mirror of
https://github.com/slint-ui/slint.git
synced 2025-08-28 06:14:10 +00:00
4e7bbcf2ba
* WIP: swrenderer: use fixed point for the pixmap font coordinate * swrenderer: signed distance field: move the glyph to the middle * swrenderer: round the advance instead of truncating it in distance field * swrenderer: actually align the gplyph on the sub-pixel precision sub-pixel within the source. * swrenderer: adapt the threshold for signed distance field sqrt(2) is the distance to the diagonal, seems like this gives sharper fonts * Fix bug in the elision, and re-upload the screenshort the screenshot changed because the afvanced is now rounded intead of truncated
822 lines
30 KiB
Rust
822 lines
30 KiB
Rust
// Copyright © SixtyFPS GmbH <info@slint.dev>
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// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
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#![allow(clippy::identity_op)] // We use x + 0 a lot here for symmetry
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//! This is the module for the functions that are drawing the pixels
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//! on the line buffer
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use super::{Fixed, PhysicalLength, PhysicalRect};
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use crate::graphics::{PixelFormat, Rgb8Pixel};
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use crate::lengths::{PointLengths, SizeLengths};
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use crate::Color;
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use derive_more::{Add, Mul, Sub};
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use integer_sqrt::IntegerSquareRoot;
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/// Draw one line of the texture in the line buffer
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///
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pub(super) fn draw_texture_line(
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span: &PhysicalRect,
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line: PhysicalLength,
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texture: &super::SceneTexture,
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line_buffer: &mut [impl TargetPixel],
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extra_clip_begin: i16,
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extra_clip_end: i16,
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) {
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let super::SceneTexture {
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data,
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format,
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pixel_stride,
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extra: super::SceneTextureExtra { colorize, alpha, rotation, dx, dy, off_x, off_y },
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} = *texture;
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let source_size = texture.source_size().cast::<i32>();
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let len = line_buffer.len();
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let y = line - span.origin.y_length();
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let y = if rotation.mirror_width() { span.size.height - y.get() - 1 } else { y.get() } as i32;
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let off_y = Fixed::<i32, 8>::from_fixed(off_y);
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let dx = Fixed::<i32, 8>::from_fixed(dx);
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let dy = Fixed::<i32, 8>::from_fixed(dy);
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let off_x = Fixed::<i32, 8>::from_fixed(off_x);
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if !rotation.is_transpose() {
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let mut delta = dx;
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let row = off_y + dy * y;
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// The position where to start in the image array for a this row
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let mut init =
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Fixed::from_integer(row.truncate() % source_size.height) * pixel_stride as i32;
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// the size of the tile in physical pixels in the target
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let tile_len = (Fixed::from_integer(source_size.width) / delta) as usize;
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// the amount of missing image pixel on one tile
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let mut remainder = Fixed::from_integer(source_size.width) % delta;
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// The position in image pixel where to get the image
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let mut pos;
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// the end index in the target buffer
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let mut end;
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// the accumulated error in image pixels
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let mut acc_err;
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if rotation.mirror_height() {
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let o = (off_x + (delta * (extra_clip_end as i32 + len as i32 - 1)))
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% Fixed::from_integer(source_size.width);
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pos = init + o;
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init += Fixed::from_integer(source_size.width);
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end = (o / delta) as usize + 1;
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acc_err = -delta + o % delta;
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delta = -delta;
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remainder = -remainder;
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} else {
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let o =
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(off_x + delta * extra_clip_begin as i32) % Fixed::from_integer(source_size.width);
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pos = init + o;
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end = ((Fixed::from_integer(source_size.width) - o) / delta) as usize;
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acc_err = (Fixed::from_integer(source_size.width) - o) % delta;
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if acc_err != Fixed::default() {
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acc_err = delta - acc_err;
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end += 1;
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}
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}
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end = end.min(len);
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let mut begin = 0;
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let row_fract = row.fract();
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while begin < len {
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fetch_blend_pixel(
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&mut line_buffer[begin..end],
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format,
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data,
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alpha,
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colorize,
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(pixel_stride as usize, dy),
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#[inline(always)]
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|bpp| {
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let p = (pos.truncate() as usize * bpp, pos.fract(), row_fract);
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pos += delta;
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p
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},
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);
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begin = end;
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end += tile_len;
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pos = init;
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pos += acc_err;
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if remainder != Fixed::from_integer(0) {
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acc_err -= remainder;
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let wrap = if rotation.mirror_height() {
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acc_err >= Fixed::from_integer(0)
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} else {
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acc_err < Fixed::from_integer(0)
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};
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if wrap {
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acc_err += delta;
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end += 1;
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}
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};
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end = end.min(len);
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}
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} else {
