GROBW/GROBH vs GROBW_P/GROBH_P

[toml_12953]

(10-11-2018 02:34 AM)sasa Wrote:  Thank you for your respond. I understand these functions are for Cartesian plane - the screen coordinate system have top left corner defined as (0,0) (a relict from early CRT time), while in Cartesian plane (0,0) is the center...

The beauty of using Cartesian coordinates is that you can define the screen to be anything you want. (0,0) can be in the lower left if you only want to deal with quadrant 1. See how much simpler the following program is with a user-defined coordinate system?

Code:

EXPORT SINWAVE()
BEGIN
Xmin:=0; Xmax:=2*PI;
Ymin=-.85; Ymax=1;
RECT(0);
LINE(0,0,2*PI,0,#777777);
FOR A FROM 0 TO 2*PI STEP .01 DO
  PIXON(A,SIN(A),#00FF00);
  PIXON(A,COS(A),#0000FF);
END;
FREEZE;
END;

Think of how you'd have to write those LINE and PIXON statements if (0,0) was the upper-left corner and (319,239) was the lower-right!