1. A computer-readable storage medium, excluding signals per se, comprising instructions stored thereon that, responsive to execution on one or more computers causes the one or more computer to perform operations comprising: displaying an image on a computer display, the displayed image corresponds to image data; receiving input via application of one or more tools applied to a specified portion of the displayed image as specified by a user, the input specifying one or more depth constraints for at least the specified portion of the image to set a curvature that specifies a relationship between depth values of pixels in the specified portion with respect to depth values of neighboring pixels; automatically determining a depth map for the image data subject to the one or more depth constraints; and displaying a representation of the depth map on the computer display.