As I said before, images are compressed when it is on disk. Now, bitmap.getByteCount() method will return 3.1 MB. We switch inJustDecodeBounds to false and get bitmap with options instance. inJustDecodeBounds = false Bitmap smallBitmap = BitmapFactory. inSampleSize = calculateInSampleSize(options, 500,500) options.
#Android studio bitmap android
You can check the inSampleSize calculation code from android documentation. But you can also calculate your inSampleSize by incrementin it 1 by 1. In android documentation, they calculate it power of two based. I mean, you can write your algorithm according to your needs. So we have to do a calculation according to image size.Ĭalculating inSampleSize is up to you. We can not set scale factor as a constant. Some images have to be scaled down 2 times. Some images have to be scaled down 5 times. If it is small image and we make it more smaller, our user can see some pixels instead of image. Because we don’t know what image size is. hqimage, options) Ĭan we use it just like this? No. BitmapFactory.Options options = new BitmapFactory.Options() options.inJustDecodeBounds = true options.inSampleSize = 3 BitmapFactory. If we have 200x400 image and we set inSampleSize 5, we will have 40x80 image after decoding. We will have 500x500 image after decoding operation. If we have an image 1000x1000 and we set inSampleSize 2 before decoding. What is inSampleSize? inSampleSize is a scale factor that belongs to BitmapFactory.Options class. Now it is time to calculate inSampleSize. And I just wanted to see if bitmap is really null. When we run this code and log options value: options.outHeight : 1126 options.outWidth : 2000 options.bitmap : null So we can calculate scale factor with that information. We just want to get information(width, height, etc.) about image.
What is the meaning of inJustDecodeBounds? It means that we don’t want to load bitmap into memory. You can see that we configured our “options” by setting inJustDecodeBounds true. We pass BitmapFactory.Options instance to codeSource() method. BitmapFactory.Options options = new BitmapFactory.Options() options.inJustDecodeBounds = true BitmapFactory. We can use this class to achieve first step. This class is a metadata provider for us.
Calculate scale factor with image’s size.Get size of image without loading into memory.Once you load the image into memory, it is no longer compressed and takes up as much memory as is necessary for all the pixels. The image is compressed when it is on disk (stored in a JPG, PNG, or similar format). You may think that Image’s actual size on disk is about 3.5 MB and getByteCount() is showing larger than disk size. Here is the total bytes of bitmap in the memory: 12262248 Bytes, which equals to 12,3 MB. Let’s check out decoded bitmap size in our memory.īitmap.getByteCount() method will return it’s size. But there is a problem which i am going to tell you. All you need is decode your image using BitmapFactory. I suggest you to use Picasso or Glide to load image. I wanted to give you logic behind decoding bitmaps. There are lots of stackoverflow questions about that and you can just skip this blogpost and keep copy-pasting when you have OOM :) But for the rest, I want to give some information about loading large bitmap and how it actually works. Android has a limited memory as we all know. We all see OOM(Out Of Memory) errors in our crash reports because of large images. Loading large bitmaps into memory is always a pain. Loading Large Bitmaps Efficiently in Android
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