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Properly use premultiplied alpha

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Chlorospingus
2025-05-28 14:34:21 -07:00
parent 3bcccb2e87
commit 1eff2cd4f7
6 changed files with 69 additions and 54 deletions
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13
src/graphics/circle.rs
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@@ -24,19 +24,18 @@ impl Drawable for Circle {
for l_row in 1..self.radius {
let inner_diff = (((self.radius-1).pow(2) - l_row.pow(2)) as f64).sqrt();
let outer_diff = ((self.radius.pow(2) - l_row.pow(2)) as f64).sqrt();
let row: Vec<u32> = vec![self.color; 2*(inner_diff.floor() as usize)];
shm_pool.write(&row, (self.y-l_row)*buffer.width + self.x - inner_diff.floor() as usize + buffer.offset);
shm_pool.write(&row, (self.y+l_row-1)*buffer.width + self.x - inner_diff.floor() as usize + buffer.offset);
shm_pool.write(self.color, (self.y-l_row)*buffer.width + self.x - inner_diff.floor() as usize + buffer.offset, 2*(inner_diff.floor() as usize));
shm_pool.write(self.color, (self.y+l_row-1)*buffer.width + self.x - inner_diff.floor() as usize + buffer.offset, 2*(inner_diff.floor() as usize));
for l_col in (inner_diff.floor() as usize+1)..(outer_diff.ceil() as usize) {
let distance = ((l_row.pow(2) + l_col.pow(2)) as f64).sqrt();
let offset = (self.y-l_row)*buffer.width + self.x - l_col + buffer.offset;
shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset).unwrap(), distance.fract()), offset);
shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
let offset = (self.y-l_row)*buffer.width + self.x + l_col-1 + buffer.offset;
shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset).unwrap(), distance.fract()), offset);
shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
let offset = (self.y+l_row-1)*buffer.width + self.x - l_col + buffer.offset;
shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset).unwrap(), distance.fract()), offset);
shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
let offset = (self.y+l_row-1)*buffer.width + self.x + l_col-1 + buffer.offset;
shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset).unwrap(), distance.fract()), offset);
shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
}
}
}

65
src/graphics/drawable.rs
View File

@@ -1,34 +1,51 @@
use crate::wayland::{shm::ShmPool, wl_shm::wl_buffer};
pub fn rgb_blend(col1: u32, col2: u32, diff: f64) -> u32 {
let r1 = (col1 & 0x00ff0000) >> 16;
let g1 = (col1 & 0x0000ff00) >> 8;
let b1 = col1 & 0x000000ff;
let r2 = (col2 & 0x00ff0000) >> 16;
let g2 = (col2 & 0x0000ff00) >> 8;
let b2 = col2 & 0x000000ff;
let r3 = if r1 < r2 {
r1 + ((r2 - r1) as f64 * diff) as u32
} else {
r1 - ((r1 - r2) as f64 * diff) as u32
};
let g3 = if g1 < g2 {
g1 + ((g2 - g1) as f64 * diff) as u32
} else {
g1 - ((g1 - g2) as f64 * diff) as u32
};
let b3 = if b1 < b2 {
b1 + ((b2 - b1) as f64 * diff) as u32
} else {
b1 - ((b1 - b2) as f64 * diff) as u32
};
(r3 << 16) + (g3 << 8) + b3
pub fn premultiply(color: u32) -> u32 {
let a = (color & 0xff000000) >> 24;
let r = (color & 0x00ff0000) >> 16;
let g = (color & 0x0000ff00) >> 8;
let b = (color & 0x000000ff) >> 0;
let alpha = (a as f64 / 0xff as f64);
(a << 24) +
(((r as f64*alpha) as u32) << 16) +
(((g as f64*alpha) as u32) << 8) +
(((b as f64*alpha) as u32) << 0)
}
pub fn color_blend(col1: u32, col2: u32, diff: f64) -> u32 {
let a1 = (col1 & 0xff000000) >> 24;
let r1 = (col1 & 0x00ff0000) >> 16;
let g1 = (col1 & 0x0000ff00) >> 8;
let b1 = (col1 & 0x000000ff) >> 0;
let a2 = (col2 & 0xff000000) >> 24;
((a2 + ((a1 as f64/0xff as f64)*(0xff - a2) as f64*(1.0-diff)) as u32) << 24) + rgb_blend(col1, col2, diff * (a1 as f64 / 0xff as f64))
let r2 = (col2 & 0x00ff0000) >> 16;
let g2 = (col2 & 0x0000ff00) >> 8;
let b2 = (col2 & 0x000000ff) >> 0;
(((a1 as f64 + (a2 as f64 - a1 as f64) * diff).round() as u32) << 24) +
(((r1 as f64 + (r2 as f64 - r1 as f64) * diff).round() as u32) << 16) +
(((g1 as f64 + (b2 as f64 - g1 as f64) * diff).round() as u32) << 8 ) +
(((b1 as f64 + (g2 as f64 - b1 as f64) * diff).round() as u32) << 0 )
}
pub fn color_over(over: u32, under: u32) -> u32 {
let a_over = (over & 0xff000000) >> 24;
let a_under = (under & 0xff000000) >> 24;
if a_over == 0xff || a_under == 0 {
return over;
}
if a_over == 0 {
return under;
}
let r_over = (over & 0x00ff0000) >> 16;
let r_under = (under & 0x00ff0000) >> 16;
let g_over = (over & 0x0000ff00) >> 8;
let g_under = (under & 0x0000ff00) >> 8;
let b_over = (over & 0x000000ff) >> 0;
let b_under = (under & 0x000000ff) >> 0;
((a_over + (a_under as f64 * (0xff - a_over) as f64 / 0xff as f64) as u32).min(0xff) << 24).min(0xff) +
((r_over + (r_under as f64 * (0xff - a_over) as f64 / 0xff as f64) as u32).min(0xff) << 16).min(0xff) +
((g_over + (g_under as f64 * (0xff - a_over) as f64 / 0xff as f64) as u32).min(0xff) << 8) +
((b_over + (b_under as f64 * (0xff - a_over) as f64 / 0xff as f64) as u32).min(0xff) << 0)
}
pub trait Drawable : Send {

