How to check if a bitmap (or canvas) is empty in Android

Question

I have to implement a function that return to me a boolean if a bitmap or canvas is empty in Android.

How I can do this ?

I have tried this solution, but it doesn't work:

Bitmap emptyBitmap = Bitmap.createBitmap(myBitmap.getWidth(), myBitmap.getHeight(), myBitmap.getConfig());
if (myBitmap.sameAs(emptyBitmap)) {
    // myBitmap is empty/blank
}

How to check if a Bitmap is empty (blank) on Android

Another solution that I have considerated is:

Fastest way to check if an image is all white or all transparent

But I can't check every pixels, I spend so much time in this operation

If i am correct, you need to check if user draw on canvas/bitmap or not.right? — Divyesh Patel, Nov 10 '16 at 14:12
Yes :) I have a surfaceView where the user can draw, in a second time the draw is converted in bitmap. if bitmap is not empty i want save it, else no — Mattia, Nov 10 '16 at 14:15

score 2 · Accepted Answer · edited Jan 10 '17 at 00:16

2

Sorry it's so late apparently the best way to do this is to create a bitmap and check if it's the same so boolean Res (bitmap.sameAs())

edited Jan 10 '17 at 00:16

RBT

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answered Jan 08 '17 at 21:18

Martin Seal

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Bitmap emptyBitmap = Bitmap.createBitmap(myBitmap.getWidth(), myBitmap.getHeight(), myBitmap.getConfig()); if (myBitmap.sameAs(emptyBitmap)) { // myBitmap is empty/blank } – Martin Seal Jan 08 '17 at 21:19

How to check if a bitmap (or canvas) is empty in Android

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