bevy/crates/bevy_text/src/glyph_brush.rs
Nicola Papale afcb1fee90
Cleanup some bevy_text pipeline.rs (#9111)
## Objective

- `bevy_text/src/pipeline.rs` had some crufty code.

## Solution

Remove the cruft.

- `&mut self` argument was unused by
`TextPipeline::create_text_measure`, so we replace it with a constructor
`TextMeasureInfo::from_text`.
- We also pass a `&Text` to `from_text` since there is no reason to
split the struct before passing it as argument.
- from_text also checks beforehand that every Font exist in the
Assets<Font>. This allows rust to skip the drop code on the Vecs we
create in the method, since there is no early exit.
- We also remove the scaled_fonts field on `TextMeasureInfo`. This
avoids an additional allocation. We can re-use the font on `fonts`
instead in `compute_size`. Building a `ScaledFont` seems fairly cheap,
when looking at the ab_glyph internals.
- We also implement ToSectionText on TextMeasureSection, this let us
skip creating a whole new Vec each time we call compute_size.
- This let us remove compute_size_from_section_text, since its only
purpose was to not have to allocate the Vec we just made redundant.
- Make some immutabe `Vec<T>` into `Box<[T]>` and `String` into
`Box<str>`
- `{min,max}_width_content_size` fields of `TextMeasureInfo` have name
`width` in them, yet the contain information on both width and height.
- `TextMeasureInfo::linebreak_behaviour`  -> `linebreak_behavior`

## Migration Guide

- The `ResMut<TextPipeline>` argument to `measure_text_system` doesn't
exist anymore. If you were calling this system manually, you should
remove the argument.
- The `{min,max}_width_content_size` fields of `TextMeasureInfo` are
renamed to `min` and `max` respectively
- Other changes to `TextMeasureInfo` may also break your code if you
were manually building it. Please consider using the new
`TextMeasureInfo::from_text` to build one instead.
- `TextPipeline::create_text_measure` has been removed in favor of
`TextMeasureInfo::from_text`
2023-08-28 16:46:16 +00:00

