vectorcraft/crates/doc/src/text.rs

364 lines
12 KiB
Rust

//! Text objects (model only; layout and glyph outlines live in `vectorcraft-text`).
use serde::{Deserialize, Serialize};
use vectorcraft_color::{Color, Paint};
use vectorcraft_geom::{Affine, PathData, Point, Rect};
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
pub enum Justify {
#[default]
Left,
Center,
Right,
JustifyLeft,
JustifyCenter,
JustifyRight,
JustifyAll,
}
/// Character attributes (the Character panel).
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub struct CharStyle {
pub font_family: String,
#[serde(default = "regular")]
pub font_style: String,
/// Size in points.
pub size: f64,
/// Leading in points; None = Auto (120% of size).
#[serde(default, skip_serializing_if = "Option::is_none")]
pub leading: Option<f64>,
/// Tracking in 1/1000 em.
#[serde(default)]
pub tracking: f64,
/// Kerning: None = Auto (metrics), Some(v) = manual in 1/1000 em.
#[serde(default, skip_serializing_if = "Option::is_none")]
pub kerning: Option<f64>,
#[serde(default)]
pub baseline_shift: f64,
#[serde(default = "hundred")]
pub h_scale: f64,
#[serde(default = "hundred")]
pub v_scale: f64,
#[serde(default)]
pub rotation: f64,
pub fill: Paint,
#[serde(default)]
pub stroke: Paint,
#[serde(default)]
pub stroke_width: f64,
#[serde(default)]
pub underline: bool,
#[serde(default)]
pub strikethrough: bool,
#[serde(default)]
pub all_caps: bool,
/// OpenType features that differ from the defaults (OpenType panel), as tags: `"dlig"` turns
/// a feature on, `"-liga"` off.
#[serde(default, skip_serializing_if = "Vec::is_empty")]
pub features: Vec<String>,
/// Character style (Character Styles panel) these attributes come from; None = Normal.
#[serde(default, skip_serializing_if = "Option::is_none")]
pub style_name: Option<String>,
}
fn regular() -> String {
"Regular".into()
}
fn hundred() -> f64 {
100.0
}
impl Default for CharStyle {
fn default() -> Self {
Self {
font_family: "Source Sans 3".into(),
font_style: "Regular".into(),
size: 12.0,
leading: None,
tracking: 0.0,
kerning: None,
baseline_shift: 0.0,
h_scale: 100.0,
v_scale: 100.0,
rotation: 0.0,
fill: Paint::solid(Color::BLACK),
stroke: Paint::None,
stroke_width: 0.0,
underline: false,
strikethrough: false,
all_caps: false,
features: vec![],
style_name: None,
}
}
}
impl CharStyle {
pub fn effective_leading(&self) -> f64 {
self.leading.unwrap_or(self.size * 1.2)
}
}
/// Tab stop alignment (Tabs panel).
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub enum TabAlign {
#[default]
Left,
Center,
Right,
/// Aligns on the first `align_on` character (a decimal point by default).
Decimal,
}
/// A tab stop, measured from the left edge of the text (area type: the frame's left edge).
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct TabStop {
pub position: f64,
#[serde(default)]
pub align: TabAlign,
/// Leader characters repeated across the tab's gap (e.g. ". ").
#[serde(default, skip_serializing_if = "String::is_empty")]
pub leader: String,
/// Decimal tabs align on this character.
#[serde(default = "default_align_on")]
pub align_on: char,
}
fn default_align_on() -> char {
'.'
}
/// Distance between default tab stops when no explicit stop applies (½ inch).
pub const DEFAULT_TAB_INTERVAL: f64 = 36.0;
/// Paragraph attributes (the Paragraph panel).
