在JES(Python)中裁剪图像

Question

所以我对这个Python的东西真的很陌生，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，此时我可以使用任何我能得到的帮助。这是我到目前为止的代码：

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

Answer 1

粘贴代码似乎有点问题; 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，那么问题就更容易看到......

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

行target = makeEmptyPicture发生的事情是，您将变量目标分配给实际函数makeEmptyPicture，而不是通过调用该函数返回的内容。

出于兴趣，在将函数分配给变量一文中有更多关于您实际上想要如何/为什么这样做的信息。

要解决此问题，只需在调用makeEmptyPicture时添加两个参数来表示裁剪图像的高度和宽度。 注意：你可以硬编码几个数字来检查它是否首先工作。即 target = makeEmptyPicture(50, 50)