, h, img.as_raw())
}
/// A premultiplied pixmap from straight RGBA8 rows. None for empty, oversized or mis-sized input
/// (the pixmap constructor asserts the length).
fn premul_pixmap(w: u32, h: u32, rgba: &[u8]) -> Option<Pixmap> {
if w == 0 || h == 0 || w > u16::MAX as u32 || h > u16::MAX as u32 {
return None;
}
if rgba.len() != (w as usize * h as usize).saturating_mul(4) {
return None;
}
let data: Vec<vello_cpu::color::PremulRgba8> = rgba
.as_chunks::<4>()
.0
.iter()
.map(|p| {
let a = p[3] as u16;
let m = |c: u8| ((c as u16 * a + 127) / 255) as u8;
vello_cpu::color::PremulRgba8 { r: m(p[0]), g: m(p[1]), b: m(p[2]), a: p[3] }
})
.collect();
Some(Pixmap::from_parts(data, w as u16, h as u16))
}
/// Pixel size of an encoded image.
pub fn image_size(bytes: &[u8]) -> Option<(u32, u32)> {
image::ImageReader::new(std::io::Cursor::new(bytes)).with_guessed_format().ok()?.into_dimensions().ok()
}
/// The natural size in points of a Windows Metafile or Enhanced Metafile picture, and the file
/// extension it is stored under (`"wmf"` or `"emf"`), or None for anything else (#802). Very large
/// frames are scaled down to 22 inches on the longer side, keeping the shape.
pub fn metafile_size(bytes: &[u8]) -> Option<(f32, f32, &'static str)> {
if !wordcraft_metafile::is_metafile(bytes) {
return None;
}
let pic = wordcraft_metafile::parse(bytes).ok()?;
let (w, h) = (pic.width, pic.height);
if !(w.is_finite() && h.is_finite() && w > 0.0 && h > 0.0) {
return None;
}
let k = (1584.0 / w.max(h)).min(1.0);
// An EMF starts with its header record, type 1.
let ext = if bytes.get(..4) == Some(&[1, 0, 0, 0]) { "emf" } else { "wmf" };
Some((w * k, h * k, ext))
}
/// A metafile (WMF/EMF) picture, parsed once. The geometry comes placed by the metafile crate; the
/// bitmaps are pixmaps, one per picture item (None for paths and undecodable bitmaps).
struct Vector {
pic: Picture,
pixmaps: Vec<Option<Arc<Pixmap>>>,
}
impl Vector {
/// Approximate memory held: pixels and path segments.
fn bytes(&self) -> usize {
let px: usize = self.pixmaps.iter().flatten().map(|p| p.width() as usize * p.height() as usize * 4).sum();
let segs: usize = self
.pic
.items
.iter()
.map(|it| match it {
Item::Path { segs, .. } => segs.len() * std::mem::size_of::<Seg>(),
Item::Bitmap { .. } => 0,
Item::Text(t) => t.text.len() + t.dx.len() * 4,
})
.sum();
px + segs
}
}
/// The metafile picture for a media key. None when the bytes are not a metafile or do not parse, so
/// the caller falls back to the raster path (and the grey box).
fn vector_for(doc: &Document, key: &str) -> Option<Arc<Vector>> {
let bytes = doc.media.get(key)?;
if !wordcraft_metafile::is_metafile(bytes) {
return None;
}
if let Some(v) = lock(vectors()).get(key, bytes) {
return v;
}
let v = build_vector(bytes).map(Arc::new);
if v.is_none() {
log::warn!("picture `{key}` is a metafile that could not be read");
}
let size = v.as_ref().map_or(0, |v| v.bytes());
lock(vectors()).insert(key, bytes, v.clone(), size);
v
}
/// Parses a metafile and decodes its bitmaps. None when the picture has no usable size.
fn build_vector(bytes: &[u8]) -> Option<Vector> {
let mut pic = wordcraft_metafile::parse(bytes).ok()?;
if !pic.has_size() {
return None;
}
// The pixels move into the pixmaps; the picture keeps only the geometry.
let pixmaps = pic.items.iter_mut().map(|it| it.take_pixels().and_then(|(w, h, px)| premul_pixmap(w, h, &px)).map(Arc::new)).collect();
Some(Vector { pic, pixmaps })
}
fn rgba_color(c: [u8; 4]) -> peniko::Color {
peniko::Color::from_rgba8(c[0], c[1], c[2], c[3])
}
/// Draws a metafile picture into `r` (page points): fills and strokes in page space (so strokes keep
/// their width under non-uniform scaling), bitmaps stretched, all clipped to `r` and faded by `alpha`.
/// Strokes have round caps and joins, as GDI draws them, and are at least one device pixel wide, so
/// cosmetic (width 0) pens show as hairlines at any zoom.
fn draw_vector(ctx: &mut RenderContext, v: &Vector, r: &kurbo::Rect, crop: &[f32; 4], alpha: f32, view: Affine) {
ctx.set_transform(view);
let alpha = if alpha.is_finite() { alpha.clamp(0.0, 1.0) } else { 1.0 };
let faded = alpha < 1.0;
if faded {
ctx.push_opacity_layer(alpha);
}
ctx.push_clip_layer(&r.to_path(0.1));
let pixel = device_pixel(view);
for it in v.pic.place(*r, *crop) {
match it {
PlacedItem::Path { path, fill, stroke, even_odd } => {
if let Some(f) = fill {
ctx.set_paint(rgba_color(f));
ctx.set_fill_rule(if even_odd { peniko::Fill::EvenOdd } else { peniko::Fill::NonZero });
ctx.fill_path(&path);
}
if let Some((s, w)) = stroke {
ctx.set_paint(rgba_color(s));
ctx.set_stroke(kurbo::Stroke::new(w.max(pixel)).with_caps(kurbo::Cap::Round).with_join(kurbo::Join::Round));
ctx.stroke_path(&path);
}
}
PlacedItem::Bitmap { index, rect } => {
let Some(Some(pm)) = v.pixmaps.get(index) else { continue };
let (pw, ph) = (pm.width().max(1) as f64, pm.height().max(1) as f64);
ctx.set_paint(vello_cpu::Image {
image: vello_cpu::ImageSource::Pixmap(pm.clone()),
sampler: peniko::ImageSampler::default().with_quality(peniko::ImageQuality::Medium),
});
ctx.set_paint_transform(Affine::translate((rect.x0, rect.y0)) * Affine::scale_non_uniform(rect.width() / pw, rect.height() / ph));
ctx.fill_rect(&rect);
ctx.reset_paint_transform();
}
PlacedItem::Text { index, tf } => {
if let Some(Item::Text(t)) = v.pic.items.get(index) {
draw_vector_text(ctx, t, view * tf);
}
ctx.set_transform(view);
}
}
}
ctx.set_fill_rule(peniko::Fill::NonZero);
ctx.pop_layer();
if faded {
ctx.pop_layer();
}
}
/// Draws a metafile text run: `tf` maps the run's own space (see [`PlacedItem::Text`]) to the device.
