Mm_anisotropic: converts the logical unit to any unit with any proportional axis. You can use the setwindowext and setviewportext functions to specify the unit, direction, and ratio.
Mm_hienglish: each logical unit is converted to 0.001 inch. The positive direction of X is to the right, and the positive direction of Y is to the upward direction.
Mm_himetric: each logical unit is converted to 0.01mm. The positive direction of X is right, and the positive direction of Y is upward.
Mm_isotropic: the logical unit is converted to any unit with an equal proportional axis, that is, a unit along the X axis is equal to a unit along the Y axis, the setjavaswext and setviewportext functions can be used to specify the unit and direction of the axis. The graphic device interface (GDI) needs to be adjusted to ensure that the units of X and Y are the same size (when the window range is set, the view is adjusted to the same size ).
Mm_loenglish: Each logic unit is converted to 0.01 inch. The positive direction of X is right, and the positive direction of Y is upward.
Mm_lometric: each logical unit is converted to 0.1mm. The positive direction of X is right, and the positive direction of Y is upward.
Mm_text: each logical unit is converted to an element. The positive direction of X is right, and the positive direction of Y is downward.
Mm_twips; each logical unit is converted to 1/20 (1/1400 inch) of the print point. The positive direction of X is right, and the direction of Y is upward.
Return Value: if the function is successfully called, the return value specifies the previous ing method. Otherwise, the return value is zero. To obtain more error information, call the getlasterror function.