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buffer.rs
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buffer.rs
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// SPDX-License-Identifier: MIT OR Apache-2.0
#[cfg(not(feature = "std"))]
use alloc::{string::String, vec::Vec};
use core::{cmp, fmt};
use unicode_segmentation::UnicodeSegmentation;
use crate::{
Affinity, Attrs, AttrsList, BidiParagraphs, BorrowedWithFontSystem, BufferLine, Color, Cursor,
FontSystem, LayoutCursor, LayoutGlyph, LayoutLine, LineEnding, LineIter, Motion, Scroll,
ShapeBuffer, ShapeLine, Shaping, Wrap,
};
/// A line of visible text for rendering
#[derive(Debug)]
pub struct LayoutRun<'a> {
/// The index of the original text line
pub line_i: usize,
/// The original text line
pub text: &'a str,
/// True if the original paragraph direction is RTL
pub rtl: bool,
/// The array of layout glyphs to draw
pub glyphs: &'a [LayoutGlyph],
/// Y offset to baseline of line
pub line_y: f32,
/// Y offset to top of line
pub line_top: f32,
/// Y offset to next line
pub line_height: f32,
/// Width of line
pub line_w: f32,
}
impl<'a> LayoutRun<'a> {
/// Return the pixel span `Some((x_left, x_width))` of the highlighted area between `cursor_start`
/// and `cursor_end` within this run, or None if the cursor range does not intersect this run.
/// This may return widths of zero if `cursor_start == cursor_end`, if the run is empty, or if the
/// region's left start boundary is the same as the cursor's end boundary or vice versa.
pub fn highlight(&self, cursor_start: Cursor, cursor_end: Cursor) -> Option<(f32, f32)> {
let mut x_start = None;
let mut x_end = None;
let rtl_factor = if self.rtl { 1. } else { 0. };
let ltr_factor = 1. - rtl_factor;
for glyph in self.glyphs.iter() {
let cursor = self.cursor_from_glyph_left(glyph);
if cursor >= cursor_start && cursor <= cursor_end {
if x_start.is_none() {
x_start = Some(glyph.x + glyph.w * rtl_factor);
}
x_end = Some(glyph.x + glyph.w * rtl_factor);
}
let cursor = self.cursor_from_glyph_right(glyph);
if cursor >= cursor_start && cursor <= cursor_end {
if x_start.is_none() {
x_start = Some(glyph.x + glyph.w * ltr_factor);
}
x_end = Some(glyph.x + glyph.w * ltr_factor);
}
}
if let Some(x_start) = x_start {
let x_end = x_end.expect("end of cursor not found");
let (x_start, x_end) = if x_start < x_end {
(x_start, x_end)
} else {
(x_end, x_start)
};
Some((x_start, x_end - x_start))
} else {
None
}
}
fn cursor_from_glyph_left(&self, glyph: &LayoutGlyph) -> Cursor {
if self.rtl {
Cursor::new_with_affinity(self.line_i, glyph.end, Affinity::Before)
} else {
Cursor::new_with_affinity(self.line_i, glyph.start, Affinity::After)
}
}
fn cursor_from_glyph_right(&self, glyph: &LayoutGlyph) -> Cursor {
if self.rtl {
Cursor::new_with_affinity(self.line_i, glyph.start, Affinity::After)
} else {
Cursor::new_with_affinity(self.line_i, glyph.end, Affinity::Before)
}
}
}
/// An iterator of visible text lines, see [`LayoutRun`]
#[derive(Debug)]
pub struct LayoutRunIter<'b> {
buffer: &'b Buffer,
line_i: usize,
layout_i: usize,
total_height: f32,
line_top: f32,
}
impl<'b> LayoutRunIter<'b> {
pub fn new(buffer: &'b Buffer) -> Self {
Self {
buffer,
line_i: buffer.scroll.line,
layout_i: 0,
total_height: 0.0,
line_top: 0.0,
}
}
}
impl<'b> Iterator for LayoutRunIter<'b> {
type Item = LayoutRun<'b>;
fn next(&mut self) -> Option<Self::Item> {
while let Some(line) = self.buffer.lines.get(self.line_i) {
let shape = line.shape_opt().as_ref()?;
