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Diffstat (limited to 'vendor/image/src/imageops/mod.rs')
| -rw-r--r-- | vendor/image/src/imageops/mod.rs | 485 |
1 files changed, 485 insertions, 0 deletions
diff --git a/vendor/image/src/imageops/mod.rs b/vendor/image/src/imageops/mod.rs new file mode 100644 index 0000000..fdd2bf3 --- /dev/null +++ b/vendor/image/src/imageops/mod.rs @@ -0,0 +1,485 @@ +//! Image Processing Functions +use std::cmp; + +use crate::image::{GenericImage, GenericImageView, SubImage}; +use crate::traits::{Lerp, Pixel, Primitive}; + +pub use self::sample::FilterType; + +pub use self::sample::FilterType::{CatmullRom, Gaussian, Lanczos3, Nearest, Triangle}; + +/// Affine transformations +pub use self::affine::{ + flip_horizontal, flip_horizontal_in, flip_horizontal_in_place, flip_vertical, flip_vertical_in, + flip_vertical_in_place, rotate180, rotate180_in, rotate180_in_place, rotate270, rotate270_in, + rotate90, rotate90_in, +}; + +/// Image sampling +pub use self::sample::{ + blur, filter3x3, interpolate_bilinear, interpolate_nearest, resize, sample_bilinear, + sample_nearest, thumbnail, unsharpen, +}; + +/// Color operations +pub use self::colorops::{ + brighten, contrast, dither, grayscale, grayscale_alpha, grayscale_with_type, + grayscale_with_type_alpha, huerotate, index_colors, invert, BiLevel, ColorMap, +}; + +mod affine; +// Public only because of Rust bug: +// https://github.com/rust-lang/rust/issues/18241 +pub mod colorops; +mod sample; + +/// Return a mutable view into an image +/// The coordinates set the position of the top left corner of the crop. +pub fn crop<I: GenericImageView>( + image: &mut I, + x: u32, + y: u32, + width: u32, + height: u32, +) -> SubImage<&mut I> { + let (x, y, width, height) = crop_dimms(image, x, y, width, height); + SubImage::new(image, x, y, width, height) +} + +/// Return an immutable view into an image +/// The coordinates set the position of the top left corner of the crop. +pub fn crop_imm<I: GenericImageView>( + image: &I, + x: u32, + y: u32, + width: u32, + height: u32, +) -> SubImage<&I> { + let (x, y, width, height) = crop_dimms(image, x, y, width, height); + SubImage::new(image, x, y, width, height) +} + +fn crop_dimms<I: GenericImageView>( + image: &I, + x: u32, + y: u32, + width: u32, + height: u32, +) -> (u32, u32, u32, u32) { + let (iwidth, iheight) = image.dimensions(); + + let x = cmp::min(x, iwidth); + let y = cmp::min(y, iheight); + + let height = cmp::min(height, iheight - y); + let width = cmp::min(width, iwidth - x); + + (x, y, width, height) +} + +/// Calculate the region that can be copied from top to bottom. +/// +/// Given image size of bottom and top image, and a point at which we want to place the top image +/// onto the bottom image, how large can we be? Have to wary of the following issues: +/// * Top might be larger than bottom +/// * Overflows in the computation +/// * Coordinates could be completely out of bounds +/// +/// The main idea is to make use of inequalities provided by the nature of `saturating_add` and +/// `saturating_sub`. These intrinsically validate that all resulting coordinates will be in bounds +/// for both images. +/// +/// We want that all these coordinate accesses are safe: +/// 1. `bottom.get_pixel(x + [0..x_range), y + [0..y_range))` +/// 2. `top.get_pixel([0..x_range), [0..y_range))` +/// +/// Proof that the function provides the necessary bounds for width. Note that all unaugmented math +/// operations are to be read in standard arithmetic, not integer arithmetic. Since no direct +/// integer arithmetic occurs in the implementation, this is unambiguous. +/// +/// ```text +/// Three short notes/lemmata: +/// - Iff `(a - b) <= 0` then `a.saturating_sub(b) = 0` +/// - Iff `(a - b) >= 0` then `a.saturating_sub(b) = a - b` +/// - If `a <= c` then `a.saturating_sub(b) <= c.saturating_sub(b)` +/// +/// 1.1 We show that if `bottom_width <= x`, then `x_range = 0` therefore `x + [0..x_range)` is