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let bpp = format.bpp();
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let col = off_x + dx * y;
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let col_fract = col.fract();
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let col = (col.truncate() % source_size.width) as usize * bpp;
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let stride = pixel_stride as usize * bpp;
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let mut row_delta = dy;
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let tile_len = (Fixed::from_integer(source_size.height) / row_delta) as usize;
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let mut remainder = Fixed::from_integer(source_size.height) % row_delta;
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let mut end;
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let mut row_init = Fixed::default();
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let mut row;
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let mut acc_err;
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if rotation.mirror_height() {
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row_init = Fixed::from_integer(source_size.height);
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row = (off_y + (row_delta * (extra_clip_end as i32 + len as i32 - 1)))
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% Fixed::from_integer(source_size.height);
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end = (row / row_delta) as usize + 1;
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acc_err = -row_delta + row % row_delta;
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row_delta = -row_delta;
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remainder = -remainder;
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} else {
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row = (off_y + row_delta * extra_clip_begin as i32)
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% Fixed::from_integer(source_size.height);
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end = ((Fixed::from_integer(source_size.height) - row) / row_delta) as usize;
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acc_err = (Fixed::from_integer(source_size.height) - row) % row_delta;
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if acc_err != Fixed::default() {
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acc_err = row_delta - acc_err;
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end += 1;
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}
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};
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end = end.min(len);
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let mut begin = 0;
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while begin < len {
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fetch_blend_pixel(
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&mut line_buffer[begin..end],
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format,
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data,
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alpha,
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colorize,
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(stride, dy),
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#[inline(always)]
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|_| {
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let pos = (row.truncate() as usize * stride + col, col_fract, row.fract());
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row += row_delta;
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pos
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},
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);
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begin = end;
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end += tile_len;
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row = row_init;
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row += acc_err;
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if remainder != Fixed::from_integer(0) {
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acc_err -= remainder;
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let wrap = if rotation.mirror_height() {
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acc_err >= Fixed::from_integer(0)
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} else {
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acc_err < Fixed::from_integer(0)
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};
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if wrap {
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acc_err += row_delta;
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end += 1;
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}
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};
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end = end.min(len);
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}
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};
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fn fetch_blend_pixel(
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line_buffer: &mut [impl TargetPixel],
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format: PixelFormat,
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data: &[u8],
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alpha: u8,
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color: Color,
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(stride, delta): (usize, Fixed<i32, 8>),
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mut pos: impl FnMut(usize) -> (usize, u8, u8),
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) {
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match format {
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PixelFormat::Rgb => {
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for pix in line_buffer {
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let pos = pos(3).0;
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let p = &data[pos..pos + 3];
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if alpha == 0xff {
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*pix = TargetPixel::from_rgb(p[0], p[1], p[2]);
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} else {
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pix.blend(PremultipliedRgbaColor::premultiply(Color::from_argb_u8(
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alpha, p[0], p[1], p[2],
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)))
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}
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}
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}
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PixelFormat::Rgba => {
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if color.alpha() == 0 {
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for pix in line_buffer {
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let pos = pos(4).0;
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let alpha = ((data[pos + 3] as u16 * alpha as u16) / 255) as u8;
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let c = PremultipliedRgbaColor::premultiply(Color::from_argb_u8(
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alpha,
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data[pos + 0],
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data[pos + 1],
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data[pos + 2],
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));
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pix.blend(c);
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}
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} else {
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for pix in line_buffer {
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let pos = pos(4).0;
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let alpha = ((data[pos + 3] as u16 * alpha as u16) / 255) as u8;
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let c = PremultipliedRgbaColor::premultiply(Color::from_argb_u8(
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alpha,
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color.red(),
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color.green(),
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color.blue(),
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));
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pix.blend(c);
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}
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}
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}
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PixelFormat::RgbaPremultiplied => {
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if color.alpha() > 0 {
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for pix in line_buffer {
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let pos = pos(4).0;
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let c = PremultipliedRgbaColor::premultiply(Color::from_argb_u8(
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((data[pos + 3] as u16 * alpha as u16) / 255) as u8,
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color.red(),
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color.green(),
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color.blue(),
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));
