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WIP: text_system

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Mikayla 2024-01-22 09:35:01 -08:00
parent 0c3fb449f0
commit a99d5b87e8
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5 changed files with 106 additions and 36 deletions
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90
crates/gpui/src/text_system.rs
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@ -26,15 +26,18 @@ use std::{
sync::Arc,
};
/// An opaque identifier for a specific font.
#[derive(Hash, PartialEq, Eq, Clone, Copy, Debug)]
#[repr(C)]
pub struct FontId(pub usize);
/// An opaque identifier for a specific font family.
#[derive(Hash, PartialEq, Eq, Clone, Copy, Debug)]
pub struct FontFamilyId(pub usize);
pub(crate) const SUBPIXEL_VARIANTS: u8 = 4;
/// The GPUI text layout and rendering sub system.
pub struct TextSystem {
line_layout_cache: Arc<LineLayoutCache>,
platform_text_system: Arc<dyn PlatformTextSystem>,
@ -65,6 +68,7 @@ impl TextSystem {
}
}
/// Get a list of all available font names from the operating system.
pub fn all_font_names(&self) -> Vec<String> {
let mut names: BTreeSet<_> = self
.platform_text_system
@ -79,10 +83,13 @@ impl TextSystem {
);
names.into_iter().collect()
}
/// Add a font's data to the text system.
pub fn add_fonts(&self, fonts: &[Arc<Vec<u8>>]) -> Result<()> {
self.platform_text_system.add_fonts(fonts)
}
/// Get the FontId for the configure font family and style.
pub fn font_id(&self, font: &Font) -> Result<FontId> {
let font_id = self.font_ids_by_font.read().get(font).copied();
if let Some(font_id) = font_id {
@ -120,10 +127,14 @@ impl TextSystem {
);
}
/// Get the bounding box for the given font and font size.
/// A font's bounding box is the smallest rectangle that could enclose all glyphs
/// in the font. superimposed over one another.
pub fn bounding_box(&self, font_id: FontId, font_size: Pixels) -> Bounds<Pixels> {
self.read_metrics(font_id, |metrics| metrics.bounding_box(font_size))
}
/// Get the typographic bounds for the given character, in the given font and size.
pub fn typographic_bounds(
&self,
font_id: FontId,
@ -142,6 +153,7 @@ impl TextSystem {
}))
}
/// Get the advance width for the given character, in the given font and size.
pub fn advance(&self, font_id: FontId, font_size: Pixels, ch: char) -> Result<Size<Pixels>> {
let glyph_id = self
.platform_text_system
@ -153,26 +165,35 @@ impl TextSystem {
Ok(result * font_size)
}
/// Get the number of font size units per 'em square',
/// Per MDN: "an abstract square whose height is the intended distance between
/// lines of type in the same type size"
pub fn units_per_em(&self, font_id: FontId) -> u32 {
self.read_metrics(font_id, |metrics| metrics.units_per_em)
}
/// Get the height of a captial letter in the given font and size.
pub fn cap_height(&self, font_id: FontId, font_size: Pixels) -> Pixels {
self.read_metrics(font_id, |metrics| metrics.cap_height(font_size))
}
/// Get the height of the x character in the given font and size.
pub fn x_height(&self, font_id: FontId, font_size: Pixels) -> Pixels {
self.read_metrics(font_id, |metrics| metrics.x_height(font_size))
}
/// Get the recommended distance from the baseline for the given font
pub fn ascent(&self, font_id: FontId, font_size: Pixels) -> Pixels {
self.read_metrics(font_id, |metrics| metrics.ascent(font_size))
}
/// Get the recommended distance below the baseline for the given font,
/// in single spaced text.
pub fn descent(&self, font_id: FontId, font_size: Pixels) -> Pixels {
self.read_metrics(font_id, |metrics| metrics.descent(font_size))
}
/// Get the recommended baseline offset for the given font and line height.
pub fn baseline_offset(
&self,
font_id: FontId,
@ -199,10 +220,14 @@ impl TextSystem {
}
}
pub fn with_view<R>(&self, view_id: EntityId, f: impl FnOnce() -> R) -> R {
pub(crate) fn with_view<R>(&self, view_id: EntityId, f: impl FnOnce() -> R) -> R {
self.line_layout_cache.with_view(view_id, f)
}
/// Layout the given line of text, at the given font_size.
/// Subsets of the line can be styled independently with the `runs` parameter.
