Getting a bitmap's dimensions in Android without reading the entire file

Question

I would like to get a bitmap's dimensions in Android without reading the entire file.

I tried using the recommended inJustDecodeBounds and a custom InputStream that logged the read()s. Unfortunately based on this, the Android BitmapFactory appears to read a large amount of bytes.

Similar to: Java/ImageIO getting image dimensions without reading the entire file? for Android, without using ImageIO.

score 14 · Accepted Answer · answered Aug 18 '12 at 12:56

14

You are right to use inJustDecodeBounds. Set it to true and make sure to include Options in decode. This just reads the image size.

There is no need to read a stream. Just specify the path in the decode.

BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(<pathName>, options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;

answered Aug 18 '12 at 12:56

IAmGroot

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I need to use an `InputStream` because I'm reading from the network. I want to minimize the network traffic. `BitmapFactory` also forwards the method with a file to the stream - http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.1.1_r1/android/graphics/BitmapFactory.java#BitmapFactory.decodeFile%28java.lang.String%2Candroid.graphics.BitmapFactory.Options%29 – mparaz Aug 18 '12 at 14:13
1

@mparaz Then use `BitmapFactory.decodeStream(InputStream is, Rect outPadding, BitmapFactory.Options opts)`. If you already have, then its likely a limitation of applying this method to a stream over a network. Aka, you may need to get the full stream over the network first before you can decode. – IAmGroot Aug 18 '12 at 15:05

score 0 · Answer 2 · answered Dec 12 '17 at 18:42

java.net.URL imageUrl = new java.net.URL("https://yourUrl.com");
HttpURLConnection connection = (HttpURLConnection)imageUrl.openConnection();
connection.connect();
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(connection.getInputStream(), null, options);
int imageWidth = options.outWidth;
int imageHeight = options.outHeight;

Getting a bitmap's dimensions in Android without reading the entire file

2 Answers2