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From "Christopher Bailey (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CB-14) CameraLauncher Plugin enhancement for loading big image files to avoid OutOfMemory exceptions
Date Mon, 23 Apr 2012 19:48:36 GMT

    [ https://issues.apache.org/jira/browse/CB-14?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13259883#comment-13259883
] 

Christopher Bailey commented on CB-14:
--------------------------------------

@Joe I too am facing the same issue. Asking people to implement their own camera solution
for anyone needing to use the camera api is far from ideal. I think you could go some way
to mitigating this issue if the cordova app saved it's application state (or rather that of
it's plugins) using the onSaveInstanceState hook provided by Android:
http://developer.android.com/reference/android/app/Activity.html#onSaveInstanceState(android.os.Bundle)
Cordova could then check the bundle in the onCreate method to recreate the relevant plugins
and allow the intent to be passed back to the application (obviously it would still be up
to application developers to maintain their own app's state using the js destroy/resume events).
                
> CameraLauncher Plugin enhancement for loading big image files to avoid OutOfMemory exceptions
> ---------------------------------------------------------------------------------------------
>
>                 Key: CB-14
>                 URL: https://issues.apache.org/jira/browse/CB-14
>             Project: Apache Callback
>          Issue Type: Improvement
>          Components: Android
>    Affects Versions: 1.1.0
>         Environment: Android SDK: 2.x & above
> JDK: 1.6
> Eclipse: Helios
>            Reporter: Bright Zheng
>            Assignee: Joe Bowser
>            Priority: Critical
>              Labels: CameraLauncher, OutOfMemory, decodeStream
>             Fix For: 1.6.0
>
>
> Currently the CameraLauncher plugin of Phonegap (or Apache Callback) is using Android
default API for stream decoding.
> It will be very easy to get crash by throwing out the OutOfMemory exceptions while loading
bigger image files.
> So I add a new method called safeDecodeStream for better stream decoding.
> {code:title=safeDecodeStream method|borderStyle=solid}
>     /**
>      * A safer decodeStream method
>      * rather than the one of {@link BitmapFactory}
>      * which will be easy to get OutOfMemory Exception
>      * while loading a big image file.
>      * 
>      * @param uri
>      * @param width
>      * @param height
>      * @return
>      * @throws FileNotFoundException
>      */
>     protected Bitmap safeDecodeStream(Uri uri, int width, int height)
>     throws FileNotFoundException{
> 		int scale = 1;
> 		BitmapFactory.Options options = new BitmapFactory.Options();
> 		android.content.ContentResolver resolver = this.ctx.getContentResolver();
> 		
> 		if(width>0 || height>0){
> 			// Decode image size without loading all data into memory
> 			options.inJustDecodeBounds = true;
> 			BitmapFactory.decodeStream(
> 					new BufferedInputStream(resolver.openInputStream(uri), 16*1024),
> 					null,
> 					options);
> 			
> 			int w = options.outWidth;
> 			int h = options.outHeight;
> 			while (true) {
> 				if ((width>0 && w/2 < width)
> 						|| (height>0 && h/2 < height)){
> 					break;
> 				}
> 				w /= 2;
> 				h /= 2;
> 				scale *= 2;
> 			}
> 		}
> 		// Decode with inSampleSize option
> 		options.inJustDecodeBounds = false;
> 		options.inSampleSize = scale;
> 		return BitmapFactory.decodeStream(
> 				new BufferedInputStream(resolver.openInputStream(uri), 16*1024), 
> 				null, 
> 				options);
> 	}  
> {code} 
> And then change all the codes which are invoking the Android decodeStream API directly
to this method.
> e.g.
> {code:title=usage example|borderStyle=solid}
> //Updated by Bright for safer decodeStream
> //android.content.ContentResolver resolver = this.ctx.getContentResolver();
> //bitmap = android.graphics.BitmapFactory.decodeStream(resolver.openInputStream(uri));
> bitmap = safeDecodeStream(uri, this.targetWidth, this.targetHeight);
> {code} 

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