Write block of data to region of image
adapter.writeRegion(region_start, region_data) writes a contiguous block of data to a region of the image. The method writes the block of data specified by the region_data argument. The two-element vector, region_start, specifies the [row col] location of the first pixel (minimum-row, minimum-column) of the target region in the image. When you construct a class that inherits from the ImageAdapter class, implement this method if you need to write data.