Share the frame render logic across all display backends (color term, Y4M video)

src/render.rs

@@ -1,16 +1,42 @@
 use ansi_term::Color::RGB;
 use crate::{consts, Material as _, SimState};
+use image::{RgbImage, Rgb};
+use std::convert::TryInto as _;
 use std::fmt::Write as _;
 use std::fs::File;
 use std::path::PathBuf;
-use y4m::{Colorspace, encode, Encoder, Frame, Ratio};
+use y4m;
+
+fn simstate_to_image(state: &SimState) -> RgbImage {
+    let w = state.width().try_into().unwrap();
+    let h = state.height().try_into().unwrap();
+    let mut image = RgbImage::new(w, h);
+    for y in 0..h {
+        for x in 0..w {
+            let cell = state.get(x as usize, y as usize);
+            //let r = norm_color(cell.bz() * consts::C);
+            //let r = 0;
+            let r = norm_color(cell.mat().mz()*1.0e-2);
+            let b = (55.0*cell.mat().conductivity()).min(255.0) as u8;
+            //let b = 0;
+            //let b = norm_color(cell.ey());
+            //let g = 0;
+            //let g = norm_color(cell.ex());
+            //let g = norm_color(curl(cell.ex(), cell.ey()));
+            let g = norm_color((cell.bz() * 1.0e4).into());
+            image.put_pixel(x, y, Rgb([r, g, b]));
+        }
+    }
+    image
+}
 
-pub struct NumericTermRenderer;
 
 pub trait Renderer {
     fn render(&mut self, state: &SimState);
 }
 
+pub struct NumericTermRenderer;
+
 impl Renderer for NumericTermRenderer {
     fn render(&mut self, state: &SimState) {
         for y in 0..state.height() {
@@ -50,33 +76,24 @@ fn curl(x: f64, y: f64) -> f64 {
 
 impl Renderer for ColorTermRenderer {
     fn render(&mut self, state: &SimState) {
-        let mut buf = String::new();
         let square = "█";
-        for y in 0..state.height() {
-            for x in 0..state.width() {
-                let cell = state.get(x, y);
-                //let r = norm_color(cell.bz() * consts::C);
-                //let r = 0;
-                let r = norm_color(cell.mat().mz()*1.0e-2);
-                let b = (55.0*cell.mat().conductivity()).min(255.0) as u8;
-                //let b = 0;
-                //let b = norm_color(cell.ey());
-                //let g = 0;
-                //let g = norm_color(cell.ex());
-                //let g = norm_color(curl(cell.ex(), cell.ey()));
-                let g = norm_color((cell.bz() * 1.0e4).into());
-                //let g = norm_color(cell.ey().into());
-                write!(&mut buf, "{}", RGB(r, g, b).paint(square));
-            }
-            write!(&mut buf, "\n");
-        }
-        println!("{}\ntime: {:.3e} (fr {})", buf, state.time(), state.step_no());
+        let im = simstate_to_image(state);
+        let buf: String = im
+            .enumerate_rows()
+            .map(|(_y, row)| {
+                format!("{}\n", row.map(|(_x, _y, p)| {
+                    format!("{}", RGB(p.0[0], p.0[1], p.0[2]).paint(square))
+                }).collect::<String>())
+            })
+            .collect();
+
+        println!("{}time: {:.3e} (fr {})", buf, state.time(), state.step_no());
     }
 }
 
 pub struct Y4MRenderer {
     out_path: PathBuf,
-    encoder: Option<Encoder<File>>,
+    encoder: Option<y4m::Encoder<File>>,
 }
 
 impl Y4MRenderer {
@@ -90,10 +107,11 @@ impl Y4MRenderer {
 
 impl Renderer for Y4MRenderer {
     fn render(&mut self, state: &SimState) {
+        let im = simstate_to_image(state);
         if self.encoder.is_none() {
             let writer = File::create(&self.out_path).unwrap();
-            self.encoder = Some(encode(state.width(), state.height(), Ratio::new(30, 1))
-                .with_colorspace(Colorspace::C444)
+            self.encoder = Some(y4m::encode(im.width() as usize, im.height() as usize, y4m::Ratio::new(30, 1))
+                .with_colorspace(y4m::Colorspace::C444)
                 .write_header(writer)
                 .unwrap()
             );
@@ -102,27 +120,13 @@ impl Renderer for Y4MRenderer {
         let mut pix_y = Vec::new();
         let mut pix_u = Vec::new();
         let mut pix_v = Vec::new();
-        for y in 0..state.height() {
-            for x in 0..state.width() {
-                let cell = state.get(x, y);
-                //let r = norm_color(cell.bz() * consts::C);
-                //let r = 0;
-                let r = norm_color(cell.mat().mz()*1.0e-2);
-                let b = (55.0*cell.mat().conductivity()).min(255.0) as u8;
-                //let b = 0;
-                //let b = norm_color(cell.ey());
-                //let g = 0;
-                //let g = norm_color(cell.ex());
-                //let g = norm_color(curl(cell.ex(), cell.ey()));
-                let g = norm_color((cell.bz() * 1.0e4).into());
-                //let g = norm_color(cell.ey().into());
-                pix_y.push(r);
-                pix_u.push(g);
-                pix_v.push(b);
-            }
+        for &Rgb([r, g, b]) in im.pixels() {
+            pix_y.push(r);
+            pix_u.push(g);
+            pix_v.push(b);
         }
 
-        let frame = Frame::new([&*pix_y, &*pix_u, &*pix_v], None);
+        let frame = y4m::Frame::new([&*pix_y, &*pix_u, &*pix_v], None);
         let enc = self.encoder.as_mut().unwrap();
         enc.write_frame(&frame).unwrap()
     }