Struct cosmic_text::SwashCache

source ·
pub struct SwashCache<'a> {
    pub image_cache: Map<CacheKey, Option<SwashImage>>,
    pub outline_command_cache: Map<CacheKey, Option<Vec<Command>>>,
    /* private fields */
}
Expand description

Cache for rasterizing with the swash scaler

Fields§

§image_cache: Map<CacheKey, Option<SwashImage>>§outline_command_cache: Map<CacheKey, Option<Vec<Command>>>

Implementations§

Create a new swash cache

Create a swash Image from a cache key, without caching results

Create a swash Image from a cache key, caching results

Examples found in repository?
src/swash.rs (line 129)
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    pub fn with_pixels<F: FnMut(i32, i32, Color)>(
        &mut self,
        cache_key: CacheKey,
        base: Color,
        mut f: F
    ) {
        if let Some(image) = self.get_image(cache_key) {
            let x = image.placement.left;
            let y = -image.placement.top;

            match image.content {
                Content::Mask => {
                    let mut i = 0;
                    for off_y in 0..image.placement.height as i32 {
                        for off_x in 0..image.placement.width as i32 {
                            //TODO: blend base alpha?
                            f(
                                x + off_x,
                                y + off_y,
                                Color(
                                    ((image.data[i] as u32) << 24) |
                                    base.0 & 0xFF_FF_FF
                                )
                            );
                            i += 1;
                        }
                    }
                }
                Content::Color => {
                    let mut i = 0;
                    for off_y in 0..image.placement.height as i32 {
                        for off_x in 0..image.placement.width as i32 {
                            //TODO: blend base alpha?
                            f(
                                x + off_x,
                                y + off_y,
                                Color::rgba(
                                    image.data[i],
                                    image.data[i + 1],
                                    image.data[i + 2],
                                    image.data[i + 3]
                                )
                            );
                            i += 4;
                        }
                    }
                }
                Content::SubpixelMask => {
                    log::warn!("TODO: SubpixelMask");
                }
            }
        }
    }

Enumerate pixels in an Image, use with_image for better performance

Examples found in repository?
src/buffer.rs (lines 548-550)
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    pub fn draw<F>(&self, cache: &mut crate::SwashCache, color: Color, mut f: F)
        where F: FnMut(i32, i32, u32, u32, Color)
    {
        for run in self.layout_runs() {
            for glyph in run.glyphs.iter() {
                let (cache_key, x_int, y_int) = (glyph.cache_key, glyph.x_int, glyph.y_int);

                let glyph_color = match glyph.color_opt {
                    Some(some) => some,
                    None => color,
                };

                cache.with_pixels(cache_key, glyph_color, |x, y, color| {
                    f(x_int + x, run.line_y + y_int + y, 1, 1, color);
                });
            }
        }
    }
More examples
Hide additional examples
src/edit/editor.rs (lines 672-674)
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    fn draw<F>(&self, cache: &mut crate::SwashCache, color: Color, mut f: F)
        where F: FnMut(i32, i32, u32, u32, Color)
    {
        let font_size = self.buffer.metrics().font_size;
        let line_height = self.buffer.metrics().line_height;

        for run in self.buffer.layout_runs() {
            let line_i = run.line_i;
            let line_y = run.line_y;

            let cursor_glyph_opt = |cursor: &Cursor| -> Option<(usize, f32)> {
                if cursor.line == line_i {
                    for (glyph_i, glyph) in run.glyphs.iter().enumerate() {
                        if cursor.index == glyph.start {
                            return Some((glyph_i, 0.0));
                        } else if cursor.index > glyph.start && cursor.index < glyph.end {
                            // Guess x offset based on characters
                            let mut before = 0;
                            let mut total = 0;

                            let cluster = &run.text[glyph.start..glyph.end];
                            for (i, _) in cluster.grapheme_indices(true) {
                                if glyph.start + i < cursor.index {
                                    before += 1;
                                }
                                total += 1;
                            }

