175. Playing with picture

• brighter - take all pixels in a picture and increase the RGB value in each pixel

def brighter(picture):
		for px in getPixels(picture):
			r = getRed(px) #取得紅色的數值
	    g = geGreen(px) 
	    b = getBlue(px)
	    new_color = makeColor(r*1.3, g*1.3, b*1.3) #自定義顏色
	    setColor(px, new_color) #改顏色

#load program
f = pickAFile() #給定路徑
p = makePicture(f) #開啟圖片
brigher(p) #執行調亮函數
explore(p) #開啟圖片

• Fake Sunset - decrease each pixel's green and blue values by 30%. Each pixel’s redness becomes more dominant.

def make_sunset(picture):
  for px in getPixels(picture):
    b = getBlue(px) #取得藍色的數值
    g = geGreen(px)
    setBlue(p, b*0.7) #重設藍色的數值
    setGreen(p, g*0.7)
 
#load program
f = pickAFile()
p = makePicture(f)
make_sunset(p)
explore(p)

• Negate a picture - a negative image is a total inversion
• newColoreChannel = 255 - oldColorChannel

def negative(picture):
  for px in getPixels(picture):
    r = getRed(px) #取得紅色的數值
    g = geGreen(px)
    b = getBlue(px)
    negColor = makeColor(255-r, 255-g, 255-b) #自定義顏色
    setColor(px, negColor) #改顏色

#load program
f = pickAFile()
p = makePicture(f) 
negative(p)
explore(p)

176. Playing with Picture – Grayscale

The RGB scale is calibrated so that when a color's three red/green/blue numbers are equal, the color is a shade of gray.

def grayscale(picture):
  for px in getPixels(picture):
    x = (geRed(px) + geGreen(px) + getBlue(px))/3
    grayColor = makeColor(x, x, x)
    setColor(px, grayColor)

#load program
f = pickAFile()
p = makePicture(f) 
grayscale(p)
explore(p)

177. Playing with Picture – Copy Top Half

A : 複製上半段旋轉至下半段

Index means the distance of the first index to our current index (counting from the left), and len(list) – 1 – index means the distance of the last index to the mirrored point (counting from the right).