fn draw_vector_text(ctx: &mut RenderContext, t: &wordcraft_metafile::Text, tf: Affine) {
let face = wordcraft_fonts::word::resolve(&t.font, t.bold, t.italic).face;
let shaped = wordcraft_fonts::shape(&face, &t.text, &[], |c| c);
let glyphs: Vec<_> = shaped.iter().map(|g| (g.cluster, f64::from(g.x_advance), f64::from(g.x_offset), f64::from(g.y_offset))).collect();
let Some(lay) = t.layout(face.upem, face.ascent, face.descent, &glyphs) else { return };
let k = lay.em / face.upem.max(1.0);
ctx.set_paint(rgba_color(t.color));
let db = FontDb::global();
let canvas = kurbo::Rect::new(0.0, 0.0, f64::from(ctx.width()), f64::from(ctx.height()));
let mut oversized = 0usize;
for (g, (x, y)) in shaped.iter().zip(&lay.glyphs) {
let o = db.outline(&face, g.gid);
let m = tf * Affine::translate((*x, *y)) * Affine::scale(k);
// A record's font size is file data: a glyph many canvases tall (or off the canvas) would
// have its outline flattened into millions of segments for nothing, so it is left out.
let b = m.transform_rect_bbox(o.bounding_box());
let sane = [b.x0, b.y0, b.x1, b.y1].iter().all(|v| v.is_finite()) && b.width() <= MAX_GLYPH_PIXELS && b.height() <= MAX_GLYPH_PIXELS;
if !sane {
oversized = oversized.saturating_add(1);
continue;
}
if !b.overlaps(canvas) {
continue;
}
ctx.set_transform(m);
ctx.fill_path(&o);
}
note_oversized_glyphs(&OVERSIZED_GLYPHS_NOTED, oversized);
}
/// Largest metafile glyph drawn, in device pixels per side (four times the widest canvas).
const MAX_GLYPH_PIXELS: f64 = 65_536.0;
/// Whether metafile glyphs left out for their size have been logged ([`note_oversized_glyphs`]).
static OVERSIZED_GLYPHS_NOTED: std::sync::atomic::AtomicBool = std::sync::atomic::AtomicBool::new(false);
/// Logs that `n` glyphs of a metafile text run were left out for being larger than
/// [`MAX_GLYPH_PIXELS`] (or of no finite size), the first time any are this run (`noted`): a
/// page is drawn again on every repaint, so a warning each time would flood the log. True when
/// this call logged it.
fn note_oversized_glyphs(noted: &std::sync::atomic::AtomicBool, n: usize) -> bool {
if n == 0 || noted.swap(true, std::sync::atomic::Ordering::Relaxed) {
return false;
}
log::warn!(
"a picture's text has {n} letter(s) larger than {MAX_GLYPH_PIXELS} pixels drawn, left out (logged once a run; later ones are left out too)"
);
true
}
/// One device pixel in page points under `view` (its mean axis scale); 1 for a degenerate transform.
fn device_pixel(view: Affine) -> f64 {
let c = view.as_coeffs();
let scale = (c[0].hypot(c[1]) + c[2].hypot(c[3])) / 2.0;
if scale.is_finite() && scale > 1e-9 { 1.0 / scale } else { 1.0 }
}
/// Largest page-background picture decoded, in pixels (hostile files).
const MAX_BACKGROUND_PIXELS: u64 = 64 * 1024 * 1024;
/// Draw the page's picture or texture fill (Design › Page Color › Fill Effects) behind the content:
/// tiled at its natural size (96 dpi) for a `tile` fill, stretched over the page otherwise.
fn draw_page_picture(ctx: &mut RenderContext, doc: &Document, page: &Page, view: Affine) {
let Some(pic) = &doc.settings.page_picture else { return };
let Some(bytes) = doc.media.get(&pic.media) else { return };
let (nw, nh) = match image_size(bytes) {
Some((w, h)) if w > 0 && h > 0 && (w as u64) * (h as u64) <= MAX_BACKGROUND_PIXELS => (w as f64, h as f64),
_ => return,
};
let Some(pm) = pixmap_for(doc, &pic.media) else { return };
let (pw, ph) = (pm.width().max(1) as f64, pm.height().max(1) as f64);
let (w, h) = (page.w as f64, (page.h as f64).min(1e6));
if !(w.is_finite() && h.is_finite() && w > 0.0 && h > 0.0) {
return;
}
let tile = pic.fill_type.eq_ignore_ascii_case("tile");
// Tiles at the picture's natural size, whatever size its cached pixmap is kept at.
let (sx, sy) = if tile { (0.75 * nw / pw, 0.75 * nh / ph) } else { (w / pw, h / ph) };
let extend = if tile { peniko::Extend::Repeat } else { peniko::Extend::Pad };
ctx.set_transform(view);
ctx.set_paint(vello_cpu::Image {
image: vello_cpu::ImageSource::Pixmap(pm),
sampler: peniko::ImageSampler::default().with_quality(peniko::ImageQuality::Medium).with_extend(extend),
});
ctx.set_paint_transform(Affine::scale_non_uniform(sx, sy));
ctx.fill_rect(&kurbo::Rect::new(0.0, 0.0, w, h));
ctx.reset_paint_transform();
}
fn pixmap_for(doc: &Document, key: &str) -> Option<Arc<Pixmap>> {
let bytes = doc.media.get(key)?;
if let Some(v) = lock(images()).get(key, bytes) {
return v;
}
let pm = decode_pixmap(bytes).map(|p| Arc::new(cacheable(p)));
let size = pm.as_ref().map_or(0, |p| p.width() as usize * p.height() as usize * 4);
lock(images()).insert(key, bytes, pm.clone(), size);
pm
}
/// A decoded picture at a size the media cache keeps. One too large for the whole cache is
/// box-averaged down to half of it, so it is decoded once instead of on every render (#3665); pages
/// draw it scaled to its frame either way.
fn cacheable(pm: Pixmap) -> Pixmap {
let bytes = pm.width() as usize * pm.height() as usize * 4;
if bytes <= CACHE_BYTES {
return pm;
}
shrink(&pm, (CACHE_BYTES / 2 / 4) as u64).unwrap_or(pm)
}
/// `pm` averaged over square blocks, the smallest whole number of pixels a side that brings it to
/// at most `max_pixels`; None when it already fits or none are allowed. Premultiplied pixels
/// average without colour fringes.
fn shrink(pm: &Pixmap, max_pixels: u64) -> Option<Pixmap> {
let (w, h) = (usize::from(pm.width()), usize::from(pm.height()));
if (w * h) as u64 <= max_pixels || max_pixels == 0 {
return None;
}
let mut k = (((w * h) as f64 / max_pixels as f64).sqrt().ceil() as usize).max(2);
while (w.div_ceil(k) * h.div_ceil(k)) as u64 > max_pixels {
k += 1;
}
let (nw, nh) = (w.div_ceil(k), h.div_ceil(k));
let mut out = Vec::with_capacity(nw * nh);
let mut sums = vec![[0u64; 4]; nw];
for (oy, band) in pm.data().chunks(w * k).enumerate() {
sums.fill([0; 4]);
for row in band.chunks(w) {
for (sum, block) in sums.iter_mut().zip(row.chunks(k)) {
for p in block {
sum[0] += u64::from(p.r);
sum[1] += u64::from(p.g);
sum[2] += u64::from(p.b);
sum[3] += u64::from(p.a);
}
}
}
let rows = (h - oy * k).min(k);
for (ox, sum) in sums.iter().enumerate() {
let n = (((w - ox * k).min(k)) * rows).max(1) as u64;
let [r, g, b, a] = sum.map(|s| (s / n) as u8);
out.push(vello_cpu::color::PremulRgba8 { r, g, b, a });
}
}
Some(Pixmap::from_parts(out, nw as u16, nh as u16))
}
/// Options for a page raster.
