1 .TH ADDPT 3
2 .SH NAME
3 addpt, subpt, mulpt, divpt, rectaddpt, rectsubpt, insetrect, canonrect, eqpt, eqrect, ptinrect, rectinrect, rectXrect, rectclip, combinerect, Dx, Dy, Pt, Rect, Rpt \- arithmetic on points and rectangles
4 .SH SYNOPSIS
5 .B #include <u.h>
6 .br
7 .B #include <libc.h>
8 .br
9 .B #include <draw.h>
10 .PP
11 .B
12 Point	addpt(Point p, Point q)
13 .PP
14 .B
15 Point	subpt(Point p, Point q)
16 .PP
17 .B
18 Point	mulpt(Point p, int a)
19 .PP
20 .B
21 Point	divpt(Point p, int a)
22 .PP
23 .B
24 Rectangle	rectaddpt(Rectangle r, Point p)
25 .PP
26 .B
27 Rectangle	rectsubpt(Rectangle r, Point p)
28 .PP
29 .B
30 Rectangle	insetrect(Rectangle r, int n)
31 .PP
32 .B
33 Rectangle	canonrect(Rectangle r)
34 .PP
35 .B
36 int		eqpt(Point p, Point q)
37 .PP
38 .B
39 int		eqrect(Rectangle r, Rectangle s)
40 .PP
41 .B
42 int		ptinrect(Point p, Rectangle r)
43 .PP
44 .B
45 int		rectinrect(Rectangle r, Rectangle s)
46 .PP
47 .B
48 int		rectXrect(Rectangle r, Rectangle s)
49 .PP
50 .B
51 int		rectclip(Rectangle *rp, Rectangle b)
52 .PP
53 .B
54 void		combinerect(Rectangle *rp, Rectangle b)
55 .PP
56 .B
57 int		Dx(Rectangle r)
58 .PP
59 .B
60 int		Dy(Rectangle r)
61 .PP
62 .B
63 Point	Pt(int x, int y)
64 .PP
65 .B
66 Rectangle	Rect(int x0, int y0, int x1, int y1)
67 .PP
68 .B
69 Rectangle	Rpt(Point p, Point q)
70 .SH DESCRIPTION
71 The functions
72 .IR Pt ,
73 .I Rect
74 and
75 .I Rpt
76 construct geometrical data types from their components.
77 .PP
78 .I Addpt
79 returns the Point
80 sum of its arguments:
81 .BI Pt( p .x+ q .x,
82 .IB p .y+ q .y) \f1.
83 .I Subpt
84 returns the Point
85 difference of its arguments:
86 .BI Pt( p .x- q .x,
87 .IB p .y- q .y) \f1.
88 .I Mulpt
89 returns the Point
90 .BI Pt( p .x* a ,
91 .IB p .y* a ) \f1.
92 .I Divpt
93 returns the Point
94 .BI Pt( p .x/ a ,
95 .IB p .y/ a ) \f1.
96 .PP
97 .I Rectaddpt
98 returns the Rectangle
99 .BI Rect(add( r .min,
100 .IB p ) \f1,
101 .BI add( r .max,
102 .IB p )) \f1;
103 .I rectsubpt
104 returns the Rectangle
105 .BI Rpt(sub( r .min,
106 .IB p ),
107 .BI sub( r .max,
108 .IB p ))\fR.
109 .PP
110 .I Insetrect
111 returns the Rectangle
112 .BI Rect( r .min.x+ n \f1,
113 .IB r .min.y+ n \f1,
114 .IB r .max.x- n \f1,
115 .IB r .max.y- n ) \f1.
116 .PP
117 .I Canonrect
118 returns a rectangle with the same extent as
119 .IR r ,
120 canonicalized so that
121 .B min.x
122 ≤
123 .BR max.x ,
124 and
125 .B min.y
126 ≤
127 .BR max.y .
128 .PP
129 .I Eqpt
130 compares its argument Points and returns
131 0 if unequal,
132 1 if equal.
133 .I Eqrect
134 does the same for its argument Rectangles.
135 .PP
136 .I Ptinrect
137 returns 1 if
138 .I p
139 is a point within
140 .IR r ,
141 and 0 otherwise.
142 .PP
143 .I Rectinrect
144 returns 1 if all the pixels in
145 .I r
146 are also in
147 .IR s ,
148 and 0 otherwise.
149 .PP
150 .I RectXrect
151 returns 1 if
152 .I r
153 and
154 .I s
155 share any point, and 0 otherwise.
156 .PP
157 .I Rectclip
158 clips in place
159 the Rectangle pointed to by
160 .I rp
161 so that it is completely contained within
162 .IR b .
163 The return value is 1 if any part of
164 .RI * rp
165 is within
166 .IR b .
167 Otherwise, the return value is 0 and
168 .RI * rp
169 is unchanged.
170 .PP
171 .I Combinerect
172 overwrites
173 .B *rp
174 with the smallest rectangle sufficient to cover all the pixels of
175 .B *rp
176 and
177 .BR b .
178 .PP
179 The functions
180 .I Dx
181 and
182 .I Dy
183 give the width (Δx) and height (Δy) of a Rectangle.
184 They are implemented as macros.
185 .SH SOURCE
186 .B \*9/src/libdraw
187 .SH SEE ALSO
188 .MR graphics (3)