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