#[derive(Clone, Debug)]
pub struct RenderOptions {
pub display: DisplayOptions,
/// Paper colour (page colour from Design › Page Color, else white).
pub paper: Rgb,
/// Colour for formatting marks.
pub mark_color: Rgb,
/// Thicken glyphs slightly the way macOS draws text on screen ("font smoothing"), so pages
/// look like they do in other Mac apps. For on-screen rasters only: exports stay exact.
pub text_darkening: bool,
/// Dark page (View › Switch Modes): every colour but pictures has its lightness inverted, so
/// white paper turns black and black text white while hues stay the same. Screen only.
pub dark: bool,
/// The grey that black becomes on a dark page (white paper turns this, not pure black).
pub dark_paper: u8,
/// Read Mode's Page Color: paper drawn instead of the document's page color and page
/// picture. `None` shows the document's page background. Screen only.
pub read_paper: Option<Rgb>,
}
/// Default grey for a dark page's paper.
pub const DARK_PAPER: u8 = 0x33;
/// Read Mode's Sepia paper: Word's RGB (112, 66, 20) at 80% transparency over white.
pub const SEPIA_PAPER: Rgb = Rgb(0xE2, 0xD9, 0xD0);
impl RenderOptions {
/// The on-screen color of the paper under `doc`'s pages: [`RenderOptions::read_paper`],
/// else the document's page color, else [`RenderOptions::paper`].
pub fn paper_of(&self, doc: &Document) -> Rgb {
self.ink(self.read_paper.or(doc.settings.page_color).unwrap_or(self.paper))
}
/// The on-screen colour for a document colour (see [`RenderOptions::dark`]).
pub fn ink(&self, c: Rgb) -> Rgb {
if !self.dark {
return c;
}
// Invert, then lift the blacks to the paper grey so the page isn't a black hole.
let Rgb(r, g, b) = invert_lightness(c);
let p = self.dark_paper as u32;
let lift = |v: u8| (p + v as u32 * (255 - p) / 255).min(255) as u8;
Rgb(lift(r), lift(g), lift(b))
}
/// The on-screen colour for a text background (highlight, character shading). A dark page
/// dims it toward black, keeping its hue, instead of inverting it: inverting leaves bright
/// hues such as yellow bright, so the white text on them can't be read (#1252). Every
/// colour lands dark enough for white text (WCAG contrast ≥ 4.5); yellow turns a dim olive.
pub fn ink_bg(&self, c: Rgb) -> Rgb {
if !self.dark {
return c;
}
let f = |v: u8| (DARK_TEXT_BG_FLOOR as u32 + v as u32 * DARK_TEXT_BG_SPAN as u32 / 255).min(255) as u8;
Rgb(f(c.0), f(c.1), f(c.2))
}
/// The on-screen colour for text (or its underline) drawn on the text background `bg`, if
/// any. A dark page dims those backgrounds ([`RenderOptions::ink_bg`]), so the text takes the
/// lighter of its colour and its inverted colour (black, explicit or Automatic, turns white;
/// Automatic white on a dark highlight stays white), and white if that still falls short of
/// 4.5:1 against the dimmed background (pure blue or red on a dim olive). White always
/// reaches it: no dimmed background is lighter than #4A4A4A.
pub fn ink_text(&self, c: Rgb, bg: Option<Rgb>) -> Rgb {
let inked = self.ink(c);
let Some(bg) = bg.filter(|_| self.dark) else { return inked };
let lighter = if c.luma() > inked.luma() { c } else { inked };
if contrast(lighter, self.ink_bg(bg)) >= 4.5 { lighter } else { Rgb::WHITE }
}
}
// The dim assumes the default dark paper grey (`DARK_PAPER`; the app never sets another
// `dark_paper`): the backgrounds stay close to it and under #4A4A4A, so white text on them
// reaches 4.5:1. Revisit both if the paper grey becomes configurable.
/// Darkest channel of a text background on a dark page ([`RenderOptions::ink_bg`]).
const DARK_TEXT_BG_FLOOR: u8 = 0x10;
/// How far a full channel lifts a dark page's text background above the floor.
const DARK_TEXT_BG_SPAN: u8 = 0x3A;
/// WCAG 2 contrast ratio between two sRGB colours (1 to 21).
fn contrast(a: Rgb, b: Rgb) -> f32 {
let lin = |v: u8| {
let s = v as f32 / 255.0;
if s <= 0.04045 { s / 12.92 } else { ((s + 0.055) / 1.055).powf(2.4) }
};
let lum = |c: Rgb| 0.2126 * lin(c.0) + 0.7152 * lin(c.1) + 0.0722 * lin(c.2);
let (la, lb) = (lum(a), lum(b));
(la.max(lb) + 0.05) / (la.min(lb) + 0.05)
}
/// Invert HSL lightness, keeping hue and saturation: shifting every channel by
/// `255 - max - min` maps the lightest channel to `255 - min` and the darkest to `255 - max`.
pub fn invert_lightness(c: Rgb) -> Rgb {
let (r, g, b) = (c.0 as i32, c.1 as i32, c.2 as i32);
let d = 255 - r.max(g).max(b) - r.min(g).min(b);
let f = |v: i32| (v + d).clamp(0, 255) as u8;
Rgb(f(r), f(g), f(b))
}
impl Default for RenderOptions {
fn default() -> Self {
RenderOptions {
display: DisplayOptions::default(),
paper: Rgb::WHITE,
mark_color: Rgb(0x2B, 0x57, 0x9A),
text_darkening: false,
dark: false,
dark_paper: DARK_PAPER,
read_paper: None,
}
}
}
/// Render a whole page at `scale` pixels per point.
pub fn render_page(doc: &Document, page: &Page, scale: f32, opts: &RenderOptions) -> Rendered {
let scale = if scale.is_finite() && scale > 0.0 { scale } else { 1.0 };
let w = ((page.w * scale).ceil() as u32).clamp(1, MAX_SIDE);
let h = ((page.h.min(1e6) * scale).ceil() as u32).clamp(1, MAX_SIDE);
render_region(doc, page, w, h, Affine::scale(scale as f64), opts)
}
/// Render a page into a `w`×`h` raster with `view` (page points → pixels).
pub fn render_region(doc: &Document, page: &Page, w: u32, h: u32, view: Affine, opts: &RenderOptions) -> Rendered {
render_region_capped(doc, page, w, h, view, opts, wordcraft_geom::MAX_RASTER_PIXELS)
}
/// [`render_region`] with an explicit pixel cap (a small one in tests).
fn render_region_capped(doc: &Document, page: &Page, w: u32, h: u32, view: Affine, opts: &RenderOptions, max_pixels: u64) -> Rendered {
let (w, h) = (w.clamp(1, MAX_SIDE), h.clamp(1, MAX_SIDE));
let (cw, ch) = wordcraft_geom::fit_pixels(w, h, max_pixels);
// Over the cap the whole picture is drawn smaller, not cropped.
let view = if (cw, ch) == (w, h) { view } else { Affine::scale_non_uniform(cw as f64 / w as f64, ch as f64 / h as f64) * view };
let (w16, h16) = (cw as u16, ch as u16);
let mut ctx = context_pool::CONTEXTS.take(w16, h16);
ctx.set_transform(Affine::IDENTITY);
ctx.set_paint(color(opts.paper_of(doc), 1.0));
ctx.fill_rect(&kurbo::Rect::new(0.0, 0.0, w16 as f64, h16 as f64));
if opts.read_paper.is_none() {
draw_page_picture(&mut ctx, doc, page, view);
}
let visible = view.inverse().transform_rect_bbox(kurbo::Rect::new(0.0, 0.0, w16 as f64, h16 as f64)).inflate(40.0, 40.0);
if let Some(wm) = &doc.settings.watermark {
draw_watermark(&mut ctx, view, page, wm, opts);
}
// A dimmed layer is drawn whole, then faded once, so its overlaps don't darken.
