draw: Add ability to set individual char color

src/draw.rs

@@ -58,13 +58,68 @@ pub fn draw_text(
     Ok((x_max, y_max))
 }
 
+pub fn draw_text_individual_colors(
+    font_data: &'static [u8],
+    buf: &mut Buffer,
+    background_color: &Color,
+    color: &[Color],
+    size: f32,
+    s: &str,
+) -> Result<(u32, u32), ::std::io::Error> {
+    // Load the font
+    // This only succeeds if collection consists of one font
+    let font = Font::from_bytes(font_data as &[u8]).expect("Error constructing Font");
+
+    // The font size to use
+    let scale = Scale::uniform(size);
+
+    let v_metrics = font.v_metrics(scale);
+
+    // layout the glyphs in a line with 20 pixels padding
+    let glyphs: Vec<_> = font
+        .layout(s, scale, point(0.0, v_metrics.ascent))
+        .collect();
+
+    let mut x_max: u32 = 0;
+    let mut y_max: u32 = 0;
+    let mut x_pos: usize = 0;
+
+    // Loop through the glyphs in the text, positing each one on a line
+    for glyph in glyphs {
+        if let Some(bounding_box) = glyph.pixel_bounding_box() {
+            if bounding_box.max.x > x_max as i32 {
+                x_max = bounding_box.max.x as u32;
+            }
+            if bounding_box.max.y > y_max as i32 {
+                y_max = bounding_box.max.y as u32;
+            }
+            // Draw the glyph into the image per-pixel by using the draw closure
+            glyph.draw(|x, y, o| {
+                let x = x + bounding_box.min.x as u32;
+                let y = y + bounding_box.min.y as u32;
+                let o = if o > 1.0 {
+                    1.0
+                } else if o < 0.0 {
+                    0.0
+                } else {
+                    o
+                };
+                let _ = buf.put((x, y), &background_color.blend(&color[x_pos], o));
+            });
+            x_pos += 1;
+        }
+    }
+
+    Ok((x_max, y_max))
+}
+
 pub fn draw_text_fixed_width(
     font_data: &'static [u8],
     buf: &mut Buffer,
     background_color: &Color,
     color: &Color,
     size: f32,
-    distances: Vec<u32>,
+    distances: &[u32],
     s: &str,
 ) -> Result<(), ::std::io::Error> {
     // Load the font