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diff --git a/third_party/rust/image/src/imageops/mod.rs b/third_party/rust/image/src/imageops/mod.rs
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+++ b/third_party/rust/image/src/imageops/mod.rs
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+//! Image Processing Functions
+use std::cmp;
+
+use crate::image::{GenericImage, GenericImageView, SubImage};
+
+use crate::buffer::Pixel;
+
+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_place, flip_vertical, flip_vertical_in_place, rotate180,
+    rotate180_in_place, rotate270, rotate90, rotate180_in, rotate90_in, rotate270_in, flip_horizontal_in, flip_vertical_in
+};
+
+/// Image sampling
+pub use self::sample::{blur, filter3x3, resize, thumbnail, unsharpen};
+
+/// Color operations
+pub use self::colorops::{brighten, contrast, dither, grayscale, 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
+pub fn crop<I: GenericImageView>(
+    image: &mut I,
+    x: u32,
+    y: u32,
+    width: u32,
+    height: u32,
+) -> SubImage<&mut I> {
+    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);
+
+    SubImage::new(image, 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 `saturing_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)
+}
+
+/// Overlay an image at a given coordinate (x, y)
+pub fn overlay<I, J>(bottom: &mut I, top: &J, x: u32, y: u32)
+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 (range_width, range_height) = overlay_bounds(bottom_dims, top_dims, x, y);
+
+    for top_y in 0..range_height {
+        for top_x in 0..range_width {
+            let p = top.get_pixel(top_x, top_y);
+            let mut bottom_pixel = bottom.get_pixel(x + top_x, y + top_y);
+            bottom_pixel.blend(&p);
+
+            bottom.put_pixel(x + top_x, y + top_y, bottom_pixel);
+        }
+    }
+}
+
+/// Replace the contents of an image at a given coordinate (x, y)
+pub fn replace<I, J>(bottom: &mut I, top: &J, x: u32, y: u32)
+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 (range_width, range_height) = overlay_bounds(bottom_dims, top_dims, x, y);
+
+    for top_y in 0..range_height {
+        for top_x in 0..range_width {
+            let p = top.get_pixel(top_x, top_y);
+            bottom.put_pixel(x + top_x, y + top_y, p);
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::overlay;
+    use crate::buffer::ImageBuffer;
+    use crate::color::Rgb;
+
+    #[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, u32::max_value() - 31, 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]));
+    }
+}