Adjust the viewport so that the X and Y scales are the same

#### Description:

The viewport is adjusted so that the scales along the X and Y axes are the same number of world coordinate units per unit length. The newly created viewport fits within the old viewport.

This command is a synonym for VIEWPORT ADJUST.

#### Parameters:

The left hand edge of the world coordinate system.

The value of the global parameter PONGO_XMIN is used. If PONGO_XMIN is not defined, the default value 0.0 is used.