| /* im_point_bilinear.c |
| * |
| * Copyright: 2006, The Nottingham Trent University |
| * |
| * Author: Tom Vajzovic |
| * |
| * Written on: 2006-09-26 |
| * |
| * 9/9/09 |
| * - rewrite in terms of im_affinei() and im_avg() |
| */ |
| |
| /* |
| |
| This file is part of VIPS. |
| |
| VIPS is free software; you can redistribute it and/or modify |
| it under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| |
| */ |
| |
| /* |
| |
| These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk |
| |
| */ |
| |
| #ifdef HAVE_CONFIG_H |
| #include <config.h> |
| #endif /* HAVE_CONFIG_H */ |
| #include <vips/intl.h> |
| |
| #include <math.h> |
| |
| #include <vips/vips.h> |
| |
| #ifdef WITH_DMALLOC |
| #include <dmalloc.h> |
| #endif /*WITH_DMALLOC */ |
| |
| /** |
| * im_point: |
| * @im: image to read from |
| * @interpolate: interpolator to sample points with |
| * @x: x position to interpolate |
| * @y: y position to interpolate |
| * @band: band to read |
| * @out: return interpolated value |
| * |
| * Find the value at (@x, @y) in given band of image. |
| * Non-integral values are calculated using the supplied @interpolate. |
| * |
| * See also: im_avg(), #VipsInterpolate |
| * |
| * Returns: 0 on success, -1 on error |
| */ |
| int |
| im_point( IMAGE *im, VipsInterpolate *interpolate, |
| double x, double y, int band, double *out ) |
| { |
| IMAGE *t[2]; |
| |
| if( band >= im->Bands || |
| x < 0.0 || y < 0.0 || |
| x > im->Xsize || y > im->Ysize ) { |
| im_error( "im_point_bilinear", "%s", |
| _( "coords outside image" ) ); |
| return( -1 ); |
| } |
| |
| if( im_open_local_array( im, t, 2, "im_point_bilinear", "p" ) || |
| im_extract_band( im, t[0], band ) || |
| im_affinei( t[0], t[1], |
| interpolate, |
| 1, 0, 0, 1, |
| x - floor( x ), y - floor( y ), |
| floor( x ), floor( y ), 1, 1 ) || |
| im_avg( t[1], out ) ) |
| return( -1 ); |
| |
| return( 0 ); |
| } |
| |
| /** |
| * im_point_bilinear: |
| * @im: image to read from |
| * @x: x position to interpolate |
| * @y: y position to interpolate |
| * @band: band to read |
| * @out: return interpolated value |
| * |
| * Find the value at (@x,@y) in given band of image. |
| * Use bilinear interpolation if @x or @y are non-integral. |
| * |
| * See also: im_avg(), im_point(). |
| * |
| * Returns: 0 on success, -1 on error |
| */ |
| int |
| im_point_bilinear( IMAGE *im, double x, double y, int band, double *out ) |
| { |
| return( im_point( im, vips_interpolate_bilinear_static(), |
| x, y, band, out ) ); |
| } |
| |