Memory efficient image resize in Android

Question

I am trying to reduce the size of images retrieved form the camera (so ~5-8 mega pixels) down to one a a few smaller sizes (the largest being 1024x768). I Tried the following code but I consistently get an OutOfMemoryError.

Bitmap image = BitmapFactory.decodeStream(this.image, null, opt);
int imgWidth = image.getWidth();
int imgHeight = image.getHeight();

// Constrain to given size but keep aspect ratio
float scaleFactor = Math.min(((float) width) / imgWidth, ((float) height) / imgHeight);

Matrix scale = new Matrix();
scale.postScale(scaleFactor, scaleFactor);
final Bitmap scaledImage = Bitmap.createBitmap(image, 0, 0, imgWidth, imgHeight, scale, false);

image.recycle();

It looks like the OOM happens during the createBitmap. Is there a more memory efficient way to do this? Perhaps something that doesn't require me to load the entire original into memory?

Answer 1

When you decode the bitmap with the BitmapFactory, pass in a BitmapFactory.Options object and specify inSampleSize. This is the best way to save memory when decoding an image.

Here's a sample code Strange out of memory issue while loading an image to a Bitmap object