empty. +/// +/// x_range +/// = (top_width.saturating_add(x).min(bottom_width)).saturating_sub(x) +/// <= bottom_width.saturating_sub(x) +/// +/// bottom_width <= x +/// <==> bottom_width - x <= 0 +/// <==> bottom_width.saturating_sub(x) = 0 +/// ==> x_range <= 0 +/// ==> x_range = 0 +/// +/// 1.2 If `x < bottom_width` then `x + x_range < bottom_width` +/// +/// x + x_range +/// <= x + bottom_width.saturating_sub(x) +/// = x + (bottom_width - x) +/// = bottom_width +/// +/// 2. We show that `x_range <= top_width` +/// +/// x_range +/// = (top_width.saturating_add(x).min(bottom_width)).saturating_sub(x) +/// <= top_width.saturating_add(x).saturating_sub(x) +/// <= (top_wdith + x).saturating_sub(x) +/// = top_width (due to `top_width >= 0` and `x >= 0`) +/// ``` +/// +/// Proof is the same for height. +pub fn overlay_bounds( + (bottom_width, bottom_height): (u32, u32), + (top_width, top_height): (u32, u32), + x: u32, + y: u32, +) -> (u32, u32) { + let x_range = top_width + .saturating_add(x) // Calculate max coordinate + .min(bottom_width) // Restrict to lower width + .saturating_sub(x); // Determinate length from start `x` + let y_range = top_height + .saturating_add(y) + .min(bottom_height) + .saturating_sub(y); + (x_range, y_range) +} + +/// Calculate the region that can be copied from top to bottom. +/// +/// Given image size of bottom and top image, and a point at which we want to place the top image +/// onto the bottom image, how large can we be? Have to wary of the following issues: +/// * Top might be larger than bottom +/// * Overflows in the computation +/// * Coordinates could be completely out of bounds +/// +/// The returned value is of the form: +/// +/// `(origin_bottom_x, origin_bottom_y, origin_top_x, origin_top_y, x_range, y_range)` +/// +/// The main idea is to do computations on i64's and then clamp to image dimensions. +/// In particular, we want to ensure that all these coordinate accesses are safe: +/// 1. `bottom.get_pixel(origin_bottom_x + [0..x_range), origin_bottom_y + [0..y_range))` +/// 2. `top.get_pixel(origin_top_y + [0..x_range), origin_top_y + [0..y_range))` +/// +fn overlay_bounds_ext( + (bottom_width, bottom_height): (u32, u32), + (top_width, top_height): (u32, u32), + x: i64, + y: i64, +) -> (u32, u32, u32, u32, u32, u32) { + // Return a predictable value if the two images don't overlap at all. + if x > i64::from(bottom_width) + || y > i64::from(bottom_height) + || x.saturating_add(i64::from(top_width)) <= 0 + || y.saturating_add(i64::from(top_height)) <= 0 + { + return (0, 0, 0, 0, 0, 0); + } + + // Find the maximum x and y coordinates in terms of the bottom image. + let max_x = x.saturating_add(i64::from(top_width)); + let max_y = y.saturating_add(i64::from(top_height)); + + // Clip the origin and maximum coordinates to the bounds of the bottom image. + // Casting to a u32 is safe because both 0 and `bottom_{width,height}` fit + // into 32-bits. + let max_inbounds_x = max_x.clamp(0, i64::from(bottom_width)) as u32; + let max_inbounds_y = max_y.clamp(0, i64::from(bottom_height)) as u32; + let origin_bottom_x = x.clamp(0, i64::from(bottom_width)) as u32; + let origin_bottom_y = y.clamp(0, i64::from(bottom_height)) as u32; + + // The range is the difference between the maximum inbounds coordinates and + // the clipped origin. Unchecked subtraction is safe here because both are + // always positive and `max_inbounds_{x,y}` >= `origin_{x,y}` due to + // `top_{width,height}` being >= 0. + let x_range = max_inbounds_x - origin_bottom_x; + let y_range = max_inbounds_y - origin_bottom_y; + + // If x (or y) is negative, then the origin of the top image is shifted by -x (or -y). + let origin_top_x = x.saturating_mul(-1).clamp(0, i64::from(top_width)) as u32; + let origin_top_y = y.saturating_mul(-1).clamp(0, i64::from(top_height)) as u32; + + ( + origin_bottom_x, + origin_bottom_y, + origin_top_x, + origin_top_y, + x_range, + y_range, + ) +} + +/// Overlay an image at a given coordinate (x, y) +pub fn