| .TH IM_IFTHENELSE 3 "30 October 1992" |
| .SH NAME |
| im_ifthenelse \- use an unsigned char image to join two images together |
| .SH SYNOPSIS |
| .B #include <vips/vips.h> |
| |
| .B int im_ifthenelse(c, a, b, out) |
| .br |
| .B IMAGE *c, *a, *b, *out; |
| |
| .B int im_blend(c, a, b, out) |
| .br |
| .B IMAGE *c, *a, *b, *out; |
| |
| .SH DESCRIPTION |
| .B im_ifthenelse |
| builds an output image which uses some pels from a and some from b: if the |
| conditional image c is non-zero at that point, the pel comes from a; if it |
| is zero, the pel comes from b. |
| |
| The conditional image c can have either 1 band, in which case entire pels |
| come either from a or b, or n bands, where n is the number of bands in both a |
| and b, in which case individual band elements are chosen from a and b. |
| |
| Images a and b must match in size, type and number of bands. |
| |
| .B im_blend(3) |
| works just as im_ifthenelse(3), except that instead of selecting between a and |
| b, values in the condition image are used to softly blend between the two. 255 |
| means a only, 0 means b only, 128 means 50:50. |
| |
| .SH RETURN VALUE |
| 0 on success and -1 on error. |
| .SH SEE ALSO |
| im_equal(3), im_and(3). |
| .SH COPYRIGHT |
| National Gallery |
| .SH AUTHOR |
| J. Cupitt |