let layout = line.layout_opt().as_ref()?;
while let Some(layout_line) = layout.get(self.layout_i) {
self.layout_i += 1;
let line_height = layout_line
.line_height_opt
.unwrap_or(self.buffer.metrics.line_height);
self.total_height += line_height;
let line_top = self.line_top - self.buffer.scroll.vertical;
let glyph_height = layout_line.max_ascent + layout_line.max_descent;
let centering_offset = (line_height - glyph_height) / 2.0;
let line_y = line_top + centering_offset + layout_line.max_ascent;
if let Some(height) = self.buffer.height_opt {
if line_y > height {
return None;
}
}
self.line_top += line_height;
if line_y < 0.0 {
continue;
}
return Some(LayoutRun {
line_i: self.line_i,
text: line.text(),
rtl: shape.rtl,
glyphs: &layout_line.glyphs,
line_y,
line_top,
line_height,
line_w: layout_line.w,
});
}
self.line_i += 1;
self.layout_i = 0;
}
None
}
}
/// Metrics of text
#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct Metrics {
/// Font size in pixels
pub font_size: f32,
/// Line height in pixels
pub line_height: f32,
}
impl Metrics {
/// Create metrics with given font size and line height
pub const fn new(font_size: f32, line_height: f32) -> Self {
Self {
font_size,
line_height,
}
}
/// Create metrics with given font size and calculate line height using relative scale
pub fn relative(font_size: f32, line_height_scale: f32) -> Self {
Self {
font_size,
line_height: font_size * line_height_scale,
}
}
/// Scale font size and line height
pub fn scale(self, scale: f32) -> Self {
Self {
font_size: self.font_size * scale,
line_height: self.line_height * scale,
}
}
}
impl fmt::Display for Metrics {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}px / {}px", self.font_size, self.line_height)
}
}
/// A buffer of text that is shaped and laid out
#[derive(Debug)]
pub struct Buffer {
/// [BufferLine]s (or paragraphs) of text in the buffer
pub lines: Vec<BufferLine>,
metrics: Metrics,
width_opt: Option<f32>,
height_opt: Option<f32>,
scroll: Scroll,
/// True if a redraw is requires. Set to false after processing
redraw: bool,
wrap: Wrap,
monospace_width: Option<f32>,
tab_width: u16,
/// Scratch buffer for shaping and laying out.
scratch: ShapeBuffer,
}
impl Clone for Buffer {
fn clone(&self) -> Self {
Self {
lines: self.lines.clone(),
metrics: self.metrics,
width_opt: self.width_opt,
height_opt: self.height_opt,
scroll: self.scroll,
redraw: self.redraw,
wrap: self.wrap,
monospace_width: self.monospace_width,
tab_width: self.tab_width,
scratch: ShapeBuffer::default(),
}
}
}
impl Buffer {
/// Create an empty [`Buffer`] with the provided [`Metrics`].
/// This is useful for initializing a [`Buffer`] without a [`FontSystem`].
///
/// You must populate the [`Buffer`] with at least one [`BufferLine`] before shaping and layout,
/// for example by calling [`Buffer::set_text`].
///
/// If you have a [`FontSystem`] in scope, you should use [`Buffer::new`] instead.
///
/// # Panics
///
/// Will panic if `metrics.line_height` is zero.
pub fn new_empty(metrics: Metrics) -> Self {
assert_ne!(metrics.line_height, 0.0, "line height cannot be 0");
Self {
lines: Vec::new(),
metrics,
width_opt: None,
height_opt: None,
scroll: Scroll::default(),
redraw: false,
wrap: Wrap::WordOrGlyph,
scratch: ShapeBuffer::default(),
monospace_width: None,
tab_width: 8,
}
}
/// Create a new [`Buffer`] with the provided [`FontSystem`] and [`Metrics`]
///
/// # Panics
///
/// Will panic if `metrics.line_height` is zero.
