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所以我对这个 Python 东西真的很陌生，我正在使用 JES 并试图弄清楚如何裁剪图像。我不断收到“显示（裁剪图片）”无效的错误消息，此时我可以使用我能获得的任何帮助。到目前为止，这是我的代码：

def main():
print "Select the Media Folder"
  setMediaFolder()
  print "Select the picture (.jpg) file to crop"
  fileName = pickAFile()
  pict = makePicture(fileName)
  show(pict)

  startX = requestIntegerInRange("Enter X coordinate of upper, left-hand corner",0,getWidth(pict)-1)
  startY = requestIntegerInRange("Enter Y coordinate of upper, left-hand corner",0,getHeight(pict)-1)

  endX = requestIntegerInRange("Enter X coordinate of lower, right-hand corner",startX,getWidth(pict)-1)
  endY = requestIntegerInRange("Enter Y coordinate of lower, right-hand corner",startY,getHeight(pict)-1)      



  print "Please wait while picture is cropped from (",startX,",",startY,") to (",endX,",",endY,")."
  croppedPicture = makeCroppedPicture(pict, startX, startY, endX, endY)
  show(croppedPicture)

  newFileName = getMediaPath('croppedPicture.jpg')
  writePictureTo(croppedPicture, newFileName)

def makeCroppedPicture(pict, startX, startY, endX, endY):
  """ Makes and returns a cropped rectangular region of a picture into a new picture """

  target = makeEmptyPicture

def crop(picture):
  def crop(picture):
  width = getWidth(pict)
  height = getHeight(pict)
  canvas = makeEmptyPicture(width, height)
  targetX = 100
  for sourceX in range(100,30):
    targetY = 100
    for sourceY in range(311,433):
      color = getColor(getPixel(pict, sourceX, sourceY))
      setColor(getPixel(canvas, targetX, targetY),color)
      targetY = targetY + 1
    targetX = targetX + 1
  show(pict)
  return canvas  

  return target   # returns the cropped picture

main() # starts the program
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1 回答 1

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粘贴代码时似乎出了点问题；第 2 行缺少缩进，第 3 行有一个虚假的“在此处添加代码”字符串（crop() 函数的定义也出现了一些奇怪的问题，因为在代码运行之前需要更正缩进！）。

也就是说，通过删除当前未使用的第 29-43 行来删除crop() 函数，那么问题就会变得更容易看到......

   def makeCroppedPicture(pict, startX, startY, endX, endY):
       target = makeEmptyPicture
       return target   # returns the cropped picture

该行发生的情况target = makeEmptyPicture是您将变量目标分配给实际函数 makeEmptyPicture，而不是调用该函数返回的内容。

出于兴趣，在将函数分配给变量的帖子中，有更多关于您实际上想要如何/为什么要这样做的信息。

要解决此问题，只需在调用 makeEmptyPicture 时添加裁剪图像的高度和宽度的两个参数。注意，您可以硬编码几个数字来检查它是否首先工作。IE target = makeEmptyPicture(50, 50)

于 2015-03-13T14:45:41.080 回答