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pix.blend(c);
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}
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} else if alpha == 0xff {
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for pix in line_buffer {
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let pos = pos(4).0;
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let c = PremultipliedRgbaColor {
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alpha: data[pos + 3],
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red: data[pos + 0],
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green: data[pos + 1],
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blue: data[pos + 2],
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};
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pix.blend(c);
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}
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} else {
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for pix in line_buffer {
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let pos = pos(4).0;
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let c = PremultipliedRgbaColor {
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alpha: (data[pos + 3] as u16 * alpha as u16 / 255) as u8,
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red: (data[pos + 0] as u16 * alpha as u16 / 255) as u8,
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green: (data[pos + 1] as u16 * alpha as u16 / 255) as u8,
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blue: (data[pos + 2] as u16 * alpha as u16 / 255) as u8,
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};
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pix.blend(c);
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}
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}
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}
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PixelFormat::AlphaMap => {
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for pix in line_buffer {
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let pos = pos(1).0;
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let c = PremultipliedRgbaColor::premultiply(Color::from_argb_u8(
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((data[pos] as u16 * alpha as u16) / 255) as u8,
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color.red(),
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color.green(),
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color.blue(),
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));
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pix.blend(c);
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}
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}
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PixelFormat::SignedDistanceField => {
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const RANGE: i32 = 6;
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let factor = (362 * 256 / delta.0) * RANGE; // 362 ≃ 255 * sqrt(2)
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for pix in line_buffer {
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let (pos, col_f, row_f) = pos(1);
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let (col_f, row_f) = (col_f as i32, row_f as i32);
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let mut dist = ((data[pos] as i8 as i32) * (256 - col_f)
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+ (data[pos + 1] as i8 as i32) * col_f)
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* (256 - row_f);
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if pos + stride + 1 < data.len() {
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dist += ((data[pos + stride] as i8 as i32) * (256 - col_f)
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+ (data[pos + stride + 1] as i8 as i32) * col_f)
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* row_f
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} else {
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debug_assert_eq!(row_f, 0);
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}
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let a = ((((dist >> 8) * factor) >> 16) + 128).clamp(0, 255) * alpha as i32;
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let c = PremultipliedRgbaColor::premultiply(Color::from_argb_u8(
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(a / 255) as u8,
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color.red(),
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color.green(),
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color.blue(),
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));
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pix.blend(c);
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}
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}
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};
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}
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}
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/// draw one line of the rounded rectangle in the line buffer
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#[allow(clippy::unnecessary_cast)] // Coord
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pub(super) fn draw_rounded_rectangle_line(
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span: &PhysicalRect,
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line: PhysicalLength,
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rr: &super::RoundedRectangle,
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line_buffer: &mut [impl TargetPixel],
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extra_left_clip: i16,
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extra_right_clip: i16,
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) {
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/// This is an integer shifted by 4 bits.
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/// Note: this is not a "fixed point" because multiplication and sqrt operation operate to
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/// the shifted integer
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#[derive(Clone, Copy, PartialEq, Ord, PartialOrd, Eq, Add, Sub, Mul)]
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struct Shifted(u32);
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impl Shifted {
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const ONE: Self = Shifted(1 << 4);
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#[track_caller]
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pub fn new(value: impl TryInto<u32> + core::fmt::Debug + Copy) -> Self {
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Self(value.try_into().unwrap_or_else(|_| panic!("Overflow {value:?}")) << 4)
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}
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pub fn floor(self) -> u32 {
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self.0 >> 4
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}
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pub fn ceil(self) -> u32 {
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(self.0 + Self::ONE.0 - 1) >> 4
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}
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pub fn saturating_sub(self, other: Self) -> Self {
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Self(self.0.saturating_sub(other.0))
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}
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pub fn sqrt(self) -> Self {
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Self(self.0.integer_sqrt())
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}
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}
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impl core::ops::Mul for Shifted {
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type Output = Shifted;
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fn mul(self, rhs: Self) -> Self::Output {
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Self(self.0 * rhs.0)
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}
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}
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let width = line_buffer.len();
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let y1 = (line - span.origin.y_length()) + rr.top_clip;
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let y2 = (span.origin.y_length() + span.size.height_length() - line) + rr.bottom_clip
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- PhysicalLength::new(1);
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let y = y1.min(y2);
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debug_assert!(y.get() >= 0,);
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let border = Shifted::new(rr.width.get());
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const ONE: Shifted = Shifted::ONE;
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const ZERO: Shifted = Shifted(0);
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let anti_alias = |x1: Shifted, x2: Shifted, process_pixel: &mut dyn FnMut(usize, u32)| {
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// x1 and x2 are the coordinate on the top and bottom of the intersection of the pixel
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// line and the curve.
