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From "Bright Zheng (Created) (JIRA)" <j...@apache.org>
Subject [jira] [Created] (CB-14) CameraLauncher Plugin enhancement for loading big image files to avoid OutOfMemory exceptions
Date Tue, 08 Nov 2011 07:34:53 GMT
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
             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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