for (alpha, items) in page_layers(doc, page, &opts.display) {
let faded = alpha < 1.0 && !items.is_empty();
if faded {
ctx.push_opacity_layer(alpha);
}
for it in &items {
draw(&mut ctx, doc, it, view, &visible, opts);
}
if faded {
ctx.pop_layer();
}
}
ctx.flush();
let mut pixels = vec![0u8; w16 as usize * h16 as usize * 4];
let mut res = Resources::new();
if let Some(pm) = vello_cpu::PixmapMut::new(w16, h16, &mut pixels) {
ctx.render(pm, &mut res);
}
context_pool::CONTEXTS.give_back(ctx);
Rendered { width: w16 as u32, height: h16 as u32, pixels }
}
/// The on-screen colour behind page point (`x`, `y`): the paper (page colour), then any
/// shading, highlight or filled shape drawn over that point, blended in drawing order. Text,
/// pictures and turned or rotated content are left out. The caret takes its colour from this
/// so it shows against whatever lies behind it (#299).
pub fn background_at(doc: &Document, page: &Page, opts: &RenderOptions, x: f32, y: f32) -> Rgb {
let paper = opts.paper_of(doc);
if !(x.is_finite() && y.is_finite()) {
return paper;
}
let mut bg = [paper.0 as f32, paper.1 as f32, paper.2 as f32];
for (alpha, items) in page_layers(doc, page, &opts.display) {
// A faded layer: its own colour there, blended in at its opacity.
let mut layer = bg;
blend_backgrounds(&items, wordcraft_geom::Point::new(x, y), opts, &mut layer, 0);
for (v, n) in bg.iter_mut().zip(layer) {
*v += (n - *v) * alpha;
}
}
let c = |v: f32| v.round().clamp(0.0, 255.0) as u8;
Rgb(c(bg[0]), c(bg[1]), c(bg[2]))
}
fn blend_backgrounds(items: &[Draw], p: wordcraft_geom::Point, opts: &RenderOptions, bg: &mut [f32; 3], depth: u32) {
if depth > 16 {
return;
}
for it in items {
let (color, alpha) = match it {
Draw::Fill { rect, color, alpha, .. } if rect.contains(p) => (*color, *alpha),
// The shape's own outline (an ellipse's corners are not inside it), in its fill's
// colour and opacity there (#1500: gradients and transparency).
Draw::Shape { rect, kind, fill: Some(fill), corner, .. }
if *kind != ShapeKind::Line && rect.contains(p) && {
let r = kurbo::Rect::new(rect.x as f64, rect.y as f64, rect.right() as f64, rect.bottom() as f64);
kurbo::Shape::contains(&shape_path(*kind, r, *corner), kurbo::Point::new(p.x as f64, p.y as f64))
} =>
{
fill.at(p.x, p.y)
}
Draw::Clip { rect, items } if rect.contains(p) => {
blend_backgrounds(items, p, opts, bg, depth + 1);
continue;
}
Draw::Figure { draws, .. } => {
blend_backgrounds(draws, p, opts, bg, depth + 1);
continue;
}
_ => continue,
};
let a = if alpha.is_finite() { alpha.clamp(0.0, 1.0) } else { 1.0 };
let c = opts.ink(color);
for (v, n) in bg.iter_mut().zip([c.0, c.1, c.2]) {
*v += (n as f32 - *v) * a;
}
}
}
/// One line of `text` in `face` at `size` points, black on white, in a `w`×`h` point raster at
/// `scale` pixels per point, starting `margin` points in with the capitals centred in `h`: a font
/// list entry. Not the face's ascent: a font with a tall one (Amiri Quran's is 1.8 em) put the
/// name below the row (#2570). Outlines come straight from the face, not the shared outline
/// cache, so a face read just for the preview leaves nothing behind once dropped (#848).
pub fn render_text_line(face: &wordcraft_fonts::FontFace, text: &str, size: f32, w: f32, h: f32, margin: f32, scale: f32) -> Rendered {
let fin = |v: f32, d: f32| if v.is_finite() && v >= 0.0 { v } else { d };
let (size, w, h, margin) = (fin(size, 12.0).min(1000.0) as f64, fin(w, 1.0), fin(h, 1.0), fin(margin, 0.0).min(1000.0) as f64);
let scale = if scale.is_finite() && scale > 0.0 { scale.min(16.0) } else { 1.0 };
let (pw, ph) = (((w * scale).ceil() as u32).clamp(1, MAX_SIDE), ((h * scale).ceil() as u32).clamp(1, MAX_SIDE));
let (cw, ch) = wordcraft_geom::fit_pixels(pw, ph, wordcraft_geom::MAX_RASTER_PIXELS);
let (w16, h16) = (cw as u16, ch as u16);
let mut ctx = RenderContext::new_with(w16, h16, vello_cpu::RenderSettings { num_threads: 0, ..Default::default() });
ctx.set_transform(Affine::IDENTITY);
ctx.set_paint(color(Rgb(255, 255, 255), 1.0));
ctx.fill_rect(&kurbo::Rect::new(0.0, 0.0, w16 as f64, h16 as f64));
ctx.set_paint(color(Rgb(0, 0, 0), 1.0));
let upem = if face.upem.is_finite() && face.upem > 0.0 { face.upem } else { 1000.0 };
let k = size / upem;
let view = Affine::scale_non_uniform(cw as f64 / pw as f64, ch as f64 / ph as f64) * Affine::scale(scale as f64);
let cap = if face.cap_height.is_finite() { face.cap_height.clamp(upem * 0.3, upem) } else { upem * 0.7 };
let baseline = (h as f64 + cap * k) / 2.0;
let mut x = margin;
let colour = face.has_color_glyphs();
for g in wordcraft_fonts::shape(face, text, &[], |c| c) {
let at = view * Affine::translate((x + g.x_offset as f64 * k, baseline - g.y_offset as f64 * k)) * Affine::scale(k);
if colour && let Some(d) = color_glyph::drawable(face, g.gid, size * scale as f64, false) {
color_glyph::draw(&mut ctx, &d, at, upem, color(Rgb(0, 0, 0), 1.0), 1.0);
ctx.set_paint(color(Rgb(0, 0, 0), 1.0));
} else {
ctx.set_transform(at);
ctx.fill_path(&face.glyph_outline(g.gid));
}
x += g.x_advance as f64 * k;
if x > w as f64 {
break;
}
}
ctx.flush();
let mut pixels = vec![0u8; w16 as usize * h16 as usize * 4];
let mut res = Resources::new();
if let Some(pm) = vello_cpu::PixmapMut::new(w16, h16, &mut pixels) {
ctx.render(pm, &mut res);
}
Rendered { width: w16 as u32, height: h16 as u32, pixels }
}
fn draw_watermark(ctx: &mut RenderContext, view: Affine, page: &Page, wm: &wordcraft_doc::Watermark, opts: &RenderOptions) {
let r = wordcraft_fonts::word::resolve(&wm.font, false, false);
let face = r.face;
let glyphs = wordcraft_fonts::shape(&face, &wm.text, &[], |c| c);
let upem = face.upem.max(1.0);
let raw_w: f64 = glyphs.iter().map(|g| g.x_advance as f64).sum::<f64>() / upem;
if raw_w <= 0.0 {
return;
}
// The document page, not a Print Markup area beside it. The text stretched over its box
// (Word's `v:textpath fitshape`): its advance across the box, its em down it with the em's foot
// on the box's bottom; the box centred on the margins and, when diagonal, turned 45°.