#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize)]
pub struct ParaStyle {
#[serde(default)]
pub justify: Justify,
#[serde(default)]
pub left_indent: f64,
#[serde(default)]
pub right_indent: f64,
#[serde(default)]
pub first_line_indent: f64,
#[serde(default)]
pub space_before: f64,
#[serde(default)]
pub space_after: f64,
#[serde(default)]
pub hyphenate: bool,
/// Tab stops (Tabs panel), sorted by position.
#[serde(default, skip_serializing_if = "Vec::is_empty")]
pub tabs: Vec<TabStop>,
/// Paragraph style (Paragraph Styles panel) these attributes come from; None = Normal.
#[serde(default, skip_serializing_if = "Option::is_none")]
pub style_name: Option<String>,
}
/// Area Type Options "First Baseline" offset.
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub enum FirstBaseline {
/// The tallest glyph ascent touches the frame top (Illustrator's default).
#[default]
Ascent,
CapHeight,
XHeight,
/// The first line's leading.
Leading,
/// Exactly `first_baseline_min` below the top.
Fixed,
}
/// Text Wrap Options of a wrap object (Object → Text Wrap).
#[derive(Clone, Copy, Debug, PartialEq, Serialize, Deserialize)]
#[serde(default)]
pub struct TextWrap {
/// Distance kept between the text and the object, in points (Illustrator's default 6 pt).
pub offset: f64,
/// Invert Wrap: text flows inside the object instead of around it.
pub invert: bool,
}
impl Default for TextWrap {
fn default() -> Self {
Self { offset: 6.0, invert: false }
}
}
/// A resolved wrap shape on an area text object: the outline of a wrap object in text space.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub struct WrapShape {
pub path: PathData,
#[serde(flatten)]
pub wrap: TextWrap,
}
/// Type on a Path effect: how each glyph is oriented on the path (Type → Type on a Path).
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "camelCase")]
pub enum PathEffect {
/// Glyphs rotate with the path (the default).
#[default]
Rainbow,
/// Vertical edges stay vertical; the baseline follows the path.
Skew,
/// Horizontal edges stay horizontal; vertical edges are perpendicular to the path.
#[serde(rename = "3dRibbon")]
Ribbon3d,
/// No rotation: the left end of each glyph's baseline sits on the path.
StairStep,
/// The baseline centre sits on the path and glyphs point away from the path's centre.
Gravity,
}
impl PathEffect {
pub const ALL: [PathEffect; 5] = [PathEffect::Rainbow, PathEffect::Skew, PathEffect::Ribbon3d, PathEffect::StairStep, PathEffect::Gravity];
pub fn id(self) -> &'static str {
match self {
PathEffect::Rainbow => "rainbow",
PathEffect::Skew => "skew",
PathEffect::Ribbon3d => "3dRibbon",
PathEffect::StairStep => "stairStep",
PathEffect::Gravity => "gravity",
}
}
pub fn parse(s: &str) -> Option<Self> {
let k = s.to_ascii_lowercase().replace([' ', '-', '_'], "");
Self::ALL.into_iter().find(|e| e.id().to_ascii_lowercase() == k || (k == "ribbon3d" && *e == PathEffect::Ribbon3d))
}
}
/// Area Type Options: rows and columns, gutters, inset and first baseline of area type.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
#[serde(default, rename_all = "camelCase")]
pub struct AreaOptions {
pub rows: usize,
pub columns: usize,
/// Gutter between rows/columns in points.
pub gutter: f64,
/// Inset from the frame edges in points.
pub inset: f64,
pub first_baseline: FirstBaseline,
/// Minimum first-baseline offset in points.
pub first_baseline_min: f64,
}
impl Default for AreaOptions {
fn default() -> Self {
Self { rows: 1, columns: 1, gutter: 18.0, inset: 0.0, first_baseline: FirstBaseline::Ascent, first_baseline_min: 0.0 }
}
}
/// A named character or paragraph style: the attributes it sets (a subset of [`CharStyle`] or
/// [`ParaStyle`] fields, by their serialized names). Text using it records the name.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub struct TextStyleDef {
pub name: String,
#[serde(default)]
pub attrs: serde_json::Map<String, serde_json::Value>,
}
/// A run of text sharing one character style.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub struct TextRun {
pub text: String,
pub style: CharStyle,
}
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
#[serde(tag = "kind", rename_all = "lowercase")]
pub enum TextKind {
/// Point type: anchored at the baseline origin of the first line.