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// `process_pixel` be called for the coordinate in the array and a coverage between 0..255
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// This algorithm just go linearly which is not perfect, but good enough.
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for x in x1.floor()..x2.ceil() {
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// the coverage is basically how much of the pixel should be used
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let cov = ((ONE + Shifted::new(x) - x1).0 << 8) / (ONE + x2 - x1).0;
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process_pixel(x as usize, cov);
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}
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};
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let rev = |x: Shifted| {
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(Shifted::new(width) + Shifted::new(rr.right_clip.get() + extra_right_clip))
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.saturating_sub(x)
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};
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let calculate_xxxx = |r: i16, y: i16| {
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let r = Shifted::new(r);
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// `y` is how far away from the center of the circle the current line is.
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let y = r - Shifted::new(y);
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// Circle equation: x = √(r² - y²)
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// Coordinate from the left edge: x' = r - x
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let x2 = r - (r * r).saturating_sub(y * y).sqrt();
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let x1 = r - (r * r).saturating_sub((y - ONE) * (y - ONE)).sqrt();
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let r2 = r.saturating_sub(border);
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let x4 = r - (r2 * r2).saturating_sub(y * y).sqrt();
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let x3 = r - (r2 * r2).saturating_sub((y - ONE) * (y - ONE)).sqrt();
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(x1, x2, x3, x4)
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};
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let (x1, x2, x3, x4, x5, x6, x7, x8) = if let Some(r) = rr.radius.as_uniform() {
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let (x1, x2, x3, x4) =
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if y.get() < r { calculate_xxxx(r, y.get()) } else { (ZERO, ZERO, border, border) };
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(x1, x2, x3, x4, rev(x4), rev(x3), rev(x2), rev(x1))
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} else {
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let (x1, x2, x3, x4) = if y1 < PhysicalLength::new(rr.radius.top_left) {
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calculate_xxxx(rr.radius.top_left, y.get())
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} else if y2 < PhysicalLength::new(rr.radius.bottom_left) {
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calculate_xxxx(rr.radius.bottom_left, y.get())
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} else {
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(ZERO, ZERO, border, border)
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};
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let (x5, x6, x7, x8) = if y1 < PhysicalLength::new(rr.radius.top_right) {
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let x = calculate_xxxx(rr.radius.top_right, y.get());
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(x.3, x.2, x.1, x.0)
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} else if y2 < PhysicalLength::new(rr.radius.bottom_right) {
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let x = calculate_xxxx(rr.radius.bottom_right, y.get());
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(x.3, x.2, x.1, x.0)
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} else {
