Add colorwheel.js puppeteer example

This patch re-implements PhantomJS colorwheel example with puppeteer API.
2017-05-12 11:14:32 -07:00 · 2017-05-12 11:14:32 -07:00 · 073f6409d8
commit 073f6409d8
parent 7bf3684039
1 changed files with 71 additions and 0 deletions
--- a/examples/colorwheel.js
+++ b/examples/colorwheel.js
@ -0,0 +1,71 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+var Browser = require('../lib/Browser');
+var browser = new Browser();
+
+browser.newPage().then(async page => {
+    await page.setSize({width: 400, height: 400});
+    await page.setContent('<html><body><canvas id="surface"></canvas></body></html>');
+    await page.evaluate(drawColorWheel);
+    await page.saveScreenshot('colorwheel.png');
+    browser.close();
+});
+
+function drawColorWheel() {
+    var el = document.getElementById('surface'),
+        context = el.getContext('2d'),
+        width = window.innerWidth,
+        height = window.innerHeight,
+        cx = width / 2,
+        cy = height / 2,
+        radius = width  / 2.3,
+        imageData,
+        pixels,
+        hue, sat, value,
+        i = 0, x, y, rx, ry, d,
+        f, g, p, u, v, w, rgb;
+
+    el.width = width;
+    el.height = height;
+    imageData = context.createImageData(width, height);
+    pixels = imageData.data;
+
+    for (y = 0; y < height; y = y + 1) {
+        for (x = 0; x < width; x = x + 1, i = i + 4) {
+            rx = x - cx;
+            ry = y - cy;
+            d = rx * rx + ry * ry;
+            if (d < radius * radius) {
+                hue = 6 * (Math.atan2(ry, rx) + Math.PI) / (2 * Math.PI);
+                sat = Math.sqrt(d) / radius;
+                g = Math.floor(hue);
+                f = hue - g;
+                u = 255 * (1 - sat);
+                v = 255 * (1 - sat * f);
+                w = 255 * (1 - sat * (1 - f));
+                pixels[i] = [255, v, u, u, w, 255, 255][g];
+                pixels[i + 1] = [w, 255, 255, v, u, u, w][g];
+                pixels[i + 2] = [u, u, w, 255, 255, v, u][g];
+                pixels[i + 3] = 255;
+            }
+        }
+    }
+
+    context.putImageData(imageData, 0, 0);
+    document.body.style.backgroundColor = 'white';
+    document.body.style.margin = '0px';
+}