feat: use better calculations for distance and average color

.gitattributes

@@ -0,0 +1 @@
+Cargo.lock -diff

.gitignore

@@ -7,5 +7,8 @@
 *.heic
 *.mp4
 *.webm
+*.webp
 /.mypy_cache/
-tiles/
+/tiles/
+/input/
+/output/

Cargo.lock

@@ -23,12 +23,6 @@ dependencies = [
  "winapi",
 ]
 
-[[package]]
-name = "anyhow"
-version = "1.0.58"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bb07d2053ccdbe10e2af2995a2f116c1330396493dc1269f6a91d0ae82e19704"
-
 [[package]]
 name = "atty"
 version = "0.2.14"
@@ -46,12 +40,24 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
 
+[[package]]
+name = "bit_field"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dcb6dd1c2376d2e096796e234a70e17e94cc2d5d54ff8ce42b28cef1d0d359a4"
+
 [[package]]
 name = "bitflags"
 version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "bumpalo"
+version = "3.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37ccbd214614c6783386c1af30caf03192f17891059cecc394b4fb119e363de3"
+
 [[package]]
 name = "bytemuck"
 version = "1.10.0"
@@ -100,7 +106,6 @@ dependencies = [
  "encode_unicode",
  "libc",
  "once_cell",
- "regex",
  "terminal_size",
  "unicode-width",
  "winapi",
@@ -162,12 +167,11 @@ dependencies = [
 
 [[package]]
 name = "deflate"
-version = "0.8.6"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "73770f8e1fe7d64df17ca66ad28994a0a623ea497fa69486e14984e715c5d174"
+checksum = "c86f7e25f518f4b81808a2cf1c50996a61f5c2eb394b2393bd87f2a4780a432f"
 dependencies = [
  "adler32",
- "byteorder",
 ]
 
 [[package]]
@@ -182,6 +186,80 @@ version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a357d28ed41a50f9c765dbfe56cbc04a64e53e5fc58ba79fbc34c10ef3df831f"
 
+[[package]]
+name = "exr"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14cc0e06fb5f67e5d6beadf3a382fec9baca1aa751c6d5368fdeee7e5932c215"
+dependencies = [
+ "bit_field",
+ "deflate",
+ "flume",
+ "half",
+ "inflate",
+ "lebe",
+ "smallvec",
+ "threadpool",
+]
+
+[[package]]
+name = "eyre"
+version = "0.6.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4c2b6b5a29c02cdc822728b7d7b8ae1bab3e3b05d44522770ddd49722eeac7eb"
+dependencies = [
+ "indenter",
+ "once_cell",
+]
+
+[[package]]
+name = "flate2"
+version = "1.0.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f82b0f4c27ad9f8bfd1f3208d882da2b09c301bc1c828fd3a00d0216d2fbbff6"
+dependencies = [
+ "crc32fast",
+ "miniz_oxide",
+]
+
+[[package]]
+name = "flume"
+version = "0.10.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ceeb589a3157cac0ab8cc585feb749bd2cea5cb55a6ee802ad72d9fd38303da"
+dependencies = [
+ "futures-core",
+ "futures-sink",
+ "nanorand",
+ "pin-project",
+ "spin",
+]
+
+[[package]]
+name = "futures-core"
+version = "0.3.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0c09fd04b7e4073ac7156a9539b57a484a8ea920f79c7c675d05d289ab6110d3"
+
+[[package]]
+name = "futures-sink"
+version = "0.3.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "21163e139fa306126e6eedaf49ecdb4588f939600f0b1e770f4205ee4b7fa868"
+
+[[package]]
+name = "getrandom"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4eb1a864a501629691edf6c15a593b7a51eebaa1e8468e9ddc623de7c9b58ec6"
+dependencies = [
+ "cfg-if",
+ "js-sys",
+ "libc",
+ "wasi",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "gif"
 version = "0.11.4"
@@ -192,6 +270,12 @@ dependencies = [
  "weezl",
 ]
 
+[[package]]
+name = "half"
+version = "1.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eabb4a44450da02c90444cf74558da904edde8fb4e9035a9a6a4e15445af0bd7"
+
 [[package]]
 name = "heck"
 version = "0.3.3"
@@ -212,13 +296,14 @@ dependencies = [
 
