com.googlecode.leptonica.android

Class Clip

java.lang.Object

com.googlecode.leptonica.android.Clip

public class Clip
extends Object

Extract rectangular regions.

Constructor Summary

Constructors

Constructor and Description
Clip()

Method Summary

Modifier and Type	Method and Description
static Pix	clipRectangle(Pix source, Box box) Extract a region from a Pix.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Clip

public Clip()

Method Detail

clipRectangle

public static Pix clipRectangle(Pix source,
                                Box box)

Extract a region from a Pix.

Notes:

This should be simple, but there are choices to be made. The box is defined relative to the pix coordinates. However, if the box is not contained within the pix, we have two choices:

(1) clip the box to the pix

(2) make a new pix equal to the full box dimensions, but let rasterop do the clipping and positioning of the src with respect to the dest

Choice (2) immediately brings up the problem of what pixel values to use that were not taken from the src. For example, on a grayscale image, do you want the pixels not taken from the src to be black or white or something else? To implement choice 2, one needs to specify the color of these extra pixels.

So we adopt (1), and clip the box first, if necessary, before making the dest pix and doing the rasterop. But there is another issue to consider. If you want to paste the clipped pix back into pixs, it must be properly aligned, and it is necessary to use the clipped box for alignment.

Parameters:

source - Source pix

box - Requested clipping region

Returns:

clipped pix, or null if rectangle doesn't intersect source pix