pub fn new(font_system: &mut FontSystem, metrics: Metrics) -> Self {
let mut buffer = Self::new_empty(metrics);
buffer.set_text(font_system, "", Attrs::new(), Shaping::Advanced);
buffer
}
/// Mutably borrows the buffer together with an [`FontSystem`] for more convenient methods
pub fn borrow_with<'a>(
&'a mut self,
font_system: &'a mut FontSystem,
) -> BorrowedWithFontSystem<'a, Buffer> {
BorrowedWithFontSystem {
inner: self,
font_system,
}
}
fn relayout(&mut self, font_system: &mut FontSystem) {
#[cfg(all(feature = "std", not(target_arch = "wasm32")))]
let instant = std::time::Instant::now();
for line in &mut self.lines {
if line.shape_opt().is_some() {
line.reset_layout();
line.layout_in_buffer(
&mut self.scratch,
font_system,
self.metrics.font_size,
self.width_opt,
self.wrap,
self.monospace_width,
self.tab_width,
);
}
}
self.redraw = true;
#[cfg(all(feature = "std", not(target_arch = "wasm32")))]
log::debug!("relayout: {:?}", instant.elapsed());
}
/// Shape lines until cursor, also scrolling to include cursor in view
pub fn shape_until_cursor(
&mut self,
font_system: &mut FontSystem,
cursor: Cursor,
prune: bool,
) {
let metrics = self.metrics;
let old_scroll = self.scroll;
let layout_cursor = self
.layout_cursor(font_system, cursor)
.expect("shape_until_cursor invalid cursor");
let mut layout_y = 0.0;
let mut total_height = {
let layout = self
.line_layout(font_system, layout_cursor.line)
.expect("shape_until_cursor failed to scroll forwards");
for layout_i in 0..layout_cursor.layout {
layout_y += layout[layout_i]
.line_height_opt
.unwrap_or(metrics.line_height);
}
layout_y
+ layout[layout_cursor.layout]
.line_height_opt
.unwrap_or(metrics.line_height)
};
if self.scroll.line > layout_cursor.line
|| (self.scroll.line == layout_cursor.line && self.scroll.vertical > layout_y)
{
// Adjust scroll backwards if cursor is before it
self.scroll.line = layout_cursor.line;
self.scroll.vertical = layout_y;
} else if let Some(height) = self.height_opt {
// Adjust scroll forwards if cursor is after it
let mut line_i = layout_cursor.line;
while line_i > self.scroll.line {
line_i -= 1;
let layout = self
.line_layout(font_system, line_i)
.expect("shape_until_cursor failed to scroll forwards");
for layout_line in layout.iter() {
total_height += layout_line.line_height_opt.unwrap_or(metrics.line_height);
}
if total_height > height + self.scroll.vertical {
self.scroll.line = line_i;
self.scroll.vertical = total_height - height;
}
}
}
if old_scroll != self.scroll {
self.redraw = true;
}
self.shape_until_scroll(font_system, prune);
// Adjust horizontal scroll to include cursor
if let Some(layout_cursor) = self.layout_cursor(font_system, cursor) {
if let Some(layout_lines) = self.line_layout(font_system, layout_cursor.line) {
if let Some(layout_line) = layout_lines.get(layout_cursor.layout) {
let (x_min, x_max) = if let Some(glyph) = layout_line
.glyphs
.get(layout_cursor.glyph)
.or_else(|| layout_line.glyphs.last())
{
//TODO: use code from cursor_glyph_opt?
