Initial commit

main.js

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+/*
+
+  MIT License
+
+  Copyright (c) 2023 Michael Smith <root@retrospace.be>
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in all
+  copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+  SOFTWARE.
+
+ */
+
+import PBM from "./src/pbm.js";
+
+const thumbnailCanvas = document.getElementById("thumbnail-canvas");
+const thumbnailContext = thumbnailCanvas.getContext("2d");
+const imageCanvas = document.getElementById("image-canvas");
+const imageContext = imageCanvas.getContext("2d");
+const inputElement = document.getElementById("imagefile");
+inputElement.addEventListener("change", handleFile, false);
+
+fetch("/assets/TEST.LBM")
+  .then((response) => {
+    return response.arrayBuffer();
+  })
+  .then((buffer) => {
+    const image = loadImage(buffer);
+    drawImage(image.thumbnail, thumbnailContext);
+    drawImage(image, imageContext);
+  });
+
+function handleFile() {
+  const imageFile = this.files[0];
+  const reader = new FileReader();
+
+  reader.onload = (evt) => {
+    const image = loadImage(evt.target.result);
+    drawImage(image.thumbnail, thumbnailContext);
+    drawImage(image, imageContext);
+  };
+
+  reader.readAsArrayBuffer(imageFile);
+}
+
+function loadImage(buffer) {
+  const image = new PBM(buffer);
+  thumbnailCanvas.width = image.thumbnail.width;
+  thumbnailCanvas.height = image.thumbnail.height;
+  imageCanvas.width = image.width;
+  imageCanvas.height = image.height;
+
+  return image;
+}
+
+function drawImage(image, context) {
+  context.clearRect(0, 0, image.width, image.height);
+  let pixels = context.createImageData(image.width, image.height);
+
+  for (let x = 0; x < image.width; x++) {
+    for (let y = 0; y < image.height; y++) {
+      const index = y * image.width + x;
+      const paletteIndex = image.pixelData[index];
+      const pixelIndex = index * 4;
+
+      const r = image.palette[paletteIndex][0];
+      const g = image.palette[paletteIndex][1];
+      const b = image.palette[paletteIndex][2];
+
+      pixels.data[pixelIndex] = r;
+      pixels.data[pixelIndex + 1] = g;
+      pixels.data[pixelIndex + 2] = b;
+      pixels.data[pixelIndex + 3] = 255;
+    }
+  }
+
+  context.putImageData(pixels, 0, 0);
+}