Fixed error in implementation of ImageView::split_by_width(), ImageView::split_by_height(), ImageViewMut::split_by_width_mut() and ImageViewMut::split_by_height_mut()(#43).

2026-10-08 01:11:09 +00:00 · 2025-01-12 16:54:10 +03:00
parent 5c1f321e44
commit 74ab1beeee
7 changed files with 133 additions and 77 deletions
@@ -1,3 +1,8 @@
+## Fixed
+
+- Fixed error in implementation of `ImageView::split_by_width()`, `ImageView::split_by_height()`,
+  `ImageViewMut::split_by_width_mut()` and `ImageViewMut::split_by_height_mut()`(#43).
+
 ## [5.1.0] - 2024-12-09

 ### Changed
@@ -95,9 +95,9 @@ dependencies = [

 [[package]]
 name = "anyhow"
-version = "1.0.94"
+version = "1.0.95"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c1fd03a028ef38ba2276dce7e33fcd6369c158a1bca17946c4b1b701891c1ff7"
+checksum = "34ac096ce696dc2fcabef30516bb13c0a68a11d30131d3df6f04711467681b04"

 [[package]]
 name = "arbitrary"
@@ -165,9 +165,9 @@ checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"

 [[package]]
 name = "bitflags"
-version = "2.6.0"
+version = "2.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b048fb63fd8b5923fc5aa7b340d8e156aec7ec02f0c78fa8a6ddc2613f6f71de"
+checksum = "1be3f42a67d6d345ecd59f675f3f012d6974981560836e938c22b424b85ce1be"

 [[package]]
 name = "bitstream-io"
@@ -186,9 +186,9 @@ dependencies = [

 [[package]]
 name = "bstr"
-version = "1.11.0"
+version = "1.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1a68f1f47cdf0ec8ee4b941b2eee2a80cb796db73118c0dd09ac63fbe405be22"
+checksum = "531a9155a481e2ee699d4f98f43c0ca4ff8ee1bfd55c31e9e98fb29d2b176fe0"
 dependencies = [
 "memchr",
 "serde",
@@ -208,9 +208,9 @@ checksum = "79296716171880943b8470b5f8d03aa55eb2e645a4874bdbb28adb49162e012c"

 [[package]]
 name = "bytemuck"
-version = "1.20.0"
+version = "1.21.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8b37c88a63ffd85d15b406896cc343916d7cf57838a847b3a6f2ca5d39a5695a"
+checksum = "ef657dfab802224e671f5818e9a4935f9b1957ed18e58292690cc39e7a4092a3"

 [[package]]
 name = "byteorder"
@@ -232,9 +232,9 @@ checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"

 [[package]]
 name = "cc"
-version = "1.2.3"
+version = "1.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "27f657647bcff5394bf56c7317665bbf790a137a50eaaa5c6bfbb9e27a518f2d"
+checksum = "c8293772165d9345bdaaa39b45b2109591e63fe5e6fbc23c6ff930a048aa310b"
 dependencies = [
 "jobserver",
 "libc",
@@ -326,9 +326,9 @@ dependencies = [

 [[package]]
 name = "clap"
-version = "4.5.23"
+version = "4.5.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3135e7ec2ef7b10c6ed8950f0f792ed96ee093fa088608f1c76e569722700c84"
+checksum = "a8eb5e908ef3a6efbe1ed62520fb7287959888c88485abe072543190ecc66783"
 dependencies = [
 "clap_builder",
 "clap_derive",
@@ -346,9 +346,9 @@ dependencies = [

 [[package]]
 name = "clap_builder"
-version = "4.5.23"
+version = "4.5.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "30582fc632330df2bd26877bde0c1f4470d57c582bbc070376afcd04d8cb4838"
+checksum = "96b01801b5fc6a0a232407abc821660c9c6d25a1cafc0d4f85f29fb8d9afc121"
 dependencies = [
 "anstream",
 "anstyle",
@@ -358,9 +358,9 @@ dependencies = [

 [[package]]
 name = "clap_derive"
-version = "4.5.18"
+version = "4.5.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4ac6a0c7b1a9e9a5186361f67dfa1b88213572f427fb9ab038efb2bd8c582dab"
+checksum = "54b755194d6389280185988721fffba69495eed5ee9feeee9a599b53db80318c"
 dependencies = [
 "heck",
 "proc-macro2",
@@ -446,9 +446,9 @@ dependencies = [

