Add ColorBw for printer

Cargo.lock

@@ -148,6 +148,7 @@ dependencies = [
 name = "showbits-thermal-printer"
 version = "0.0.0"
 dependencies = [
+ "palette",
  "showbits-common",
 ]
 

Cargo.toml

@@ -7,6 +7,7 @@ version = "0.0.0"
 edition = "2021"
 
 [workspace.dependencies]
+palette = "0.7.5"
 showbits-common.path = "./showbits-common"
 
 [workspace.lints]

showbits-common/Cargo.toml

@@ -5,7 +5,7 @@ edition.workspace = true
 
 [dependencies]
 anyhow = "1.0.80"
-palette = "0.7.5"
+palette.workspace = true
 
 [lints]
 workspace = true

showbits-thermal-printer/Cargo.toml

@@ -4,6 +4,7 @@ version.workspace = true
 edition.workspace = true
 
 [dependencies]
+palette.workspace = true
 showbits-common.workspace = true
 
 [lints]

showbits-thermal-printer/src/color.rs

@@ -0,0 +1,32 @@
+use palette::Srgb;
+use showbits_common::Color;
+
+#[derive(Clone, Copy)]
+pub enum PixelBw {
+    Black,
+    White,
+    Transparent,
+    Invert,
+}
+
+impl Color for PixelBw {
+    fn to_srgb(self) -> Srgb {
+        match self {
+            Self::Black => Srgb::new(0.0, 0.0, 0.0),
+            Self::White => Srgb::new(1.0, 1.0, 1.0),
+            _ => Srgb::new(1.0, 0.0, 1.0),
+        }
+    }
+
+    fn over(self, other: Self) -> Self {
+        match (self, other) {
+            (Self::Black, _) => Self::Black,
+            (Self::White, _) => Self::White,
+            (Self::Transparent, p) => p,
+            (Self::Invert, Self::Black) => Self::White,
+            (Self::Invert, Self::White) => Self::Black,
+            (Self::Invert, Self::Invert) => Self::Transparent,
+            (Self::Invert, Self::Transparent) => Self::Invert,
+        }
+    }
+}

showbits-thermal-printer/src/main.rs

@@ -1,3 +1,5 @@
+mod color;
+
 use showbits_common::Vec2;
 
 fn main() {