From 821413607a0718156f9d25d895e89b1c3d37aa8b Mon Sep 17 00:00:00 2001
From: Daniel Narvaez <dwnarvaez@gmail.com>
Date: Wed, 06 Feb 2013 13:49:14 +0000
Subject: Copy various bits from gaia

---
(limited to 'apps/system/js/screenshot.js')

diff --git a/apps/system/js/screenshot.js b/apps/system/js/screenshot.js
new file mode 100644
index 0000000..9e8e7f6
--- /dev/null
+++ b/apps/system/js/screenshot.js
@@ -0,0 +1,115 @@
+// screenshot.js: system screenshot module
+//
+// This system module takes a screenshot of the currently running app
+// or homescreen and stores it with DeviceStorage when the user
+// presses the home and sleep buttons at the same time. It communicates
+// with gecko code running in b2g/chrome/content/shell.js using a private
+// event-based API. It is the gecko code that creates the screenshot.
+//
+// This script must be used with the defer attribute.
+//
+//
+(function() {
+  window.addEventListener('home+sleep', takeScreenshot);
+
+  // Assume that the maximum screenshot size is 4 bytes per pixel
+  // plus a bit extra. In practice, with compression, our PNG files will be
+  // much smaller than this.
+  var MAX_SCREENSHOT_SIZE = window.innerWidth * window.innerHeight * 4 + 4096;
+
+  function takeScreenshot() {
+    // Give feedback that the screenshot request was received
+    navigator.vibrate(100);
+
+    // We don't need device storage here, but check to see that
+    // it is available before sending the screenshot request to chrome.
+    // If device storage is available, the callback will be called.
+    // Otherwise, an error message notification will be displayed.
+    getDeviceStorage(function() {
+      // Let chrome know we'd like a screenshot.
+      // This is a completely non-standard undocumented API
+      // for communicating with our chrome code.
+      var screenshotProps = {
+        detail: {
+          type: 'take-screenshot'
+        }
+      };
+      window.dispatchEvent(new CustomEvent('mozContentEvent', screenshotProps));
+    });
+  }
+
+  // Display a screenshot success or failure notification.
+  // Localize the first argument, and localize the third if the second is null
+  function notify(titleid, body, bodyid) {
+    var title = navigator.mozL10n.get(titleid) || titleid;
+    body = body || navigator.mozL10n.get(bodyid);
+    navigator.mozNotification.createNotification(title, body).show();
+  }
+
+  // Get a DeviceStorage object and pass it to the callback.
+  // Or, if device storage is not available, display a notification.
+  function getDeviceStorage(callback) {
+    var storage = navigator.getDeviceStorage('pictures');
+    var availreq = storage.available();
+    availreq.onsuccess = function() {
+      var state = availreq.result;
+      if (state === 'unavailable') {
+        notify('screenshotFailed', null, 'screenshotNoSDCard');
+      }
+      else if (state === 'shared') {
+        notify('screenshotFailed', null, 'screenshotSDCardInUse');
+      }
+      else if (state === 'available') {
+        var freereq = storage.freeSpace();
+        freereq.onsuccess = function() {
+          if (freereq.result < MAX_SCREENSHOT_SIZE) {
+            notify('screenshotFailed', null, 'screenshotSDCardLow');
+          }
+          else {
+            callback(storage);
+          }
+        };
+        freereq.onerror = function() {
+          notify('screenshotFailed', freereq.error && freereq.error.name);
+        };
+      }
+    }
+    availreq.onerror = function() {
+      notify('screenshotFailed', availreq.error && availreq.error.name);
+    }
+  }
+
+  // Handle the event we get from chrome with the screenshot
+  window.addEventListener('mozChromeEvent', function ss_onMozChromeEvent(e) {
+    try {
+      if (e.detail.type === 'take-screenshot-success') {
+        getDeviceStorage(function(storage) {
+          var filename = 'screenshots/' +
+            new Date().toISOString().slice(0, -5).replace(/[:T]/g, '-') +
+            '.png';
+
+          var saveRequest = storage.addNamed(e.detail.file, filename);
+
+          saveRequest.onsuccess = function ss_onsuccess() {
+            // Vibrate again when the screenshot is saved
+            navigator.vibrate(100);
+
+            // Display filename in a notification
+            notify('screenshotSaved', filename);
+          };
+
+          saveRequest.onerror = function ss_onerror() {
+            notify('screenshotFailed', saveRequest.error.name);
+          };
+        });
+      }
+      else if (e.detail.type === 'take-screenshot-error') {
+        notify('screenshotFailed', e.detail.error);
+      }
+    }
+    catch (e) {
+      console.log('exception in screenshot handler', e);
+      notify('screenshotFailed', e.toString());
+    }
+  });
+}());
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