 [[package]]
 name = "crossbeam-deque"
-version = "0.8.5"
+version = "0.8.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
+checksum = "9dd111b7b7f7d55b72c0a6ae361660ee5853c9af73f70c3c2ef6858b950e2e51"
 dependencies = [
 "crossbeam-epoch",
 "crossbeam-utils",
@@ -465,9 +465,9 @@ dependencies = [

 [[package]]
 name = "crossbeam-utils"
-version = "0.8.20"
+version = "0.8.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "22ec99545bb0ed0ea7bb9b8e1e9122ea386ff8a48c0922e43f36d45ab09e0e80"
+checksum = "d0a5c400df2834b80a4c3327b3aad3a4c4cd4de0629063962b03235697506a28"

 [[package]]
 name = "crunchy"
@@ -518,9 +518,9 @@ checksum = "60b1af1c220855b6ceac025d3f6ecdd2b7c4894bfe9cd9bda4fbb4bc7c0d4cf0"

 [[package]]
 name = "env_filter"
-version = "0.1.2"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4f2c92ceda6ceec50f43169f9ee8424fe2db276791afde7b2cd8bc084cb376ab"
+checksum = "186e05a59d4c50738528153b83b0b0194d3a29507dfec16eccd4b342903397d0"
 dependencies = [
 "log",
 "regex",
@@ -528,9 +528,9 @@ dependencies = [

 [[package]]
 name = "env_logger"
-version = "0.11.5"
+version = "0.11.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e13fa619b91fb2381732789fc5de83b45675e882f66623b7d8cb4f643017018d"
+checksum = "dcaee3d8e3cfc3fd92428d477bc97fc29ec8716d180c0d74c643bb26166660e0"
 dependencies = [
 "anstream",
 "anstyle",
@@ -570,7 +570,7 @@ dependencies = [
 "document-features",
 "fast_image_resize",
 "image",
- "itertools 0.13.0",
+ "itertools 0.14.0",
 "libvips",
 "nix",
 "num-traits",
@@ -655,7 +655,7 @@ version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bf760ebf69878d9fd8f110c89703d90ce35095324d1f1edcb595c63945ee757"
 dependencies = [
- "bitflags 2.6.0",
+ "bitflags 2.7.0",
 "ignore",
 "walkdir",
 ]
@@ -767,9 +767,9 @@ dependencies = [

 [[package]]
 name = "image-webp"
-version = "0.2.0"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e031e8e3d94711a9ccb5d6ea357439ef3dcbed361798bd4071dc4d9793fbe22f"
+checksum = "b77d01e822461baa8409e156015a1d91735549f0f2c17691bd2d996bef238f7f"
 dependencies = [
 "byteorder-lite",
 "quick-error",
@@ -839,9 +839,9 @@ dependencies = [

 [[package]]
 name = "itertools"
-version = "0.13.0"
+version = "0.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "413ee7dfc52ee1a4949ceeb7dbc8a33f2d6c088194d9f922fb8318faf1f01186"
+checksum = "2b192c782037fadd9cfa75548310488aabdbf3d2da73885b31bd0abd03351285"
 dependencies = [
 "either",
 ]
@@ -891,9 +891,9 @@ checksum = "03087c2bad5e1034e8cace5926dec053fb3790248370865f5117a7d0213354c8"

 [[package]]
 name = "libc"
-version = "0.2.168"
+version = "0.2.169"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5aaeb2981e0606ca11d79718f8bb01164f1d6ed75080182d3abf017e6d244b6d"
+checksum = "b5aba8db14291edd000dfcc4d620c7ebfb122c613afb886ca8803fa4e128a20a"

 [[package]]
 name = "libfuzzer-sys"
@@ -966,9 +966,9 @@ checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"

 [[package]]
 name = "miniz_oxide"
-version = "0.8.0"
+version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2d80299ef12ff69b16a84bb182e3b9df68b5a91574d3d4fa6e41b65deec4df1"
+checksum = "4ffbe83022cedc1d264172192511ae958937694cd57ce297164951b8b3568394"
 dependencies = [
 "adler2",
 "simd-adler32",
@@ -986,7 +986,7 @@ version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
 dependencies = [
- "bitflags 2.6.0",
+ "bitflags 2.7.0",
 "cfg-if",
 "cfg_aliases",
 "libc",
@@ -1098,7 +1098,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b7cafe60d6cf8e62e1b9b2ea516a089c008945bb5a275416789e7db0bc199dc"
 dependencies = [
 "memchr",
- "thiserror 2.0.6",
+ "thiserror 2.0.11",
 "ucd-trie",
 ]

