libcosmic/examples/text/src/font/shape.rs

#[cfg(feature = "ab_glyph")]
use ab_glyph::Font;
use core::marker::PhantomData;

use super::{FontLayoutGlyph, FontLayoutLine, FontLineIndex};

pub struct FontShapeGlyph<'a> {
    pub start: usize,
    pub end: usize,
    pub x_advance: f32,
    pub y_advance: f32,
    pub x_offset: f32,
    pub y_offset: f32,
    #[cfg(feature = "ab_glyph")]
    pub font: &'a ab_glyph::FontRef<'a>,
    #[cfg(feature = "ab_glyph")]
    pub inner: ab_glyph::GlyphId,
    #[cfg(feature = "rusttype")]
    pub inner: rusttype::Glyph<'a>,
}

pub struct FontShapeWord<'a> {
    pub glyphs: Vec<FontShapeGlyph<'a>>,
}

pub struct FontShapeSpan<'a> {
    pub rtl: bool,
    pub words: Vec<FontShapeWord<'a>>,
}

pub struct FontShapeLine<'a> {
    pub line_i: FontLineIndex,
    pub rtl: bool,
    pub spans: Vec<FontShapeSpan<'a>>,
}

impl<'a> FontShapeLine<'a> {

    fn layout_ltr(&self, font_size: i32, line_width: i32, layout_lines: &mut Vec<FontLayoutLine<'a>>, mut layout_i: usize) {
        let mut push_line = true;
        let mut glyphs = Vec::new();

        let mut x = 0.0;
        let mut y = 0.0;
        for span in self.spans.iter() {
            for word in span.words.iter() {
                for glyph in word.glyphs.iter() {
                    let x_advance = font_size as f32 * glyph.x_advance;
                    let y_advance = font_size as f32 * glyph.y_advance;
                    let x_offset = font_size as f32 * glyph.x_offset;
                    let y_offset = font_size as f32 * glyph.y_offset;

                    //TODO: make wrapping optional
                    if x + x_advance > line_width as f32 {
                        let mut glyphs_swap = Vec::new();
                        std::mem::swap(&mut glyphs, &mut glyphs_swap);
                        layout_lines.insert(layout_i, FontLayoutLine {
                            line_i: self.line_i,
                            glyphs: glyphs_swap
                        });
                        layout_i += 1;

                        x = 0.0;
                        y = 0.0;
                    }

                    #[cfg(feature = "ab_glyph")]
                    let inner = glyph.font.outline_glyph(
                        glyph.inner.with_scale_and_position(
                            font_size as f32,
                            ab_glyph::point(
                                x + x_offset,
                                y + y_offset,
                            )
                        )
                    );

                    #[cfg(feature = "rusttype")]
                    let inner = glyph.inner.clone()
                        .scaled(rusttype::Scale::uniform(font_size as f32))
                        .positioned(rusttype::point(
                            x + x_offset,
                            y + y_offset,
                        ));

                    glyphs.push(FontLayoutGlyph {
                        start: glyph.start,
                        end: glyph.end,
                        x,
                        w: x_advance,
                        inner,
                        phantom: PhantomData,
                    });
                    push_line = true;

                    x += x_advance;
                    y += y_advance;
                }
            }
        }

        if push_line {
            layout_lines.insert(layout_i, FontLayoutLine {
                line_i: self.line_i,
                glyphs
            });
        }
    }

    fn layout_rtl(&self, font_size: i32, line_width: i32, layout_lines: &mut Vec<FontLayoutLine<'a>>, mut layout_i: usize) {
        let mut push_line = true;
        let mut glyphs = Vec::new();

        let mut x = line_width as f32;
        let mut y = 0.0;
        for span in self.spans.iter() {
            for word in span.words.iter() {
                for glyph in word.glyphs.iter().rev() {
                    let x_advance = font_size as f32 * glyph.x_advance;
                    let y_advance = font_size as f32 * glyph.y_advance;
                    let x_offset = font_size as f32 * glyph.x_offset;
                    let y_offset = font_size as f32 * glyph.y_offset;

                    //TODO: make wrapping optional
                    if x - x_advance < 0.0 {
                        let mut glyphs_swap = Vec::new();
                        std::mem::swap(&mut glyphs, &mut glyphs_swap);
                        layout_lines.insert(layout_i, FontLayoutLine {
                            line_i: self.line_i,
                            glyphs: glyphs_swap
                        });
                        layout_i += 1;

                        x = line_width as f32;
                        y = 0.0;
                    }

                    x -= x_advance;

                    #[cfg(feature = "ab_glyph")]
                    let inner = glyph.font.outline_glyph(
                        glyph.inner.with_scale_and_position(
                            font_size as f32,
                            ab_glyph::point(
                                x + x_offset,
                                y + y_offset,
                            )
                        )
                    );

                    #[cfg(feature = "rusttype")]
                    let inner = glyph.inner.clone()
                        .scaled(rusttype::Scale::uniform(font_size as f32))
                        .positioned(rusttype::point(
                            x + x_offset,
                            y + y_offset,
                        ));

                    glyphs.push(FontLayoutGlyph {
                        start: glyph.start,
                        end: glyph.end,
                        x,
                        w: x_advance,
                        inner,
                        phantom: PhantomData,
                    });
                    push_line = true;

                    y += y_advance;
                }
            }
        }

        if push_line {
            layout_lines.insert(layout_i, FontLayoutLine {
                line_i: self.line_i,
                glyphs
            });
        }

    }

    pub fn layout(&self, font_size: i32, line_width: i32, layout_lines: &mut Vec<FontLayoutLine<'a>>, layout_i: usize) {
        if self.rtl {
            self.layout_rtl(font_size, line_width, layout_lines, layout_i);
        } else {
            self.layout_ltr(font_size, line_width, layout_lines, layout_i);
        }
    }
}