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codyayoung/linedraw.py

Created November 12, 2018 05:29
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  1. codyayoung created this gist Nov 12, 2018.
    81 changes: 81 additions & 0 deletions linedraw.py
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    # Cody Young
    # Line Drawing Function - JES
    # 2018-11-13


    import math


    # Converts an image to black and white, and then turns pixels to black or white to simulate a pencil/pen drawn sketch.
    def lineDraw():
    #Input picture, get height and width variables
    pic = getPic()
    show(pic)
    height = getHeight(pic)
    width = getWidth(pic)
    print("Height: %d" % height)
    print("Width: %d" % width)

    #Convert to grayscale and return pic
    betterBnW(pic)

    #Threshold value for luminance (difference)
    threshold = 10

    for x in range (0, width-1):
    for y in range(0, height-1):
    source = getPixel(pic, x, y) #Get current pixel
    source_lum = getLuminance(source) #Luminance of current pixel
    if x >= width:
    target_right = getLuminance(getPixel(pic, x, y)) #If at last pixel on border, use it instead
    else:
    target_right = getLuminance(getPixel(pic, x+1, y)) #Pixel one to right (width + 1)
    if y >= height:
    target_below = getLuminance(getPixel(pic, x, y)) #If at last pixel on border, use it instead
    else:
    target_below = getLuminance(getPixel(pic, x, y+1)) #Pixel one below (height + 1)

    diff_right = abs(source_lum - target_right)
    diff_below = abs(source_lum - target_below)

    #If luminance difference of right and below pixels are greater than threshold, set pixel to black, else set to white
    if diff_right > threshold and diff_below > threshold:
    setColor(source, black)
    else:
    setColor(source, white)

    repaint(pic)

    #Note: Change 'dir' to your working directory
    dir = "C:\Users\Cody\Documents\CSUMB\CST 205\CST 205 - Images\Image Functions\linedrawn.jpg"
    writePictureTo(pic, dir)

    return pic


    # ----------------
    # Helper Functions
    # ----------------
    # Returns the luminance value of a pixel
    def getLuminance(pixel):
    r = getRed(pixel)
    g = getGreen(pixel)
    b = getBlue(pixel)

    luminance = (0.299 * r) + (0.587 * g) + (0.114 * b)

    return luminance

    # Converts an image to grayscale
    def betterBnW(pic):
    pixels = getPixels(pic)

    for p in pixels:
    grayscale = ((getRed(p) * 0.299) + (getGreen(p) * 0.587) + (getBlue(p) * 0.114))
    setColor = (p, makeColor(grayscale, grayscale, grayscale))

    return pic


    def getPic():
    return makePicture(pickAFile())