let x_a = glyph.x;
let x_b = glyph.x + glyph.w;
(x_a.min(x_b), x_a.max(x_b))
} else {
(0.0, 0.0)
};
if x_min < self.scroll.horizontal {
self.scroll.horizontal = x_min;
self.redraw = true;
}
if let Some(width) = self.width_opt {
if x_max > self.scroll.horizontal + width {
self.scroll.horizontal = x_max - width;
self.redraw = true;
}
}
}
}
}
}
/// Shape lines until scroll
pub fn shape_until_scroll(&mut self, font_system: &mut FontSystem, prune: bool) {
let metrics = self.metrics;
let old_scroll = self.scroll;
loop {
// Adjust scroll.layout to be positive by moving scroll.line backwards
while self.scroll.vertical < 0.0 {
if self.scroll.line > 0 {
let line_i = self.scroll.line - 1;
if let Some(layout) = self.line_layout(font_system, line_i) {
let mut layout_height = 0.0;
for layout_line in layout.iter() {
layout_height +=
layout_line.line_height_opt.unwrap_or(metrics.line_height);
}
self.scroll.line = line_i;
self.scroll.vertical += layout_height;
} else {
// If layout is missing, just assume line height
self.scroll.line = line_i;
self.scroll.vertical += metrics.line_height;
}
} else {
self.scroll.vertical = 0.0;
break;
}
}
let scroll_start = self.scroll.vertical;
let scroll_end = scroll_start + self.height_opt.unwrap_or(f32::INFINITY);
let mut total_height = 0.0;
for line_i in 0..self.lines.len() {
if line_i < self.scroll.line {
if prune {
self.lines[line_i].reset_shaping();
}
continue;
}
if total_height > scroll_end {
if prune {
self.lines[line_i].reset_shaping();
continue;
} else {
break;
}
}
let mut layout_height = 0.0;
let layout = self
.line_layout(font_system, line_i)
.expect("shape_until_scroll invalid line");
for layout_line in layout.iter() {
let line_height = layout_line.line_height_opt.unwrap_or(metrics.line_height);
layout_height += line_height;
total_height += line_height;
}
// Adjust scroll.vertical to be smaller by moving scroll.line forwards
//TODO: do we want to adjust it exactly to a layout line?
if line_i == self.scroll.line && layout_height < self.scroll.vertical {
self.scroll.line += 1;
self.scroll.vertical -= layout_height;
}
}
if total_height < scroll_end && self.scroll.line > 0 {
// Need to scroll up to stay inside of buffer
self.scroll.vertical -= scroll_end - total_height;
} else {
// Done adjusting scroll
break;
}
}
if old_scroll != self.scroll {
self.redraw = true;
}
}
/// Convert a [`Cursor`] to a [`LayoutCursor`]
pub fn layout_cursor(
&mut self,
font_system: &mut FontSystem,
cursor: Cursor,
) -> Option<LayoutCursor> {
let layout = self.line_layout(font_system, cursor.line)?;
for (layout_i, layout_line) in layout.iter().enumerate() {
for (glyph_i, glyph) in layout_line.glyphs.iter().enumerate() {
let cursor_end =
Cursor::new_with_affinity(cursor.line, glyph.end, Affinity::Before);
let cursor_start =
Cursor::new_with_affinity(cursor.line, glyph.start, Affinity::After);
let (cursor_left, cursor_right) = if glyph.level.is_ltr() {
(cursor_start, cursor_end)
} else {
(cursor_end, cursor_start)
};
if cursor == cursor_left {
return Some(LayoutCursor::new(cursor.line, layout_i, glyph_i));
}
if cursor == cursor_right {
return Some(LayoutCursor::new(cursor.line, layout_i, glyph_i + 1));
}
}
}
// Fall back to start of line
//TODO: should this be the end of the line?
Some(LayoutCursor::new(cursor.line, 0, 0))
}
/// Shape the provided line index and return the result
pub fn line_shape(
&mut self,
font_system: &mut FontSystem,
line_i: usize,
) -> Option<&ShapeLine> {
let line = self.lines.get_mut(line_i)?;
Some(line.shape_in_buffer(&mut self.scratch, font_system, self.tab_width))
}
/// Lay out the provided line index and return the result
pub fn line_layout(
&mut self,
font_system: &mut FontSystem,
line_i: usize,
) -> Option<&[LayoutLine]> {
let line = self.lines.get_mut(line_i)?;
Some(line.layout_in_buffer(
&mut self.scratch,
font_system,
self.metrics.font_size,
self.width_opt,
self.wrap,
self.monospace_width,
self.tab_width,
))
}
/// Get the current [`Metrics`]
pub fn metrics(&self) -> Metrics {
self.metrics
}
/// Set the current [`Metrics`]
///
/// # Panics
///
/// Will panic if `metrics.font_size` is zero.
