67 lines
1.6 KiB
Groff
67 lines
1.6 KiB
Groff
|
.TH MACROS 3 "11 April 1990"
|
||
|
|
.SH NAME
|
||
|
|
IM_IMAGE_ADDR, IM_IMAGE_SIZEOF_ELEMENT, IM_IMAGE_SIZEOF_PEL,
|
||
|
|
IM_IMAGE_SIZEOF_LINE, IM_IMAGE_N_ELEMENTS \-
|
||
|
|
macros for images
|
||
|
|
.SH SYNOPSIS
|
||
|
|
.B #include <vips/vips.h>
|
||
|
|
|
||
|
|
int IM_IMAGE_SIZEOF_ELEMENT( im )
|
||
|
|
.br
|
||
|
|
IMAGE *im;
|
||
|
|
|
||
|
|
int IM_IMAGE_SIZEOF_PEL( im )
|
||
|
|
.br
|
||
|
|
IMAGE *im;
|
||
|
|
|
||
|
|
int IM_IMAGE_SIZEOF_LINE( im )
|
||
|
|
.br
|
||
|
|
IMAGE *im;
|
||
|
|
|
||
|
|
int IM_IMAGE_N_ELEMENTS( im )
|
||
|
|
.br
|
||
|
|
IMAGE *im;
|
||
|
|
|
||
|
|
char *IM_IMAGE_ADDR( im, x, y )
|
||
|
|
.br
|
||
|
|
IMAGE *im;
|
||
|
|
.br
|
||
|
|
int x;
|
||
|
|
.br
|
||
|
|
int y;
|
||
|
|
|
||
|
|
.SH DESCRIPTION
|
||
|
|
These macros help to simplify address arithmetic for images.
|
||
|
|
|
||
|
|
IM_IMAGE_SIZEOF_ELEMENT(3) returns sizeof( one band element ).
|
||
|
|
|
||
|
|
IM_IMAGE_SIZEOF_PEL(3) returns sizeof( one pel ).
|
||
|
|
|
||
|
|
IM_IMAGE_SIZEOF_LINE(3) returns sizeof( one horizontal line of pels ).
|
||
|
|
|
||
|
|
IM_IMAGE_N_ELEMENTS(3) returns the number of band elements across a horizontal line.
|
||
|
|
|
||
|
|
IM_IMAGE_ADDR(3) returns a pointer to the pixel at position (x,y) in the
|
||
|
|
image. The point (x,y) should lie within the image.
|
||
|
|
|
||
|
|
If the macro DEBUG has been defined, then IM_IMAGE_ADDR(3) will also
|
||
|
|
perform bounds checking. If you ask for the address of a pel outside the
|
||
|
|
image,
|
||
|
|
then IM_IMAGE_ADDR(3) will print an error message of the form:
|
||
|
|
|
||
|
|
IM_IMAGE_ADDR: point out of bounds, file "test.c", line 18
|
||
|
|
(point x=50, y=0
|
||
|
|
should have been within Rect left=0, top=0, width=50, height=50)
|
||
|
|
|
||
|
|
and call abort(3).
|
||
|
|
|
||
|
|
DEBUG needs to be defined *before* vips.h is included. Either define DEBUG
|
||
|
|
with -D in your Makefile, or have a #define DEBUG right at the top of your
|
||
|
|
file.
|
||
|
|
.SH COPYRIGHT
|
||
|
|
National Gallery, 1993
|
||
|
|
.SH SEE ALSO
|
||
|
|
im_malloc(3), im_open_local(3).
|
||
|
|
.SH AUTHOR
|
||
|
|
J. Cupitt \- 23/7/93
|