Change to Camera code in PhoneGap 1.9.0

With the release of PhoneGap 1.9.0 I've checked in some improvements to the Camera.getPicture() functionality. First a bit of an explanation as to why there are so many issues with the Camera code.

One of the major causes of issues is that as new devices get released the cameras in them get better and better allowing you to take very high resolution images. Now when you specify a few parameters to our getPicture method like quality or targetWidth/targetHeight you can get out of memory errors. Why do you get out of memory errors you ask? Well in my honest opinion it is because Android does a real poor job of handling Bitmaps. In order to do any manipulation on an image like scaling or compression you need to load the entire image into memory.

Let's take a look at a real world example. My Samsung Galaxy Note has an 8MP camera with a resolution of 3264 by 2448. So in memory that picture assuming ARGB_8888 will be:

3264 pixels x 2448 pixels x 4 bytes/pixel = approximately 30 megabytes 

Let that sink in, approximately 30 megabytes. Considering that I read somewhere the default heap size for an app running in Dalvik is 48 megabytes you can see how you can quickly run out of memory taking pictures.

Fixing the Best Case Scenario 

I've added some code to detect the best case scenario and not load the image into memory. Here is the getPicture method to call if you want to use the best case all the time.

var options = {
    quality: 100,
    destinationType : navigator.camera.DestinationType.FILE_URI,
    sourceType: navigator.camera.PictureSourceType.CAMERA,
    encodingType: navigator.camera.EncodingType.JPEG,
  }
  navigator.camera.getPicture(win, fail, options);

The important part about the options is that you specify a quality of 100. This along with accepting the default width and height will skip the need to load the image in memory.

Reducing Memory when using targetWidth/targetHeight

Okay but if you do specify a targetWidth/targetHeight the image has to be loaded into memory. Now we do a bit of math to figure out the smallest multiple of the image that can be loaded that isn't smaller than the requested width and height. You see the Bitmap.createScaledBitmap() method allows you to specify that the bitmap be load at half, quarter, etc. size. Now if you request a 900x900 image from a 2000x2000 original image it will be loaded into memory as 1000x1000 and scaled from that point. It saves about 11 megabytes of memory doing it this way.

Respects the saveToPhotoAlbum option

Up until 1.9.0 each picture taken automatically gets added to the Android photo album/gallery. As of 1.9.0 if you want that type of behaviour to continue you need to set this option to true as the default is false.

Respects the correctOrientation option

One of the other big problems with our Camera functionality is that pictures taken in portrait mode were always displayed on their side when you attempted to view them in your app. Remember your app is based off of a WebView and the web view does not care about the exif orientation parameter. Now if correctOrientation is set to true we rotate the image so that it will show up properly in the WebView and we reset the orientation parameter to normal so it'll show up properly in desktop image viewers.

If you run into problems using the Camera in 1.9.0 please raise a bug on JIRA and give a detailed  reproduction scenario. I want to make sure this functionality is rock solid for the upcoming 2.0.0 release.