overlay<I, J>(bottom: &mut I, top: &J, x: i64, y: i64) +where + I: GenericImage, + J: GenericImageView<Pixel = I::Pixel>, +{ + let bottom_dims = bottom.dimensions(); + let top_dims = top.dimensions(); + + // Crop our top image if we're going out of bounds + let (origin_bottom_x, origin_bottom_y, origin_top_x, origin_top_y, range_width, range_height) = + overlay_bounds_ext(bottom_dims, top_dims, x, y); + + for y in 0..range_height { + for x in 0..range_width { + let p = top.get_pixel(origin_top_x + x, origin_top_y + y); + let mut bottom_pixel = bottom.get_pixel(origin_bottom_x + x, origin_bottom_y + y); + bottom_pixel.blend(&p); + + bottom.put_pixel(origin_bottom_x + x, origin_bottom_y + y, bottom_pixel); + } + } +} + +/// Tile an image by repeating it multiple times +/// +/// # Examples +/// ```no_run +/// use image::{RgbaImage}; +/// +/// let mut img = RgbaImage::new(1920, 1080); +/// let tile = image::open("tile.png").unwrap(); +/// +/// image::imageops::tile(&mut img, &tile); +/// img.save("tiled_wallpaper.png").unwrap(); +/// ``` +pub fn tile<I, J>(bottom: &mut I, top: &J) +where + I: GenericImage, + J: GenericImageView<Pixel = I::Pixel>, +{ + for x in (0..bottom.width()).step_by(top.width() as usize) { + for y in (0..bottom.height()).step_by(top.height() as usize) { + overlay(bottom, top, i64::from(x), i64::from(y)); + } + } +} + +/// Fill the image with a linear vertical gradient +/// +/// This function assumes a linear color space. +/// +/// # Examples +/// ```no_run +/// use image::{Rgba, RgbaImage, Pixel}; +/// +/// let mut img = RgbaImage::new(100, 100); +/// let start = Rgba::from_slice(&[0, 128, 0, 0]); +/// let end = Rgba::from_slice(&[255, 255, 255, 255]); +/// +/// image::imageops::vertical_gradient(&mut img, start, end); +/// img.save("vertical_gradient.png").unwrap(); +pub fn vertical_gradient<S, P, I>(img: &mut I, start: &P, stop: &P) +where + I: GenericImage<Pixel = P>, + P: Pixel<Subpixel = S> + 'static, + S: Primitive + Lerp + 'static, +{ + for y in 0..img.height() { + let pixel = start.map2(stop, |a, b| { + let y = <S::Ratio as num_traits::NumCast>::from(y).unwrap(); + let height = <S::Ratio as num_traits::NumCast>::from(img.height() - 1).unwrap(); + S::lerp(a, b, y / height) + }); + + for x in 0..img.width() { + img.put_pixel(x, y, pixel); + } + } +} + +/// Fill the image with a linear horizontal gradient +/// +/// This function assumes a linear color space. +/// +/// # Examples +/// ```no_run +/// use image::{Rgba, RgbaImage, Pixel}; +/// +/// let mut img = RgbaImage::new(100, 100); +/// let start = Rgba::from_slice(&[0, 128, 0, 0]); +/// let end = Rgba::from_slice(&[255, 255, 255, 255]); +/// +/// image::imageops::horizontal_gradient(&mut img, start, end); +/// img.save("horizontal_gradient.png").unwrap(); +pub fn horizontal_gradient<S, P, I>(img: &mut I, start: &P, stop: &P) +where + I: GenericImage<Pixel = P>, + P: Pixel<Subpixel = S> + 'static, + S: Primitive + Lerp + 'static, +{ + for x in 0..img.width() { + let pixel = start.map2(stop, |a, b| { + let x = <S::Ratio as num_traits::NumCast>::from(x).unwrap(); + let width = <S::Ratio as num_traits::NumCast>::from(img.width() - 1).unwrap(); + S::lerp(a, b, x / width) + }); + + for y in 0..img.height() { + img.put_pixel(x, y, pixel); + } + } +} + +/// Replace the contents of an image at a given coordinate (x, y) +pub fn replace<I, J>(bottom: &mut I, top: &J, x: i64, y: i64) +where + I: GenericImage, + J: GenericImageView<Pixel = I::Pixel>, +{ + let bottom_dims = bottom.dimensions(); + let top_dims = top.dimensions(); + + // Crop our top image if we're going out of bounds + let (origin_bottom_x, origin_bottom_y, origin_top_x, origin_top_y, range_width, range_height) = + overlay_bounds_ext(bottom_dims, top_dims, x, y); + + for y in 0..range_height { + for x in 0..range_width { + let p = top.get_pixel(origin_top_x + x, origin_top_y + y); + bottom.put_pixel(origin_bottom_x + x, origin_bottom_y + y, p); + } + } +} + +#[cfg(test)] +mod tests { + + use super::{overlay, overlay_bounds_ext}; + use crate::color::Rgb; + use crate::ImageBuffer; + use crate::RgbaImage; + + #[test] + fn test_overlay_bounds_ext() { + assert_eq!