migrations/egui
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Add option to truncate text at wrap width (#3244)

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* Add option to clip text to wrap width

* Spelling

* Better naming, and report back wether the text was elided

* Improve docstrings

* Simplify

* Fix max_rows with multiple paragraphs

* Add note

* Typos

* fix doclink

* Add `Label::elide`

* Label: show full non-elided text on hover

* Add demo of `Label::elide`

* Call it `Label::truncate`

* Clarify limitations of `break_anywhere`

* Better docstrings
This commit is contained in:
Emil Ernerfeldt
2023-08-14 11:22:04 +02:00
committed by GitHub
parent 1023f937a6
commit a3ae81cadb
5 changed files with 280 additions and 102 deletions
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69
crates/epaint/src/text/text_layout.rs
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@@ -1,10 +1,12 @@
use std::ops::RangeInclusive;
use std::sync::Arc;
use super::{FontsImpl, Galley, Glyph, LayoutJob, LayoutSection, Row, RowVisuals};
use crate::{Color32, Mesh, Stroke, Vertex};
use emath::*;
use crate::{Color32, Mesh, Stroke, Vertex};
use super::{FontsImpl, Galley, Glyph, LayoutJob, LayoutSection, Row, RowVisuals};
// ----------------------------------------------------------------------------
/// Represents GUI scale and convenience methods for rounding to pixels.
@@ -54,6 +56,20 @@ struct Paragraph {
/// In most cases you should use [`crate::Fonts::layout_job`] instead
/// since that memoizes the input, making subsequent layouting of the same text much faster.
pub fn layout(fonts: &mut FontsImpl, job: Arc<LayoutJob>) -> Galley {
if job.wrap.max_rows == 0 {
// Early-out: no text
return Galley {
job,
rows: Default::default(),
rect: Rect::from_min_max(Pos2::ZERO, Pos2::ZERO),
mesh_bounds: Rect::NOTHING,
num_vertices: 0,
num_indices: 0,
pixels_per_point: fonts.pixels_per_point(),
elided: true,
};
}
let mut paragraphs = vec![Paragraph::default()];
for (section_index, section) in job.sections.iter().enumerate() {
layout_section(fonts, &job, section_index as u32, section, &mut paragraphs);
@@ -61,7 +77,8 @@ pub fn layout(fonts: &mut FontsImpl, job: Arc<LayoutJob>) -> Galley {
let point_scale = PointScale::new(fonts.pixels_per_point());
let mut rows = rows_from_paragraphs(fonts, paragraphs, &job);
let mut elided = false;
let mut rows = rows_from_paragraphs(fonts, paragraphs, &job, &mut elided);
let justify = job.justify && job.wrap.max_width.is_finite();
@@ -80,7 +97,7 @@ pub fn layout(fonts: &mut FontsImpl, job: Arc<LayoutJob>) -> Galley {
}
}
galley_from_rows(point_scale, job, rows)
galley_from_rows(point_scale, job, rows, elided)
}
fn layout_section(
@@ -145,12 +162,18 @@ fn rows_from_paragraphs(
fonts: &mut FontsImpl,
paragraphs: Vec<Paragraph>,
job: &LayoutJob,
elided: &mut bool,
) -> Vec<Row> {
let num_paragraphs = paragraphs.len();
let mut rows = vec![];
for (i, paragraph) in paragraphs.into_iter().enumerate() {
if job.wrap.max_rows <= rows.len() {
*elided = true;
break;
}
let is_last_paragraph = (i + 1) == num_paragraphs;
if paragraph.glyphs.is_empty() {
@@ -166,7 +189,7 @@ fn rows_from_paragraphs(
} else {
let paragraph_max_x = paragraph.glyphs.last().unwrap().max_x();
if paragraph_max_x <= job.wrap.max_width {
// early-out optimization
// Early-out optimization: the whole paragraph fits on one row.
let paragraph_min_x = paragraph.glyphs[0].pos.x;
rows.push(Row {
glyphs: paragraph.glyphs,
@@ -175,7 +198,7 @@ fn rows_from_paragraphs(
ends_with_newline: !is_last_paragraph,
});
} else {
