[jira] [Commented] (CB-14) CameraLauncher Plugin enhancement for loading big image files to avoid OutOfMemory exceptions

["Ben Plowman (Commented) (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CB-14?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13147202#comment-13147202 ] 

Ben Plowman commented on CB-14:
-------------------------------

Definitely agree that this is important. I have found lots of OOM errors in strange places on Android before I started scaling bitmaps like this.
                
> 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
>            Priority: Critical
>              Labels: CameraLauncher, OutOfMemory, decodeStream
>             Fix For: 2.0.0
>
>
> 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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