spfinger:setShrink

Configure processing of finger print images that are received into a pixmap.

With spfinger:setShrink(), the received image can be shrunk by a constant integer factor from 1 ... 8. Shrinking is applied to both the X and Y axis. The algorithm produces a grayscale image using a simple mean value method.

With spfinger:setCrop(), the received image can be cut to size. Depending on the actual finger scanner itself, there is a large border around the image that has no useful information. The parameters x and y chose the top left edge inside the received image, while w and h chose the cropped width and height, respectively. If any of w or h is negative, it is taken as the instruction to cut that many pixels off the right or bottom. If any of w or h is zero, there is no cropping on that axis.