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(border, border, ZERO, ZERO)
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};
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(x1, x2, x3, x4, rev(x5), rev(x6), rev(x7), rev(x8))
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};
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anti_alias(
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x1.saturating_sub(Shifted::new(rr.left_clip.get() + extra_left_clip)),
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x2.saturating_sub(Shifted::new(rr.left_clip.get() + extra_left_clip)),
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&mut |x, cov| {
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if x >= width {
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return;
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}
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let c = if border == ZERO { rr.inner_color } else { rr.border_color };
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let col = PremultipliedRgbaColor {
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alpha: (((c.alpha as u32) * cov as u32) / 255) as u8,
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red: (((c.red as u32) * cov as u32) / 255) as u8,
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green: (((c.green as u32) * cov as u32) / 255) as u8,
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blue: (((c.blue as u32) * cov as u32) / 255) as u8,
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};
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line_buffer[x].blend(col);
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},
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);
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if y < rr.width {
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// up or down border (x2 .. x7)
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let l = x2
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.ceil()
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.saturating_sub((rr.left_clip.get() + extra_left_clip) as u32)
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.min(width as u32) as usize;
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let r = x7.floor().min(width as u32) as usize;
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if l < r {
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TargetPixel::blend_slice(&mut line_buffer[l..r], rr.border_color)
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}
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} else {
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if border > ZERO {
|
|
// 3. draw the border (between x2 and x3)
|
|
if ONE + x2 <= x3 {
|
|
TargetPixel::blend_slice(
|
|
&mut line_buffer[x2
|
|
.ceil()
|
|
.saturating_sub((rr.left_clip.get() + extra_left_clip) as u32)
|
|
.min(width as u32) as usize
|
|
..x3.floor()
|
|
.saturating_sub((rr.left_clip.get() + extra_left_clip) as u32)
|
|
.min(width as u32) as usize],
|
|
rr.border_color,
|
|
)
|
|
}
|
|
// 4. anti-aliasing for the contents (x3 .. x4)
|
|
anti_alias(
|
|
x3.saturating_sub(Shifted::new(rr.left_clip.get() + extra_left_clip)),
|
|
x4.saturating_sub(Shifted::new(rr.left_clip.get() + extra_left_clip)),
|
|
&mut |x, cov| {
|
|
if x >= width {
|
|
return;
|
|
}
|
|
let col = interpolate_color(cov, rr.border_color, rr.inner_color);
|
|
line_buffer[x].blend(col);
|
|
},
|
|
);
|
|
}
|
|
if rr.inner_color.alpha > 0 {
|
|
// 5. inside (x4 .. x5)
|
|
let begin = x4
|
|
.ceil()
|
|
.saturating_sub((rr.left_clip.get() + extra_left_clip) as u32)
|
|
.min(width as u32);
|
|
let end = x5.floor().min(width as u32);
|
|
if begin < end {
|
|
TargetPixel::blend_slice(
|
|
&mut line_buffer[begin as usize..end as usize],
|
|
rr.inner_color,
|
|
)
|
|
}
|
|
}
|
|
if border > ZERO {
|
|
// 6. border anti-aliasing: x5..x6
|
|
anti_alias(x5, x6, &mut |x, cov| {
|
|
if x >= width {
|
|
return;
|
|
}
|
|
let col = interpolate_color(cov, rr.inner_color, rr.border_color);
|
|
line_buffer[x].blend(col)
|
|
});
|
|
// 7. border x6 .. x7
|
|
if ONE + x6 <= x7 {
|
|
