ft: added centering flag

src/ascii_manipulation.rs

@@ -1,8 +1,9 @@
 //! This module contains all functions related to converting images to ASCII.
-use std::process::exit;
+use crate::image_manipulation::get_terminal_size;
+use crate::model_rgb_ascii::Ascii;
 use image::{DynamicImage, GenericImageView, Rgba};
 use log::error;
-use crate::model_rgb_ascii::Ascii;
+use std::process::exit;
 
 /// This constant is used to calculate braille values.
 const BRAILLE_TABLE: [[u8; 2]; 4] = [[1u8, 8u8], [2u8, 16u8], [4u8, 32u8], [64u8, 128u8]];
@@ -22,6 +23,25 @@ fn get_color(pixel: Rgba<u8>) -> u8 {
     (pixel[0] as f32 * 0.3 + pixel[1] as f32 * 0.59 + pixel[2] as f32 * 0.11) as u8
 }
 
+/// This function returns the empty space on either side of the ascii, relative to the terminal
+/// width.
+///
+/// arguments:
+/// ascii: &Vec<Vec<Ascii>> - ascii image to calculate margins for
+///
+/// returns:
+/// u32 representing the size of one margin (i.e. the empty space that should be prefixed to center
+/// the ascii)
+pub fn calc_margin(ascii: &Vec<Vec<Ascii>>) -> u32 {
+    let (max_w, _) = get_terminal_size();
+    let w = ascii[0].len() as u32; // Assume all lines have same length.
+    if w < max_w {
+        return (max_w - w) / 2 as u32;
+    } else {
+        return 0;
+    }
+}
+
 /// This function converts a given image into ASCII.
 ///
 /// arguments:
@@ -37,11 +57,11 @@ fn to_ascii(char_map: String, image: DynamicImage) -> Vec<Vec<Ascii>> {
 
     for pixel in image.pixels() {
         let mut ascii = Ascii::new(0, pixel.2[0], pixel.2[1], pixel.2[2]);
-        let ch = char_map.as_bytes()[((ascii.col_depth as f32-1.0)/255f32 * l) as usize];
+        let ch = char_map.as_bytes()[((ascii.col_depth as f32 - 1.0) / 255f32 * l) as usize];
         ascii.char = char::from(ch);
         str.push(ascii);
 
-        if pixel.0 == image.width()-1 {
+        if pixel.0 == image.width() - 1 {
             out.push(str);
             str = Vec::new();
         }
@@ -72,7 +92,10 @@ pub fn to_simple_ascii(image: DynamicImage) -> Vec<Vec<Ascii>> {
 /// returns:
 /// Vec<Vec<Ascii>> containing the converted image
 pub fn to_complex_ascii(image: DynamicImage) -> Vec<Vec<Ascii>> {
-    to_ascii(" .'`^\",:;Il!i><~+_-?][}{1)(|\\/tfjrxnuvczXYUJCLQ0OZmwqpdbkhao*#MW&8%B@$".to_owned(), image)
+    to_ascii(
+        " .'`^\",:;Il!i><~+_-?][}{1)(|\\/tfjrxnuvczXYUJCLQ0OZmwqpdbkhao*#MW&8%B@$".to_owned(),
+        image,
+    )
 }
 
 /// This wrapper function converts an image to custom ASCII.
@@ -109,16 +132,21 @@ pub fn to_braille_ascii(image: DynamicImage, threshold: u8) -> Vec<Vec<Ascii>> {
             let mut braille_value: u32 = 10240;
             for nx in 0..2 {
                 for ny in 0..4 {
-                    let pixel = image.get_pixel(x+nx, y+ny);
+                    let pixel = image.get_pixel(x + nx, y + ny);
-                    r = r+pixel[0] as u16;
+                    r = r + pixel[0] as u16;
-                    g = g+pixel[1] as u16;
+                    g = g + pixel[1] as u16;
-                    b = b+pixel[2] as u16;
+                    b = b + pixel[2] as u16;
                     if get_color(pixel) >= threshold {
                         braille_value += BRAILLE_TABLE[ny as usize][nx as usize] as u32;
                     }
                 }
             }
-            str.push(Ascii::new_with_char(char::from_u32(braille_value).unwrap(), (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

@@ -1,17 +1,22 @@
 //! This module contains all functions related to the CLI part of the program.
 //!
 //! It manages and validates flags, mostly.
+use clap::Parser;
+use log::{debug, error};
 use std::ffi::OsString;
 use std::path::PathBuf;
 use std::process::exit;
-use clap::Parser;
-use log::{debug, error};
 
