added grayscale support

src/ascii_manipulation.rs

@@ -116,7 +116,7 @@ pub fn to_braille_ascii(image: DynamicImage, threshold: u8) -> Vec<Vec<Ascii>> {
                     }
                 }
             }
-            str.push(Ascii { char: char::from_u32(braille_value).unwrap(), rgb: [(r/8) as u8, (g/8) as u8, (b/8) as u8] });
+            str.push(Ascii::new_with_char(char::from_u32(braille_value).unwrap(), (r/8) as u8, (g/8) as u8,  (b/8) as u8));
             }
         out.push(str);
         str = Vec::new();

src/cli.rs

@@ -18,8 +18,13 @@ pub struct Cli {
     #[arg(short = 'c', long)]
     pub complex: bool,
     /// Display ASCII art in full colour
+    ///
+    /// Takes priority over '--grayscale'
     #[arg(short = 'C', long)]
     pub colour: bool,
+    /// Display ASCII art in grayscale
+    #[arg(short= 'g', long)]
+    pub grayscale: bool,
     /// Use braille characters instead of ASCII
     ///
     /// Takes priority over '--complex' and '--map'
@@ -49,7 +54,7 @@ pub struct Cli {
     pub width: Option<u32>,
     /// Save the output to a file, instead of printing to terminal
     ///
-    /// Incompatible with '--colour'
+    /// Incompatible with '--colour' and '--grayscale'
     #[arg(short = 'o', long = "output")]
     pub output: Option<PathBuf>,
 }
@@ -62,6 +67,7 @@ impl Cli {
     pub fn debug_print(&self) {
         debug!("complex: {}", self.complex);
         debug!("colour: {}", self.colour);
+        debug!("grayscale: {}", self.grayscale);
         debug!("braille: {}", self.braille);
         debug!("debug: {}", self.debug);
         debug!("full: {}", self.full);

src/main.rs

@@ -14,6 +14,12 @@ mod ascii_manipulation;
 mod output;
 mod model_rgb_ascii;
 
+//todo:
+/* custom background color, print font in white
+ * --formats flag
+ * --version flag
+ */
+
 /// This is the main function.
 ///
 /// It drives the CLI module, calls the appropriate convert functions and directs output.
@@ -45,6 +51,6 @@ fn main() {
     if let Some(output) = cli.output {
         print_file(out, output);
     } else {
-        print_terminal(out, cli.colour);
+        print_terminal(out, cli.colour, cli.grayscale);
     }
 }

src/model_rgb_ascii.rs

@@ -1,9 +1,15 @@
 //! This module contains the Ascii struct.
 
 /// This struct represents one character + rgb colour.
+///
+/// attributes:
+/// char: char - the character associated with this ASCII value
+/// rgb: [u8; 3] - vec of 3 u8 values representing red, green, and blue respectively
+/// col_depthL u8 - the depth of the rgb values, calculated through the luminosity method
 pub struct Ascii {
     pub char: char,
     pub rgb: [u8; 3],
+    pub col_depth: u8,
 }
 
 impl Ascii {
@@ -21,6 +27,25 @@ impl Ascii {
         Ascii {
             char: char::from(ch),
             rgb: [r, g, b],
+            col_depth: (r as f32 * 0.3 + g as f32 * 0.59 + b as f32 * 0.11) as u8,
+        }
+    }
+
+    /// This function creates a new Ascii instance.
+    ///
+    /// Arguments:
+    /// ch: char - the character
+    /// r: u8 - Red colour value
+    /// g: u8 - Green colour value
+    /// b: u8 - Blue colour value
+    ///
+    /// returns:
+    /// self
+    pub fn new_with_char(ch: char, r: u8, g: u8, b: u8) -> Self {
+        Ascii {
+            char: ch,
+            rgb: [r, g, b],
+            col_depth: (r as f32 * 0.3 + g as f32 * 0.59 + b as f32 * 0.11) as u8,
         }
     }
 }

src/output.rs

@@ -13,7 +13,7 @@ use crate::model_rgb_ascii::Ascii;
 /// arguments:
 /// art: Vec<Vec<Ascii>> - vector of vectors representing the art
 /// in_colour: bool - whether to print in colour or as hard white
-pub fn print_terminal(art: Vec<Vec<Ascii>>, in_colour: bool) {
+pub fn print_terminal(art: Vec<Vec<Ascii>>, in_colour: bool, grayscale: bool) {
     for line in art {
         for ascii in line {
             if in_colour {
@@ -21,6 +21,11 @@ pub fn print_terminal(art: Vec<Vec<Ascii>>, in_colour: bool) {
                     SetForegroundColor(Color::Rgb {r: ascii.rgb[0], g: ascii.rgb[1], b: ascii.rgb[2]}),
                     Print(ascii.char),
                     ResetColor);
+            } else if grayscale {
+                let _ = execute!(stdout(),
+                    SetForegroundColor(Color::Rgb {r: ascii.col_depth, g: ascii.col_depth, b: ascii.col_depth}),
+                    Print(ascii.char),
+                    ResetColor);
             } else {
                 print!("{}", ascii.char);
             }