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authorLaurenz <laurmaedje@gmail.com>2020-10-03 11:09:32 +0200
committerLaurenz <laurmaedje@gmail.com>2020-10-03 11:09:32 +0200
commit730715c064294337ee9befc3b9332d45eb74818f (patch)
treee8bad130d43b3eefcb065365b223c3bdbd997026 /src/layout/text.rs
parentdc8d5d2f1eadb19d0351fa214400d7ec7ba31a20 (diff)
Rename text layouting to shaping ✏
Diffstat (limited to 'src/layout/text.rs')
-rw-r--r--src/layout/text.rs156
1 files changed, 0 insertions, 156 deletions
diff --git a/src/layout/text.rs b/src/layout/text.rs
deleted file mode 100644
index 7dd557c9..00000000
--- a/src/layout/text.rs
+++ /dev/null
@@ -1,156 +0,0 @@
-//! Layouting of continous pieces of text into boxes.
-//!
-//! The layouter picks the most suitable font for each individual character.
-//! When the primary layouting axis horizontally inversed, the word is spelled
-//! backwards. Vertical word layout is not yet supported.
-
-use fontdock::{FaceId, FaceQuery, FontStyle};
-use ttf_parser::GlyphId;
-
-use super::elements::{LayoutElement, Shaped};
-use super::*;
-use crate::font::FontLoader;
-use crate::geom::Size;
-use crate::style::TextStyle;
-
-/// Layouts text into a box.
-pub async fn layout_text(text: &str, ctx: TextContext<'_>) -> BoxLayout {
- TextLayouter::new(text, ctx).layout().await
-}
-
-/// Performs the text layouting.
-#[derive(Debug)]
-struct TextLayouter<'a> {
- ctx: TextContext<'a>,
- text: &'a str,
- shaped: Shaped,
- elements: LayoutElements,
- start: f64,
- width: f64,
-}
-
-/// The context for text layouting.
-#[derive(Debug)]
-pub struct TextContext<'a> {
- /// The font loader to retrieve fonts from when typesetting text with
- /// `layout_text`.
- pub loader: &'a mut FontLoader,
- /// The style for text: Font selection with classes, weights and variants,
- /// font sizes, spacing and so on.
- pub style: &'a TextStyle,
- /// The direction into which the word is laid out. For now, only horizontal
- /// directions are supported.
- pub dir: Dir,
- /// The alignment of the _resulting_ layout. This does not effect the line
- /// layouting itself, but rather how the finished layout will be positioned
- /// in a parent layout.
- pub align: LayoutAlign,
-}
-
-impl<'a> TextLayouter<'a> {
- fn new(text: &'a str, ctx: TextContext<'a>) -> Self {
- Self {
- text,
- shaped: Shaped::new(FaceId::MAX, ctx.style.font_size()),
- elements: LayoutElements::new(),
- start: 0.0,
- width: 0.0,
- ctx,
- }
- }
-
- async fn layout(mut self) -> BoxLayout {
- // If the primary axis is negative, we layout the characters reversed.
- if self.ctx.dir.is_positive() {
- for c in self.text.chars() {
- self.layout_char(c).await;
- }
- } else {
- for c in self.text.chars().rev() {
- self.layout_char(c).await;
- }
- }
-
- // Flush the last buffered parts of the word.
- if !self.shaped.text.is_empty() {
- let pos = Size::new(self.start, 0.0);
- self.elements.push(pos, LayoutElement::Text(self.shaped));
- }
-
- BoxLayout {
- size: Size::new(self.width, self.ctx.style.font_size()),
- align: self.ctx.align,
- elements: self.elements,
- }
- }
-
- async fn layout_char(&mut self, c: char) {
- let (index, glyph, char_width) = match self.select_font(c).await {
- Some(selected) => selected,
- // TODO: Issue warning about missing character.
- None => return,
- };
-
- // Flush the buffer and issue a font setting action if the font differs
- // from the last character's one.
- if self.shaped.face != index {
- if !self.shaped.text.is_empty() {
- let pos = Size::new(self.start, 0.0);
- let shaped = std::mem::replace(
- &mut self.shaped,
- Shaped::new(FaceId::MAX, self.ctx.style.font_size()),
- );
-
- self.elements.push(pos, LayoutElement::Text(shaped));
- self.start = self.width;
- }
-
- self.shaped.face = index;
- }
-
- self.shaped.text.push(c);
- self.shaped.glyphs.push(glyph);
- self.shaped.offsets.push(self.width - self.start);
-
- self.width += char_width;
- }
-
- async fn select_font(&mut self, c: char) -> Option<(FaceId, GlyphId, f64)> {
- let mut variant = self.ctx.style.variant;
-
- if self.ctx.style.bolder {
- variant.weight = variant.weight.thicken(300);
- }
-
- if self.ctx.style.italic {
- variant.style = match variant.style {
- FontStyle::Normal => FontStyle::Italic,
- FontStyle::Italic => FontStyle::Normal,
- FontStyle::Oblique => FontStyle::Normal,
- }
- }
-
- let query = FaceQuery {
- fallback: self.ctx.style.fallback.iter(),
- variant,
- c,
- };
-
- if let Some((id, owned_face)) = self.ctx.loader.query(query).await {
- let face = owned_face.get();
-
- // Determine the width of the char.
- let units_per_em = face.units_per_em().unwrap_or(1000) as f64;
- let ratio = 1.0 / units_per_em;
- let to_raw = |x| ratio * x as f64;
-
- let glyph = face.glyph_index(c)?;
- let glyph_width = face.glyph_hor_advance(glyph)?;
- let char_width = to_raw(glyph_width) * self.ctx.style.font_size();
-
- Some((id, glyph, char_width))
- } else {
- None
- }
- }
-}