 [[package]]
 name = "image"
-version = "0.23.14"
+version = "0.24.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "24ffcb7e7244a9bf19d35bf2883b9c080c4ced3c07a9895572178cdb8f13f6a1"
+checksum = "28edd9d7bc256be2502e325ac0628bde30b7001b9b52e0abe31a1a9dc2701212"
 dependencies = [
  "bytemuck",
  "byteorder",
  "color_quant",
+ "exr",
  "gif",
  "jpeg-decoder",
  "num-iter",
@@ -230,10 +315,16 @@ dependencies = [
 ]
 
 [[package]]
-name = "indicatif"
+name = "indenter"
-version = "0.15.0"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7baab56125e25686df467fe470785512329883aab42696d661247aca2a2896e4"
+checksum = "ce23b50ad8242c51a442f3ff322d56b02f08852c77e4c0b4d3fd684abc89c683"
+
+[[package]]
+name = "indicatif"
+version = "0.16.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d207dc617c7a380ab07ff572a6e52fa202a2a8f355860ac9c38e23f8196be1b"
 dependencies = [
  "console",
  "lazy_static",
@@ -245,26 +336,69 @@ dependencies = [
 ]
 
 [[package]]
-name = "jpeg-decoder"
+name = "inflate"
-version = "0.1.22"
+version = "0.4.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "229d53d58899083193af11e15917b5640cd40b29ff475a1fe4ef725deb02d0f2"
+checksum = "1cdb29978cc5797bd8dcc8e5bf7de604891df2a8dc576973d71a281e916db2ff"
+dependencies = [
+ "adler32",
+]
+
+[[package]]
+name = "jpeg-decoder"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9478aa10f73e7528198d75109c8be5cd7d15fb530238040148d5f9a22d4c5b3b"
 dependencies = [
  "rayon",
 ]
 
+[[package]]
+name = "js-sys"
+version = "0.3.58"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3fac17f7123a73ca62df411b1bf727ccc805daa070338fda671c86dac1bdc27"
+dependencies = [
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
+[[package]]
+name = "lebe"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7efd1d698db0759e6ef11a7cd44407407399a910c774dd804c64c032da7826ff"
+
 [[package]]
 name = "libc"
 version = "0.2.126"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "349d5a591cd28b49e1d1037471617a32ddcda5731b99419008085f72d5a53836"
 
+[[package]]
+name = "lock_api"
+version = "0.4.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "327fa5b6a6940e4699ec49a9beae1ea4845c6bab9314e4f84ac68742139d8c53"
+dependencies = [
+ "autocfg",
+ "scopeguard",
+]
+
+[[package]]
+name = "log"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "memoffset"
 version = "0.6.5"
@@ -276,30 +410,20 @@ dependencies = [
 
 [[package]]
 name = "miniz_oxide"
-version = "0.3.7"
+version = "0.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "791daaae1ed6889560f8c4359194f56648355540573244a5448a83ba1ecc7435"
+checksum = "6f5c75688da582b8ffc1f1799e9db273f32133c49e048f614d22ec3256773ccc"
-dependencies = [
- "adler32",
-]
-
-[[package]]
-name = "miniz_oxide"
-version = "0.4.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a92518e98c078586bc6c934028adcca4c92a53d6a958196de835170a01d84e4b"
 dependencies = [
  "adler",
- "autocfg",
 ]
 
 [[package]]
-name = "noisy_float"
+name = "nanorand"
-version = "0.1.15"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3deb89f8062c0dce4c805a987daff07f92e17c560f7c3ed631282555af902258"
+checksum = "6a51313c5820b0b02bd422f4b44776fbf47961755c74ce64afc73bfad10226c3"
 dependencies = [
- "num-traits",
+ "getrandom",
 ]
 
 [[package]]
@@ -325,9 +449,9 @@ dependencies = [
 
 [[package]]
 name = "num-rational"
-version = "0.3.2"
+version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "12ac428b1cb17fce6f731001d307d351ec70a6d202fc2e60f7d4c5e42d8f4f07"
+checksum = "0638a1c9d0a3c0914158145bc76cff373a75a627e6ecbfb71cbe6f453a5a19b0"
 dependencies = [
  "autocfg",
  "num-integer",
@@ -355,9 +479,9 @@ dependencies = [
 
 [[package]]
 name = "number_prefix"
-version = "0.3.0"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "17b02fc0ff9a9e4b35b3342880f48e896ebf69f2967921fe8646bf5b7125956a"
+checksum = "830b246a0e5f20af87141b25c173cd1b609bd7779a4617d6ec582abaf90870f3"
 
