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use super::Image;
#[allow(dead_code)]
pub trait ImageCollect {
/// Populate a vector with pixels where the mask value is non-zero.
///
/// When encountering a zero mask value, then the pixel is ignored.
///
/// Returns an empty vector when no pixels were collected.
fn collect_pixels_as_vec(&self, mask: &Image) -> anyhow::Result<Vec<u8>>;
/// Extract pixels where the mask value is non-zero.
///
/// When encountering a zero mask value, then the pixel is ignored.
///
/// Returns an image that is N pixels wide an 1 pixels tall.
///
/// Returns an error when no pixels were collected.
fn collect_pixels_as_image(&self, mask: &Image) -> anyhow::Result<Image>;
}
impl ImageCollect for Image {
fn collect_pixels_as_vec(&self, mask: &Image) -> anyhow::Result<Vec<u8>> {
if self.size() != mask.size() {
return Err(anyhow::anyhow!("Both images must have same size"));
}
let mut collected_pixels = Vec::<u8>::new();
for y in 0..self.height() {
for x in 0..self.width() {
let mask_value: u8 = mask.get(x as i32, y as i32).unwrap_or(255);
if mask_value == 0 {
continue;
}
let color: u8 = self.get(x as i32, y as i32).unwrap_or(255);
collected_pixels.push(color);
}
}
Ok(collected_pixels)
}
fn collect_pixels_as_image(&self, mask: &Image) -> anyhow::Result<Image> {
let pixels: Vec<u8> = self.collect_pixels_as_vec(mask)?;
if pixels.is_empty() {
return Err(anyhow::anyhow!("Gathered zero pixels"));
}
if pixels.len() > (u8::MAX as usize) {
return Err(anyhow::anyhow!("Gathered more pixels than what can be fitted inside an Image"));
}
let width: u8 = pixels.len() as u8;
let mut result_image = Image::zero(width, 1);
for x in 0..width {
let pixel: u8 = pixels[x as usize];
_ = result_image.set(x as i32, 0, pixel);
}
Ok(result_image)
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::arc::ImageTryCreate;
#[test]
fn test_10000_collect_with_mask() {
// Arrange
let pixels: Vec<u8> = vec![
7, 5, 2, 5, 1,
5, 4, 4, 5, 3,
5, 2, 7, 5, 3,
5, 5, 5, 3, 5,
];
let input: Image = Image::try_create(5, 4, pixels).expect("image");
let mask_pixels: Vec<u8> = vec![
0, 1, 0, 1, 0,
0, 1, 1, 0, 0,
0, 0, 0, 0, 1,
0, 0, 0, 1, 0,
];
let mask: Image = Image::try_create(5, 4, mask_pixels).expect("image");
// Act
let actual: Vec<u8> = input.collect_pixels_as_vec(&mask).expect("ok");
// Assert
assert_eq!(actual, vec![5, 5, 4, 4, 3, 3]);
}
#[test]
fn test_20000_collect_with_mask_as_image() {
// Arrange
let pixels: Vec<u8> = vec![
7, 5, 2, 5, 1,
5, 4, 4, 5, 3,
5, 2, 7, 5, 3,
5, 5, 5, 3, 5,
];
let input: Image = Image::try_create(5, 4, pixels).expect("image");
let mask_pixels: Vec<u8> = vec![
0, 1, 0, 1, 0,
0, 1, 1, 0, 0,
0, 0, 0, 0, 1,
0, 0, 0, 1, 0,
];
let mask: Image = Image::try_create(5, 4, mask_pixels).expect("image");
// Act
let actual: Image = input.collect_pixels_as_image(&mask).expect("ok");
// Assert
let expected_pixels: Vec<u8> = vec![
5, 5, 4, 4, 3, 3,
];
let expected: Image = Image::try_create(6, 1, expected_pixels).expect("image");
assert_eq!(actual, expected);
}
#[test]
fn test_20001_collect_with_mask_as_image_zero_pixels() {
// Arrange
let pixels: Vec<u8> = vec![
7, 5, 2, 5, 1,
5, 4, 4, 5, 3,
5, 2, 7, 5, 3,
5, 5, 5, 3, 5,
];
let input: Image = Image::try_create(5, 4, pixels).expect("image");
let mask_pixels: Vec<u8> = vec![
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
0, 0, 0, 0, 0,
];
let mask: Image = Image::try_create(5, 4, mask_pixels).expect("image");
// Act
let error = input.collect_pixels_as_image(&mask).expect_err("is supposed to fail");
// Assert
let message: String = format!("{:?}", error);
assert_eq!(message.contains("Gathered zero pixels"), true);
}
}
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