GUIMath
d2line · d2line_seg · feround · inside

# GUIMath

class GUIMath
Syntax:

`obj = new GUIMath()`

Description:

Contains functions which calculate common relationships between graphics objects.

GUIMath.d2line()
Syntax:

`d = math.d2line(xpoint, ypoint, xline0, yline0, xline1, yline1)`

Description:

Return distance between the point (xpoint,ypoint) and the (infinitely long) line defined by the 0 and 1 points.

GUIMath.d2line_seg()
Syntax:

`d = math.d2line_seg(xpoint, ypoint, xline0, yline0, xline1, yline1)`

Description:

Return distance between the point (xpoint,ypoint) and the line segment line defined by the 0 and 1 points.

GUIMath.inside()
Syntax:

`boolean = math.inside(xpoint, ypoint, left, bottom, right, top)`

Description:

return 1 if the point is inside the box, 0 otherwise

GUIMath.feround()
Syntax:

`mode = math.feround()`

`lastmode = math.feround(mode)`

Description:

Set the floating point rounding mode. Mode 1, 2, 3, 4 refers to FE_DOWNWARD, FE_TONEAREST, FE_TOWARDZERO, FE_UPWARD respectively. The default, and most accurate, mode is FE_TONEAREST. The mode is changed only if the argument is 1-4. If there is no support for this function the return value is 0.

This function is useful to determine if a simulation depends unduly on double precision round-off error.

Example:

```objref gm
gm = new GUIMath()
{printf("default rounding mode %d\n", gm.feround())}

proc test_round() {local i, old, x  localobj gm
gm = new GUIMath()
old = gm.feround(\$1)
x = 0
for i=1, 1000000 x += 0.1
printf("rounding mode %d x=%25.17lf\n", \$1, x)
gm.feround(old)
}

for i=1, 4 test_round(i)
```