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ADD(9.3) ADD(9.3) NAME add, sub, mul, div, eqpt, eqrect, inset, muldiv, ptinrect, raddp, rsubp, rectXrect, rectclip - arithmetic on points and rectangles SYNOPSIS #include <jerq.h> Point add(p, q) Point p, q; Point sub(p, q) Point p, q; Point mul(p, a) Point p; int a; Point div(p, a) Point p; int a; int eqpt(p, q) Point p, q; int eqrect(r, s) Rectangle r, s; Rectangle inset(r, n) Rectangle r; int n; int muldiv(a, b, c) int a, b, c; int ptinrect(p, r) Point p; Rectangle r; Rectangle raddp(r, p) Rectangle r; Point p; Rectangle rsubp(r, p) Rectangle r; Point p; int rectXrect(r, s) Rectangle r, s; int rectclip(rp, s) Rectangle *rp, s; DESCRIPTION Add returns the Point sum of its arguments: Pt(p.x+q.x, p.y+q.y). Sub returns the Point difference of its arguments: Pt(p.x-q.x, p.y-q.y). Mul returns the Point Pt(p.x*a, p.y*a). Div returns the Point Pt(p.x/a, p.y/a). Eqpt and eqrect compare their arguments and return 0 if unequal, 1 if equal. Inset returns the Rectangle Rect(r.origin.x+n, r.origin.y+n, r.cor- ner.x-n, r.corner.y-n). The following code creates a clear rectangle r with a 2-pixel wide border inside r: rectf(&display, r, F_OR); rectf(&display, inset(r, 2), F_CLR); Muldiv is a macro that returns the 16-bit result (a*b)/c, with (a*b) calculated to 32 bits, so no precision is lost. Ptinrect returns 1 if p is a point within r, and 0 otherwise. Raddp returns the Rectangle Rect(add(r.origin, p), add(r.corner, p)); rsubp returns the Rectangle Rect(sub(r.origin, p), sub(r.corner, p)). RectXrect returns 1 if r and s share any point; 0 otherwise. Rectclip clips in place the Rectangle pointed to by rp so that it is completely contained within s. The return value is 1 if any part of *rp is within s. Otherwise, the return value is 0 and *rp is un- changed. SEE ALSO types(9.5) ADD(9.3)