TargetPixel::blend_slice(
|
|
&mut line_buffer[x6.ceil().min(width as u32) as usize
|
|
..x7.floor().min(width as u32) as usize],
|
|
rr.border_color,
|
|
)
|
|
}
|
|
}
|
|
}
|
|
anti_alias(x7, x8, &mut |x, cov| {
|
|
if x >= width {
|
|
return;
|
|
}
|
|
let c = if border == ZERO { rr.inner_color } else { rr.border_color };
|
|
let col = PremultipliedRgbaColor {
|
|
alpha: (((c.alpha as u32) * (255 - cov) as u32) / 255) as u8,
|
|
red: (((c.red as u32) * (255 - cov) as u32) / 255) as u8,
|
|
green: (((c.green as u32) * (255 - cov) as u32) / 255) as u8,
|
|
blue: (((c.blue as u32) * (255 - cov) as u32) / 255) as u8,
|
|
};
|
|
line_buffer[x].blend(col);
|
|
});
|
|
}
|
|
|
|
// a is between 0 and 255. When 0, we get color1, when 255 we get color2
|
|
fn interpolate_color(
|
|
a: u32,
|
|
color1: PremultipliedRgbaColor,
|
|
color2: PremultipliedRgbaColor,
|
|
) -> PremultipliedRgbaColor {
|
|
let b = 255 - a;
|
|
|
|
let al1 = color1.alpha as u32;
|
|
let al2 = color2.alpha as u32;
|
|
|
|
let a_ = a * al2;
|
|
let b_ = b * al1;
|
|
let m = a_ + b_;
|
|
|
|
if m == 0 {
|
|
return PremultipliedRgbaColor::default();
|
|
}
|
|
|
|
PremultipliedRgbaColor {
|
|
alpha: (m / 255) as u8,
|
|
red: ((b * color1.red as u32 + a * color2.red as u32) / 255) as u8,
|
|
green: ((b * color1.green as u32 + a * color2.green as u32) / 255) as u8,
|
|
blue: ((b * color1.blue as u32 + a * color2.blue as u32) / 255) as u8,
|
|
}
|
|
}
|
|
|
|
pub(super) fn draw_gradient_line(
|
|
rect: &PhysicalRect,
|
|
line: PhysicalLength,
|
|
g: &super::GradientCommand,
|
|
mut buffer: &mut [impl TargetPixel],
|
|
extra_left_clip: i16,
|
|
) {
|
|
let fill_col1 = g.flags & 0b010 != 0;
|
|
let fill_col2 = g.flags & 0b100 != 0;
|
|
let invert_slope = g.flags & 0b1 != 0;
|
|
|
|
let y = (line.get() - rect.min_y() + g.top_clip.get()) as i32;
|
|
let size_y = (rect.height() + g.top_clip.get() + g.bottom_clip.get()) as i32;
|
|
let start = g.start as i32;
|
|
|
|
let (mut color1, mut color2) = (g.color1, g.color2);
|
|
|
|
if g.start == 0 {
|
|
let p = if invert_slope {
|
|
(255 - start) * y / size_y
|
|
} else {
|
|
start + (255 - start) * y / size_y
|
|
};
|
|
if (fill_col1 || p >= 0) && (fill_col2 || p < 255) {
|
|
let col = interpolate_color(p.clamp(0, 255) as u32, color1, color2);
|
|
TargetPixel::blend_slice(buffer, col);
|
|
}
|
|
return;
|
|
}
|
|
|
|
let size_x = (rect.width() + g.left_clip.get() + g.right_clip.get()) as i32;
|
|
|
|
let mut x = if invert_slope {
|
|
(y * size_x * (255 - start)) / (size_y * start)
|
|
} else {
|
|
(size_y - y) * size_x * (255 - start) / (size_y * start)
|
|
} + g.left_clip.get() as i32
|
|
+ extra_left_clip as i32;
|
|
|
|
let len = ((255 * size_x) / start) as usize;
|
|
|
|
if x < 0 {
|
|
let l = (-x as usize).min(buffer.len());
|
|
if invert_slope {
|
|
if fill_col1 {
|
|
TargetPixel::blend_slice(&mut buffer[..l], g.color1);
|
|
}
|
|
} else if fill_col2 {
|
|
TargetPixel::blend_slice(&mut buffer[..l], g.color2);
|
|
}
|
|
buffer = &mut buffer[l..];
|
|
x = 0;
|
|
}
|
|
|
|
if buffer.len() + x as usize > len {
|
|
let l = len.saturating_sub(x as usize);
|
|
if invert_slope {
|
|
if fill_col2 {
|
|
TargetPixel::blend_slice(&mut buffer[l..], g.color2);
|
|
}
|
|
} else if fill_col1 {
|
|
TargetPixel::blend_slice(&mut buffer[l..], g.color1);
|
|
}
|
|
buffer = &mut buffer[..l];
|
|
}
|
|
|
|
if buffer.is_empty() {
|
|
return;
|
|
}
|
|
|
|
if !invert_slope {
|
|
core::mem::swap(&mut color1, &mut color2);
|
|
}
|
|
|
|
let dr = (((color2.red as i32 - color1.red as i32) * start) << 15) / (255 * size_x);
|
|
let dg = (((color2.green as i32 - color1.green as i32) * start) << 15) / (255 * size_x);
|
|
let db = (((color2.blue as i32 - color1.blue as i32) * start) << 15) / (255 * size_x);
|
|
let da = (((color2.alpha as i32 - color1.alpha as i32) * start) << 15) / (255 * size_x);
|
|
|
|
let mut r = ((color1.red as u32) << 15).wrapping_add((x * dr) as _);
|
|
let mut g = ((color1.green as u32) << 15).wrapping_add((x * dg) as _);
|
|
let mut b = ((color1.blue as u32) << 15).wrapping_add((x * db) as _);
|
|
let mut a = ((color1.alpha as u32) << 15).wrapping_add((x * da) as _);
|
|
|
|
