10564b1175
groff 1.23.0 added .MR to its -man macro package. The NEWS file states
that the inclusion of the macro "was prompted by its introduction to
Plan 9 from User Space's troff in August 2020." From d32deab it seems
that the name for Plan 9 from User Space's implementation was suggested
by groff maintainer G. Brandon Robinson.
Not sure if the intention was to make these definitions compatible, but
it would be nice if they were.
Currently, Plan 9 from User Space's .MR expects its second argument to
be parenthesized. groff's .MR does not. This results in extra
parentheses appearing in manual references when viewing Plan 9 from User
Space's manual pages on a system using groff.
189 lines
2.9 KiB
Groff
189 lines
2.9 KiB
Groff
.TH ADDPT 3
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.SH NAME
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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
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.SH SYNOPSIS
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.B #include <u.h>
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.br
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.B #include <libc.h>
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.br
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.B #include <draw.h>
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.PP
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.B
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Point addpt(Point p, Point q)
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.PP
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.B
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Point subpt(Point p, Point q)
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.PP
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.B
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Point mulpt(Point p, int a)
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.PP
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.B
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Point divpt(Point p, int a)
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.PP
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.B
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Rectangle rectaddpt(Rectangle r, Point p)
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.PP
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.B
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Rectangle rectsubpt(Rectangle r, Point p)
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.PP
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.B
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Rectangle insetrect(Rectangle r, int n)
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.PP
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.B
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Rectangle canonrect(Rectangle r)
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.PP
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.B
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int eqpt(Point p, Point q)
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.PP
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.B
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int eqrect(Rectangle r, Rectangle s)
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.PP
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.B
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int ptinrect(Point p, Rectangle r)
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.PP
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.B
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int rectinrect(Rectangle r, Rectangle s)
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.PP
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.B
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int rectXrect(Rectangle r, Rectangle s)
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.PP
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.B
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int rectclip(Rectangle *rp, Rectangle b)
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.PP
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.B
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void combinerect(Rectangle *rp, Rectangle b)
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.PP
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.B
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int Dx(Rectangle r)
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.PP
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.B
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int Dy(Rectangle r)
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.PP
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.B
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Point Pt(int x, int y)
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.PP
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.B
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Rectangle Rect(int x0, int y0, int x1, int y1)
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.PP
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.B
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Rectangle Rpt(Point p, Point q)
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.SH DESCRIPTION
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The functions
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.IR Pt ,
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.I Rect
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and
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.I Rpt
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construct geometrical data types from their components.
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.PP
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.I Addpt
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returns the Point
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sum of its arguments:
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.BI Pt( p .x+ q .x,
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.IB p .y+ q .y) \f1.
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.I Subpt
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returns the Point
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difference of its arguments:
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.BI Pt( p .x- q .x,
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.IB p .y- q .y) \f1.
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.I Mulpt
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returns the Point
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.BI Pt( p .x* a ,
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.IB p .y* a ) \f1.
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.I Divpt
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returns the Point
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.BI Pt( p .x/ a ,
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.IB p .y/ a ) \f1.
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.PP
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.I Rectaddpt
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returns the Rectangle
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.BI Rect(add( r .min,
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.IB p ) \f1,
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.BI add( r .max,
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.IB p )) \f1;
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.I rectsubpt
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returns the Rectangle
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.BI Rpt(sub( r .min,
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.IB p ),
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.BI sub( r .max,
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.IB p ))\fR.
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.PP
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.I Insetrect
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returns the Rectangle
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.BI Rect( r .min.x+ n \f1,
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.IB r .min.y+ n \f1,
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.IB r .max.x- n \f1,
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.IB r .max.y- n ) \f1.
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.PP
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.I Canonrect
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returns a rectangle with the same extent as
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.IR r ,
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canonicalized so that
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.B min.x
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≤
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.BR max.x ,
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and
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.B min.y
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≤
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.BR max.y .
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.PP
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.I Eqpt
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compares its argument Points and returns
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0 if unequal,
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1 if equal.
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.I Eqrect
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does the same for its argument Rectangles.
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.PP
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.I Ptinrect
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returns 1 if
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.I p
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is a point within
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.IR r ,
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and 0 otherwise.
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.PP
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.I Rectinrect
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returns 1 if all the pixels in
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.I r
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are also in
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.IR s ,
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and 0 otherwise.
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.PP
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.I RectXrect
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returns 1 if
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.I r
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and
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.I s
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share any point, and 0 otherwise.
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.PP
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.I Rectclip
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clips in place
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the Rectangle pointed to by
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.I rp
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so that it is completely contained within
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.IR b .
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The return value is 1 if any part of
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.RI * rp
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is within
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.IR b .
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Otherwise, the return value is 0 and
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.RI * rp
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is unchanged.
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.PP
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.I Combinerect
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overwrites
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.B *rp
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with the smallest rectangle sufficient to cover all the pixels of
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.B *rp
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and
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.BR b .
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.PP
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The functions
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.I Dx
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and
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.I Dy
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give the width (Δx) and height (Δy) of a Rectangle.
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They are implemented as macros.
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.SH SOURCE
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.B \*9/src/libdraw
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.SH SEE ALSO
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.MR graphics 3
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