void doPixelsMatch(final int x, final int y, final int a, final int b) {
        if (!componentMatch(a, b, 0, 2) || !componentMatch(a, b, 8, 2) || !componentMatch(a, b, 16, 2) || !componentMatch(a, b, 24, 2)) {

            final String complaint = String.format("Pixel mismatch at (%d,%d): 0x%08x 0x%08x", x, y, a, b);
            fail(complaint);
        }
    }
Checks to see if a pixel component (A, R, G, or B) for two specified values are within a specified tolerance.

@param a          the first value
@param b          the second value
@param iShift     a multiple of 8 telling how far to shift values to extract components (24, 16, 8, or zero for ARGB)
@param iTolerance a small positive integer
@return true if the components of the values match
src/test/java/org/apache/commons/imaging/formats/tiff/TiffAlphaRoundTripTest.java