 /// Convert an image to ASCII art and print it to the terminal.
 ///
 /// Configuration is done using flags.
 #[derive(Parser)]
 pub struct Cli {
+    /// Center the output in terminal.
+    ///
+    /// Incompatible with '--output'
+    #[arg(short = 'm', long)]
+    pub center: bool,
     /// Use a larger range of characters
     ///
     /// Takes priority over '--map'
@@ -30,7 +35,7 @@ pub struct Cli {
     /// Display ASCII art in grayscale
     ///
     /// incompatible with '--color'
-    #[arg(short= 'g', long)]
+    #[arg(short = 'g', long)]
     pub grayscale: bool,
     /// Use braille characters instead of ASCII
     ///
@@ -66,12 +71,12 @@ pub struct Cli {
     pub output: Option<PathBuf>,
 }
 
-
 impl Cli {
     /// This function prints all parts of Cli.
     ///
     /// used for debugging.
     pub fn debug_print(&self) {
+        debug!("center: {}", self.center);
         debug!("complex: {}", self.complex);
         debug!("colour: {}", self.colour);
         debug!("background: {}", self.background);
@@ -128,7 +133,9 @@ impl Cli {
 
     /// This function initializes logging (dependent on cli.debug flag)
     pub fn init(&self) {
-        if self.debug {std::env::set_var("RUST_LOG", "trace")}
+        if self.debug {
+            std::env::set_var("RUST_LOG", "trace")
+        }
         env_logger::init();
         self.debug_print();
     }
@@ -144,14 +151,14 @@ impl Cli {
 fn is_image(path: &PathBuf) -> bool {
     let ext = path.extension();
     match ext {
-        Some(ext) => {
+        Some(ext) => vec![
-            vec![OsString::from("png"),
+            OsString::from("png"),
             OsString::from("jpg"),
             OsString::from("jpeg"),
-                 OsString::from("webp")]
+            OsString::from("webp"),
-                .contains(&ext.to_ascii_lowercase())
+        ]
-        }
+        .contains(&ext.to_ascii_lowercase()),
-        None => false
+        None => false,
     }
 }
 

src/image_manipulation.rs

@@ -1,21 +1,19 @@
 //! This module contains all functions related to image manipulation.
 use crossterm::terminal;
-use log::{debug, error};
-use std::process::exit;
-use std::path::PathBuf;
-use image::DynamicImage;
 use image::imageops::FilterType;
+use image::DynamicImage;
+use log::{debug, error};
+use std::path::PathBuf;
+use std::process::exit;
 
 /// This function returns the (width, length) of stdout
 ///
 /// returns:
 /// (u32, u32) representing the (width, length) of stdout
-fn get_terminal_size() -> (u32, u32) {
+pub(crate) fn get_terminal_size() -> (u32, u32) {
     let size = terminal::size();
     match size {
-        Ok(size) => {
+        Ok(size) => (size.0 as u32, size.1 as u32),
-            (size.0 as u32, size.1 as u32)
-        }
         Err(e) => {
             error!("Failed to get terminal size: {}", e.to_string());
             exit(1);
@@ -35,22 +33,27 @@ fn get_terminal_size() -> (u32, u32) {
 ///
 /// returns:
 /// DynamicImage, resized
-pub fn resize_image(img: DynamicImage, full: bool, braille: bool, opt_w: Option<u32>) -> DynamicImage {
+pub fn resize_image(
+    img: DynamicImage,
+    full: bool,
+    braille: bool,
+    opt_w: Option<u32>,
+) -> DynamicImage {
     //compiler complains that these v values are never read; this is true, however they are necessary because otherwise the program simply will not compile.
-    let (mut w, mut h) = (1,1);
+    let (mut w, mut h) = (1, 1);
     let (max_w, max_h) = get_terminal_size();
     if full {
-        w = max_w-1;
+        w = max_w - 1;
         h = (img.height() as f32 * w as f32 / img.width() as f32 * 0.5) as u32;
     } else if let Some(act_w) = opt_w {
         w = act_w;
         h = (img.height() as f32 * w as f32 / img.width() as f32 * 0.5) as u32;
     } else {
-        h = max_h-1;
+        h = max_h - 1;
         w = (img.width() as f32 * h as f32 / img.height() as f32 * 2.0) as u32;
 
         if w >= max_w {
-            w = max_w-1;
+            w = max_w - 1;
             h = (img.height() as f32 * w as f32 / img.width() as f32 * 0.5) as u32;
         }
     }

src/main.rs

@@ -1,5 +1,4 @@
 //! Driver module.
-#![feature(file_create_new)]
 
