added support for colouring th background instead of the foreground

src/cli.rs

@@ -22,7 +22,14 @@ pub struct Cli {
     /// Takes priority over '--grayscale'
     #[arg(short = 'C', long)]
     pub colour: bool,
+    /// Colour the background instead of the foreground
+    ///
+    /// Requires '--colour' or '--grayscale' to be passed
+    #[arg(long)]
+    pub background: bool,
     /// Display ASCII art in grayscale
+    ///
+    /// incompatible with '--color'
     #[arg(short= 'g', long)]
     pub grayscale: bool,
     /// Use braille characters instead of ASCII
@@ -67,6 +74,7 @@ impl Cli {
     pub fn debug_print(&self) {
         debug!("complex: {}", self.complex);
         debug!("colour: {}", self.colour);
+        debug!("background: {}", self.background);
         debug!("grayscale: {}", self.grayscale);
         debug!("braille: {}", self.braille);
         debug!("debug: {}", self.debug);

src/main.rs

@@ -14,12 +14,6 @@ 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.
@@ -51,6 +45,10 @@ fn main() {
     if let Some(output) = cli.output {
         print_file(out, output);
     } else {
-        print_terminal(out, cli.colour, cli.grayscale);
+        if cli.background && (cli.colour || cli.grayscale) {
+            print_terminal_background(out, cli.colour, cli.grayscale);
+        } else {
+            print_terminal(out, cli.colour, cli.grayscale);
+        }
     }
 }

src/output.rs

@@ -4,7 +4,7 @@ use std::io::{stdout, Write};
 use std::path::PathBuf;
 use std::process::exit;
 use crossterm::execute;
-use crossterm::style::{Color, SetForegroundColor, Print, ResetColor};
+use crossterm::style::{Color, SetForegroundColor, SetBackgroundColor, Print, ResetColor};
 use log::error;
 use crate::model_rgb_ascii::Ascii;
 
@@ -13,6 +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
+/// grayscale: bool - whether to print grayscale
 pub fn print_terminal(art: Vec<Vec<Ascii>>, in_colour: bool, grayscale: bool) {
     for line in art {
         for ascii in line {
@@ -34,6 +35,36 @@ pub fn print_terminal(art: Vec<Vec<Ascii>>, in_colour: bool, grayscale: bool) {
     }
 }
 
+/// This function prints ASCII art to the background of stdout.
+///
+/// arguments:
+/// art: Vec<Vec<Ascii>> - vector of vectors representing the art
+/// in_colour: bool - whether to print in colour
+/// grayscale: bool - whether to print grayscale
+pub fn print_terminal_background(art: Vec<Vec<Ascii>>, in_colour: bool, grayscale: bool) {
+    for line in art {
+        for ascii in line {
+            if in_colour {
+                let _ = execute!(stdout(),
+                    SetBackgroundColor(Color::Rgb {r: ascii.rgb[0], g: ascii.rgb[1], b: ascii.rgb[2]}),
+                    SetForegroundColor(Color::Rgb {r: 255-ascii.rgb[0], g: 255-ascii.rgb[1], b: 255-ascii.rgb[2]}),
+                    Print(ascii.char),
+                    ResetColor);
+            } else if grayscale {
+                let _ = execute!(stdout(),
+                    SetBackgroundColor(Color::Rgb {r: ascii.col_depth, g: ascii.col_depth, b: ascii.col_depth}),
+                    SetForegroundColor(Color::Rgb {r: 255-ascii.col_depth, g: 255-ascii.col_depth, b: 255-ascii.col_depth}),
+                    Print(ascii.char),
+                    ResetColor);
+            } else {
+                error!("This should be unreachable!");
+                exit(1);
+            }
+        }
+        println!();
+    }
+}
+
 /// This function prints ASCII art to a file.
 ///
 /// arguments: