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Improve text wrapping related to first line indentation and logograms

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This commit is contained in:
Emil Ernerfeldt 2021-02-06 15:19:04 +01:00
parent 91ce18d62f
commit 8189a78284
1 changed files with 41 additions and 18 deletions
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59
epaint/src/text/font.rs
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@ -419,7 +419,24 @@ impl Font {
let potential_row_width = first_row_indentation + x - row_start_x;
if potential_row_width > max_width_in_points {
if let Some(last_kept_index) = row_break_candidates.get() {
let is_first_row = out_rows.is_empty();
if is_first_row
&& first_row_indentation > 0.0
&& !row_break_candidates.has_word_boundary()
{
// Allow the first row to be completely empty, because we know there will be more space on the next row:
assert_eq!(row_start_idx, 0);
let row = Row {
x_offsets: vec![first_row_indentation],
y_min: cursor_y,
y_max: cursor_y + self.row_height(),
ends_with_newline: false,
};
row.sanity_check();
out_rows.push(row);
cursor_y = self.round_to_pixel(cursor_y + self.row_height());
first_row_indentation = 0.0; // Continue all other rows as if there is no indentation
} else if let Some(last_kept_index) = row_break_candidates.get() {
let row = Row {
x_offsets: full_x_offsets[row_start_idx..=last_kept_index + 1]
.iter()
@ -436,19 +453,6 @@ impl Font {
row_start_x = first_row_indentation + full_x_offsets[row_start_idx];
row_break_candidates = Default::default();
cursor_y = self.round_to_pixel(cursor_y + self.row_height());
} else if out_rows.is_empty() && first_row_indentation > 0.0 {
assert_eq!(row_start_idx, 0);
// Allow the first row to be completely empty, because we know there will be more space on the next row:
let row = Row {
x_offsets: vec![first_row_indentation],
y_min: cursor_y,
y_max: cursor_y + self.row_height(),
ends_with_newline: false,
};
row.sanity_check();
out_rows.push(row);
cursor_y = self.round_to_pixel(cursor_y + self.row_height());
first_row_indentation = 0.0; // Continue all other rows as if there is no indentation
}
}
@ -480,6 +484,8 @@ struct RowBreakCandidates {
/// Breaking at ` ` or other whitespace
/// is always the primary candidate.
space: Option<usize>,
/// Logogram (single character representing a whole word) are good candidates for line break.
logogram: Option<usize>,
/// Breaking at a dash is super-
/// good idea.
dash: Option<usize>,
@ -496,20 +502,37 @@ impl RowBreakCandidates {
const NON_BREAKING_SPACE: char = '\u{A0}';
if chr.is_whitespace() && chr != NON_BREAKING_SPACE {
self.space = Some(index);
}
if chr == '-' {
} else if is_chinese(chr) {
self.logogram = Some(index);
} else if chr == '-' {
self.dash = Some(index);
} else if chr.is_ascii_punctuation() {
self.punctuation = Some(index);
}
} else {
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.dash).or(self.punctuation).or(self.any)
self.space
.or(self.logogram)
.or(self.dash)
.or(self.punctuation)
.or(self.any)
}
}
#[inline]
fn is_chinese(c: char) -> bool {
('\u{4E00}' <= c && c <= '\u{9FFF}')
|| ('\u{3400}' <= c && c <= '\u{4DBF}')
|| ('\u{2B740}' <= c && c <= '\u{2B81F}')
}
fn allocate_glyph(
atlas: &mut TextureAtlas,
glyph: rusttype::Glyph<'static>,