This commit is contained in:
Alex Bethel 2021-11-29 17:16:25 -07:00
parent b174559a68
commit 4adb0cfda7
2 changed files with 55 additions and 18 deletions

View file

@ -1,6 +1,6 @@
#![allow(dead_code, unused)]
use ab_glyph::FontRef;
use ab_glyph::{FontRef, ScaleFont};
use able_graphics_library::{AglApi, FrameBuffer, Point, HEIGHT, RGBA, WIDTH};
use mini_gl_fb::glutin::platform::unix::x11::ffi::XK_R10;
@ -78,25 +78,50 @@ impl AglApi for GraphicsRenderer {
fn draw_text(&mut self, coords: Point, scale: u8, color: RGBA, text: String) {
use ab_glyph::{point, Font, FontRef, Glyph};
let font: FontRef =
FontRef::try_from_slice(include_bytes!("../font/Roboto-Regular.ttf")).unwrap();
let font = FontRef::try_from_slice(include_bytes!("../font/Roboto-Regular.ttf")).unwrap();
let font_scaled = font.as_scaled(scale as f32);
// Get a glyph for 'q' with a scale & position.
let q_glyph: Glyph = font
.glyph_id('a')
.with_scale_and_position(scale as f32, point(coords.x as f32, coords.y as f32));
// Draw it.
if let Some(q) = font.outline_glyph(q_glyph) {
// dbg!(q);
// Individual characters are drawn at floating-point offsets.
let mut coords = point(coords.x as f32, coords.y as f32);
let mut last_char = None;
q.draw(|x, y, c| {
/* draw pixel `(x, y)` with coverage: `c` */
dbg!(x, y, c);
for ch in text.chars() {
let glyph_id = font.glyph_id(ch);
let coordinates = x as u16 + (WIDTH as u16).wrapping_mul(y as u16);
// Kern character pairs as necessary.
if let Some(last) = last_char {
coords.x -= font_scaled.kern(last, glyph_id);
}
last_char = Some(font.glyph_id(ch));
self.buff[coordinates as usize] = color;
});
// Get a glyph with a scale & position.
let glyph: Glyph = glyph_id
.with_scale_and_position(scale as f32, point(coords.x as f32, coords.y as f32));
// Draw it.
if let Some(outline) = font.outline_glyph(glyph) {
outline.draw(|x, y, c| {
// ab_glyph gives us coordinates within the
// bounding box; convert these to coordinates
// within the image.
let corner = outline.px_bounds().min;
let (x, y) = (x + corner.x as u32, y + corner.y as u32);
// Flip y to draw characters right-side-up.
let y = 2 * coords.y as u32 - y;
// draw pixel `(x, y)` with coverage: `c`
let coordinates = x as u16 + (WIDTH as u16).wrapping_mul(y as u16);
let pixel = &mut self.buff[coordinates as usize];
// Interpolate between the existing background
// character and the new foreground color.
*pixel = lerp_rgba(*pixel, color, c);
});
}
// Advance to the next glyph's position.
coords.x += font_scaled.h_advance(glyph_id);
}
}
/// Actually move the double buffer to the single buffer and "update" the screen
@ -107,3 +132,15 @@ impl AglApi for GraphicsRenderer {
}
}
}
/// Interpolate between two colors according to a factor.
fn lerp_rgba(a: RGBA, b: RGBA, fac: f32) -> RGBA {
// TODO: This is probably the wrong way to mix colors, but it's
// simple and works for now.
RGBA {
r: ((b.r as f32 - a.r as f32) * fac + a.r as f32) as _,
g: ((b.g as f32 - a.g as f32) * fac + a.g as f32) as _,
b: ((b.b as f32 - a.b as f32) * fac + a.b as f32) as _,
a: ((b.a as f32 - a.a as f32) * fac + a.a as f32) as _,
}
}

View file

@ -73,8 +73,8 @@ fn main() {
);
xyz.draw_text(
Point { x: 1000, y: 90 },
1,
Point { x: 100, y: 90 },
24,
RGBA {
r: 0,
g: 0,