ADDITION(3) ADDITION(3)
NAME
im_add, im_gadd, im_gaddim, im_gfadd - add two images
SYNOPSIS
#include <vips/vips.h>
int im_add(in1, in2, out)
IMAGE *in1, *in2, *out;
int im_gadd(a, in1, b, in2, c, out)
double a, b, c;
IMAGE *in1, *in2, *out;
int im_gaddim(a, in1, b, in2, c, out)
double a, b, c;
IMAGE *in1, *in2, *out;
int im_gfadd(a, in1, b, in2, c, out)
double a, b, c;
IMAGE *in1, *in2, *out;
DESCRIPTION
These functions operate on two images held by image descriptors in1 and
in2 and write the result to the image descriptor out. Input images in1
and in2 should have the same channels and the same size; however they
can be of different types. Only the history of the image descriptor
pointed by in1 is copied to out.
im_add(3)
For two integer images, add the two images and write the output as
in1 - uchar char ushort short uint int
-------|-----------------------------------------
in2 |
uchar | ushort short ushort short uint int
char | short short short short int int
ushort | ushort short ushort short uint int
short | short short short short int int
uint | uint int uint int uint int
int | int int int int int int
If one or more of the images is a floating point type, the output is
FMTFLOAT, unless one or more of the inputs is FMTDOUBLE, in which case
the output is also FMTDOUBLE.
If one or more of the images is a complex type, the output is FMTCOM-
PLEX, unless one or more of the inputs is FMTDPCOMPLEX, in which case
the output is also FMTDPCOMPLEX.
im_gadd(3) performs generalised addition of two images by calling
im_gaddim(3) and im_gfadd(3). These are very old and tired things, and
should not be used.
Input should be non complex. Output depends on input according to
function called. The result at each point is: a * pel1 + b * pel2 + c,
properly rounded if necessary. Pel1 and pel2 are the corresponding
pixels from in1 and in2 respectively.
im_gaddim() performs generalised addition of in1 and in2, on the condi-
tion they are neither float nor double nor complex. The format of the
resultant image is given by the table:
in1 - uchar char ushort short uint int
-------|-----------------------------------------
in2 |
uchar | ushort short ushort short uint int
char | short short short short int int
ushort | ushort short ushort short uint int
short | short short short short int int
uint | uint int uint int uint int
int | int int int int int int
The result at each point is: a * pel1 + b * pel2 + c, properly rounded.
Pel1 and pel2 are the corresponding pixels from in1 and in2 respec-
tively.
im_gfadd(3) adds the non-complex images pointed by in1 and in2. Result
is float except if one (or both) inputs is double. In the latter case
the result is double. The result at each point is: a * pel1 + b * pel2
+ c. Pel1 and pel2 are the corresponding pixels from in1 and in2
respectively.
BUGS
None of the functions checks the result for over/underflow.
RETURN VALUE
All functions return 0 on success and -1 on error.
SEE ALSO
im_subtract(3), im_lintra(3), im_multiply(3).
AUTHOR
N. Dessipris - 22/04/1991
J. Cupitt, im_add(), - 21/7/93
24 April 1991 ADDITION(3)
im_add 7.14.5 - Generated Fri Sep 5 19:28:12 CDT 2008