@@ -1138,18 +1138,18 @@ dependencies = [

 [[package]]
 name = "phf"
-version = "0.11.2"
+version = "0.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ade2d8b8f33c7333b51bcf0428d37e217e9f32192ae4772156f65063b8ce03dc"
+checksum = "1fd6780a80ae0c52cc120a26a1a42c1ae51b247a253e4e06113d23d2c2edd078"
 dependencies = [
 "phf_shared",
 ]

 [[package]]
 name = "phf_codegen"
-version = "0.11.2"
+version = "0.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e8d39688d359e6b34654d328e262234662d16cc0f60ec8dcbe5e718709342a5a"
+checksum = "aef8048c789fa5e851558d709946d6d79a8ff88c0440c587967f8e94bfb1216a"
 dependencies = [
 "phf_generator",
 "phf_shared",
@@ -1157,9 +1157,9 @@ dependencies = [

 [[package]]
 name = "phf_generator"
-version = "0.11.2"
+version = "0.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "48e4cc64c2ad9ebe670cb8fd69dd50ae301650392e81c05f9bfcb2d5bdbc24b0"
+checksum = "3c80231409c20246a13fddb31776fb942c38553c51e871f8cbd687a4cfb5843d"
 dependencies = [
 "phf_shared",
 "rand",
@@ -1167,9 +1167,9 @@ dependencies = [

 [[package]]
 name = "phf_shared"
-version = "0.11.2"
+version = "0.11.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "90fcb95eef784c2ac79119d1dd819e162b5da872ce6f3c3abe1e8ca1c082f72b"
+checksum = "67eabc2ef2a60eb7faa00097bd1ffdb5bd28e62bf39990626a582201b7a754e5"
 dependencies = [
 "siphasher",
 ]
@@ -1182,9 +1182,9 @@ checksum = "953ec861398dccce10c670dfeaf3ec4911ca479e9c02154b3a215178c5f566f2"

 [[package]]
 name = "png"
-version = "0.17.15"
+version = "0.17.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b67582bd5b65bdff614270e2ea89a1cf15bef71245cc1e5f7ea126977144211d"
+checksum = "82151a2fc869e011c153adc57cf2789ccb8d9906ce52c0b39a6b5697749d7526"
 dependencies = [
 "bitflags 1.3.2",
 "crc32fast",
@@ -1204,9 +1204,9 @@ dependencies = [

 [[package]]
 name = "proc-macro2"
-version = "1.0.92"
+version = "1.0.93"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "37d3544b3f2748c54e147655edb5025752e2303145b5aefb3c3ea2c78b973bb0"
+checksum = "60946a68e5f9d28b0dc1c21bb8a97ee7d018a8b322fa57838ba31cc878e22d99"
 dependencies = [
 "unicode-ident",
 ]
@@ -1247,9 +1247,9 @@ checksum = "a993555f31e5a609f617c12db6250dedcac1b0a85076912c436e6fc9b2c8e6a3"

 [[package]]
 name = "quote"
-version = "1.0.37"
+version = "1.0.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5b9d34b8991d19d98081b46eacdd8eb58c6f2b201139f7c5f643cc155a633af"
+checksum = "0e4dccaaaf89514f546c693ddc140f729f958c247918a13380cccc6078391acc"
 dependencies = [
 "proc-macro2",
 ]
@@ -1433,18 +1433,18 @@ dependencies = [

 [[package]]
 name = "serde"
-version = "1.0.215"
+version = "1.0.217"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6513c1ad0b11a9376da888e3e0baa0077f1aed55c17f50e7b2397136129fb88f"
+checksum = "02fc4265df13d6fa1d00ecff087228cc0a2b5f3c0e87e258d8b94a156e984c70"
 dependencies = [
 "serde_derive",
 ]

 [[package]]
 name = "serde_derive"
-version = "1.0.215"
+version = "1.0.217"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ad1e866f866923f252f05c889987993144fb74e722403468a4ebd70c3cd756c0"
+checksum = "5a9bf7cf98d04a2b28aead066b7496853d4779c9cc183c440dbac457641e19a0"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -1453,9 +1453,9 @@ dependencies = [

