Initial commit.

.babelrc

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+{
+  "presets": ["latest"]
+}

.editorconfig

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+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+end_of_line = lf
+trim_trailing_whitespace = true
+insert_final_newline = true
+

.gitignore

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+node_modules
+lib

package.json

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+{
+  "name": "themer-wallpaper-block-wave",
+  "version": "1.0.0",
+  "description": "Wallpaper generator for themer.",
+  "main": "lib/index.js",
+  "author": "mjswensen",
+  "license": "MIT",
+  "jest": {
+    "rootDir": "lib"
+  },
+  "scripts": {
+    "build": "babel --out-dir lib src",
+    "start": "watch 'yarn run build' src",
+    "test": "jest"
+  },
+  "devDependencies": {
+    "babel-cli": "^6.18.0",
+    "babel-preset-latest": "^6.16.0",
+    "jest-cli": "^17.0.3",
+    "watch": "^1.0.1"
+  },
+  "dependencies": {
+    "svg2png": "^4.1.0"
+  }
+}

src/index.js

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+import weightedRandom from './weighted-random';
+import svg2png from 'svg2png';
+
+export const render = (colors, options) => {
+
+  const colorWeights = new Map([
+    ['accent0', 1],
+    ['accent1', 1],
+    ['accent2', 1],
+    ['accent3', 1],
+    ['accent4', 1],
+    ['accent5', 1],
+    ['accent6', 1],
+    ['accent7', 1],
+    ['shade0', 0],
+    ['shade1', 8],
+    ['shade2', 6],
+    ['shade3', 4],
+    ['shade4', 3],
+    ['shade5', 2],
+    ['shade6', 1],
+    ['shade7', 1],
+  ]);
+
+  const colorSets = [{ name: 'dark', colors: colors.dark }, { name: 'light', colors: colors.light }].filter(colorSet => !!colorSet.colors);
+
+  const sizes = [ // TODO: get from args with this and a device being the default
+    {
+      w: 2880,
+      h: 1800,
+      s: 36,
+    },
+  ];
+
+  const deepFlatten = arr => arr.reduce((cumulative, inner) => cumulative.concat(Array.isArray(inner) ? deepFlatten(inner) : inner), []);
+
+  return deepFlatten(colorSets.map(colorSet => sizes.map(size => {
+      let blockMaxSize = size.s / 3;
+      let blockMinSize = blockMaxSize * 2/3;
+      let blocks = [];
+      for (let i = 0; i < size.w; i += size.s) {
+        for (let j = 0; j < size.h; j += size.s) {
+          let color = colorSet.colors[weightedRandom(colorWeights)];
+          let xPosition = (i + size.s / 2) / size.w;
+          let yPosition = (j + size.s / 2) / size.h;
+          let positionScaleFactor = Math.abs(xPosition - yPosition);
+          let blockSize = blockMaxSize - (blockMaxSize - blockMinSize) * positionScaleFactor;
+          let padding = (size.s - blockSize) / 2;
+          blocks.push({
+            x: i + padding,
+            y: j + padding,
+            w: blockSize,
+            h: blockSize,
+            c: color,
+            g: Math.random() < 0.01,
+          });
+        }
+      }
+      return { size: size, blocks: blocks };
+    }).map(svgData => {
+      const svgString = `
+        <svg xmlns="http://www.w3.org/2000/svg" style="background-color: ${colorSet.colors.shade0};" width="${svgData.size.w}" height="${svgData.size.h}" viewBox="0 0 ${svgData.size.w} ${svgData.size.h}">
+          <defs>
+            <linearGradient id="overlay" x1="1" y1="0" x2="0" y2="1">
+              <stop offset="0%" stop-color="${colorSet.colors.shade0}"/>
+              <stop offset="50%" stop-color="${colorSet.colors.shade0}" stop-opacity="0"/>
+              <stop offset="100%" stop-color="${colorSet.colors.shade0}"/>
+            </linearGradient>
+            <filter id="glow">
+              <feGaussianBlur stdDeviation="5" result="coloredBlur"/>
+              <feMerge>
+                <feMergeNode in="coloredBlur"/>
+                <feMergeNode in="SourceGraphic"/>
+              </feMerge>
+            </filter>
+          </defs>
+          ${svgData.blocks.map(block => `<rect x="${block.x}" y="${block.y}" width="${block.w}" height="${block.h}" fill="${block.c}" rx="2" ry="2" ${block.g ? `filter="url(#glow)"` : ''} />`).join('\n')}
+          <rect x="0" y="0" width="${svgData.size.w}" height="${svgData.size.h}" fill="url(#overlay)"/>
+        </svg>
+      `;
+      const basename = `themer-wallpaper-block-wave-${colorSet.name}-${svgData.size.w}x${svgData.size.h}`;
+      const svgBuffer = new Buffer(svgString, 'utf-8');
+      return [
+        Promise.resolve({ name: `${basename}.svg`, contents: svgBuffer }),
+        svg2png(svgBuffer).then(pngBuffer => ({ name: `${basename}.png`, contents: pngBuffer })),
+      ];
+    })
+  ));
+
+};

src/weighted-random.js

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+export default map => {
+  const cumulativeWeights = Array.from(map.values()).reduce((c, weight, i) => c.concat(weight + (i === 0 ? 0 : c[i-1])), []);
+  const random = cumulativeWeights[cumulativeWeights.length-1] * Math.random();
+  return Array.from(map.keys())[cumulativeWeights.findIndex(cw => random < cw)];
+};

src/weighted-random.test.js

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+import wr from './weighted-random';
+
+describe('weighted random', () => {
+  it('selects a random key from a map of keys to weights', () => {
+
+    const testData = new Map([
+      ['a', 1],
+      ['b', 3],
+      ['c', 1],
+    ]);
+    const total = Array.from(testData.values()).reduce((total, weight) => total + weight, 0);
+    const samples = 1000;
+
+    let frequency = {
+      'a': 0,
+      'b': 0,
+      'c': 0,
+    };
+
+    for (let i = 0; i < total * samples; i++) frequency[wr(testData)]++;
+
+    expect(Math.round(frequency['a'] / samples)).toBe(1);
+    expect(Math.round(frequency['b'] / samples)).toBe(3);
+    expect(Math.round(frequency['c'] / samples)).toBe(1);
+
+  });
+});