line_break(fonts, &paragraph, job, &mut rows);
line_break(fonts, &paragraph, job, &mut rows, elided);
rows.last_mut().unwrap().ends_with_newline = !is_last_paragraph;
}
}
@@ -189,6 +212,7 @@ fn line_break(
paragraph: &Paragraph,
job: &LayoutJob,
out_rows: &mut Vec<Row>,
elided: &mut bool,
) {
// Keeps track of good places to insert row break if we exceed `wrap_width`.
let mut row_break_candidates = RowBreakCandidates::default();
@@ -196,16 +220,18 @@ fn line_break(
let mut first_row_indentation = paragraph.glyphs[0].pos.x;
let mut row_start_x = 0.0;
let mut row_start_idx = 0;
let mut non_empty_rows = 0;
for i in 0..paragraph.glyphs.len() {
let potential_row_width = paragraph.glyphs[i].max_x() - row_start_x;
if job.wrap.max_rows > 0 && non_empty_rows >= job.wrap.max_rows {
if job.wrap.max_rows <= out_rows.len() {
*elided = true;
break;
}
if potential_row_width > job.wrap.max_width {
if job.wrap.max_width < potential_row_width {
// Row break:
if first_row_indentation > 0.0
&& !row_break_candidates.has_good_candidate(job.wrap.break_anywhere)
{
@@ -240,10 +266,10 @@ fn line_break(
ends_with_newline: false,
});
// Start a new row:
row_start_idx = last_kept_index + 1;
row_start_x = paragraph.glyphs[row_start_idx].pos.x;
row_break_candidates = Default::default();
non_empty_rows += 1;
} else {
// Found no place to break, so we have to overrun wrap_width.
}
@@ -253,9 +279,12 @@ fn line_break(
}
if row_start_idx < paragraph.glyphs.len() {
if job.wrap.max_rows > 0 && non_empty_rows == job.wrap.max_rows {
// Final row of text:
if job.wrap.max_rows <= out_rows.len() {
if let Some(last_row) = out_rows.last_mut() {
replace_last_glyph_with_overflow_character(fonts, job, last_row);
*elided = true;
}
} else {
let glyphs: Vec<Glyph> = paragraph.glyphs[row_start_idx..]
@@ -280,6 +309,7 @@ fn line_break(
}
}
/// Trims the last glyphs in the row and replaces it with an overflow character (e.g. `…`).
fn replace_last_glyph_with_overflow_character(
fonts: &mut FontsImpl,
job: &LayoutJob,
@@ -318,6 +348,7 @@ fn replace_last_glyph_with_overflow_character(
let (font_impl, glyph_info) = font.glyph_info_and_font_impl(last_glyph.chr);
last_glyph.size = vec2(glyph_info.advance_width, font_height);
last_glyph.uv_rect = glyph_info.uv_rect;
last_glyph.ascent = glyph_info.ascent;
// reapply kerning
last_glyph.pos.x += font_impl
@@ -325,16 +356,20 @@ fn replace_last_glyph_with_overflow_character(
.map(|(font_impl, prev_glyph_id)| font_impl.pair_kerning(prev_glyph_id, glyph_info.id))
.unwrap_or_default();
// check if we're still within width budget
row.rect.max.x = last_glyph.max_x();
// check if we're within width budget
let row_end_x = last_glyph.max_x();
let row_start_x = row.glyphs.first().unwrap().pos.x; // if `last_mut()` returned `Some`, then so will `first()`
let row_width = row_end_x - row_start_x;
if row_width <= job.wrap.max_width {
break;
return; // we are done
}
row.glyphs.pop();
}
// We failed to insert `overflow_character` without exceeding `wrap_width`.
}
fn halign_and_justify_row(
@@ -428,7 +463,12 @@ fn halign_and_justify_row(
}
/// Calculate the Y positions and tessellate the text.
fn galley_from_rows(point_scale: PointScale, job: Arc<LayoutJob>, mut rows: Vec<Row>) -> Galley {
fn galley_from_rows(
point_scale: PointScale,
job: Arc<LayoutJob>,
mut rows: Vec<Row>,
elided: bool,
) -> Galley {
let mut first_row_min_height = job.first_row_min_height;
let mut cursor_y = 0.0;
let mut min_x: f32 = 0.0;
@@ -489,6 +529,7 @@ fn galley_from_rows(point_scale: PointScale, job: Arc<LayoutJob>, mut rows: Vec<
Galley {
job,
rows,
elided,
rect,
mesh_bounds,
num_vertices,