From 0085199914f64098dc3b93d31d2a3980d99bd587 Mon Sep 17 00:00:00 2001
From: Vladimir Serov <me@cab404.ru>
Date: Sun, 9 Feb 2020 15:51:37 +0300
Subject: [PATCH] utf-8: initial support

---
 src/render/utf8.rs | 74 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 src/render/utf8.rs

diff --git a/src/render/utf8.rs b/src/render/utf8.rs
new file mode 100644
index 0000000..c01aaf7
--- /dev/null
+++ b/src/render/utf8.rs
@@ -0,0 +1,74 @@
+//! UTF-8 rendering, with 2 pixels per symbol.
+
+use crate::render::{Canvas as RenderCanvas, Pixel, Color};
+
+impl Pixel for u8 {
+    type Image = String;
+    type Canvas = Canvas;
+    fn default_color(color: Color) -> u8 {if color == Color::Dark {1} else {0}}
+    fn default_unit_size() -> (u32, u32) { (1, 1) }
+}
+
+pub struct Canvas {
+    canvas: Vec<u8>,
+    width: u32,
+    dark_pixel: u8
+}
+
+impl RenderCanvas for Canvas {
+
+    type Pixel = u8;
+    type Image = String;
+
+    
+    fn new(width: u32, height: u32, dark_pixel: u8, light_pixel: u8) -> Self { 
+        let a = vec![light_pixel; (width * height) as usize];
+        Canvas {
+            width: width,
+            canvas: a,
+            dark_pixel: dark_pixel
+        }
+    }
+
+    fn draw_dark_pixel(&mut self, x: u32, y: u32) { 
+        self.canvas[(x + y * self.width) as usize] = self.dark_pixel;
+    }
+
+    fn into_image(self) -> String { 
+        self.canvas
+            // Chopping array into 1-line sized fragments
+            .chunks_exact(self.width as usize)
+            .collect::<Vec<&[u8]>>()
+            // And then glueing every 2 lines.
+            .chunks(2)
+            .map(|rows|
+                {
+                    // Then zipping those 2 lines together into a single 2-bit number list.
+                    if rows.len() == 2 {
+                        rows[0].iter().zip(rows[1]).map(|(top,bot)| (top * 2 + bot)).collect::<Vec<u8>>()
+                    } else {
+                        rows[0].iter().map(|a| (a * 2)).collect::<Vec<u8>>()
+                    }
+                }.iter()
+                // Mapping those 2-bit numbers to corresponding pixels.
+                .map(|sym| [" ","\u{2584}","\u{2580}","\u{2588}"][*sym as usize])
+                .collect::<Vec<&str>>()
+                .concat()
+            )
+            .collect::<Vec<String>>()
+            .join("\n")
+    }
+}
+
+#[test]
+fn test_render_to_utf8_string() {
+    use crate::render::Renderer;
+    let colors = &[Color::Dark, Color::Light, Color::Light, Color::Dark];
+    let image: String = Renderer::<u8>::new(colors, 2, 1).build();
+    
+    assert_eq!(&image, " ▄  \n  ▀ ");
+
+    let image2 = Renderer::<u8>::new(colors, 2, 1).module_dimensions(2, 2).build();
+
+    assert_eq!(&image2, "        \n  ██    \n    ██  \n        ");
+}