Point,
/// Area type flowed inside `frame` (document coordinates, untransformed by `xf`).
Area { frame: PathData },
/// Type on a path, starting at `start` (0..1 of the path length).
OnPath { path: PathData, start: f64 },
}
/// A text object. `runs` split into paragraphs at `\n`.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
pub struct TextObject {
pub kind: TextKind,
/// Maps text space (origin = first baseline start for point type) to the document.
pub xf: Affine,
pub runs: Vec<TextRun>,
#[serde(default)]
pub para: ParaStyle,
/// Area Type Options (area type only).
#[serde(default, skip_serializing_if = "crate::skip::is_default")]
pub area: AreaOptions,
/// Type on a Path effect (type on a path only).
#[serde(default, rename = "pathEffect", skip_serializing_if = "crate::skip::is_default")]
pub path_effect: PathEffect,
/// Wrap objects above this area type, resolved by the engine after each edit (text space).
#[serde(default, skip_serializing_if = "Vec::is_empty")]
pub wrap: Vec<WrapShape>,
/// Cached layout bounds in text space, filled in by the layout engine (not serialized).
#[serde(skip)]
pub cached_bounds: Option<Rect>,
}
impl TextObject {
pub fn point(origin: Point, text: &str, style: CharStyle) -> Self {
Self {
kind: TextKind::Point,
xf: Affine::translate(origin.to_vec2()),
runs: vec![TextRun { text: text.into(), style }],
para: ParaStyle::default(),
area: AreaOptions::default(),
path_effect: PathEffect::default(),
wrap: Vec::new(),
cached_bounds: None,
}
}
pub fn plain_text(&self) -> String {
self.runs.iter().map(|r| r.text.as_str()).collect()
}
pub fn first_style(&self) -> CharStyle {
self.runs.first().map(|r| r.style.clone()).unwrap_or_default()
}
/// Approximate bounds when no layout cache is available (0.55 em average advance).
pub fn estimate_bounds(&self) -> Rect {
let st = self.first_style();
let text = self.plain_text();
let lines: Vec<&str> = text.split('\n').collect();
let w = lines.iter().map(|l| l.chars().count()).max().unwrap_or(0) as f64 * st.size * 0.55;
let lead = st.effective_leading();
Rect::new(0.0, -st.size * 0.8, w.max(1.0), -st.size * 0.8 + lead * lines.len().max(1) as f64)
}
pub fn bounds(&self) -> Option<Rect> {
match &self.kind {
TextKind::Area { frame } => frame.bounds().map(|b| self.xf.transform_rect_bbox(b)),
TextKind::OnPath { path, .. } => path.bounds().map(|b| self.xf.transform_rect_bbox(b)),
TextKind::Point => Some(self.xf.transform_rect_bbox(self.cached_bounds.unwrap_or_else(|| self.estimate_bounds()))),
}
}
pub fn transform(&mut self, a: Affine) {
self.xf = a * self.xf;
}
/// Layout bounds in text space (the layout cache, else the estimate): the box an unplaced run
/// gradient fits, as the renderers lay it out.
pub fn local_bounds(&self) -> Rect {
self.cached_bounds.unwrap_or_else(|| self.estimate_bounds())
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn point_text_basics() {
let t = TextObject::point(Point::new(10.0, 20.0), "Hello", CharStyle::default());
assert_eq!(t.plain_text(), "Hello");
let b = t.bounds().unwrap();
assert!(b.x0 >= 10.0 - 1e-9 && b.y1 > 20.0);
assert_eq!(CharStyle::default().effective_leading(), 14.399999999999999);
}
}