 [[package]]
 name = "once_cell"
@@ -366,15 +490,35 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "18a6dbe30758c9f83eb00cbea4ac95966305f5a7772f3f42ebfc7fc7eddbd8e1"
 
 [[package]]
-name = "png"
+name = "pin-project"
-version = "0.16.8"
+version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3c3287920cb847dee3de33d301c463fba14dda99db24214ddf93f83d3021f4c6"
+checksum = "78203e83c48cffbe01e4a2d35d566ca4de445d79a85372fc64e378bfc812a260"
+dependencies = [
+ "pin-project-internal",
+]
+
+[[package]]
+name = "pin-project-internal"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "710faf75e1b33345361201d36d04e98ac1ed8909151a017ed384700836104c74"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "png"
+version = "0.17.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc38c0ad57efb786dd57b9864e5b18bae478c00c824dc55a38bbc9da95dde3ba"
 dependencies = [
  "bitflags",
  "crc32fast",
  "deflate",
- "miniz_oxide 0.3.7",
+ "miniz_oxide",
 ]
 
 [[package]]
@@ -470,6 +614,21 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
+[[package]]
+name = "smallvec"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fd0db749597d91ff862fd1d55ea87f7855a744a8425a64695b6fca237d1dad1"
+
+[[package]]
+name = "spin"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f6002a767bff9e83f8eeecf883ecb8011875a21ae8da43bffb817a57e78cc09"
+dependencies = [
+ "lock_api",
+]
+
 [[package]]
 name = "strsim"
 version = "0.8.0"
@@ -534,22 +693,30 @@ dependencies = [
 name = "themis"
 version = "1.2.0"
 dependencies = [
- "anyhow",
+ "eyre",
  "image",
  "indicatif",
- "noisy_float",
  "rayon",
  "structopt",
 ]
 
 [[package]]
-name = "tiff"
+name = "threadpool"
-version = "0.6.1"
+version = "1.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a53f4706d65497df0c4349241deddf35f84cee19c87ed86ea8ca590f4464437"
+checksum = "d050e60b33d41c19108b32cea32164033a9013fe3b46cbd4457559bfbf77afaa"
 dependencies = [
+ "num_cpus",
+]
+
+[[package]]
+name = "tiff"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7cfada0986f446a770eca461e8c6566cb879682f7d687c8348aa0c857bd52286"
+dependencies = [
+ "flate2",
  "jpeg-decoder",
- "miniz_oxide 0.4.4",
  "weezl",
 ]
 
@@ -583,6 +750,66 @@ version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
+
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c53b543413a17a202f4be280a7e5c62a1c69345f5de525ee64f8cfdbc954994"
+dependencies = [
+ "cfg-if",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5491a68ab4500fa6b4d726bd67408630c3dbe9c4fe7bda16d5c82a1fd8c7340a"
+dependencies = [
+ "bumpalo",
+ "lazy_static",
+ "log",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c441e177922bc58f1e12c022624b6216378e5febc2f0533e41ba443d505b80aa"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7d94ac45fcf608c1f45ef53e748d35660f168490c10b23704c7779ab8f5c3048"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a89911bd99e5f3659ec4acf9c4d93b0a90fe4a2a11f15328472058edc5261be"
+
 [[package]]
 name = "weezl"
 version = "0.1.7"

Cargo.toml

@@ -6,9 +6,10 @@ license = "GPL-3.0-only"
 edition = "2018"
 
 [dependencies]
-image = "0.23.6"
+image = "0.24.2"
-anyhow = "1.0.31"
+rayon = "1.5.3"
-rayon = "1.3.1"
+indicatif = { version = "0.16.2", features = ["rayon", "improved_unicode"] }
-indicatif = { version = "0.15.0", features = ["rayon", "improved_unicode"] }
+structopt = "0.3.26"
-noisy_float = "0.1.12"
+eyre = "0.6.8"
-structopt = "0.3.15"
+
+[features]

justfile

@@ -0,0 +1,7 @@
+set shell := ["pwsh.exe", "-c"]
+
+run side *args:
+    cargo run --release -- -i input -t tiles -k -m {{side}} {{args}}
+
+run-debug side *args:
+    cargo run -- -i input -t tiles -k -m {{side}} {{args}}

src/main.rs

@@ -2,10 +2,11 @@ use std::collections::{HashMap, HashSet};
 use std::fs;
 use std::path::{Path, PathBuf};
 