 [[package]]
 name = "serde_json"
-version = "1.0.133"
+version = "1.0.135"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c7fceb2473b9166b2294ef05efcb65a3db80803f0b03ef86a5fc88a2b85ee377"
+checksum = "2b0d7ba2887406110130a978386c4e1befb98c674b4fba677954e4db976630d9"
 dependencies = [
 "itoa",
 "memchr",
@@ -1506,9 +1506,9 @@ dependencies = [

 [[package]]
 name = "siphasher"
-version = "0.3.11"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38b58827f4464d87d377d175e90bf58eb00fd8716ff0a62f80356b5e61555d0d"
+checksum = "56199f7ddabf13fe5074ce809e7d3f42b42ae711800501b5b16ea82ad029c39d"

 [[package]]
 name = "slug"
@@ -1534,9 +1534,9 @@ checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"

 [[package]]
 name = "syn"
-version = "2.0.90"
+version = "2.0.96"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "919d3b74a5dd0ccd15aeb8f93e7006bd9e14c295087c9896a110f490752bcf31"
+checksum = "d5d0adab1ae378d7f53bdebc67a39f1f151407ef230f0ce2883572f5d8985c80"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -1603,11 +1603,11 @@ dependencies = [

 [[package]]
 name = "thiserror"
-version = "2.0.6"
+version = "2.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8fec2a1820ebd077e2b90c4df007bebf344cd394098a13c563957d0afc83ea47"
+checksum = "d452f284b73e6d76dd36758a0c8684b1d5be31f92b89d07fd5822175732206fc"
 dependencies = [
- "thiserror-impl 2.0.6",
+ "thiserror-impl 2.0.11",
 ]

 [[package]]
@@ -1623,9 +1623,9 @@ dependencies = [

 [[package]]
 name = "thiserror-impl"
-version = "2.0.6"
+version = "2.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d65750cab40f4ff1929fb1ba509e9914eb756131cef4210da8d5d700d26f6312"
+checksum = "26afc1baea8a989337eeb52b6e72a039780ce45c3edfcc9c5b9d112feeb173c2"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -1962,9 +1962,9 @@ checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"

 [[package]]
 name = "winnow"
-version = "0.6.20"
+version = "0.6.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "36c1fec1a2bb5866f07c25f68c26e565c4c200aebb96d7e55710c19d3e8ac49b"
+checksum = "c8d71a593cc5c42ad7876e2c1fda56f314f3754c084128833e64f1345ff8a03a"
 dependencies = [
 "memchr",
 ]
@@ -2007,9 +2007,9 @@ dependencies = [

 [[package]]
 name = "zune-jpeg"
-version = "0.4.13"
+version = "0.4.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "16099418600b4d8f028622f73ff6e3deaabdff330fb9a2a131dea781ee8b0768"
+checksum = "99a5bab8d7dedf81405c4bb1f2b83ea057643d9cb28778cea9eecddeedd2e028"
 dependencies = [
 "zune-core",
 ]
@@ -45,11 +45,11 @@ only_u8x4 = ["testing/only_u8x4"]  # This can be used to experiment with the cra
 fast_image_resize = { path = ".", features = ["for_testing"] }
 resize = { version = "0.8.7", default-features = false, features = ["std"] }
 rgb = "0.8.50"
-png = "0.17.14"
+png = "0.17.16"
 serde = { version = "1.0", features = ["serde_derive"] }
 serde_json = "1.0"
 walkdir = "2.5"
-itertools = "0.13.0"
+itertools = "0.14.0"
 criterion = { version = "0.5.1", default-features = false, features = ["cargo_bench_support"] }
 tera = "1.20"
 testing = { path = "testing" }
@@ -86,7 +86,7 @@ pub unsafe trait ImageView: Sync + Send + Sized {
        let width = self.width();
        for _ in 0..num_parts {
            top_f += step;
-            let part_height = top_f as u32 - top;
+            let part_height = top_f.round() as u32 - top;
            let image = TypedCroppedImage::from_ref(self, 0, top, width, part_height).unwrap();
            res.push(image);
            top += part_height;
@@ -116,7 +116,7 @@ pub unsafe trait ImageView: Sync + Send + Sized {
        let height = self.height();
        for _ in 0..num_parts {
            right_f += step;
-            let part_width = right_f as u32 - left;
+            let part_width = right_f.round() as u32 - left;
            let image = TypedCroppedImage::from_ref(self, left, 0, part_width, height).unwrap();
            res.push(image);
            left += part_width;
@@ -168,7 +168,7 @@ pub unsafe trait ImageViewMut: ImageView {
        let unsafe_image = UnsafeImageMut::new(self);
        for _ in 0..num_parts {
            top_f += step;
-            let part_height = top_f as u32 - top;
+            let part_height = top_f.round() as u32 - top;
            let image = TypedCroppedImageMut::new(unsafe_image.clone(), 0, top, width, part_height)
                .unwrap();
            res.push(image);
@@ -200,7 +200,7 @@ pub unsafe trait ImageViewMut: ImageView {
        let unsafe_image = UnsafeImageMut::new(self);
        for _ in 0..num_parts {
            right_f += step;
-            let part_width = right_f as u32 - left;
+            let part_width = right_f.round() as u32 - left;
            let image =
                TypedCroppedImageMut::new(unsafe_image.clone(), left, 0, part_width, height)
                    .unwrap();
@@ -233,7 +233,7 @@ unsafe impl<'a, P: InnerPixel> ImageView for TypedImage<'a, P> {
        let mut remains_pixels = self.pixels.borrow().split_at(top as usize * row_size).1;
        for _ in 0..num_parts {
            bottom_f += step;
-            let height = bottom_f as u32 - top;
+            let height = bottom_f.round() as u32 - top;
            let parts = remains_pixels.split_at(height as usize * row_size);
            let image = TypedImageRef::new(self.width, height, parts.0).unwrap();
            res.push(image);
@@ -283,7 +283,7 @@ unsafe impl<'a, P: InnerPixel> ImageViewMut for TypedImage<'a, P> {
            .1;
        for _ in 0..num_parts {
            bottom_f += step;
-            let height = bottom_f as u32 - top;
+            let height = bottom_f.round() as u32 - top;
            let parts = remains_pixels.split_at_mut(height as usize * row_size);
            let image = TypedImage::from_pixels_slice(self.width, height, parts.0).unwrap();
            res.push(image);
@@ -1,5 +1,6 @@
 use std::fs::File;
 use std::io::BufReader;
+use std::num::NonZeroU32;
 use std::ops::Deref;

