PIL question about crop method

[Diez B. Roggisch]

John Salerno schrieb:
> I might be way off target even looking into this method for what I need 
> to do, but I'm still a little confused about the description of it:
> 
> crop
> im.crop(box) => image
> 
> Returns a rectangular region from the current image. The box is a 
> 4-tuple defining the left, upper, right, and lower pixel coordinate.
> 
> I'm probably just being a little dense again, but how exactly do you 
> write the tuple? Wouldn't a coordinates parameter be a tuple of tuples? 
> It sounds like here you only need four numbers, but I don't understand 
> what 'left, upper, right, and lower pixel coordinate' means. It doesn't 
> seem like it's asking for a set of coordinates for each corner of the 
> box, or for a set at all. How do four separate numbers make up coordinates?

You can think of a rect as two coordinates - e.g. (10, 20), (30, 100)

Alternatively you can see it as boundary lines, in the order left, top, 
right, bottom.

(10, 20, 30, 100)

The latter is what you need.

Diez