np/cv2 blending modes

blend.py

import numpy as np
import cv2

def NormalComposition(srcRGBA, dstRGBA):
    srcA = np.dstack((srcRGBA[:,:,3]/255,)*3)
    srcRGB = srcRGBA[:,:,:3]
    dstA = np.dstack((dstRGBA[:,:,3]/255,)*3)
    dstRGB = dstRGBA[:,:,:3]

    outA = srcA + dstA*(1-srcA)
    outRGB = (srcRGB*srcA + dstRGB*dstA*(1-srcA)) / outA
    outRGBA = np.dstack((outRGB,outA[:,:,0]*255)).astype(np.uint8)

    return outRGBA

def EraseComposition(srcRGBA, dstRGBA):
    srcA = srcRGBA[:,:,3]/255
    dstA = dstRGBA[:,:,3]/255
    dstRGB = dstRGBA[:,:,:3]

    outA = dstA*(1-srcA)*255
    outRGBA = np.dstack((dstRGB,outA)).astype(np.uint8)
    return outRGBA

def HSVComposition(srcRGBA, dstRGBA, permutation):
    dstRGB = dstRGBA[:,:,:3]
    srcA = (srcRGBA[:,:,3]/255)[...,np.newaxis]

    srcHSV = cv2.cvtColor(np.ascontiguousarray(srcRGBA[:,:,:3]), cv2.COLOR_RGB2HSV_FULL)
    dstHSV = cv2.cvtColor(np.ascontiguousarray(dstRGBA[:,:,:3]), cv2.COLOR_RGB2HSV_FULL)

    outHSV = np.dstack(permutation(srcHSV[:,:,0], srcHSV[:,:,1], srcHSV[:,:,2], dstHSV[:,:,0], dstHSV[:,:,1], dstHSV[:,:,2]))

    outRGB = cv2.cvtColor(outHSV, cv2.COLOR_HSV2RGB_FULL)
    outRGB = (dstRGB*(1-srcA) + outRGB*srcA)
    outRGBA = np.dstack((outRGB, dstRGBA[:,:,3])).astype(np.uint8)

    return outRGBA

def HLSComposition(srcRGBA, dstRGBA, permutation):
    dstRGB = dstRGBA[:,:,:3]
    srcA = (srcRGBA[:,:,3]/255)[...,np.newaxis]

    srcHLS = cv2.cvtColor(np.ascontiguousarray(srcRGBA[:,:,:3]), cv2.COLOR_RGB2HLS_FULL)
    dstHLS = cv2.cvtColor(np.ascontiguousarray(dstRGBA[:,:,:3]), cv2.COLOR_RGB2HLS_FULL)

    outHLS = np.dstack(permutation(srcHLS[:,:,0], srcHLS[:,:,1], srcHLS[:,:,2], dstHLS[:,:,0], dstHLS[:,:,1], dstHLS[:,:,2]))

    outRGB = cv2.cvtColor(outHLS, cv2.COLOR_HLS2RGB_FULL)
    outRGB = (dstRGB*(1-srcA) + outRGB*srcA)
    outRGBA = np.dstack((outRGB, dstRGBA[:,:,3])).astype(np.uint8)

    return outRGBA

def HueComposition(srcRGBA, dstRGBA):
    return HSVComposition(srcRGBA, dstRGBA, lambda sH,sS,sV,dH,dS,dV: (sH,dS,dV))

def SaturationComposition(srcRGBA, dstRGBA):
    return HSVComposition(srcRGBA, dstRGBA, lambda sH,sS,sV,dH,dS,dV: (dH,sS,dV))

def ValueComposition(srcRGBA, dstRGBA):
    return HSVComposition(srcRGBA, dstRGBA, lambda sH,sS,sV,dH,dS,dV: (dH,dS,sV))

def ColorComposition(srcRGBA, dstRGBA):
    return HLSComposition(srcRGBA, dstRGBA, lambda sH,sL,sS,dH,dL,dS: (sH,dL,sS))