use super::*;
pub(super) fn load_overrides(
assignments: &[String],
width: u32,
height: u32,
) -> Result<Vec<(String, Vec<u8>)>> {
let mut result = Vec::new();
for assignment in assignments {
let (name, path) = split_assignment(assignment)?;
let image = ImageReader::open(path)
.with_context(|| format!("failed to open buffer override {}", path.display()))?
.decode()
.with_context(|| format!("failed to decode buffer override {}", path.display()))?
.to_rgba8();
let dimensions = image.dimensions();
if dimensions != (width, height) {
bail!(
"buffer override '{}' is {}x{} but render is {}x{}; use an exact-size image",
name,
dimensions.0,
dimensions.1,
width,
height
);
}
let mut rgba = image.into_raw();
flip_rgba_rows(&mut rgba, width, height);
result.push((name.to_string(), rgba));
}
Ok(result)
}
pub(super) fn split_assignment(value: &str) -> Result<(&str, &Path)> {
let (name, path) = value
.split_once('=')
.with_context(|| format!("expected BUFFER=IMAGE, got '{value}'"))?;
if name.trim().is_empty() || path.trim().is_empty() {
bail!("expected non-empty BUFFER=IMAGE assignment, got '{value}'");
}
Ok((name.trim(), Path::new(path.trim())))
}
pub(super) fn save_rgb_png(image: &RgbImage, output: &Path) -> Result<()> {
let mut pixels = image.pixels.clone();
flip_rgb_rows(&mut pixels, image.width, image.height);
::image::save_buffer(
output,
&pixels,
image.width,
image.height,
::image::ColorType::Rgb8,
)
.with_context(|| format!("failed to write PNG {}", output.display()))
}
pub fn rgb_png_bytes(image: &RgbImage) -> Result<Vec<u8>> {
let mut pixels = image.pixels.clone();
flip_rgb_rows(&mut pixels, image.width, image.height);
let mut cursor = std::io::Cursor::new(Vec::new());
::image::write_buffer_with_format(
&mut cursor,
&pixels,
image.width,
image.height,
::image::ColorType::Rgb8,
::image::ImageFormat::Png,
)
.context("failed to encode preview PNG")?;
Ok(cursor.into_inner())
}
pub fn flip_rgb_rows(data: &mut [u8], width: u32, height: u32) {
flip_rows(data, width, height, 3);
}
pub(super) fn flip_rgba_rows(data: &mut [u8], width: u32, height: u32) {
flip_rows(data, width, height, 4);
}
fn flip_rows(data: &mut [u8], width: u32, height: u32, channels: usize) {
let Some(row) = (width as usize).checked_mul(channels) else {
debug_assert!(false, "row size overflow");
return;
};
let Some(expected_len) = row.checked_mul(height as usize) else {
debug_assert!(false, "image size overflow");
return;
};
debug_assert_eq!(data.len(), expected_len);
for y in 0..(height as usize / 2) {
let opposite = height as usize - 1 - y;
let (before_opposite, opposite_and_after) = data.split_at_mut(opposite * row);
let top = &mut before_opposite[y * row..(y + 1) * row];
let bottom = &mut opposite_and_after[..row];
top.swap_with_slice(bottom);
}
}