if color1.alpha == 255 && color2.alpha == 255 {
|
|
buffer.fill_with(|| {
|
|
let pix = TargetPixel::from_rgb((r >> 15) as u8, (g >> 15) as u8, (b >> 15) as u8);
|
|
r = r.wrapping_add(dr as _);
|
|
g = g.wrapping_add(dg as _);
|
|
b = b.wrapping_add(db as _);
|
|
pix
|
|
})
|
|
} else {
|
|
for pix in buffer {
|
|
pix.blend(PremultipliedRgbaColor {
|
|
red: (r >> 15) as u8,
|
|
green: (g >> 15) as u8,
|
|
blue: (b >> 15) as u8,
|
|
alpha: (a >> 15) as u8,
|
|
});
|
|
r = r.wrapping_add(dr as _);
|
|
g = g.wrapping_add(dg as _);
|
|
b = b.wrapping_add(db as _);
|
|
a = a.wrapping_add(da as _);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// A color whose component have been pre-multiplied by alpha
|
|
///
|
|
/// The renderer operates faster on pre-multiplied color since it
|
|
/// caches the multiplication of its component
|
|
///
|
|
/// PremultipliedRgbaColor can be constructed from a [`Color`] with
|
|
/// the [`From`] trait. This conversion will pre-multiply the color
|
|
/// components
|
|
#[allow(missing_docs)]
|
|
#[derive(Clone, Copy, Debug, Default, bytemuck::Pod, bytemuck::Zeroable)]
|
|
#[repr(C)]
|
|
pub struct PremultipliedRgbaColor {
|
|
pub red: u8,
|
|
pub green: u8,
|
|
pub blue: u8,
|
|
pub alpha: u8,
|
|
}
|
|
|
|
/// Convert a non-premultiplied color to a premultiplied one
|
|
impl From<Color> for PremultipliedRgbaColor {
|
|
fn from(col: Color) -> Self {
|
|
Self::premultiply(col)
|
|
}
|
|
}
|
|
|
|
impl PremultipliedRgbaColor {
|
|
/// Convert a non premultiplied color to a premultiplied one
|
|
fn premultiply(col: Color) -> Self {
|
|
let a = col.alpha() as u16;
|
|
Self {
|
|
alpha: col.alpha(),
|
|
red: (col.red() as u16 * a / 255) as u8,
|
|
green: (col.green() as u16 * a / 255) as u8,
|
|
blue: (col.blue() as u16 * a / 255) as u8,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Trait for the pixels in the buffer
|
|
pub trait TargetPixel: Sized + Copy {
|
|
/// Blend a single pixel with a color
|
|
fn blend(&mut self, color: PremultipliedRgbaColor);
|
|
/// Blend a color to all the pixel in the slice.
|
|
fn blend_slice(slice: &mut [Self], color: PremultipliedRgbaColor) {
|
|
if color.alpha == u8::MAX {
|
|
slice.fill(Self::from_rgb(color.red, color.green, color.blue))
|
|
} else {
|
|
for x in slice {
|
|
Self::blend(x, color);
|
|
}
|
|
}
|
|
}
|
|
/// Create a pixel from the red, gree, blue component in the range 0..=255
|
|
fn from_rgb(red: u8, green: u8, blue: u8) -> Self;
|
|
|
|
/// Pixel which will be filled as the background in case the slint view has transparency
|
|
fn background() -> Self {
|
|
Self::from_rgb(0, 0, 0)
|
|
}
|
|
}
|
|
|
|
impl TargetPixel for crate::graphics::image::Rgb8Pixel {
|
|
fn blend(&mut self, color: PremultipliedRgbaColor) {
|
|
let a = (u8::MAX - color.alpha) as u16;
|
|
self.r = (self.r as u16 * a / 255) as u8 + color.red;
|
|
self.g = (self.g as u16 * a / 255) as u8 + color.green;
|
|
self.b = (self.b as u16 * a / 255) as u8 + color.blue;
|
|
}
|
|
|
|
fn from_rgb(r: u8, g: u8, b: u8) -> Self {
|
|
Self::new(r, g, b)
|
|
}
|
|
}
|
|
|
|
impl TargetPixel for PremultipliedRgbaColor {
|
|
fn blend(&mut self, color: PremultipliedRgbaColor) {
|
|
let a = (u8::MAX - color.alpha) as u16;
|
|
self.red = (self.red as u16 * a / 255) as u8 + color.red;
|
|
self.green = (self.green as u16 * a / 255) as u8 + color.green;
|
|
self.blue = (self.blue as u16 * a / 255) as u8 + color.blue;
|
|
self.alpha = (self.alpha as u16 + color.alpha as u16
|
|
- (self.alpha as u16 * color.alpha as u16) / 255) as u8;
|
|
}
|
|
|
|
fn from_rgb(r: u8, g: u8, b: u8) -> Self {
|
|
Self { red: r, green: g, blue: b, alpha: 255 }
|
|
}
|
|
|
|
fn background() -> Self {
|
|
Self { red: 0, green: 0, blue: 0, alpha: 0 }
|
|
}
|
|
}
|
|
|
|
/// A 16bit pixel that has 5 red bits, 6 green bits and 5 blue bits
|
|
#[repr(transparent)]
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, Default, bytemuck::Pod, bytemuck::Zeroable)]
|
|
pub struct Rgb565Pixel(pub u16);
|
|
|
|
impl Rgb565Pixel {
|
|
const R_MASK: u16 = 0b1111_1000_0000_0000;
|
|
const G_MASK: u16 = 0b0000_0111_1110_0000;
|
|
const B_MASK: u16 = 0b0000_0000_0001_1111;
|
|
|
|
/// Return the red component as a u8.