/// Generally, you should prefer to use `TextLayout::shape_line` instead, which
/// can be painted directly.
pub fn layout_line(
&self,
text: &str,
@ -234,6 +259,12 @@ impl TextSystem {
Ok(layout)
}
/// Shape the given line, at the given font_size, for painting to the screen.
/// Subsets of the line can be styled independently with the `runs` parameter.
///
/// Note that this method can only shape a single line of text. It will panic
/// if the text contains newlines. If you need to shape multiple lines of text,
/// use `TextLayout::shape_text` instead.
pub fn shape_line(
&self,
text: SharedString,
@ -273,6 +304,9 @@ impl TextSystem {
})
}
/// Shape a multi line string of text, at the given font_size, for painting to the screen.
/// Subsets of the text can be styled independently with the `runs` parameter.
/// If `wrap_width` is provided, the line breaks will be adjusted to fit within the given width.
pub fn shape_text(
&self,
text: SharedString,
@ -381,6 +415,7 @@ impl TextSystem {
self.line_layout_cache.finish_frame(reused_views)
}
/// Returns a handle to a line wrapper, for the given font and font size.
pub fn line_wrapper(self: &Arc<Self>, font: Font, font_size: Pixels) -> LineWrapperHandle {
let lock = &mut self.wrapper_pool.lock();
let font_id = self.resolve_font(&font);
@ -397,7 +432,8 @@ impl TextSystem {
}
}
pub fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
/// Get the rasterized size and location of a specific, rendered glyph.
pub(crate) fn raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>> {
let raster_bounds = self.raster_bounds.upgradable_read();
if let Some(bounds) = raster_bounds.get(params) {
Ok(*bounds)
@ -409,7 +445,7 @@ impl TextSystem {
}
}
pub fn rasterize_glyph(
pub(crate) fn rasterize_glyph(
&self,
params: &RenderGlyphParams,
) -> Result<(Size<DevicePixels>, Vec<u8>)> {
@ -425,6 +461,7 @@ struct FontIdWithSize {
font_size: Pixels,
}
/// A handle into the text system, which can be used to compute the wrapped layout of text
pub struct LineWrapperHandle {
wrapper: Option<LineWrapper>,
text_system: Arc<TextSystem>,
@ -517,40 +554,28 @@ impl Display for FontStyle {
}
}
/// A styled run of text, for use in [`TextLayout`].
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct TextRun {
// number of utf8 bytes
/// A number of utf8 bytes
pub len: usize,
/// The font to use for this run.
pub font: Font,
/// The color
pub color: Hsla,
/// The background color (if any)
pub background_color: Option<Hsla>,
/// The underline style (if any)
pub underline: Option<UnderlineStyle>,
}
/// An identifier for a specific glyph, as returned by [`TextSystem::layout_line`].
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
#[repr(C)]
pub struct GlyphId(u32);
impl From<GlyphId> for u32 {
fn from(value: GlyphId) -> Self {
value.0
}
}
impl From<u16> for GlyphId {
fn from(num: u16) -> Self {
GlyphId(num as u32)
}
}
impl From<u32> for GlyphId {
fn from(num: u32) -> Self {
GlyphId(num)
}
}
pub struct GlyphId(pub(crate) u32);
#[derive(Clone, Debug, PartialEq)]
pub struct RenderGlyphParams {
pub(crate) struct RenderGlyphParams {
pub(crate) font_id: FontId,
pub(crate) glyph_id: GlyphId,
pub(crate) font_size: Pixels,
@ -571,6 +596,7 @@ impl Hash for RenderGlyphParams {
}
}
/// The parameters for rendering an emoji glyph.
#[derive(Clone, Debug, PartialEq)]
pub struct RenderEmojiParams {
pub(crate) font_id: FontId,
@ -590,14 +616,23 @@ impl Hash for RenderEmojiParams {
}
}
/// The configuration details for identifying a specific font.
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
pub struct Font {
/// The font family name.
pub family: SharedString,
/// The font features to use.
pub features: FontFeatures,
/// The font weight.
pub weight: FontWeight,
/// The font style.
pub style: FontStyle,
}
/// Get a [`Font`] for a given name.
pub fn font(family: impl Into<SharedString>) -> Font {
Font {
family: family.into(),
@ -608,10 +643,17 @@ pub fn font(family: impl Into<SharedString>) -> Font {
}
impl Font {
/// Set this Font to be bold
pub fn bold(mut self) -> Self {
self.weight = FontWeight::BOLD;
self
}
/// Set this Font to be italic
pub fn italic(mut self) -> Self {
self.style = FontStyle::Italic;
self
}
}
/// A struct for storing font metrics.