Pikchr

Line objects may have a single "chop" attribute. When the chop attribute is present, and if the line starts or ends at the center of a block object, then that start or end is automatically moved to the edge of the object. For example:

file "A"
cylinder "B" at 5cm heading 125 from A
arrow <-> from A to B "from A to B" aligned above color red
arrow <-> from A to B chop "from A to B chop" aligned below color blue

In the example, both of the arrows use "from A to B" The difference is that the blue line adds the "chop" keyword whereas the red line does not.

The chop feature only works if one or both ends of the line land on the center of a block object. If neither end of a line is on the center of a block object, then the "chop" attribute is a no-op

Different From Legacy PIC

The chop attribute in Pikchr differs from the chop attribute in legacy PIC. In PIC, the "chop" keyword can be followed by a distance and can appear twice. The chop keyword causes the line to be shortened by the amount specified, or by circlerad if no distance is given. The legacy "chop" works okay if you are drawing lines between circles, but it mostly pointless for lines between all other kinds of objects. The enhanced "chop" in Pikchr is intended to make the feature helpful on a wider variety of diagrams.