-use anyhow::Result;
+use eyre::Result;
-use image::{DynamicImage, GenericImage, GenericImageView, Pixel, Rgba};
+use image::{DynamicImage, GenericImage, GenericImageView, Rgba};
-use indicatif::{ParallelProgressIterator, ProgressBar, ProgressIterator, ProgressStyle};
+use indicatif::{
-use noisy_float::prelude::*;
+    ParallelProgressIterator, ProgressBar, ProgressFinish, ProgressIterator, ProgressStyle,
+};
 use rayon::prelude::*;
 use structopt::StructOpt;
 
@@ -15,28 +16,26 @@ fn average_color(image: &DynamicImage) -> Rgba<u8> {
 
     let (mut r, mut g, mut b, mut a) = (0., 0., 0., 0.);
     for (_x, _y, Rgba([pr, pg, pb, pa])) in image.pixels() {
-        r += pr as f64;
+        r += pr as f64 * pr as f64;
-        g += pg as f64;
+        g += pg as f64 * pg as f64;
-        b += pb as f64;
+        b += pb as f64 * pb as f64;
-        a += pa as f64;
+        a += pa as f64 * pa as f64;
     }
-
+    let r = (r / pixel_count).sqrt() as u8;
-    let r = (r / pixel_count) as u8;
+    let g = (g / pixel_count).sqrt() as u8;
-    let g = (g / pixel_count) as u8;
+    let b = (b / pixel_count).sqrt() as u8;
-    let b = (b / pixel_count) as u8;
+    let a = (a / pixel_count).sqrt() as u8;
-    let a = (a / pixel_count) as u8;
     Rgba([r, g, b, a])
 }
 
-/// Calculate the euclidean distance between two pixels
+/// Calculate the distance (squared) between two colors
-fn distance(pixel1: Rgba<u8>, pixel2: Rgba<u8>) -> R64 {
+/// Code adapted from https://stackoverflow.com/a/9085524/13204109
-    r64(pixel1
+fn distance(Rgba([r1, g1, b1, _]): Rgba<u8>, Rgba([r2, g2, b2, _]): Rgba<u8>) -> i64 {
-        .map2(&pixel2, |l, r| if l < r { r - l } else { l - r })
+    let rmean = (i64::from(r1) + i64::from(r2)) / 2;
-        .channels()
+    let r = i64::from(r1) - i64::from(r2);
-        .iter()
+    let g = i64::from(g1) - i64::from(g2);
-        .map(|&n| (n as f64).powi(2))
+    let b = i64::from(b1) - i64::from(b2);
-        .sum::<f64>()
+    (((512 + rmean) * r * r) >> 8) + 4 * g * g + (((767 - rmean) * b * b) >> 8)
-        .sqrt())
 }
 
 /// Choose the image in the given tileset whose average color is closest to the given pixel
@@ -54,6 +53,7 @@ fn pick_image_for_pixel(
 fn load_images<P: AsRef<Path>>(dir: P, tile_side: u32) -> Result<Vec<(DynamicImage, Rgba<u8>)>> {
     let dir = fs::read_dir(dir)?.collect::<Result<Vec<_>, _>>()?;
     let len = dir.len();
+
     Ok(dir
         .into_par_iter()
         .progress_with(make_pbar("images loaded", len as _))
@@ -68,37 +68,52 @@ fn load_images<P: AsRef<Path>>(dir: P, tile_side: u32) -> Result<Vec<(DynamicIma
 }
 
 /// Create a styled progress bar
-fn make_pbar(msg: &str, len: u64) -> ProgressBar {
+fn make_pbar(msg: &'static str, len: u64) -> ProgressBar {
     let bar = ProgressBar::new(len);
     bar.set_message(msg);
     bar.set_style(
         ProgressStyle::default_bar()
             .template("[{elapsed_precise}/{eta_precise}] {bar:40.green/red} {pos:>4}/{len:4} {msg}")
-            .progress_chars("##-"),
+            .progress_chars("##-")
+            .on_finish(ProgressFinish::AndLeave),
     );
     bar
 }
 