let pw = (page.w - page.markup.max(0.0)).max(1.0) as f64;
let [bw, bh] = wm.frame(pw as f32, page.h).map(f64::from);
let size = bh.min(2000.0);
let k = size / upem;
let stretch = bw / (raw_w * size);
let descent = (wordcraft_fonts::word::line_metrics(&face).1 / upem).clamp(0.0, 1.0);
let angle = if wm.diagonal { -std::f64::consts::FRAC_PI_4 } else { 0.0 };
let b = page.body;
let (cx, cy) =
if b.w > 0.0 && b.h > 0.0 { (f64::from(b.x + b.w / 2.0), f64::from(b.y + b.h / 2.0)) } else { (pw / 2.0, page.h.min(2000.0) as f64 / 2.0) };
let base = Affine::translate((cx, cy))
* Affine::rotate(angle)
* Affine::translate((-bw / 2.0, bh / 2.0 - descent * bh))
* Affine::scale_non_uniform(stretch, 1.0);
ctx.set_paint(color(opts.ink(wm.color), if wm.semitransparent { 0.35 } else { 0.8 }));
let db = FontDb::global();
let mut x = 0.0;
for g in &glyphs {
let o = db.outline(&face, g.gid);
ctx.set_transform(view * base * Affine::translate((x, 0.0)) * Affine::scale(k));
ctx.fill_path(&o);
x += g.x_advance as f64 * k;
}
}
/// How far, in device pixels, macOS-style font smoothing pushes each side of a glyph outline out
/// at `ppem` device pixels per em. Values from Pathfinder (MIT/Apache-2.0), which measured them
/// against macOS: 1.21% of the pixel size horizontally and 1.25 times that vertically, each
/// capped at 0.3 px, and no darkening past 72 px per em. We stroke the outline, which grows it
/// evenly, so this is the mean of the two.
pub fn stem_darkening(ppem: f64) -> f64 {
const FACTOR: [f64; 2] = [0.0121, 0.0121 * 1.25];
const MAX_PX: f64 = 0.3;
const MAX_PPEM: f64 = 72.0;
if !ppem.is_finite() || ppem <= 0.0 || ppem > MAX_PPEM {
return 0.0;
}
FACTOR.iter().map(|f| (ppem * f).min(MAX_PX)).sum::<f64>() / 2.0
}
/// A wavy line from `(x0, y0)` to `(x1, y1)`; at most 20 000 units long, so a huge extent can't make it endless.
fn wave_path(x0: f64, y0: f64, x1: f64, y1: f64, amp: f64) -> BezPath {
let mut p = BezPath::new();
let (dx, dy) = (x1 - x0, y1 - y0);
let len = (dx * dx + dy * dy).sqrt();
if !len.is_finite() || len < 1e-3 {
return p;
}
let (ux, uy) = (dx / len, dy / len);
let (nx, ny) = (-uy, ux);
let step = amp * 2.0;
p.move_to((x0, y0));
// Past about 1e16 a step no longer changes coordinates: stop instead of pushing curves forever.
if x0 + ux * step == x0 && y0 + uy * step == y0 {
return p;
}
let mut t = 0.0;
let mut up = true;
while t < len && t < 20_000.0 {
let nt = (t + step).min(len);
if nt <= t {
break;
}
let mid_t = (t + nt) / 2.0;
let sign = if up { -1.0 } else { 1.0 };
let cx = x0 + ux * mid_t + nx * amp * sign;
let cy = y0 + uy * mid_t + ny * amp * sign;
let ex = x0 + ux * nt;
let ey = y0 + uy * nt;
p.quad_to((cx, cy), (ex, ey));
t = nt;
up = !up;
}
p
}
/// Most pieces one dashed stroke may be cut into; past it the stroke is drawn solid. kurbo's dash
/// iterator makes no progress along a segment when a dash is too small next to it (it never ends),
/// and every piece is more stroke to build.
const MAX_DASH_PIECES: f64 = 100_000.0;
/// `dashes` to stroke a path at most `len` long with, or none (solid) when they can't be drawn: a
/// negative or non-finite length, a pattern that adds up to nothing, or more than
/// [`MAX_DASH_PIECES`] pieces along the path.
fn safe_dashes(dashes: impl IntoIterator<Item = f64>, len: f64) -> Vec<f64> {
let d: Vec<f64> = dashes.into_iter().take(MAX_DASH_PIECES as usize + 1).collect();
let period: f64 = d.iter().sum();
let ok = d.iter().all(|v| v.is_finite() && *v >= 0.0) && period > 0.0 && period.is_finite() && len.is_finite();
// Each repeat of the pattern is up to `d.len()` pieces; a partial repeat at each end counts too.
if ok && (len / period + 2.0) * d.len() as f64 <= MAX_DASH_PIECES { d } else { Vec::new() }
}
/// An upper bound on `path`'s length: its control polygon's (a curve is no longer than it).
fn path_len_bound(path: &BezPath) -> f64 {
let (mut len, mut at, mut start) = (0.0, kurbo::Point::ZERO, kurbo::Point::ZERO);
for el in path.elements() {
let pts: &[kurbo::Point] = match el {
kurbo::PathEl::MoveTo(p) => {
(at, start) = (*p, *p);
continue;
}
kurbo::PathEl::LineTo(p) => std::slice::from_ref(p),
kurbo::PathEl::QuadTo(a, b) => &[*a, *b],
kurbo::PathEl::CurveTo(a, b, c) => &[*a, *b, *c],
kurbo::PathEl::ClosePath => std::slice::from_ref(&start),
};
for p in pts {
len += at.distance(*p);
at = *p;
}
}
len
}
/// Rasterize one display item with `view` mapping its current point coordinates to pixels.
/// `visible` is a culling area in those point coordinates; nested clips intersect it and turns
/// transform it into the child's coordinates. Shape and path strokes apply their stored caps,
/// while ink uses its tool's round ends and joins.
fn draw(ctx: &mut RenderContext, doc: &Document, it: &Draw, view: Affine, visible: &kurbo::Rect, opts: &RenderOptions) {
match it {
Draw::Figure { draws, .. } => {
for d in draws {
draw(ctx, doc, d, view, visible, opts);
}
}
Draw::Fill { rect, color: c, alpha, text_bg } => {
let r = kurbo::Rect::new(rect.x as f64, rect.y as f64, rect.right() as f64, rect.bottom() as f64);
if !r.overlaps(*visible) {
return;
}
ctx.set_transform(view);
ctx.set_paint(color(if *text_bg { opts.ink_bg(*c) } else { opts.ink(*c) }, *alpha));
ctx.fill_rect(&r);
}
Draw::Line { x0, y0, x1, y1, width, color: c, stroke, alpha, text_bg } => {
ctx.set_transform(view);
ctx.set_paint(color(opts.ink_text(*c, *text_bg), *alpha));
let w = *width as f64;
// Flat ends, like the PDF export and Word: a round cap sticks half the width out past
// every end, blobbing over the neighbouring border at a table's corners (#2892). Wavy
// underlines keep round ends, as the PDF draws them.
