198 lines
3 KiB
Plaintext
198 lines
3 KiB
Plaintext
.TH ADDPT 2
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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, badrect, 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 badrect(Rectangle r)
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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 Rpt(addpt( r .min,
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.IB p ) \f1,
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.BI addpt( 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(subpt( r .min,
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.IB p ),
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.BI subpt( 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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.I Badrect
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returns 1 if
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.I r
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is zero, negative size or insanely huge rectangle.
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It returns 0 otherwise.
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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 /sys/src/libdraw
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.SH SEE ALSO
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.IR graphics (2)
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