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[epaint] Add more text wrapping options (#1291)

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This commit is contained in:
awaken1ng
2022-04-04 01:28:47 +07:00
committed by GitHub
parent d09fa63d9c
commit 901b7c7994
11 changed files with 256 additions and 57 deletions
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167
epaint/src/text/text_layout.rs
View File

@@ -58,16 +58,22 @@ 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(paragraphs, job.wrap_width);
let mut rows = rows_from_paragraphs(fonts, paragraphs, &job);
let justify = job.justify && job.wrap_width.is_finite();
let justify = job.justify && job.wrap.max_width.is_finite();
if justify || job.halign != Align::LEFT {
let num_rows = rows.len();
for (i, row) in rows.iter_mut().enumerate() {
let is_last_row = i + 1 == num_rows;
let justify_row = justify && !row.ends_with_newline && !is_last_row;
halign_and_jusitfy_row(point_scale, row, job.halign, job.wrap_width, justify_row);
halign_and_jusitfy_row(
point_scale,
row,
job.halign,
job.wrap.max_width,
justify_row,
);
}
}
@@ -131,7 +137,11 @@ fn rect_from_x_range(x_range: RangeInclusive<f32>) -> Rect {
Rect::from_x_y_ranges(x_range, 0.0..=0.0)
}
fn rows_from_paragraphs(paragraphs: Vec<Paragraph>, wrap_width: f32) -> Vec<Row> {
fn rows_from_paragraphs(
fonts: &mut FontsImpl,
paragraphs: Vec<Paragraph>,
job: &LayoutJob,
) -> Vec<Row> {
let num_paragraphs = paragraphs.len();
let mut rows = vec![];
@@ -151,7 +161,7 @@ fn rows_from_paragraphs(paragraphs: Vec<Paragraph>, wrap_width: f32) -> Vec<Row>
});
} else {
let paragraph_max_x = paragraph.glyphs.last().unwrap().max_x();
if paragraph_max_x <= wrap_width {
if paragraph_max_x <= job.wrap.max_width {
// early-out optimization
let paragraph_min_x = paragraph.glyphs[0].pos.x;
rows.push(Row {
@@ -161,7 +171,7 @@ fn rows_from_paragraphs(paragraphs: Vec<Paragraph>, wrap_width: f32) -> Vec<Row>
ends_with_newline: !is_last_paragraph,
});
} else {
line_break(&paragraph, wrap_width, &mut rows);
line_break(fonts, &paragraph, job, &mut rows);
rows.last_mut().unwrap().ends_with_newline = !is_last_paragraph;
}
}
@@ -170,19 +180,31 @@ fn rows_from_paragraphs(paragraphs: Vec<Paragraph>, wrap_width: f32) -> Vec<Row>
rows
}
fn line_break(paragraph: &Paragraph, wrap_width: f32, out_rows: &mut Vec<Row>) {
fn line_break(
fonts: &mut FontsImpl,
paragraph: &Paragraph,
job: &LayoutJob,
out_rows: &mut Vec<Row>,
) {
// Keeps track of good places to insert row break if we exceed `wrap_width`.
let mut row_break_candidates = RowBreakCandidates::default();
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, glyph) in paragraph.glyphs.iter().enumerate() {
let potential_row_width = glyph.max_x() - row_start_x;
if potential_row_width > wrap_width {
if first_row_indentation > 0.0 && !row_break_candidates.has_word_boundary() {
if job.wrap.max_rows > 0 && non_empty_rows >= job.wrap.max_rows {
break;
}
if potential_row_width > job.wrap.max_width {
if first_row_indentation > 0.0
&& !row_break_candidates.has_good_candidate(job.wrap.break_anywhere)
{
// Allow the first row to be completely empty, because we know there will be more space on the next row:
// TODO: this records the height of this first row as zero, though that is probably fine since first_row_indentation usually comes with a first_row_min_height.
