From cccde01c4b4e376e0d1b5f58bdc9b1fe70a9b930 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Fri, 8 May 2020 20:08:18 -0400
Subject: Allow specifying each channel's bit depth separately

---
 src/color/source.rs | 15 +++++----------
 src/main.rs         | 44 ++++++++++++++++++++++++++++++++++----------
 2 files changed, 39 insertions(+), 20 deletions(-)

(limited to 'src')

diff --git a/src/color/source.rs b/src/color/source.rs
index bd752d9..00a6326 100644
--- a/src/color/source.rs
+++ b/src/color/source.rs
@@ -17,20 +17,15 @@ pub trait ColorSource {
 #[derive(Debug)]
 pub struct AllColors {
     dims: [usize; 3],
-    shifts: [usize; 3],
+    shifts: [u32; 3],
 }
 
 impl AllColors {
-    /// Create an AllColors source with the given bit depth.
-    pub fn new(bits: usize) -> Self {
-        // Allocate bits from most to least perceptually important
-        let gbits = (bits + 2) / 3;
-        let rbits = (bits + 1) / 3;
-        let bbits = bits / 3;
-
+    /// Create an AllColors source with the given bit depths.
+    pub fn new(r: u32, g: u32, b: u32) -> Self {
         Self {
-            dims: [1 << rbits, 1 << gbits, 1 << bbits],
-            shifts: [8 - rbits, 8 - gbits, 8 - bbits],
+            dims: [1 << r, 1 << g, 1 << b],
+            shifts: [8 - r, 8 - g, 8 - b],
         }
     }
 }
diff --git a/src/main.rs b/src/main.rs
index 05e9afe..d0899be 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -31,8 +31,8 @@ use std::time::Instant;
 /// The color source specified on the command line.
 #[derive(Debug, Eq, PartialEq)]
 enum SourceArg {
-    /// All RGB colors of the given bit depth.
-    AllRgb(u32),
+    /// All RGB colors of the given bit depth(s).
+    AllRgb(u32, u32, u32),
     /// Take the colors from an image.
     Image(PathBuf),
 }
@@ -197,13 +197,36 @@ impl Args {
         let source = if let Some(input) = args.value_of("INPUT") {
             SourceArg::Image(PathBuf::from(input))
         } else {
-            let depth = parse_arg(args.value_of("DEPTH"))?.unwrap_or(24);
-            if depth > 24 {
+            let arg = args.value_of("DEPTH");
+            let depths: Vec<_> = arg
+                .iter()
+                .map(|s| s.split(","))
+                .flatten()
+                .map(|n| n.parse().ok())
+                .collect();
+
+            let (r, g, b) = match depths.as_slice() {
+                [] => (8, 8, 8),
+
+                // Allocate bits from most to least perceptually important
+                [Some(d)] => ((d + 1) / 3, (d + 2) / 3, d / 3),
+
+                [Some(r), Some(g), Some(b)] => (*r, *g, *b),
+
+                _ => {
+                    return Err(AppError::invalid_value(
+                        &format!("invalid bit depth {}", arg.unwrap()),
+                    ));
+                }
+            };
+
+            if r > 8 || g > 8 || b > 8 {
                 return Err(AppError::invalid_value(
-                    &format!("bit depth of {} is too deep!", depth),
+                    &format!("bit depth of {} is too deep!", arg.unwrap()),
                 ));
             }
-            SourceArg::AllRgb(depth)
+
+            SourceArg::AllRgb(r, g, b)
         };
 
         let order = if args.is_present("RANDOM") {
@@ -296,10 +319,11 @@ impl App {
 
     fn run(&mut self) -> AppResult<()> {
         let colors = match self.args.source {
-            SourceArg::AllRgb(depth) => {
-                self.width.get_or_insert(1u32 << ((depth + 1) / 2));
-                self.height.get_or_insert(1u32 << (depth / 2));
-                self.get_colors(AllColors::new(depth as usize))
+            SourceArg::AllRgb(r, g, b) => {
+                let total = r + g + b;
+                self.width.get_or_insert(1u32 << ((total + 1) / 2));
+                self.height.get_or_insert(1u32 << (total / 2));
+                self.get_colors(AllColors::new(r, g, b))
             }
             SourceArg::Image(ref path) => {
                 let img = image::open(path)?.into_rgb();
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