pub fn set_metrics(&mut self, font_system: &mut FontSystem, metrics: Metrics) {
self.set_metrics_and_size(font_system, metrics, self.width_opt, self.height_opt);
}
/// Get the current [`Wrap`]
pub fn wrap(&self) -> Wrap {
self.wrap
}
/// Set the current [`Wrap`]
pub fn set_wrap(&mut self, font_system: &mut FontSystem, wrap: Wrap) {
if wrap != self.wrap {
self.wrap = wrap;
self.relayout(font_system);
self.shape_until_scroll(font_system, false);
}
}
/// Get the current `monospace_width`
pub fn monospace_width(&self) -> Option<f32> {
self.monospace_width
}
/// Set monospace width monospace glyphs should be resized to match. `None` means don't resize
pub fn set_monospace_width(
&mut self,
font_system: &mut FontSystem,
monospace_width: Option<f32>,
) {
if monospace_width != self.monospace_width {
self.monospace_width = monospace_width;
self.relayout(font_system);
self.shape_until_scroll(font_system, false);
}
}
/// Get the current `tab_width`
pub fn tab_width(&self) -> u16 {
self.tab_width
}
/// Set tab width (number of spaces between tab stops)
pub fn set_tab_width(&mut self, font_system: &mut FontSystem, tab_width: u16) {
// A tab width of 0 is not allowed
if tab_width == 0 {
return;
}
if tab_width != self.tab_width {
self.tab_width = tab_width;
// Shaping must be reset when tab width is changed
for line in self.lines.iter_mut() {
if line.shape_opt().is_some() {
if line.text().contains('\t') {
line.reset_shaping();
}
}
}
self.redraw = true;
self.shape_until_scroll(font_system, false);
}
}
/// Get the current buffer dimensions (width, height)
pub fn size(&self) -> (Option<f32>, Option<f32>) {
(self.width_opt, self.height_opt)
}
/// Set the current buffer dimensions
pub fn set_size(
&mut self,
font_system: &mut FontSystem,
width_opt: Option<f32>,
height_opt: Option<f32>,
) {
self.set_metrics_and_size(font_system, self.metrics, width_opt, height_opt);
}
/// Set the current [`Metrics`] and buffer dimensions at the same time
///
/// # Panics
///
/// Will panic if `metrics.font_size` is zero.
pub fn set_metrics_and_size(
&mut self,
font_system: &mut FontSystem,
metrics: Metrics,
width_opt: Option<f32>,
height_opt: Option<f32>,
) {
let clamped_width_opt = width_opt.map(|width| width.max(0.0));
let clamped_height_opt = height_opt.map(|height| height.max(0.0));
if metrics != self.metrics
|| clamped_width_opt != self.width_opt
|| clamped_height_opt != self.height_opt
{
assert_ne!(metrics.font_size, 0.0, "font size cannot be 0");
self.metrics = metrics;
self.width_opt = clamped_width_opt;
self.height_opt = clamped_height_opt;
self.relayout(font_system);
self.shape_until_scroll(font_system, false);
}
}
/// Get the current scroll location
pub fn scroll(&self) -> Scroll {
self.scroll
}
/// Set the current scroll location
pub fn set_scroll(&mut self, scroll: Scroll) {
if scroll != self.scroll {
self.scroll = scroll;
self.redraw = true;
}
}
/// Set text of buffer, using provided attributes for each line by default
pub fn set_text(
&mut self,
font_system: &mut FontSystem,
text: &str,
attrs: Attrs,
shaping: Shaping,
) {
self.lines.clear();
for (range, ending) in LineIter::new(text) {
self.lines.push(BufferLine::new(
&text[range],
ending,
AttrsList::new(attrs),
shaping,
));
}
if self.lines.is_empty() {
self.lines.push(BufferLine::new(
"",
LineEnding::default(),
AttrsList::new(attrs),
shaping,
));
}
self.scroll = Scroll::default();
self.shape_until_scroll(font_system, false);
}
/// Set text of buffer, using an iterator of styled spans (pairs of text and attributes)
///
/// ```
/// # use cosmic_text::{Attrs, Buffer, Family, FontSystem, Metrics, Shaping};
/// # let mut font_system = FontSystem::new();
/// let mut buffer = Buffer::new_empty(Metrics::new(32.0, 44.0));
