Better zooming

mas/fractals/mandel/Cargo.toml

@@ -8,4 +8,8 @@ edition = "2021"
 [dependencies]
 num = "0.4.0"
 matrix = "0.22.0"
-sdl2 = "0.35.2"
+
+[dependencies.sdl2]
+version = "0.35.2"
+default-features = false
+features = ["ttf"]

mas/fractals/mandel/src/main.rs

@@ -15,9 +15,9 @@ fn main() {
     */
     let (width, height) = (640, 480);
     let (mut dx, mut dy) = (0.0, 0.0);
-    let (mut zx, mut zy) = (0.0, 0.0);
+    let (mut zx, mut zy) = (2.0, 2.0);
     let mut step = 0.05;
-    let (mut dzx, mut dzy) = (0.4, 0.2);
+    let (mut zoom_in, mut zoom_out) = (1.1, 0.9);
     let depth = 1000;
     
     let (window, ctx, vid_sys) = render::create_window("Mandelbrot set", width, height);
@@ -60,14 +60,14 @@ fn main() {
                 Event::KeyDown { keycode: Some(Keycode::Space), .. } => {
                     println!("ZOOM+");
                     render_new = true;
-                    zy -= dzy;
+                    zy *= zoom_in;
-                    zx -= dzx;
+                    zx *= zoom_in;
                 },
                 Event::KeyDown { keycode: Some(Keycode::LShift), .. } => {
                     println!("ZOOM-");
                     render_new = true;
-                    zy += dzy;
+                    zy *= zoom_out;
-                    zx += dzx;
+                    zx *= zoom_out;
                 },
                 _ => {}
             }

mas/fractals/mandel/src/mandel.rs

@@ -33,9 +33,9 @@ pub fn mandelbrot(canvas: &mut Canvas<sdl2::video::Window>, w: u32, h: u32, dept
    */
 
     for dx in 0..w {
-        let x0 = ((dx as f32) / (w as f32)) * (3.5 + xzoom) - (2.5 - xoffset);
+        let x0 = ((dx as f32) / (w as f32)) * (xzoom) - (2.5 - xoffset);
         for dy in 0..h {
-            let y0 = ((dy as f32) / (h as f32)) * (2.0 + yzoom) - (1.0 + yoffset);
+            let y0 = ((dy as f32) / (h as f32)) * (yzoom) - (1.0 + yoffset);
 
         let (mut x, mut y) = (0.0, 0.0);
             let mut i: u32 = 0;

mas/fractals/mandel/src/render.rs

@@ -2,6 +2,7 @@ extern crate sdl2;
 use sdl2::pixels::Color;
 use sdl2::rect::Rect;
 use sdl2::render::Canvas;
+use sdl2::ttf::Font;
 
 pub fn create_window(title: &str, width: u32, height: u32) 
     -> (sdl2::video::Window, sdl2::Sdl, sdl2::VideoSubsystem) 
@@ -16,6 +17,20 @@ pub fn create_window(title: &str, width: u32, height: u32)
     return (window, ctx, vid_sys);
 }
 
+/*
+pub fn text(x: u32, y: u32, text: &str, font_path: &str) {
+    let ttf_context = sdl2::ttf::init();
+    let mut font = ttf_context.load_font(font_path, 128);
+    font.set_style(sdl2::ttf::FontStyle::BOLD);
+
+    // render a surface, and convert it to a texture bound to the canvas
+    let surface = font
+        .render(text)
+        .blended(Color::RGBA(255, 255, 255, 255))
+        .map_err(|e| e.to_string())?;
+}
+*/
+
 pub fn set_pixel(canvas: &mut Canvas<sdl2::video::Window>, x: i32, y: i32, color: Color) {
     canvas.set_draw_color(color);
     canvas.fill_rect(Rect::new(x, y, 1, 1));