14
src/graphics/rectangle.rs
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@@ -24,24 +24,24 @@ impl Drawable for Rectangle {
fn draw(&self, buffer: &wl_buffer, shm_pool: &mut ShmPool) {
for g_row in self.y+self.radius..self.y+self.height-self.radius+1 {
shm_pool.write(&vec![self.color; self.width], g_row*buffer.width as usize+self.x + buffer.offset);
shm_pool.write(self.color, g_row*buffer.width as usize+self.x + buffer.offset, self.width);
}
for l_row in 1..self.radius {
let inner_diff = (((self.radius-1).pow(2) - l_row.pow(2)) as f64).sqrt();
let outer_diff = ((self.radius.pow(2) - l_row.pow(2)) as f64).sqrt();
shm_pool.write(&vec![self.color; self.width - (2*(self.radius - inner_diff.floor() as usize-1))], (self.y+self.radius-l_row)*buffer.width as usize + self.x + self.radius - inner_diff.floor() as usize-1 + buffer.offset);
shm_pool.write(&vec![self.color; self.width - (2*(self.radius - inner_diff.floor() as usize-1))], (self.y+self.height-self.radius+l_row)*buffer.width as usize + self.x + self.radius - inner_diff.floor() as usize-1 + buffer.offset);
shm_pool.write(self.color, (self.y+self.radius-l_row)*buffer.width as usize + self.x + self.radius - inner_diff.floor() as usize-1 + buffer.offset, self.width - (2*(self.radius - inner_diff.floor() as usize-1)));
shm_pool.write(self.color, (self.y+self.height-self.radius+l_row)*buffer.width as usize + self.x + self.radius - inner_diff.floor() as usize-1 + buffer.offset, self.width - (2*(self.radius - inner_diff.floor() as usize-1)));
for l_col in inner_diff.floor() as usize+1..outer_diff.ceil() as usize {
// TODO: handle error from read_pixel
let distance = ((l_row.pow(2) + l_col.pow(2)) as f64).sqrt();
let offset = (self.y+self.radius-l_row)*buffer.width as usize + self.x + self.radius - l_col - 1 + buffer.offset;
shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset).unwrap(), distance.fract()), offset);
shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
let offset = (self.y+self.radius-l_row)*buffer.width as usize + self.x + self.width - self.radius + l_col + buffer.offset;
shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset).unwrap(), distance.fract()), offset);
shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
let offset = (self.y+self.height-self.radius+l_row)*buffer.width as usize + self.x + self.radius - l_col - 1 + buffer.offset;
shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset).unwrap(), distance.fract()), offset);
shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
let offset = (self.y+self.height-self.radius+l_row)*buffer.width as usize + self.x + self.width - self.radius + l_col + buffer.offset;
shm_pool.write_pixel(color_blend(self.color, shm_pool.read_pixel(offset).unwrap(), distance.fract()), offset);
shm_pool.write_pixel(color_blend(self.color, 0, distance.fract()), offset);
}
}
}