python之将图像宽度增加一个像素

我正在尝试实现一个程序，它将图像的宽度增加一个像素。然后我想采用新的最大 x 坐标并将其与随机 y 坐标(在图像范围内)放在一起以创建一个新像素。

 for x in range (0,getWidth(pic)): 
    for y in range (0,getHeight(pic)): 
      X=getWidth(pic) 
      newX = (X+1) 
      colr=(255,0,0) 
      newPixel = getPixel (pic, newX, y)//line 25 
      setColor(newPixel, colr) 
      Y=getHeight(pic) 
      newY= (Y+1) 
      newPixel = getPixel( pic,x, newY) 
      setColor(newPixel, colr) 

我收到这个错误:

getPixel(picture,x,y): x (= 226) is less than 0 or bigger than the width (= 224) 
The error was: 
Inappropriate argument value (of correct type). 
An error occurred attempting to pass an argument to a function. 
Please check line 25 of D:\bla bla 

我知道它超出了范围。我做错了什么？

请您参考如下方法:

这是增加图像大小并保持其当前内容的通用方法:

随时适应。

# Increase a picture given an offset, a color and the anciant  
# content must be centered or not. 
# Offsets must be positive. 
def increaseAndCopy(pic, offsetX, offsetY, bg_color=black, center=True): 
 
  # Offsets must be positive 
  if (offsetX < 0.0) or (offsetY < 0.0): 
    printNow("Error: Offsets must be positive !") 
    return None 
 
  new_w = pic.getWidth() + int(2*offsetX) 
  new_h = pic.getHeight() + int(2*offsetY) 
 
  startX = 0 
  startY = 0 
  if (center) and (offsetX > 1.0): 
    startX = int(offsetX) 
  if (center) and (offsetY > 1.0): 
    startY = int(offsetY) 
 
  new_pic = makeEmptyPicture(new_w, new_h) 
  # Fill with background color 
  setAllPixelsToAColor(new_pic, bg_color) 
 
  # Process copy 
  for x in xrange(pic.getWidth()): 
    for y in xrange(pic.getHeight()): 
      px = getPixel(pic, x, y) 
      new_px = getPixel(new_pic, x + startX, y + startY) 
      setColor(new_px, getColor(px)) 
 
  return new_pic 
 
file = pickAFile() 
picture = makePicture(file) 
 
# Pass an offset of 0.5 to increase by 1 pixel 
#new_picture = increaseAndCopy(picture, 0.5, 0, blue) 
new_picture = increaseAndCopy(picture, 10, 20, gray, True) 
 
if (new_picture): 
  writePictureTo(new_picture, "/home/biggerPic.png") 
  show(new_picture) 

输出(Jean-Michel Basquiat 的绘画):

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