/// let attrs = Attrs::new().family(Family::Serif);
/// buffer.set_rich_text(
/// &mut font_system,
/// [
/// ("hello, ", attrs),
/// ("cosmic\ntext", attrs.family(Family::Monospace)),
/// ],
/// attrs,
/// Shaping::Advanced,
/// );
/// ```
pub fn set_rich_text<'r, 's, I>(
&mut self,
font_system: &mut FontSystem,
spans: I,
default_attrs: Attrs,
shaping: Shaping,
) where
I: IntoIterator<Item = (&'s str, Attrs<'r>)>,
{
self.lines.clear();
let mut attrs_list = AttrsList::new(default_attrs);
let mut line_string = String::new();
let mut end = 0;
let (string, spans_data): (String, Vec<_>) = spans
.into_iter()
.map(|(s, attrs)| {
let start = end;
end += s.len();
(s, (attrs, start..end))
})
.unzip();
let mut spans_iter = spans_data.into_iter();
let mut maybe_span = spans_iter.next();
// split the string into lines, as ranges
let string_start = string.as_ptr() as usize;
let mut lines_iter = BidiParagraphs::new(&string).map(|line: &str| {
let start = line.as_ptr() as usize - string_start;
let end = start + line.len();
start..end
});
let mut maybe_line = lines_iter.next();
//TODO: set this based on information from spans
let line_ending = LineEnding::default();
loop {
let (Some(line_range), Some((attrs, span_range))) = (&maybe_line, &maybe_span) else {
// this is reached only if this text is empty
self.lines.push(BufferLine::new(
String::new(),
line_ending,
AttrsList::new(default_attrs),
shaping,
));
break;
};
// start..end is the intersection of this line and this span
let start = line_range.start.max(span_range.start);
let end = line_range.end.min(span_range.end);
if start < end {
let text = &string[start..end];
let text_start = line_string.len();
line_string.push_str(text);
let text_end = line_string.len();
// Only add attrs if they don't match the defaults
if *attrs != attrs_list.defaults() {
attrs_list.add_span(text_start..text_end, *attrs);
}
}
// we know that at the end of a line,
// span text's end index is always >= line text's end index
// so if this span ends before this line ends,
// there is another span in this line.
// otherwise, we move on to the next line.
if span_range.end < line_range.end {
maybe_span = spans_iter.next();
} else {
maybe_line = lines_iter.next();
if maybe_line.is_some() {
// finalize this line and start a new line
let prev_attrs_list =
core::mem::replace(&mut attrs_list, AttrsList::new(default_attrs));
let prev_line_string = core::mem::take(&mut line_string);
let buffer_line =
BufferLine::new(prev_line_string, line_ending, prev_attrs_list, shaping);
self.lines.push(buffer_line);
} else {
// finalize the final line
let buffer_line =
BufferLine::new(line_string, line_ending, attrs_list, shaping);
self.lines.push(buffer_line);
break;
}
}
}
self.scroll = Scroll::default();
self.shape_until_scroll(font_system, false);
}
/// True if a redraw is needed
pub fn redraw(&self) -> bool {
self.redraw
}
/// Set redraw needed flag
pub fn set_redraw(&mut self, redraw: bool) {
self.redraw = redraw;
}
/// Get the visible layout runs for rendering and other tasks
pub fn layout_runs(&self) -> LayoutRunIter {
LayoutRunIter::new(self)
}
/// Convert x, y position to Cursor (hit detection)
pub fn hit(&self, x: f32, y: f32) -> Option<Cursor> {
#[cfg(all(feature = "std", not(target_arch = "wasm32")))]
let instant = std::time::Instant::now();
let mut new_cursor_opt = None;
let mut runs = self.layout_runs().peekable();
let mut first_run = true;
while let Some(run) = runs.next() {
let line_top = run.line_top;
let line_height = run.line_height;
if first_run && y < line_top {
first_run = false;
let new_cursor = Cursor::new(run.line_i, 0);
new_cursor_opt = Some(new_cursor);
} else if y >= line_top && y < line_top + line_height {