out_rows.push(Row {
@@ -193,7 +215,8 @@ fn line_break(paragraph: &Paragraph, wrap_width: f32, out_rows: &mut Vec<Row>) {
});
row_start_x += first_row_indentation;
first_row_indentation = 0.0;
} else if let Some(last_kept_index) = row_break_candidates.get() {
} else if let Some(last_kept_index) = row_break_candidates.get(job.wrap.break_anywhere)
{
let glyphs: Vec<Glyph> = paragraph.glyphs[row_start_idx..=last_kept_index]
.iter()
.copied()
@@ -216,6 +239,7 @@ fn line_break(paragraph: &Paragraph, wrap_width: f32, out_rows: &mut Vec<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.
}
@@ -225,24 +249,90 @@ fn line_break(paragraph: &Paragraph, wrap_width: f32, out_rows: &mut Vec<Row>) {
}
if row_start_idx < paragraph.glyphs.len() {
let glyphs: Vec<Glyph> = paragraph.glyphs[row_start_idx..]
.iter()
.copied()
.map(|mut glyph| {
glyph.pos.x -= row_start_x;
glyph
})
.collect();
if non_empty_rows == job.wrap.max_rows {
replace_last_glyph_with_overflow_character(fonts, job, out_rows);
} else {
let glyphs: Vec<Glyph> = paragraph.glyphs[row_start_idx..]
.iter()
.copied()
.map(|mut glyph| {
glyph.pos.x -= row_start_x;
glyph
})
.collect();
let paragraph_min_x = glyphs[0].pos.x;
let paragraph_max_x = glyphs.last().unwrap().max_x();
let paragraph_min_x = glyphs[0].pos.x;
let paragraph_max_x = glyphs.last().unwrap().max_x();
out_rows.push(Row {
glyphs,
visuals: Default::default(),
rect: rect_from_x_range(paragraph_min_x..=paragraph_max_x),
ends_with_newline: false,
out_rows.push(Row {
glyphs,
visuals: Default::default(),
rect: rect_from_x_range(paragraph_min_x..=paragraph_max_x),
ends_with_newline: false,
});
}
}
}
fn replace_last_glyph_with_overflow_character(
fonts: &mut FontsImpl,
job: &LayoutJob,
out_rows: &mut Vec<Row>,
) {
let overflow_character = match job.wrap.overflow_character {
Some(c) => c,
None => return,
};
let row = match out_rows.last_mut() {
Some(r) => r,
None => return,
};
loop {
let (prev_glyph, last_glyph) = match row.glyphs.as_mut_slice() {
[.., prev, last] => (Some(prev), last),
[.., last] => (None, last),
_ => break,
};
let section = &job.sections[last_glyph.section_index as usize];
let font = fonts.font(&section.format.font_id);
let font_height = font.row_height();
let prev_glyph_id = prev_glyph.map(|prev_glyph| {
let (_, prev_glyph_info) = font.glyph_info_and_font_impl(prev_glyph.chr);
prev_glyph_info.id
});
// undo kerning with previous glyph
let (font_impl, glyph_info) = font.glyph_info_and_font_impl(last_glyph.chr);
last_glyph.pos.x -= font_impl
.zip(prev_glyph_id)
.map(|(font_impl, prev_glyph_id)| font_impl.pair_kerning(prev_glyph_id, glyph_info.id))
.unwrap_or_default();
// replace the glyph
last_glyph.chr = 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;
// reapply kerning
last_glyph.pos.x += font_impl
.zip(prev_glyph_id)
.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
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;
}
row.glyphs.pop();
}
}
@@ -651,21 +741,32 @@ impl RowBreakCandidates {
self.dash = Some(index);
} else if chr.is_ascii_punctuation() {
self.punctuation = Some(index);
} else {
self.any = Some(index);
}
self.any = Some(index);
}
fn has_word_boundary(&self) -> bool {
self.space.is_some() || self.logogram.is_some()
}
fn get(&self) -> Option<usize> {
self.space
.or(self.logogram)
.or(self.dash)
.or(self.punctuation)
.or(self.any)
fn has_good_candidate(&self, break_anywhere: bool) -> bool {
if break_anywhere {
self.any.is_some()
} else {
self.has_word_boundary()
}
}
fn get(&self, break_anywhere: bool) -> Option<usize> {
if break_anywhere {
self.any
} else {
self.space
.or(self.logogram)
.or(self.dash)
.or(self.punctuation)
.or(self.any)
}
}
}

68
epaint/src/text/text_layout_types.rs
View File

@@ -48,10 +48,7 @@ pub struct LayoutJob {
/// The different section, which can have different fonts, colors, etc.
