CIGAL Reference Manual, Chapter 6 (RealTime): r_bset
r_bset -- Move a box pointer to an X-Y position
usage: r_bset opflg eflag ltime Point Box Flag
R_BSET is a REALTIME operator. It is used to position a rectangular region for subsequent screen I/O, without itself causing any change to occur on the screen. R_BSET modifies the coordinates of a rectangular region, BOX, to correspond to a new screen location specified by POINT. BOX is a short integer array with 4 values that define the size of the rectangle (left, top, right, bottom). POINT is a short integer array with 2 elements, which are interpreted as the new X and Y coordinates.
The FLAG argument is a bitflag that provides the following options:
1 - center the rectangle at the POINT, otherwise the upper left corner of the rectangle is placed at POINT 2 - treat the X,Y values in POINT as relative offsets 4 - treat the X,Y values in POINT as relative offsets, but reverse the direction of motion (i.e., treat POINT as -X,-Y)
When R_BSET is done the coordinates in the BOX array are updated to reflect the new position of the rectangle.