set Minimum Tile Dpi
By default, image tiles are at least as high resolution as the screen. For a retina screen this may not be necessary, and may increase the likelihood of an OutOfMemoryError. This method sets a DPI at which higher resolution tiles should be loaded. Using a lower number will on average use less memory but result in a lower quality image. 160-240dpi will usually be enough. This should be called before setting the image source, because it affects which tiles get loaded. When using an untiled source image this method has no effect.
Parameters
minimum Tile Dpi
Tile loading threshold.