( + overlay_bounds_ext((10, 10), (10, 10), 0, 0), + (0, 0, 0, 0, 10, 10) + ); + assert_eq!( + overlay_bounds_ext((10, 10), (10, 10), 1, 0), + (1, 0, 0, 0, 9, 10) + ); + assert_eq!( + overlay_bounds_ext((10, 10), (10, 10), 0, 11), + (0, 0, 0, 0, 0, 0) + ); + assert_eq!( + overlay_bounds_ext((10, 10), (10, 10), -1, 0), + (0, 0, 1, 0, 9, 10) + ); + assert_eq!( + overlay_bounds_ext((10, 10), (10, 10), -10, 0), + (0, 0, 0, 0, 0, 0) + ); + assert_eq!( + overlay_bounds_ext((10, 10), (10, 10), 1i64 << 50, 0), + (0, 0, 0, 0, 0, 0) + ); + assert_eq!( + overlay_bounds_ext((10, 10), (10, 10), -(1i64 << 50), 0), + (0, 0, 0, 0, 0, 0) + ); + assert_eq!( + overlay_bounds_ext((10, 10), (u32::MAX, 10), 10 - i64::from(u32::MAX), 0), + (0, 0, u32::MAX - 10, 0, 10, 10) + ); + } + + #[test] + /// Test that images written into other images works + fn test_image_in_image() { + let mut target = ImageBuffer::new(32, 32); + let source = ImageBuffer::from_pixel(16, 16, Rgb([255u8, 0, 0])); + overlay(&mut target, &source, 0, 0); + assert!(*target.get_pixel(0, 0) == Rgb([255u8, 0, 0])); + assert!(*target.get_pixel(15, 0) == Rgb([255u8, 0, 0])); + assert!(*target.get_pixel(16, 0) == Rgb([0u8, 0, 0])); + assert!(*target.get_pixel(0, 15) == Rgb([255u8, 0, 0])); + assert!(*target.get_pixel(0, 16) == Rgb([0u8, 0, 0])); + } + + #[test] + /// Test that images written outside of a frame doesn't blow up + fn test_image_in_image_outside_of_bounds() { + let mut target = ImageBuffer::new(32, 32); + let source = ImageBuffer::from_pixel(32, 32, Rgb([255u8, 0, 0])); + overlay(&mut target, &source, 1, 1); + assert!(*target.get_pixel(0, 0) == Rgb([0, 0, 0])); + assert!(*target.get_pixel(1, 1) == Rgb([255u8, 0, 0])); + assert!(*target.get_pixel(31, 31) == Rgb([255u8, 0, 0])); + } + + #[test] + /// Test that images written to coordinates out of the frame doesn't blow up + /// (issue came up in #848) + fn test_image_outside_image_no_wrap_around() { + let mut target = ImageBuffer::new(32, 32); + let source = ImageBuffer::from_pixel(32, 32, Rgb([255u8, 0, 0])); + overlay(&mut target, &source, 33, 33); + assert!(*target.get_pixel(0, 0) == Rgb([0, 0, 0])); + assert!(*target.get_pixel(1, 1) == Rgb([0, 0, 0])); + assert!(*target.get_pixel(31, 31) == Rgb([0, 0, 0])); + } + + #[test] + /// Test that images written to coordinates with overflow works + fn test_image_coordinate_overflow() { + let mut target = ImageBuffer::new(16, 16); + let source = ImageBuffer::from_pixel(32, 32, Rgb([255u8, 0, 0])); + // Overflows to 'sane' coordinates but top is larger than bot. + overlay( + &mut target, + &source, + i64::from(u32::max_value() - 31), + i64::from(u32::max_value() - 31), + ); + assert!(*target.get_pixel(0, 0) == Rgb([0, 0, 0])); + assert!(*target.get_pixel(1, 1) == Rgb([0, 0, 0])); + assert!(*target.get_pixel(15, 15) == Rgb([0, 0, 0])); + } + + use super::{horizontal_gradient, vertical_gradient}; + + #[test] + /// Test that horizontal gradients are correctly generated + fn test_image_horizontal_gradient_limits() { + let mut img = ImageBuffer::new(100, 1); + + let start = Rgb([0u8, 128, 0]); + let end = Rgb([255u8, 255, 255]); + + horizontal_gradient(&mut img, &start, &end); + + assert_eq!(img.get_pixel(0, 0), &start); + assert_eq!(img.get_pixel(img.width() - 1, 0), &end); + } + + #[test] + /// Test that vertical gradients are correctly generated + fn test_image_vertical_gradient_limits() { + let mut img = ImageBuffer::new(1, 100); + + let start = Rgb([0u8, 128, 0]); + let end = Rgb([255u8, 255, 255]); + + vertical_gradient(&mut img, &start, &end); + + assert_eq!(img.get_pixel(0, 0), &start); + assert_eq!(img.get_pixel(0, img.height() - 1), &end); + } + + #[test] + /// Test blur doesn't panick when passed 0.0 + fn test_blur_zero() { + let image = RgbaImage::new(50, 50); + let _ = super::blur(&image, 0.0); + } +} |