Question

I’m making bitmap (that will be printed on paper, later) and using canvas to draw on it.
But after saving it always have 72 dpi resolution. I tried to use bitmap.setDensity(96);but it does not seems to work.

This is how I make bitmap and save it, nothing fancy

Bitmap outBitmap = Bitmap.createBitmap(378,559,Bitmap.Config.RGB_565);
         OutputStream outStream = null;
         File file = new File(Environment.getExternalStorageDirectory(),
         "96dpiBitmap.png");
         try {
         outStream = new FileOutputStream(file);
         outBitmap.compress(Bitmap.CompressFormat.PNG, 100, outStream);
         outStream.flush();
         outStream.close();
         } catch (FileNotFoundException e) {
         // doh
         } catch (IOException e) {
         // doh
         }

So. How do I save bitmap with dpi > 72?

Answer 1

you have to create scaled bitmap from the original one for ex :

MyNewBitmap = Bitmap.createScaledBitmap(myOldOne,612,612,false); 

where 612 width and 612 height the result will be image squared. i’m using this method to prevent instagram from scaling or cutting my image so its perfectly fit into instagram image cropping :).
anyway you have to find the proper way to scale your image to fit 72dpi. i guess 800×600 will do the trick. try to create new bitmap and scale the old one and then save the newBitmap.
good luck