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NAME
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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
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#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
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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 Rectangle
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 otherwise.
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 unchanged.
The functions
Dx
and
Dy
give the width (x) and height (y) of a Rectangle.
They are implemented as macros.
SOURCE
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/sys/src/libg
SEE ALSO
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graphics(2)
Copyright © 1995 Lucent Technologies. All rights reserved.