fix dithering and indexing for image

index.pug

@@ -56,14 +56,14 @@ html(lang="en-gb")
 
                                 label
                                     | brightness
-                                    input#brightness(type="range" min=-64 max=64 value=0)
+                                    input#brightness(type="range" min=-96 max=96 value=0)
-                            td
+                            td(style="vertical-align: top;")
                                 label
                                     | palette
                                     select#palette
 
                                 label
-                                    input#dither(type="checkbox")
+                                    input#dither(type="checkbox" checked=true)
                                     | dither
                                 br
 

script.js

@@ -93,7 +93,7 @@ async function run() {
     }
 
     function new_game() {
-        load_default_game()
+        console.debug(load_default_game());
         textareaGameDataInput.value = output();
         checkGameData();
         // we don't need to look at the default game data, so skip ahead to the image page
@@ -121,7 +121,8 @@ async function run() {
     });
 
     function setPaletteDropdown() {
-        let palettes = JSON.parse(get_palettes());
+        const palettes = JSON.parse(get_palettes());
+        console.debug(palettes);
 
         selectPalette.innerHTML = "";
 

src/lib.rs

@@ -4,6 +4,8 @@ use bitsy_parser::game::Game;
 use bitsy_parser::image::Image;
 use bitsy_parser::tile::Tile;
 use image::{GenericImageView, Pixel, DynamicImage};
+use image::imageops::ColorMap;
+use image::imageops::FilterType::CatmullRom;
 use lazy_static::lazy_static;
 use std::sync::Mutex;
 use wasm_bindgen::prelude::*;
@@ -62,7 +64,7 @@ pub fn load_game(game_data: String) -> String {
             let palette_id = game.palette_ids()[0].clone();
             state.game    = Some(game);
             state.palette = Some(palette_id);
-            "".to_string()
+            format!("Loaded game")
         },
         _ => {
             state.game    = None;
@@ -83,6 +85,7 @@ pub fn load_image(image_base64: String) -> String {
         Ok(image) => {
             match image::load_from_memory(image.as_ref()) {
                 Ok(image) => {
+                    // todo get rid of magic numbers! what about Bitsy HD?
                     let image = image.resize(128, 128, CatmullRom);
                     state.image = Some(image);
                     "OK"
@@ -166,15 +169,36 @@ fn render_preview(state: &State) -> DynamicImage {
 
     // todo get actual chosen palette
     let palette_id   = state.palette.as_ref().unwrap();
-    let palette = &state.game.as_ref().unwrap().get_palette(palette_id).unwrap();
+    let palette     = *&state.game.as_ref().unwrap().get_palette(palette_id).unwrap();
     let colour_map = crate::ColourMap::from(palette);
 
-    image::imageops::brighten(&mut buffer, state.brightness);
+    let mut buffer = image::imageops::brighten(&mut buffer, state.brightness);
 
     if state.dither {
         image::imageops::dither(&mut buffer, &colour_map);
     } else {
-        image::imageops::colorops::index_colors(&mut buffer, &colour_map);
+        // just do colour indexing
+        let indices = image::imageops::colorops::index_colors(&mut buffer, &colour_map);
+
+        // todo get rid of magic numbers! what about Bitsy HD?
+        buffer = image::ImageBuffer::from_fn(128, 128, |x, y| -> image::Rgba<u8> {
+            let p = indices.get_pixel(x, y);
+            colour_map
+                .lookup(p.0[0] as usize)
+                .expect("indexed color out-of-range")
+                .into()
+        });
+        let mut indexed = buffer.clone();
+        for (i, pixel) in buffer.pixels().enumerate() {
+            // todo get rid of magic numbers! what about Bitsy HD?
+            let mut pixel = image::Rgba::from(pixel.0);
+            colour_map.map_color(&mut pixel);
+            indexed.put_pixel(
+                (i % 128) as u32,
+                (i / 128) as u32,
+                pixel
+            );
+        }
     }
 
     image::DynamicImage::ImageRgba8(buffer)