Add rasterization to bitmap to sixel.

.gitignore

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+/target

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
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+checksum = "2e57e16b3fe8ff4364c0661fdaac543fb38b29ea9bc9c2f45612d90adf931d2b"
+dependencies = [
+ "hashbrown",
+ "ttf-parser",
+]
+
+[[package]]
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+dependencies = [
+ "allocator-api2",
+ "equivalent",
+ "foldhash",
+]
+
+[[package]]
+name = "icy_sixel"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
+name = "rustex"
+version = "0.1.0"
+dependencies = [
+ "fontdue",
+ "icy_sixel",
+ "lazy_static",
+]
+
+[[package]]
+name = "ttf-parser"
+version = "0.21.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c591d83f69777866b9126b24c6dd9a18351f177e49d625920d19f989fd31cf8"

Cargo.toml

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+[package]
+name = "rustex"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+fontdue = "0.9.3"
+icy_sixel = "0.1.3"
+lazy_static = "1.5.0"

src/fonts.rs

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+use fontdue::Font;
+use lazy_static::lazy_static;
+
+pub static KaTeX_Main_Regular: &'static [u8] = include_bytes!("../fonts/KaTeX_Main-Regular.ttf");
+
+lazy_static! {
+    pub static ref FONTS: Vec<Font> = vec![
+        Font::from_bytes(KaTeX_Main_Regular, fontdue::FontSettings::default()).unwrap(),
+    ];
+}

src/main.rs

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+#[allow(non_upper_case_globals)] 
+
+mod fonts;
+
+use fontdue::{layout::{CoordinateSystem, Layout, LayoutSettings, TextStyle}};
+use icy_sixel::{
+    DiffusionMethod, MethodForLargest, MethodForRep, PixelFormat, Quality, sixel_string,
+};
+
+fn main() -> Result<(), std::fmt::Error> {
+    let mut rustex = RusTeX::new();
+    rustex.add_text(&TextStyle::new("testi12345ng! e^23", 35.0, 0));
+    let (bitmap, (width, height)) = rustex.rasterize();
+    print_bitmap(&bitmap, width, height);
+    Ok(())
+}
+
+struct RusTeX {
+    layout: Layout,
+}
+
+impl RusTeX {
+    pub fn new() -> Self {
+        let mut layout = Layout::new(CoordinateSystem::PositiveYDown);
+        // By default, layout is initialized with the default layout settings. This call is redundant, but
+        // demonstrates setting the value with your custom settings.
+        layout.reset(&LayoutSettings {
+            ..LayoutSettings::default()
+        });
+
+        Self {
+            layout,
+        }
+    }
+
+    pub fn add_text(&mut self, text_style: &TextStyle) {
+        self.layout.append(&fonts::FONTS, text_style);
+    }
+
+    pub fn rasterize(&mut self) -> (Vec<u8>, (usize, usize)) {
+        let (mut maxx, mut maxy): (usize, usize) = (0,0);
+        for glyph in self.layout.glyphs() {
+            maxx = maxx.max(glyph.x as usize + glyph.width);
+            maxy = maxy.max(glyph.y as usize + glyph.height);
+        }
+
+        let mut bitmap: Vec<u8> = vec![0; maxx*maxy];
+        
+        for glyph in self.layout.glyphs() {
+
+            let font = &fonts::FONTS[glyph.font_index];
+            let (metrics, char_bitmap) = font.rasterize_config(glyph.key);
+
+            
+            
+            for y in 0..metrics.height {
+                for x in 0..metrics.width {
+                    let pixel = char_bitmap[y*glyph.width + x];
+
+                    // let index = (x+glyph.x as usize)*maxy + (y+glyph.y as usize);
+                    let index = (y+glyph.y as usize)*maxx + (x+glyph.x as usize);
+
+                    bitmap[index] = pixel;
+                }
+            }
+        }
+
+        (bitmap, (maxx, maxy))
+    }
+}
+
+/// Prints a 1 byte per pixel greyscale bitmap to Sixel format in console
+fn print_bitmap(bitmap: &Vec<u8>, width: usize, height: usize) {
+    let mut bitmap_rgb888 = vec![0; width*height*3];
+
+
+    for y in 0..height {
+        for x in 0..width {
+            let index = y*width + x;
+
+            let pixel = bitmap[index];
+
+            bitmap_rgb888[index*3] = pixel;
+            bitmap_rgb888[index*3 + 1] = pixel;
+            bitmap_rgb888[index*3 + 2] = pixel;
+        }
+    }
+    
+
+
+
+    let sixel_data = sixel_string(
+        &bitmap_rgb888,
+        width as i32,
+        height as i32,
+        PixelFormat::RGB888,
+        DiffusionMethod::None,
+        MethodForLargest::Auto,
+        MethodForRep::Auto,
+        Quality::AUTO,
+    ).unwrap();
+
+    println!("{}", sixel_data);
+
+}