                            let offset = glyph.w * (before as f32) / (total as f32);
                            return Some((glyph_i, offset));
                        }
                    }
                    match run.glyphs.last() {
                        Some(glyph) => {
                            if cursor.index == glyph.end {
                                return Some((run.glyphs.len(), 0.0));
                            }
                        },
                        None => {
                            return Some((0, 0.0));
                        }
                    }
                }
                None
            };

            // Highlight selection (TODO: HIGHLIGHT COLOR!)
            if let Some(select) = self.select_opt {
                let (start, end) = match select.line.cmp(&self.cursor.line) {
                    cmp::Ordering::Greater => (self.cursor, select),
                    cmp::Ordering::Less => (select, self.cursor),
                    cmp::Ordering::Equal => {
                        /* select.line == self.cursor.line */
                        if select.index < self.cursor.index {
                            (select, self.cursor)
                        } else {
                            /* select.index >= self.cursor.index */
                            (self.cursor, select)
                        }
                    }
                };

                if line_i >= start.line && line_i <= end.line {
                    let mut range_opt = None;
                    for glyph in run.glyphs.iter() {
                        // Guess x offset based on characters
                        let cluster = &run.text[glyph.start..glyph.end];
                        let total = cluster.grapheme_indices(true).count();
                        let mut c_x = glyph.x;
                        let c_w = glyph.w / total as f32;
                        for (i, c) in cluster.grapheme_indices(true) {
                            let c_start = glyph.start + i;
                            let c_end = glyph.start + i + c.len();
                            if (start.line != line_i || c_end > start.index)
                            && (end.line != line_i || c_start < end.index) {
                                range_opt = match range_opt.take() {
                                    Some((min, max)) => Some((
                                        cmp::min(min, c_x as i32),
                                        cmp::max(max, (c_x + c_w) as i32),
                                    )),
                                    None => Some((
                                        c_x as i32,
                                        (c_x + c_w) as i32,
                                    ))
                                };
                            } else if let Some((min, max)) = range_opt.take() {
                                f(
                                    min,
                                    line_y - font_size,
                                    cmp::max(0, max - min) as u32,
                                    line_height as u32,
                                    Color::rgba(color.r(), color.g(), color.b(), 0x33)
                                );
                            }
                            c_x += c_w;
                        }
                    }

                    if run.glyphs.is_empty() && end.line > line_i{
                        // Highlight all of internal empty lines
                        range_opt = Some((0, self.buffer.size().0));
                    }

                    if let Some((mut min, mut max)) = range_opt.take() {
                        if end.line > line_i {
                            // Draw to end of line
                            if run.rtl {
                                min = 0;
                            } else {
                                max = self.buffer.size().0;
                            }
                        }
                        f(
                            min,
                            line_y - font_size,
                            cmp::max(0, max - min) as u32,
                            line_height as u32,
                            Color::rgba(color.r(), color.g(), color.b(), 0x33)
                        );
                    }
                }
            }

            // Draw cursor
            if let Some((cursor_glyph, cursor_glyph_offset)) = cursor_glyph_opt(&self.cursor) {
                let x = match run.glyphs.get(cursor_glyph) {
                    Some(glyph) => {
                        // Start of detected glyph
                        if glyph.level.is_rtl() {
                            (glyph.x + glyph.w - cursor_glyph_offset) as i32
                        } else {
                            (glyph.x + cursor_glyph_offset) as i32
                        }
                    },
                    None => match run.glyphs.last() {
                        Some(glyph) => {
                            // End of last glyph
                            if glyph.level.is_rtl() {
                                glyph.x as i32
                            } else {
                                (glyph.x + glyph.w) as i32
                            }
                        },
                        None => {
                            // Start of empty line
                            0
                        }
                    }
                };

                f(
                    x,
                    line_y - font_size,
                    1,
                    line_height as u32,
                    color,
                );
            }

            for glyph in run.glyphs.iter() {
                let (cache_key, x_int, y_int) = (glyph.cache_key, glyph.x_int, glyph.y_int);

                let glyph_color = match glyph.color_opt {
                    Some(some) => some,
                    None => color,
                };

                cache.with_pixels(cache_key, glyph_color, |x, y, color| {
                    f(x_int + x, line_y + y_int + y, 1, 1, color);
                });
            }
        }
    }

Auto Trait Implementations§

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Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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