term% cat index.txt ADD(2) System Calls Manual ADD(2)
NAME
add, sub, mul, div, raddp, rsubp, rmul, rdiv, rshift, inset, rcanon,
eqpt, eqrect, ptinrect, rectinrect, rectXrect, rectclip, Dx, Dy, Pt,
Rect, Rpt - arithmetic on points and rectangles
SYNOPSIS
#include <u.h>
#include <libc.h>
#include <libg.h>
Point add(Point p, Point q)
Point sub(Point p, Point q)
Point mul(Point p, int a)
Point div(Point p, int a)
Rectangle raddp(Rectangle r, Point p)
Rectangle rsubp(Rectangle r, Point p)
Rectangle rmul(Rectangle r, int a)
Rectangle rdiv(Rectangle r, int a)
Rectangle rshift(Rectangle r, int a)
Rectangle inset(Rectangle r, int n)
Rectangle rcanon(Rectangle r)
int eqpt(Point p, Point q)
int eqrect(Rectangle r, Rectangle s)
int ptinrect(Point p, Rectangle r)
int rectinrect(Rectangle r, Rectangle s)
int rectXrect(Rectangle r, Rectangle s)
int rectclip(Rectangle *rp, Rectangle b)
int Dx(Rectangle r)
int Dy(Rectangle r)
Point Pt(int x, int y)
Rectangle Rect(int x0, int y0, int x1, int y1)
Rectangle Rpt(Point p, Point q)
DESCRIPTION
The functions Pt, Rect and Rpt construct geometrical data types from
their components. These are implemented as macros.
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).
Raddp returns the Rectangle Rect(add(r.min, p), add(r.max, p)); rsubp
returns the Rectangle Rpt(sub(r.min, p), sub(r.max, p)). Rmul returns
the Rectangle Rpt(mul(r.min,a), mul(r.max,a)); Rdiv returns the Rectan‐
gle Rpt(div(r.min,a), div(r.max,a)).
Rshift returns the rectangle r with all coordinates either left-shifted
or right-shifted by a, depending on whether a is positive or negative,
respectively.
Inset returns the Rectangle Rect(r.min.x+n, r.min.y+n, r.max.x-n,
r.max.y-n).
Rcanon returns a rectangle with the same extent as r, canonicalized so
that min.x ⤠max.x, and min.y ⤠max.y.
Eqpt compares its argument Points and returns 0 if unequal, 1 if equal.
Eqrect does the same for its argument Rectangles.
Ptinrect returns 1 if p is a point within r, and 0 otherwise.
Rectinrect returns 1 if all the pixels in r are also in s, and 0 other‐
wise.
RectXrect returns 1 if r and s share any point, and 0 otherwise.
Rectclip clips in place the Rectangle pointed to by rp so that it is
completely contained within b. The return value is 1 if any part of
*rp is within b. Otherwise, the return value is 0 and *rp is un‐
changed.
The functions Dx and Dy give the width (x) and height (y) of a Rectan‐
gle. They are implemented as macros.
SOURCE
/sys/src/libg
SEE ALSO
graphics(2)
ADD(2)