+/// Create a styled spinner
+fn make_spinner(msg: &'static str, done_msg: &'static str) -> ProgressBar {
+    let bar = ProgressBar::new(0);
+    bar.set_message(msg);
+    bar.set_style(
+        ProgressStyle::default_bar()
+            .template("{spinner:.yellow} {msg}")
+            .progress_chars("##-")
+            .on_finish(ProgressFinish::WithMessage(done_msg)),
+    );
+    bar.enable_steady_tick(100);
+    bar
+}
+
 #[derive(StructOpt)]
 struct Opt {
     /// The image to turn into a mosaic
-    #[structopt(parse(from_os_str))]
+    #[structopt(short, long, parse(from_os_str))]
-    image: PathBuf,
+    input_dir: PathBuf,
 
     /// The directory containing the tiles to utilize
-    #[structopt(parse(from_os_str))]
+    #[structopt(short, long, parse(from_os_str))]
-    tiles_directory: PathBuf,
+    tiles_dir: PathBuf,
 
     /// Where to save the finished mosaic
-    #[structopt(short, long, parse(from_os_str), default_value = "mosaic.png")]
+    #[structopt(short, long, parse(from_os_str), default_value = "output")]
-    output: PathBuf,
+    output_dir: PathBuf,
 
     /// The side length that the target image'll be resized to.
     #[structopt(short, long, default_value = "128")]
     mosaic_size: u32,
 
     /// The side length of each tile.
-    #[structopt(short, long, default_value = "26")]
+    #[structopt(long, default_value = "26")]
     tile_size: u32,
 
     /// Keep the image's aspect ratio
@@ -108,31 +123,48 @@ struct Opt {
 
 fn main() -> Result<()> {
     let Opt {
-        image,
+        input_dir,
-        tiles_directory,
+        tiles_dir,
         mosaic_size,
         tile_size,
         keep_aspect_ratio,
-        output,
+        output_dir,
     } = Opt::from_args();
 
-    let possible_tiles = load_images(tiles_directory, tile_size)?;
+    fs::create_dir_all(&output_dir)?;
-    let image = image::open(image)?;
+
-    let image = if keep_aspect_ratio {
+    let possible_tiles = load_images(tiles_dir, tile_size)?;
-        image.thumbnail(mosaic_size, mosaic_size)
+
+    let input_dir = fs::read_dir(input_dir)?.collect::<Result<Vec<_>, _>>()?;
+
+    for image in input_dir {
+        let input_path = image.path();
+        eprintln!("Processing {}", input_path.display());
+
+        let output = output_dir.join(format!(
+            "{}.mosaic{mosaic_size}.png",
+            input_path.file_stem().unwrap().to_string_lossy()
+        ));
+        if output.exists() {
+            continue;
+        }
+
+        let img = image::open(&input_path)?;
+        let img = if keep_aspect_ratio {
+            img.thumbnail(mosaic_size, mosaic_size)
         } else {
-        image.thumbnail_exact(mosaic_size, mosaic_size)
+            img.thumbnail_exact(mosaic_size, mosaic_size)
         };
 
         // For every unique pixel in the image, find its most appropiate tile
-    let unique_pixels = image
+        let unique_pixels = img
             .pixels()
             .map(|(_x, _y, pixel)| pixel)
             .collect::<HashSet<_>>();
-    let pbar = make_pbar("pixels", unique_pixels.len() as _);
+        let len = unique_pixels.len();
         let tiles = unique_pixels
             .into_par_iter()
-        .progress_with(pbar)
+            .progress_with(make_pbar("pixels", len as _))
             .filter_map(|pixel| {
                 let tile = pick_image_for_pixel(pixel, &possible_tiles)?;
                 Some((pixel, tile))
@@ -140,14 +172,18 @@ fn main() -> Result<()> {
             .collect::<HashMap<_, _>>();
 
         // Apply the mapping previously calculated and save the mosaic
-    let mut mosaic = DynamicImage::new_rgba8(image.width() * tile_size, image.height() * tile_size);
+        let mut mosaic = DynamicImage::new_rgba8(img.width() * tile_size, img.height() * tile_size);
-    for (x, y, pixel) in image.pixels().progress_with(make_pbar(
+        for (x, y, pixel) in img.pixels().progress_with(make_pbar(
             "actual pixels",
-        u64::from(image.width() * image.height()),
+            u64::from(img.width() * img.height()),
         )) {
             mosaic.copy_from(&**tiles.get(&pixel).unwrap(), x * tile_size, y * tile_size)?;
         }
+
+        let spinner = make_spinner("Saving", "Saved!");
         mosaic.save(output)?;
+        spinner.finish_using_style();
+    }
 
     Ok(())
 }