 use image::ImageReader;
@@ -9,6 +10,10 @@ use fast_image_resize::images::Image;
 use fast_image_resize::pixels::*;
 use fast_image_resize::{change_type_of_pixel_components, CpuExtensions, PixelTrait, PixelType};

+pub fn non_zero_u32(v: u32) -> NonZeroU32 {
+    NonZeroU32::new(v).unwrap()
+}
+
 pub fn image_checksum<P: PixelTrait, const N: usize>(image: &Image) -> [u64; N] {
    let buffer = image.buffer();
    let mut res = [0u64; N];
@@ -0,0 +1,46 @@
+use fast_image_resize::images::TypedImage;
+use fast_image_resize::pixels::U8;
+use fast_image_resize::{ImageView, ImageViewMut};
+use testing::non_zero_u32;
+
+#[test]
+fn split_by_width() {
+    let mut img: TypedImage<U8> = TypedImage::new(512, 384);
+    for num_parts in 1..16 {
+        let res = img
+            .split_by_width(0, non_zero_u32(512), non_zero_u32(num_parts))
+            .unwrap();
+        assert_eq!(res.len() as u32, num_parts);
+        let sum_width = res.iter().map(|v| v.width()).sum::<u32>();
+        assert_eq!(sum_width, 512);
+        drop(res);
+
+        let res = img
+            .split_by_width_mut(0, non_zero_u32(512), non_zero_u32(num_parts))
+            .unwrap();
+        assert_eq!(res.len() as u32, num_parts);
+        let sum_width = res.iter().map(|v| v.width()).sum::<u32>();
+        assert_eq!(sum_width, 512);
+    }
+}
+
+#[test]
+fn split_by_height() {
+    let mut img: TypedImage<U8> = TypedImage::new(384, 512);
+    for num_parts in 1..16 {
+        let res = img
+            .split_by_height(0, non_zero_u32(512), non_zero_u32(num_parts))
+            .unwrap();
+        assert_eq!(res.len() as u32, num_parts);
+        let sum_height = res.iter().map(|v| v.height()).sum::<u32>();
+        assert_eq!(sum_height, 512);
+        drop(res);
+
+        let res = img
+            .split_by_height_mut(0, non_zero_u32(512), non_zero_u32(num_parts))
+            .unwrap();
+        assert_eq!(res.len() as u32, num_parts);
+        let sum_height = res.iter().map(|v| v.height()).sum::<u32>();
+        assert_eq!(sum_height, 512);
+    }
+}