 use crate::ascii_manipulation::*;
 use crate::cli::Cli;
@@ -45,10 +44,16 @@ fn main() {
     if let Some(output) = cli.output {
         print_file(out, output);
     } else {
-        if cli.background && (cli.colour || cli.grayscale) {
+        let prefix;
-            print_terminal_background(out, cli.colour, cli.grayscale);
+        if cli.center {
+            prefix = calc_margin(&out);
         } else {
-            print_terminal(out, cli.colour, cli.grayscale);
+            prefix = 0;
+        }
+        if cli.background && (cli.colour || cli.grayscale) {
+            print_terminal_background(out, cli.colour, cli.grayscale, prefix);
+        } else {
+            print_terminal(out, cli.colour, cli.grayscale, prefix);
         }
     }
 }

src/output.rs

@@ -1,12 +1,12 @@
 //! This module contains functions related to output.
+use crate::model_rgb_ascii::Ascii;
+use crossterm::execute;
+use crossterm::style::{Color, Print, ResetColor, SetBackgroundColor, SetForegroundColor};
+use log::error;
 use std::fs::File;
 use std::io::{stdout, Write};
 use std::path::PathBuf;
 use std::process::exit;
-use crossterm::execute;
-use crossterm::style::{Color, SetForegroundColor, SetBackgroundColor, Print, ResetColor};
-use log::error;
-use crate::model_rgb_ascii::Ascii;
 
 /// This function prints ASCII art to stdout.
 ///
@@ -14,19 +14,34 @@ use crate::model_rgb_ascii::Ascii;
 /// 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) {
+/// prefix: u32 - number of empty spaces to prepend to each line
+pub fn print_terminal(art: Vec<Vec<Ascii>>, in_colour: bool, grayscale: bool, prefix: u32) {
+    let prefix_str = " ".repeat(prefix as usize);
     for line in art {
+        let _ = execute!(stdout(), Print(prefix_str.clone()));
         for ascii in line {
             if in_colour {
-                let _ = execute!(stdout(),
+                let _ = execute!(
-                    SetForegroundColor(Color::Rgb {r: ascii.rgb[0], g: ascii.rgb[1], b: ascii.rgb[2]}),
+                    stdout(),
+                    SetForegroundColor(Color::Rgb {
+                        r: ascii.rgb[0],
+                        g: ascii.rgb[1],
+                        b: ascii.rgb[2]
+                    }),
                     Print(ascii.char),
-                    ResetColor);
+                    ResetColor
+                );
             } else if grayscale {
-                let _ = execute!(stdout(),
+                let _ = execute!(
-                    SetForegroundColor(Color::Rgb {r: ascii.col_depth, g: ascii.col_depth, b: ascii.col_depth}),
+                    stdout(),
+                    SetForegroundColor(Color::Rgb {
+                        r: ascii.col_depth,
+                        g: ascii.col_depth,
+                        b: ascii.col_depth
+                    }),
                     Print(ascii.char),
-                    ResetColor);
+                    ResetColor
+                );
             } else {
                 print!("{}", ascii.char);
             }
@@ -41,21 +56,49 @@ pub fn print_terminal(art: Vec<Vec<Ascii>>, in_colour: bool, grayscale: bool) {
 /// 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) {
+/// prefix: u32 - number of empty spaces to prepend to each line
+pub fn print_terminal_background(
+    art: Vec<Vec<Ascii>>,
+    in_colour: bool,
+    grayscale: bool,
+    prefix: u32,
+) {
+    let prefix_str = " ".repeat(prefix as usize);
     for line in art {
+        let _ = execute!(stdout(), Print(prefix_str.clone()));
         for ascii in line {
             if in_colour {
-                let _ = execute!(stdout(),
+                let _ = execute!(
-                    SetBackgroundColor(Color::Rgb {r: ascii.rgb[0], g: ascii.rgb[1], b: ascii.rgb[2]}),
+                    stdout(),
-                    SetForegroundColor(Color::Rgb {r: 255-ascii.rgb[0], g: 255-ascii.rgb[1], b: 255-ascii.rgb[2]}),
+                    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);
+                    ResetColor
+                );
             } else if grayscale {
-                let _ = execute!(stdout(),
+                let _ = execute!(
-                    SetBackgroundColor(Color::Rgb {r: ascii.col_depth, g: ascii.col_depth, b: ascii.col_depth}),
+                    stdout(),
-                    SetForegroundColor(Color::Rgb {r: 255-ascii.col_depth, g: 255-ascii.col_depth, b: 255-ascii.col_depth}),
+                    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);
+                    ResetColor
+                );
             } else {
                 error!("This should be unreachable!");
                 exit(1);