let mut st = kurbo::Stroke::new(w).with_caps(kurbo::Cap::Butt);
let (x0, y0, x1, y1) = (*x0 as f64, *y0 as f64, *x1 as f64, *y1 as f64);
if let Some(d) = stroke.dashes() {
st = st.with_dashes(0.0, safe_dashes(d.iter().map(|k| f64::from(*k) * w), (x1 - x0).hypot(y1 - y0)));
}
let line = |ctx: &mut RenderContext, ox: f64, oy: f64| {
let mut p = BezPath::new();
p.move_to((x0 + ox, y0 + oy));
p.line_to((x1 + ox, y1 + oy));
ctx.stroke_path(&p);
};
if *stroke == Stroke::Wave {
let amp = (w * 1.2).max(0.8);
let p = wave_path(x0, y0, x1, y1, amp);
ctx.set_stroke(kurbo::Stroke::new(w * 0.8));
ctx.stroke_path(&p);
return;
}
if *stroke == Stroke::Triple {
// Three thin lines, spaced as a double's, across the line's direction (so a
// vertical border's lines stand side by side).
let (dx, dy) = (x1 - x0, y1 - y0);
let len = (dx * dx + dy * dy).sqrt().max(1e-3);
let (nx, ny) = (-dy / len * w * 1.8, dx / len * w * 1.8);
ctx.set_stroke(kurbo::Stroke::new(w * 0.6));
for k in [-1.0, 0.0, 1.0] {
line(ctx, nx * k, ny * k);
}
return;
}
if *stroke == Stroke::Double {
let (dx, dy) = (x1 - x0, y1 - y0);
let len = (dx * dx + dy * dy).sqrt().max(1e-3);
let (nx, ny) = (-dy / len * w * 0.9, dx / len * w * 0.9);
ctx.set_stroke(kurbo::Stroke::new(w * 0.6).with_caps(kurbo::Cap::Butt));
line(ctx, nx, ny);
line(ctx, -nx, -ny);
return;
}
ctx.set_stroke(st);
line(ctx, 0.0, 0.0);
}
Draw::Glyphs { face, size, glyphs, color: c, alpha, synth_bold, synth_italic, text_bg, x_scale, .. } => {
// Invisible glyphs (WordArt letters are drawn from their outlines) carry text only.
if *alpha <= 0.0 {
return;
}
let db = FontDb::global();
let k = *size as f64 / face.upem.max(1.0);
ctx.set_paint(color(opts.ink_text(*c, *text_bg), *alpha));
let skew = if *synth_italic { Affine::new([1.0, 0.0, -0.21, 1.0, 0.0, 0.0]) } else { Affine::IDENTITY };
// Scaled letters (`w:w`): each glyph stretched across from its pen position.
let sx = if x_scale.is_finite() && *x_scale > 0.0 { f64::from(*x_scale) } else { 1.0 };
let skew = Affine::scale_non_uniform(sx, 1.0) * skew;
// Outline strokes, in font units: synthetic bold, then on-screen stem darkening (a
// stroke grows the outline by half its width on each side). Darkening is skipped for
// translucent text, where the stroke overlapping the fill would show as a darker rim.
let px_per_pt = view.determinant().abs().sqrt();
let darken_px = if opts.text_darkening && *alpha >= 1.0 { stem_darkening(*size as f64 * px_per_pt) } else { 0.0 };
let darken = if darken_px > 0.0 && k * px_per_pt > 0.0 { 2.0 * darken_px / (k * px_per_pt) } else { 0.0 };
let outline_stroke = if *synth_bold { face.upem * 0.03 } else { 0.0 } + darken;
if outline_stroke > 0.0 {
let join = if darken > 0.0 { kurbo::Join::Round } else { kurbo::Join::Miter };
ctx.set_stroke(kurbo::Stroke::new(outline_stroke).with_join(join));
}
// Emoji and other colour glyphs (#1269) are drawn from the font's colour data.
let colour = face.has_color_glyphs();
let ppem = *size as f64 * px_per_pt;
for (gid, x, y) in glyphs {
let (gx, gy) = (*x as f64, *y as f64);
// Written so a NaN position is skipped too.
let near = gx >= visible.x0 - 100.0 && gx <= visible.x1 && gy >= visible.y0 && gy <= visible.y1 + 200.0;
if !near {
continue;
}
if colour && let Some(d) = color_glyph::drawable(face, *gid, ppem, true) {
let at = view * Affine::translate((gx, gy)) * skew * Affine::scale(k);
color_glyph::draw(ctx, &d, at, face.upem, color(opts.ink(*c), 1.0), *alpha);
ctx.set_paint(color(opts.ink(*c), *alpha));
continue;
}
let o = db.outline(face, *gid);
if o.elements().is_empty() {
continue;
}
ctx.set_transform(view * Affine::translate((gx, gy)) * skew * Affine::scale(k));
ctx.fill_path(&o);
if outline_stroke > 0.0 {
ctx.stroke_path(&o);
}
}
}
Draw::Mark { x, baseline, size, ch, color: mark } => {
let face = wordcraft_fonts::word::resolve("Source Sans 3", false, false).face;
let gid = face.glyph_for(*ch);
let face = if gid == 0 {
match FontDb::global().fallback_for(*ch, face.id()) {
Some(f) => wordcraft_fonts::FaceRef::of(&f),
None => return,
}
} else {
face
};
let gid = face.glyph_for(*ch);
let o = FontDb::global().outline(&face, gid);
let k = *size as f64 / face.upem.max(1.0);
ctx.set_paint(color(opts.ink(mark.unwrap_or(opts.mark_color)), 0.9));
ctx.set_transform(view * Affine::translate((*x as f64, *baseline as f64)) * Affine::scale(k));
ctx.fill_path(&o);
}
Draw::MarkText { x, baseline, size, text } => {
let base_face = wordcraft_fonts::word::resolve("Source Sans 3", false, false).face;
ctx.set_paint(color(opts.ink(opts.mark_color), 0.9));
let mut gx = *x as f64;
for ch in text.chars() {
let mut face = base_face;
if face.glyph_for(ch) == 0
&& let Some(f) = FontDb::global().fallback_for(ch, face.id())
{
face = wordcraft_fonts::FaceRef::of(&f);
}
let gid = face.glyph_for(ch);
let k = *size as f64 / face.upem.max(1.0);
let o = FontDb::global().outline(&face, gid);
ctx.set_transform(view * Affine::translate((gx, *baseline as f64)) * Affine::scale(k));
ctx.fill_path(&o);
gx += face.advance(gid) * k;
}
}
Draw::Image { rect, media, crop, alpha, .. } => {
let r = kurbo::Rect::new(rect.x as f64, rect.y as f64, rect.right() as f64, rect.bottom() as f64);
if !r.overlaps(*visible) {
return;
}
if let Some(v) = vector_for(doc, media) {
draw_vector(ctx, &v, &r, crop, *alpha, view);
return;
}
let Some(pm) = pixmap_for(doc, media) else {
ctx.set_transform(view);
ctx.set_paint(color(opts.ink(Rgb(0xD0, 0xD0, 0xD0)), 1.0));
ctx.fill_rect(&r);
return;
};
let (pw, ph) = (pm.width().max(1) as f64, pm.height().max(1) as f64);
let [cl, ct, vis_w, vis_h] = wordcraft_metafile::crop_window(*crop);
let sx = r.width() / (pw * vis_w);
let sy = r.height() / (ph * vis_h);
ctx.set_transform(view);
// vello_cpu panics on image paints with sampler alpha != 1, so fade through a layer.
