80 lines
2.2 KiB
Groff
80 lines
2.2 KiB
Groff
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.TH Rect 3 "2 May 1991"
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.SH NAME
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im_rect_marginadjust, im_rect_includespoint, im_rect_includesrect,
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im_rect_intersectrect, im_rect_isempty, im_rect_unionrect, im_rect_normalise,
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im_rect_equalsrect, im_rect_dup,
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IM_RECT_RIGHT, IM_RECT_BOTTOM, IM_RECT_HCENTRE, IM_RECT_VCENTRE
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\- rectangle algebra functions
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.SH SYNOPSIS
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#include <vips/vips.h>
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typedef struct {
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.br
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int left, top, width, height;
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.br
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} Rect;
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#define IM_RECT_RIGHT(R) ((R)->left + (R)->width)
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.br
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#define IM_RECT_BOTTOM(R) ((R)->top + (R)->height)
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.br
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#define IM_RECT_HCENTRE(R) ((R)->left + (R)->width / 2)
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.br
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#define IM_RECT_VCENTRE(R) ((R)->top + (R)->height / 2)
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void im_rect_marginadjust( Rect *r, int n );
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.br
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int im_rect_includespoint( Rect *r, int x, int y );
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.br
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int im_rect_includesrect( Rect *r1, Rect *r2 );
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.br
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void im_rect_intersectrect( Rect *r1, Rect *r2, Rect *r3 );
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.br
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int im_rect_isempty( Rect *r );
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.br
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void im_rect_unionrect( Rect *r1, Rect *r2, Rect *r3 );
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.br
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int im_rect_equalsrect( Rect *r1, Rect *r2 );
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.br
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Rect *im_rect_dup( Rect *r );
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.br
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void im_rect_normalise( Rect *r );
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.SH DESCRIPTION
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These functions perform simple algebra on Rect structs. There should also be a
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set of functions to do rectlist algebra.
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im_rect_marginadjust(3) expands a Rect by n units up, down, left and right.
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Negative expansions shrink the Rect.
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im_rect_includespoint(3) returns non-zero
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if point (x,y) lies within Rect r.
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im_rect_includesrect(3) returns non-zero if
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Rect r2 lies completely within Rect r1.
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im_rect_intersectrect(3) fills Rect r3
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with the intersection of Rects r1 and r2.
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im_rect_isempty(3) returns non-zero
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if Rect r has either width less than or equal to 0 or height less than or
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equal to 0.
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im_rect_unionrect(3) fills Rect r3 with the bounding box of Rect r1 and Rect
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r2. A proper union operation requires lists of rectangles, sadly.
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im_rect_equalsrect(3) returns non-zero if r1 and r2 are identical.
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im_rect_dup(3) allocates memory for a new Rect structure and copies the
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elements of r into it. It returns a pointer to the new struct, or NULL on
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error.
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im_rect_normalise(3) flips r so that the same pixels are enclosed,
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but width and height are guaranteed >=0.
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.SH SEE ALSO
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im_prepare(3), im_region_create(3)
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.SH COPYRIGHT
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National Gallery, 1992
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.SH AUTHOR
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J. Cupitt
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