pub sections: Vec<LayoutSection>,
/// Try to break text so that no row is wider than this.
/// Set to [`f32::INFINITY`] to turn off wrapping.
/// Note that `\n` always produces a new line.
pub wrap_width: f32,
pub wrap: TextWrapping,
/// The first row must be at least this high.
/// This is in case we lay out text that is the continuation
@@ -78,7 +75,7 @@ impl Default for LayoutJob {
Self {
text: Default::default(),
sections: Default::default(),
wrap_width: f32::INFINITY,
wrap: Default::default(),
first_row_min_height: 0.0,
break_on_newline: true,
halign: Align::LEFT,
@@ -98,7 +95,10 @@ impl LayoutJob {
format: TextFormat::simple(font_id, color),
}],
text,
wrap_width,
wrap: TextWrapping {
max_width: wrap_width,
..Default::default()
},
break_on_newline: true,
..Default::default()
}
@@ -114,7 +114,7 @@ impl LayoutJob {
format: TextFormat::simple(font_id, color),
}],
text,
wrap_width: f32::INFINITY,
wrap: Default::default(),
break_on_newline: false,
..Default::default()
}
@@ -129,7 +129,7 @@ impl LayoutJob {
format,
}],
text,
wrap_width: f32::INFINITY,
wrap: Default::default(),
break_on_newline: true,
..Default::default()
}
@@ -168,7 +168,7 @@ impl std::hash::Hash for LayoutJob {
let Self {
text,
sections,
wrap_width,
wrap,
first_row_min_height,
break_on_newline,
halign,
@@ -177,7 +177,7 @@ impl std::hash::Hash for LayoutJob {
text.hash(state);
sections.hash(state);
crate::f32_hash(state, *wrap_width);
wrap.hash(state);
crate::f32_hash(state, *first_row_min_height);
break_on_newline.hash(state);
halign.hash(state);
@@ -257,6 +257,54 @@ impl TextFormat {
// ----------------------------------------------------------------------------
#[derive(Clone, Debug, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
pub struct TextWrapping {
/// Try to break text so that no row is wider than this.
/// Set to [`f32::INFINITY`] to turn off wrapping.
/// Note that `\n` always produces a new line.
pub max_width: f32,
/// Maximum amount of rows the text should have.
/// Set to `0` to disable this.
pub max_rows: usize,
/// Don't try to break text at an appropriate place.
pub break_anywhere: bool,
/// Character to use to represent clipped text, `…` for example, which is the default.
pub overflow_character: Option<char>,
}
impl std::hash::Hash for TextWrapping {
#[inline]
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
let Self {
max_width,
max_rows,
break_anywhere,
overflow_character,
} = self;
crate::f32_hash(state, *max_width);
max_rows.hash(state);
break_anywhere.hash(state);
overflow_character.hash(state);
}
}
impl Default for TextWrapping {
fn default() -> Self {
Self {
max_width: f32::INFINITY,
max_rows: 0,
break_anywhere: false,
overflow_character: Some('…'),
}
}
}
// ----------------------------------------------------------------------------
/// Text that has been layed out, ready for painting.
///
/// You can create a [`Galley`] using [`crate::Fonts::layout_job`];