let alpha = if alpha.is_finite() { alpha.clamp(0.0, 1.0) } else { 1.0 };
let faded = alpha < 1.0;
if faded {
ctx.push_opacity_layer(alpha);
}
ctx.set_paint(vello_cpu::Image {
image: vello_cpu::ImageSource::Pixmap(pm),
sampler: peniko::ImageSampler::default().with_quality(peniko::ImageQuality::Medium),
});
ctx.set_paint_transform(Affine::translate((r.x0 - cl * pw * sx, r.y0 - ct * ph * sy)) * Affine::scale_non_uniform(sx, sy));
ctx.fill_rect(&r);
ctx.reset_paint_transform();
if faded {
ctx.pop_layer();
}
}
Draw::Path { segs, fill, stroke, stroke_width, dash, cap } => {
let path = wordcraft_layout::display::seg_path(segs);
if path.elements().is_empty() {
return;
}
ctx.set_transform(view);
if let Some(f) = fill {
set_paint(ctx, f, opts);
ctx.fill_path(&path);
}
if let Some(s) = stroke {
// Width 0 (or none) is a hairline.
let w = if stroke_width.is_finite() && *stroke_width > 0.0 { stroke_width.clamp(0.25, 200.0) } else { 0.75 };
ctx.set_paint(color(opts.ink(*s), 1.0));
ctx.set_stroke(
kurbo::Stroke::new(w as f64)
.with_caps(screen_cap(*cap))
.with_dashes(0.0, safe_dashes(dash.iter().map(|v| f64::from(*v)), path_len_bound(&path))),
);
ctx.stroke_path(&path);
}
}
Draw::Art { path, fx, color: c, alpha, text_bg } => {
let Some(b) = wordcraft_layout::wordart::path_box(path) else { return };
if !b.inflate(200.0, 200.0).overlaps(*visible) {
return;
}
ctx.set_transform(view);
for l in wordcraft_layout::wordart::art_layers(path, fx, *c, *alpha) {
// The letters read against their highlight like plain text (#1252); shadows don't.
let ink = |c: Rgb| if l.letters { opts.ink_text(c, *text_bg) } else { opts.ink(c) };
set_paint_inked(ctx, &l.paint, ink);
match l.stroke {
Some(w) => {
ctx.set_stroke(kurbo::Stroke::new(f64::from(w.clamp(0.1, 400.0))).with_join(kurbo::Join::Round));
ctx.stroke_path(&l.path);
}
None => ctx.fill_path(&l.path),
}
}
}
Draw::Ink { pts, color: c, width, alpha } => {
let Some(path) = ink_path(pts) else { return };
if !path.bounding_box().inflate(*width as f64, *width as f64).overlaps(*visible) {
return;
}
ctx.set_transform(view);
ctx.set_paint(color(opts.ink(*c), *alpha));
let w = if width.is_finite() { width.clamp(0.25, 200.0) } else { 1.0 };
ctx.set_stroke(kurbo::Stroke::new(w as f64).with_caps(kurbo::Cap::Round).with_join(kurbo::Join::Round));
ctx.stroke_path(&path);
}
Draw::Shape { rect, kind, fill, stroke, stroke_width, effects, corner, dash, cap } => {
let r = kurbo::Rect::new(rect.x as f64, rect.y as f64, rect.right() as f64, rect.bottom() as f64);
let path = shape_path(*kind, r, *corner);
ctx.set_transform(view);
let fx = effects.sanitized();
let can_fill = *kind != ShapeKind::Line && fill.is_some();
if !fx.is_empty() && (can_fill || stroke.is_some()) {
let sw = if stroke_width.is_finite() { stroke_width.clamp(0.25, 200.0) as f64 } else { 0.75 };
// The shape's silhouette grown by `g` points and moved by `d`, in the current paint.
let silhouette = |ctx: &mut RenderContext, g: f32, d: kurbo::Vec2| {
let g = g as f64;
if can_fill {
let grow = g + if stroke.is_some() { sw / 2.0 } else { 0.0 };
let rr = r.inflate(grow, grow) + d;
if rr.width() > 0.0 && rr.height() > 0.0 {
ctx.fill_path(&shape_path(*kind, rr, *corner));
}
} else if sw + 2.0 * g > 0.05 {
ctx.set_stroke(kurbo::Stroke::new(sw + 2.0 * g));
ctx.stroke_path(&shape_path(*kind, r + d, *corner));
}
};
if let Some(sh) = fx.shadow {
let (dx, dy) = sh.offset();
for (g, a) in wordcraft_doc::effects::bands(-sh.blur / 2.0, sh.blur / 2.0, sh.opacity()) {
ctx.set_paint(color(opts.ink(sh.color), a));
silhouette(ctx, g, kurbo::Vec2::new(dx as f64, dy as f64));
}
}
if let Some(gl) = fx.glow {
for (g, a) in wordcraft_doc::effects::bands(0.0, gl.size, gl.opacity()) {
ctx.set_paint(color(opts.ink(gl.color), a));
silhouette(ctx, g, kurbo::Vec2::ZERO);
}
}
}
// Soft edges: the fill fades out toward the outline (which fades with it).
if let (Some(rad), Some(f), true) = (fx.soft_edge, fill, can_fill) {
let rad = rad.min(rect.w.min(rect.h) / 2.0).max(0.0);
for (g, a) in wordcraft_doc::effects::bands(-rad, 0.0, 1.0) {
let rr = r.inflate(g as f64, g as f64);
if rr.width() > 0.0 && rr.height() > 0.0 {
set_paint(ctx, &f.faded(a), opts);
ctx.fill_path(&shape_path(*kind, rr, *corner));
}
}
return;
}
if let Some(f) = fill {
set_paint(ctx, f, opts);
ctx.fill_path(&path);
}
if let Some(s) = stroke {
ctx.set_paint(color(opts.ink(*s), 1.0));
ctx.set_stroke(
kurbo::Stroke::new(if stroke_width.is_nan() { 0.25 } else { stroke_width.clamp(0.25, 200.0) } as f64)
.with_caps(screen_cap(*cap))
.with_dashes(0.0, safe_dashes(dash.iter().map(|v| f64::from(*v)), path_len_bound(&path))),
);
ctx.stroke_path(&path);
}
}
Draw::Clip { rect, items } => {
let r = kurbo::Rect::new(rect.x as f64, rect.y as f64, rect.right() as f64, rect.bottom() as f64);
if !r.is_finite() || !r.overlaps(*visible) {
return;
}
ctx.set_transform(view);
ctx.push_clip_layer(&r.to_path(0.1));
let local = r.intersect(*visible);
for it in items {
draw(ctx, doc, it, view, &local, opts);
}
ctx.pop_layer();
}
Draw::Turned { x, y, turn, items } => {
let m = Affine::new(Draw::turn_matrix(*turn, *x, *y).map(f64::from));
let local = m.inverse().transform_rect_bbox(*visible);
for it in items {
draw(ctx, doc, it, view * m, &local, opts);
}
}
Draw::Rotated { cx, cy, spin, items } => {
let m = Affine::new(spin.matrix(*cx, *cy).map(f64::from));
let local = m.inverse().transform_rect_bbox(*visible);
for it in items {
draw(ctx, doc, it, view * m, &local, opts);
}
}
}
}
/// The line through an ink stroke's points (finite ones only); a single point is a dot.