let mut new_cursor_glyph = run.glyphs.len();
let mut new_cursor_char = 0;
let mut new_cursor_affinity = Affinity::After;
let mut first_glyph = true;
'hit: for (glyph_i, glyph) in run.glyphs.iter().enumerate() {
if first_glyph {
first_glyph = false;
if (run.rtl && x > glyph.x) || (!run.rtl && x < 0.0) {
new_cursor_glyph = 0;
new_cursor_char = 0;
}
}
if x >= glyph.x && x <= glyph.x + glyph.w {
new_cursor_glyph = glyph_i;
let cluster = &run.text[glyph.start..glyph.end];
let total = cluster.grapheme_indices(true).count();
let mut egc_x = glyph.x;
let egc_w = glyph.w / (total as f32);
for (egc_i, egc) in cluster.grapheme_indices(true) {
if x >= egc_x && x <= egc_x + egc_w {
new_cursor_char = egc_i;
let right_half = x >= egc_x + egc_w / 2.0;
if right_half != glyph.level.is_rtl() {
// If clicking on last half of glyph, move cursor past glyph
new_cursor_char += egc.len();
new_cursor_affinity = Affinity::Before;
}
break 'hit;
}
egc_x += egc_w;
}
let right_half = x >= glyph.x + glyph.w / 2.0;
if right_half != glyph.level.is_rtl() {
// If clicking on last half of glyph, move cursor past glyph
new_cursor_char = cluster.len();
new_cursor_affinity = Affinity::Before;
}
break 'hit;
}
}
let mut new_cursor = Cursor::new(run.line_i, 0);
match run.glyphs.get(new_cursor_glyph) {
Some(glyph) => {
// Position at glyph
new_cursor.index = glyph.start + new_cursor_char;
new_cursor.affinity = new_cursor_affinity;
}
None => {
if let Some(glyph) = run.glyphs.last() {
// Position at end of line
new_cursor.index = glyph.end;
new_cursor.affinity = Affinity::Before;
}
}
}
new_cursor_opt = Some(new_cursor);
break;
} else if runs.peek().is_none() && y > run.line_y {
let mut new_cursor = Cursor::new(run.line_i, 0);
if let Some(glyph) = run.glyphs.last() {
new_cursor = run.cursor_from_glyph_right(glyph);
}
new_cursor_opt = Some(new_cursor);
}
}
#[cfg(all(feature = "std", not(target_arch = "wasm32")))]
log::trace!("click({}, {}): {:?}", x, y, instant.elapsed());
new_cursor_opt
}
/// Apply a [`Motion`] to a [`Cursor`]
pub fn cursor_motion(
&mut self,
font_system: &mut FontSystem,
mut cursor: Cursor,
mut cursor_x_opt: Option<i32>,
motion: Motion,
) -> Option<(Cursor, Option<i32>)> {
match motion {
Motion::LayoutCursor(layout_cursor) => {
let layout = self.line_layout(font_system, layout_cursor.line)?;
let layout_line = match layout.get(layout_cursor.layout) {
Some(some) => some,
None => match layout.last() {
Some(some) => some,
None => {
return None;
}
},
};
let (new_index, new_affinity) = match layout_line.glyphs.get(layout_cursor.glyph) {
Some(glyph) => (glyph.start, Affinity::After),
None => match layout_line.glyphs.last() {
Some(glyph) => (glyph.end, Affinity::Before),
//TODO: is this correct?
None => (0, Affinity::After),
},
};
if cursor.line != layout_cursor.line
|| cursor.index != new_index
|| cursor.affinity != new_affinity
{
cursor.line = layout_cursor.line;
cursor.index = new_index;
cursor.affinity = new_affinity;
}
}
Motion::Previous => {
let line = self.lines.get(cursor.line)?;
if cursor.index > 0 {
// Find previous character index
let mut prev_index = 0;
for (i, _) in line.text().grapheme_indices(true) {
if i < cursor.index {
prev_index = i;
} else {
break;
}
}
cursor.index = prev_index;
cursor.affinity = Affinity::After;
} else if cursor.line > 0 {
cursor.line -= 1;
cursor.index = self.lines.get(cursor.line)?.text().len();
cursor.affinity = Affinity::After;
}
cursor_x_opt = None;
}
Motion::Next => {
let line = self.lines.get(cursor.line)?;
if cursor.index < line.text().len() {
for (i, c) in line.text().grapheme_indices(true) {
if i == cursor.index {
cursor.index += c.len();
cursor.affinity = Affinity::Before;
break;
}
}
} else if cursor.line + 1 < self.lines.len() {