glyph metrics

src/editor_render.rs

@@ -7,9 +7,16 @@ use std::{fs::File, path::Path, io::Read};
 
 use sdl2::rect::Point;
 
-const GLYPH_WIDTH:  usize = 8;
-const GLYPH_HEIGHT: usize = 14;
-const GLYPH_AREA:   usize = GLYPH_WIDTH * GLYPH_HEIGHT;
+pub struct GlyphMetrics {
+    width:  usize,
+    height: usize,
+}
+
+impl GlyphMetrics {
+    fn area(&self) -> usize {
+        self.width * self.height
+    }
+}
 
 type Glyph = Vec<Point>;
 
@@ -28,16 +35,20 @@ fn read_file(file_name: String) -> Vec<u8> {
     file_content
 }
 
-pub fn generate_glyph_atlas() -> Vec<Glyph> {
+pub fn generate_glyph_data() -> (Vec<Glyph>, GlyphMetrics) {
     // Retrieve font data from file
     let file_path = String::from("./fonts/Terminus14x8.data");
     let contents = read_file(file_path);
 
+    // Get glyph metrics
+    let glyph_metrics = GlyphMetrics { width: 8, height: 16 };
+    let glyph_width   = glyph_metrics.width;
+
     // Get width of image for proper positioning of pixels
     let width_left_byte  = contents[0];
     let width_right_byte = contents[1];
-    let number = [width_left_byte, width_right_byte];
-    let width = u16::from_be_bytes(number);
+    let width_bytes = [width_left_byte, width_right_byte];
+    let width = u16::from_be_bytes(width_bytes);
     println!("Left Byte: {width_left_byte}, Right Byte: {width_right_byte}, Byte Pair: {width}");
 
     let gtable_prune = &contents[width as usize + 2 ..];
@@ -47,12 +58,13 @@ pub fn generate_glyph_atlas() -> Vec<Glyph> {
     for glyph in 0..96 {
         let mut new_glyph: Glyph = vec![];
 
-        for p in 0..GLYPH_AREA as u16 {
-            let x = p % GLYPH_WIDTH as u16;
-            let y = p / GLYPH_WIDTH as u16;
+        let glyph_area = glyph_metrics.area();
+        for p in 0..glyph_area as u16 {
+            let x = p % glyph_width as u16;
+            let y = p / glyph_width as u16;
 
             let multiplier = y * width;
-            let offset = glyph * GLYPH_WIDTH as u16;
+            let offset = glyph * glyph_width as u16;
             let position = (x + multiplier + offset) as usize;
 
             if gtable_prune[position] == 1 {
@@ -61,13 +73,16 @@ pub fn generate_glyph_atlas() -> Vec<Glyph> {
         }
         glyph_atlas.push(new_glyph);
     }
-    glyph_atlas
+    (glyph_atlas, glyph_metrics)
 }
 
 /// Method for generating points to render, using given string
-pub fn draw_text(glyph_atlas: &Vec<Glyph>, content: &str, offset: Point) -> Vec<Point> {
+pub fn draw_text(glyph_atlas: &Vec<Glyph>, glyph_metrics: &GlyphMetrics, content: &str, offset: Point) -> Vec<Point> {
     let mut points: Vec<Point> = vec![];
 
+    let glyph_width   = glyph_metrics.width;
+    let glyph_height  = glyph_metrics.height;
+
     let lines = content.split('\n');
     for (y, chars) in lines.enumerate() {
         for (x, chara) in chars.chars().enumerate() {
@@ -79,8 +94,8 @@ pub fn draw_text(glyph_atlas: &Vec<Glyph>, content: &str, offset: Point) -> Vec<
             }
 
             for pixel in &glyph_atlas[index - 32] {
-                let x_glyph = x * GLYPH_WIDTH;
-                let y_glyph = y * GLYPH_HEIGHT;
+                let x_glyph = x * glyph_width;
+                let y_glyph = y * glyph_height;
 
                 let positioned_pixel = Point::new(
                     pixel.x + x_glyph as i32 + offset.x,
@@ -93,10 +108,12 @@ pub fn draw_text(glyph_atlas: &Vec<Glyph>, content: &str, offset: Point) -> Vec<
     points
 }
 
-pub fn draw_cursor(mut cursor_position: usize, content: &str, offset: Point) -> (Point, Point) {
+pub fn draw_cursor(glyph_metrics: &GlyphMetrics, mut cursor_position: usize, content: &str, offset: Point) -> (Point, Point) {
+    let glyph_width   = glyph_metrics.width;
+    let glyph_height  = glyph_metrics.height;
+
     let mut x = 0;
     let mut y = 0;
-
     if cursor_position > 0 {
         cursor_position = cursor_position.checked_sub(1).unwrap_or(0);
         for (idx, chara) in content.chars().enumerate() {
@@ -107,15 +124,15 @@ pub fn draw_cursor(mut cursor_position: usize, content: &str, offset: Point) ->
                 y += 1;
             }
             if idx == cursor_position {
-                let point_a = Point::new((x * GLYPH_WIDTH)  as i32 + offset.x,
-                                         (y * GLYPH_HEIGHT) as i32 + offset.y
+                let point_a = Point::new((x * glyph_width)  as i32 + offset.x,
+                                         (y * glyph_height) as i32 + offset.y
                 );
                 let point_b = Point::new(point_a.x,
-                                         point_a.y + GLYPH_HEIGHT as i32
+                                         point_a.y + glyph_height as i32
                 );
                 return (point_a, point_b)
             }
         }
     }
-    (Point::new(offset.x, offset.y), Point::new(offset.x, offset.y + GLYPH_HEIGHT as i32))
+    (Point::new(offset.x, offset.y), Point::new(offset.x, offset.y + glyph_height as i32))
 }

src/main.rs

@@ -19,7 +19,7 @@ struct ModifierKeys {
 
 pub fn main() -> Result<(), String> {
     let mut clipboard_context: ClipboardContext = ClipboardProvider::new().unwrap();
-    let glyph_atlas = editor_render::generate_glyph_atlas();
+    let (glyph_atlas, glyph_metrics) = editor_render::generate_glyph_data();
 
     let sdl_context = sdl2::init()?;
     let video_subsys = sdl_context.video()?;
@@ -48,6 +48,7 @@ pub fn main() -> Result<(), String> {
         canvas.set_draw_color(Color::RGB(240, 240, 240));
         let fb_text = editor_render::draw_text(
             &glyph_atlas,
+            &glyph_metrics,
             text,
             pad_offset
         );
@@ -56,6 +57,7 @@ pub fn main() -> Result<(), String> {
         // Draw cursor
         canvas.set_draw_color(Color::RGB(64, 240, 240));
         let fb_cursor = editor_render::draw_cursor(
+            &glyph_metrics,
             pos,
             text,
             pad_offset
@@ -233,6 +235,7 @@ pub fn main() -> Result<(), String> {
             }
         }
     }
+    format!("{selection_anchor:?}");
     println!("{buffer}");
     Ok(())
 }