Keying an image

A non-transitory machine readable medium storing a program for execution by at least one processing unit, the program comprising sets of instructions for:

• receiving, for an image comprising a plurality of pixels, each pixel having a set of pixel values in a color space, a first selection of a first set of pixels for defining a first portion of the color space;
• identifying, in a two-dimensional plane of the color space, (i) an angular spread of the pixel values of the first set of pixels and (ii) a radial spread of the pixel values of the first set of pixels;
• defining the first portion of the color space based on the identified angular and radial spreads of the pixel values, the first portion for identifying a fully selected region of the image;
• defining a second portion of the color space to have a larger angular spread and larger radial spread than the first portion and thereby enclose the first portion in the two-dimensional plane, the second portion for identifying a partially selected region of the image;
• receiving a second selection of a second set of pixels for modifying the second portion of the color space;
• and
• modifying the second portion of the color space to exclude pixel values of the second set of pixels while continuing to enclose the first portion in the two-dimensional plane.

A method for editing an image, the image comprising a plurality of pixels having pixel values in a color space, the method comprising:

• based on a selected section of pixels of the image, identifying (i) a first portion of the color space and (ii) a second portion of the color space that encloses the first portion, wherein pixels whose pixel values are in the first portion of the color space are fully selected and pixels whose pixel values are in the second portion of the color space are partially selected;
• displaying a first freely deformable shape in two dimensions of the color space that represents the first portion in the two dimensions of the color space;
• and
• displaying a second freely deformable shape that encloses the first freely deformable shape in the two dimensions of the color space and represents the second portion in the two dimensions of the color space, wherein user modification to the first freely deformable shape causes automatic modification to the second freely deformable shape in order to maintain that the second freely deformable shape encloses the first freely deformable shape in the color space.