231 lines
7.3 KiB
Rust

use ab_glyph::{Font as _, FontArc, Glyph, PxScaleFont, ScaleFont as _};
use bevy_asset::{Assets, Handle};
use bevy_math::{Rect, Vec2};
use bevy_render::texture::Image;
use bevy_sprite::TextureAtlas;
use bevy_utils::tracing::warn;
use glyph_brush_layout::{
BuiltInLineBreaker, FontId, GlyphPositioner, Layout, SectionGeometry, SectionGlyph,
SectionText, ToSectionText,
};
use crate::{
error::TextError, BreakLineOn, Font, FontAtlasSet, FontAtlasWarning, GlyphAtlasInfo,
TextAlignment, TextSettings, YAxisOrientation,
};
pub struct GlyphBrush {
fonts: Vec<FontArc>,
handles: Vec<Handle<Font>>,
latest_font_id: FontId,
}
impl Default for GlyphBrush {
fn default() -> Self {
GlyphBrush {
fonts: Vec::new(),
handles: Vec::new(),
latest_font_id: FontId(0),
}
}
}
impl GlyphBrush {
pub fn compute_glyphs<S: ToSectionText>(
&self,
sections: &[S],
bounds: Vec2,
text_alignment: TextAlignment,
linebreak_behavior: BreakLineOn,
) -> Result<Vec<SectionGlyph>, TextError> {
let geom = SectionGeometry {
bounds: (bounds.x, bounds.y),
..Default::default()
};
let lbb: BuiltInLineBreaker = linebreak_behavior.into();
let section_glyphs = Layout::default()
.h_align(text_alignment.into())
.line_breaker(lbb)
.calculate_glyphs(&self.fonts, &geom, sections);
Ok(section_glyphs)
}
#[allow(clippy::too_many_arguments)]
pub fn process_glyphs(
&self,
glyphs: Vec<SectionGlyph>,
sections: &[SectionText],
font_atlas_set_storage: &mut Assets<FontAtlasSet>,
fonts: &Assets<Font>,
texture_atlases: &mut Assets<TextureAtlas>,
textures: &mut Assets<Image>,
text_settings: &TextSettings,
font_atlas_warning: &mut FontAtlasWarning,
y_axis_orientation: YAxisOrientation,
) -> Result<Vec<PositionedGlyph>, TextError> {
if glyphs.is_empty() {
return Ok(Vec::new());
}
let sections_data = sections
.iter()
.map(|section| {
let handle = &self.handles[section.font_id.0];
let font = fonts.get(handle).ok_or(TextError::NoSuchFont)?;
let font_size = section.scale.y;
Ok((
handle,
font,
font_size,
ab_glyph::Font::as_scaled(&font.font, font_size),
))
})
.collect::<Result<Vec<_>, _>>()?;
let text_bounds = compute_text_bounds(&glyphs, |index| sections_data[index].3);
let mut positioned_glyphs = Vec::new();
for sg in glyphs {
let SectionGlyph {
section_index: _,
byte_index,
mut glyph,
font_id: _,
} = sg;
let glyph_id = glyph.id;
let glyph_position = glyph.position;
let adjust = GlyphPlacementAdjuster::new(&mut glyph);
let section_data = sections_data[sg.section_index];
if let Some(outlined_glyph) = section_data.1.font.outline_glyph(glyph) {
let bounds = outlined_glyph.px_bounds();
let handle_font_atlas: Handle<FontAtlasSet> = section_data.0.cast_weak();
let font_atlas_set = font_atlas_set_storage
.get_or_insert_with(handle_font_atlas, FontAtlasSet::default);
let atlas_info = font_atlas_set
.get_glyph_atlas_info(section_data.2, glyph_id, glyph_position)
.map(Ok)
.unwrap_or_else(|| {
font_atlas_set.add_glyph_to_atlas(texture_atlases, textures, outlined_glyph)
})?;
if !text_settings.allow_dynamic_font_size
&& !font_atlas_warning.warned
&& font_atlas_set.num_font_atlases() > text_settings.max_font_atlases.get()
{
warn!("warning[B0005]: Number of font atlases has exceeded the maximum of {}. Performance and memory usage may suffer.", text_settings.max_font_atlases.get());
font_atlas_warning.warned = true;
}
let texture_atlas = texture_atlases.get(&atlas_info.texture_atlas).unwrap();
let glyph_rect = texture_atlas.textures[atlas_info.glyph_index];
let size = Vec2::new(glyph_rect.width(), glyph_rect.height());
let x = bounds.min.x + size.x / 2.0 - text_bounds.min.x;
let y = match y_axis_orientation {
YAxisOrientation::BottomToTop => {
text_bounds.max.y - bounds.max.y + size.y / 2.0
}
YAxisOrientation::TopToBottom => {
bounds.min.y + size.y / 2.0 - text_bounds.min.y
}
};
let position = adjust.position(Vec2::new(x, y));
positioned_glyphs.push(PositionedGlyph {
position,
size,
atlas_info,
section_index: sg.section_index,
byte_index,
});
}
}
Ok(positioned_glyphs)
}
pub fn add_font(&mut self, handle: Handle<Font>, font: FontArc) -> FontId {
self.fonts.push(font);
self.handles.push(handle);
let font_id = self.latest_font_id;
self.latest_font_id = FontId(font_id.0 + 1);
font_id
}
}
#[derive(Debug, Clone)]
pub struct PositionedGlyph {
pub position: Vec2,
pub size: Vec2,
pub atlas_info: GlyphAtlasInfo,
pub section_index: usize,
pub byte_index: usize,
}
#[cfg(feature = "subpixel_glyph_atlas")]
struct GlyphPlacementAdjuster;
#[cfg(feature = "subpixel_glyph_atlas")]
impl GlyphPlacementAdjuster {
#[inline(always)]
pub fn new(_: &mut Glyph) -> Self {
Self
}
#[inline(always)]
pub fn position(&self, p: Vec2) -> Vec2 {
p
}
}
#[cfg(not(feature = "subpixel_glyph_atlas"))]
struct GlyphPlacementAdjuster(f32);
#[cfg(not(feature = "subpixel_glyph_atlas"))]
impl GlyphPlacementAdjuster {
#[inline(always)]
pub fn new(glyph: &mut Glyph) -> Self {
let v = glyph.position.x.round();
glyph.position.x = 0.;
glyph.position.y = glyph.position.y.ceil();
Self(v)
}
#[inline(always)]
pub fn position(&self, v: Vec2) -> Vec2 {
Vec2::new(self.0, 0.) + v
}
}
/// Computes the minimal bounding rectangle for a block of text.
/// Ignores empty trailing lines.
pub(crate) fn compute_text_bounds<T>(
section_glyphs: &[SectionGlyph],
get_scaled_font: impl Fn(usize) -> PxScaleFont<T>,
) -> bevy_math::Rect
where
T: ab_glyph::Font,
{
let mut text_bounds = Rect {
min: Vec2::splat(std::f32::MAX),
max: Vec2::splat(std::f32::MIN),
};
for sg in section_glyphs {
let scaled_font = get_scaled_font(sg.section_index);
let glyph = &sg.glyph;
text_bounds = text_bounds.union(Rect {
min: Vec2::new(glyph.position.x, 0.),
max: Vec2::new(
glyph.position.x + scaled_font.h_advance(glyph.id),
glyph.position.y - scaled_font.descent(),
),
});
}
text_bounds
}