xamarin.android - Being double the length and width of the image, why?

Question

I have this code:

BitmapDrawable bd = (BitmapDrawable)this.GetDrawable(Resource.Drawable.add1);
int height = bd.Bitmap.Height;
int width = bd.Bitmap.Width;
Toast.MakeText(this, width.ToString() + "  " + height.ToString(), ToastLength.Long).Show();

The width and height of add1.png is 55*55 pixels, but Toast showes 110 * 110 pixels, why?

Answer 1

This issue is caused by the resolution of the device. The value returned by bitmap.Width will be adjusted according to the different dpi, this dpi may be different for different models. If the device has a higher resolution, higher numbers may be printed here.

To get the original size of the image file, you need to divide the size by the dpi value.

var density = Resources.DisplayMetrics.Density;

BitmapDrawable bd = (BitmapDrawable)this.GetDrawable(Resource.Drawable.test);
var the_original_height = bd.Bitmap.Height / density;
var the_orignial_width = bd.Bitmap.Width / density;

Toast.MakeText(this, the_original_height.ToString() + "*" + the_original_height.ToString(), ToastLength.Long).Show();