|
|
///
|
|
/// The bits are shifted so that the result is between 0 and 255
|
|
fn red(self) -> u8 {
|
|
((self.0 & Self::R_MASK) >> 8) as u8
|
|
}
|
|
/// Return the green component as a u8.
|
|
///
|
|
/// The bits are shifted so that the result is between 0 and 255
|
|
fn green(self) -> u8 {
|
|
((self.0 & Self::G_MASK) >> 3) as u8
|
|
}
|
|
/// Return the blue component as a u8.
|
|
///
|
|
/// The bits are shifted so that the result is between 0 and 255
|
|
fn blue(self) -> u8 {
|
|
((self.0 & Self::B_MASK) << 3) as u8
|
|
}
|
|
}
|
|
|
|
impl TargetPixel for Rgb565Pixel {
|
|
fn blend(&mut self, color: PremultipliedRgbaColor) {
|
|
let a = (u8::MAX - color.alpha) as u32;
|
|
// convert to 5 bits
|
|
let a = (a + 4) >> 3;
|
|
|
|
// 00000ggg_ggg00000_rrrrr000_000bbbbb
|
|
let expanded = (self.0 & (Self::R_MASK | Self::B_MASK)) as u32
|
|
| (((self.0 & Self::G_MASK) as u32) << 16);
|
|
|
|
// gggggggg_000rrrrr_rrr000bb_bbbbbb00
|
|
let c =
|
|
((color.red as u32) << 13) | ((color.green as u32) << 24) | ((color.blue as u32) << 2);
|
|
// gggggg00_000rrrrr_000000bb_bbb00000
|
|
let c = c & 0b11111100_00011111_00000011_11100000;
|
|
|
|
let res = expanded * a + c;
|
|
|
|
self.0 = ((res >> 21) as u16 & Self::G_MASK)
|
|
| ((res >> 5) as u16 & (Self::R_MASK | Self::B_MASK));
|
|
}
|
|
|
|
fn from_rgb(r: u8, g: u8, b: u8) -> Self {
|
|
Self(((r as u16 & 0b11111000) << 8) | ((g as u16 & 0b11111100) << 3) | (b as u16 >> 3))
|
|
}
|
|
}
|
|
|
|
impl From<Rgb8Pixel> for Rgb565Pixel {
|
|
fn from(p: Rgb8Pixel) -> Self {
|
|
Self::from_rgb(p.r, p.g, p.b)
|
|
}
|
|
}
|
|
|
|
impl From<Rgb565Pixel> for Rgb8Pixel {
|
|
fn from(p: Rgb565Pixel) -> Self {
|
|
Rgb8Pixel { r: p.red(), g: p.green(), b: p.blue() }
|
|
}
|
|
}
|
|
|
|
#[test]
|
|
fn rgb565() {
|
|
let pix565 = Rgb565Pixel::from_rgb(0xff, 0x25, 0);
|
|
let pix888: Rgb8Pixel = pix565.into();
|
|
assert_eq!(pix565, pix888.into());
|
|
|
|
let pix565 = Rgb565Pixel::from_rgb(0x56, 0x42, 0xe3);
|
|
let pix888: Rgb8Pixel = pix565.into();
|
|
assert_eq!(pix565, pix888.into());
|
|
}
|