fn ink_path(pts: &[(f32, f32)]) -> Option<BezPath> {
let mut p = BezPath::new();
let mut last = None;
for &(x, y) in pts.iter().filter(|(x, y)| x.is_finite() && y.is_finite() && x.abs() < 1e6 && y.abs() < 1e6) {
let pt = (x as f64, y as f64);
if last.is_none() {
p.move_to(pt);
} else {
p.line_to(pt);
}
last = Some(pt);
}
// Only sanitized points reach the path: a tap is drawn at the one usable point.
let only = last?;
if p.elements().len() == 1 {
// A tap: a zero-length line, which round caps draw as a dot.
p.line_to(only);
}
Some(p)
}
/// Map the document cap to the raster backend without changing ink-tool stroke styles.
fn screen_cap(cap: wordcraft_doc::connector::LineCap) -> kurbo::Cap {
match cap {
wordcraft_doc::connector::LineCap::Flat => kurbo::Cap::Butt,
wordcraft_doc::connector::LineCap::Square => kurbo::Cap::Square,
wordcraft_doc::connector::LineCap::Round => kurbo::Cap::Round,
}
}
/// Outline of a basic shape in a rectangle; `corner` is a rounded rectangle's
/// ([`wordcraft_doc::connector::ShapeExtra::corner`]).
pub fn shape_path(kind: ShapeKind, r: kurbo::Rect, corner: Option<u32>) -> BezPath {
let (cx, cy) = (r.center().x, r.center().y);
let poly = |pts: &[(f64, f64)]| {
let mut p = BezPath::new();
for (i, (x, y)) in pts.iter().enumerate() {
if i == 0 {
p.move_to((*x, *y));
} else {
p.line_to((*x, *y));
}
}
p.close_path();
p
};
match kind {
// A freeform is drawn from its own paths; without them, its frame.
ShapeKind::Rectangle | ShapeKind::TextBox | ShapeKind::Freeform => r.to_path(0.1),
ShapeKind::RoundedRectangle => {
let radius = wordcraft_doc::connector::corner_radius(corner, r.width() as f32, r.height() as f32);
kurbo::RoundedRect::from_rect(r, f64::from(radius)).to_path(0.1)
}
ShapeKind::Ellipse => kurbo::Ellipse::from_rect(r).to_path(0.1),
ShapeKind::FlowchartOr => {
let mut p = kurbo::Ellipse::from_rect(r).to_path(0.1);
p.move_to((r.x0, cy));
p.line_to((r.x1, cy));
p.move_to((cx, r.y0));
p.line_to((cx, r.y1));
p
}
ShapeKind::Triangle => poly(&[(cx, r.y0), (r.x1, r.y1), (r.x0, r.y1)]),
ShapeKind::RightTriangle => poly(&[(r.x0, r.y0), (r.x1, r.y1), (r.x0, r.y1)]),
ShapeKind::Diamond => poly(&[(cx, r.y0), (r.x1, cy), (cx, r.y1), (r.x0, cy)]),
// DrawingML's `line`: top-left to bottom-right (flips give the other directions).
ShapeKind::Line => {
let mut p = BezPath::new();
p.move_to((r.x0, r.y0));
p.line_to((r.x1, r.y1));
p
}
// Connectors are drawn as paths (`Draw::Path`); this is their frame's diagonal.
ShapeKind::StraightConnector | ShapeKind::ElbowConnector | ShapeKind::CurvedConnector => {
let mut p = BezPath::new();
p.move_to((r.x0, r.y0));
p.line_to((r.x1, r.y1));
p
}
ShapeKind::Arrow | ShapeKind::ArrowLeft | ShapeKind::ArrowUp | ShapeKind::ArrowDown => {
let (w, h) = (r.width(), r.height());
let pts: Vec<(f64, f64)> = wordcraft_doc::wrap::arrow_outline(kind, w as f32, h as f32)
.iter()
.map(|&(u, v)| (r.x0 + f64::from(u) * w, r.y0 + f64::from(v) * h))
.collect();
poly(&pts)
}
ShapeKind::Star => {
let mut pts = Vec::new();
for i in 0..10 {
let a = std::f64::consts::PI * (i as f64) / 5.0 - std::f64::consts::FRAC_PI_2;
let rad = if i % 2 == 0 { 1.0 } else { 0.4 };
pts.push((cx + a.cos() * r.width() / 2.0 * rad, cy + a.sin() * r.height() / 2.0 * rad));
}
poly(&pts)
}
ShapeKind::Heart => {
let (w, h) = (r.width(), r.height());
let mut p = BezPath::new();
p.move_to((cx, r.y0 + h * 0.3));
p.curve_to((cx, r.y0), (r.x0, r.y0), (r.x0, r.y0 + h * 0.3));
p.curve_to((r.x0, r.y0 + h * 0.6), (cx - w * 0.1, r.y0 + h * 0.75), (cx, r.y1));
p.curve_to((cx + w * 0.1, r.y0 + h * 0.75), (r.x1, r.y0 + h * 0.6), (r.x1, r.y0 + h * 0.3));
p.curve_to((r.x1, r.y0), (cx, r.y0), (cx, r.y0 + h * 0.3));
p.close_path();
p
}
}
}
/// Render the page area (`x`, `y`, `w`×`h` points) at `scale` px/pt — for previews and thumbnails.
pub fn render_area(doc: &Document, page: &Page, x: f32, y: f32, w: f32, h: f32, scale: f32, opts: &RenderOptions) -> Rendered {
let scale = if scale.is_finite() && scale > 0.0 { scale } else { 1.0 };
let pw = ((w * scale).ceil() as u32).clamp(1, MAX_SIDE);
let ph = ((h * scale).ceil() as u32).clamp(1, MAX_SIDE);
let view = Affine::scale(scale as f64) * Affine::translate((-x as f64, -y as f64));
render_region(doc, page, pw, ph, view, opts)
}
/// Draw `items` (page points) alone, on nothing, over the page area (`x`, `y`, `w`×`h` points)
/// at `scale` px/pt: no paper, no watermark. A dragged object's preview.
pub fn render_items(doc: &Document, items: &[Draw], x: f32, y: f32, w: f32, h: f32, scale: f32, opts: &RenderOptions) -> Rendered {
let scale = if scale.is_finite() && scale > 0.0 { scale } else { 1.0 };
let (pw, ph) = (((w * scale).ceil() as u32).clamp(1, MAX_SIDE), ((h * scale).ceil() as u32).clamp(1, MAX_SIDE));
let (cw, ch) = wordcraft_geom::fit_pixels(pw, ph, wordcraft_geom::MAX_RASTER_PIXELS);
let (w16, h16) = (cw as u16, ch as u16);
let view = Affine::scale_non_uniform(cw as f64 / pw as f64, ch as f64 / ph as f64)
* Affine::scale(scale as f64)
* Affine::translate((-x as f64, -y as f64));
let mut ctx = RenderContext::new_with(w16, h16, vello_cpu::RenderSettings { num_threads: 0, ..Default::default() });
let visible = view.inverse().transform_rect_bbox(kurbo::Rect::new(0.0, 0.0, w16 as f64, h16 as f64)).inflate(40.0, 40.0);
for it in items {
draw(&mut ctx, doc, it, view, &visible, opts);
}
ctx.flush();
let mut pixels = vec![0u8; w16 as usize * h16 as usize * 4];
let mut res = Resources::new();
if let Some(pm) = vello_cpu::PixmapMut::new(w16, h16, &mut pixels) {
ctx.render(pm, &mut res);
}
Rendered { width: w16 as u32, height: h16 as u32, pixels }
}
#[cfg(test)]
mod tests;
#[cfg(test)]
mod cache_tests;
#[cfg(test)]
mod tests_color_glyphs;