/* Subtract two images * * Copyright: 1990, N. Dessipris. * * Author: Nicos Dessipris * Written on: 02/05/1990 * Modified on: * 29/4/93 J.Cupitt * - now works for partial images * 1/7/93 JC * - adapted for partial v2 * 9/5/95 JC * - simplified: now just handles 10 cases (instead of 50), using * im_clip2*() to help * - now uses im_wrapmany() rather than im_generate() * 12/6/95 JC * - new im_add() adapted to make this * 31/5/96 JC * - what was this SWAP() stuff? failed for small - big! * 22/8/03 JC * - cast up more quickly to help accuracy * 27/9/04 * - updated for 1 band $op n band image -> n band image case * 8/12/06 * - add liboil support * 18/8/08 * - revise upcasting system * - add gtkdoc comments * - remove separate complex case, just double size * 31/7/10 * - remove liboil * 23/8/11 * - rewrite as a class from add.c */ /* Copyright (C) 1991-2005 The National Gallery This library 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 2.1 of the License, or (at your option) any later version. This library 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 library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /* These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk */ /* #define DEBUG */ #ifdef HAVE_CONFIG_H #include #endif /*HAVE_CONFIG_H*/ #include #include #include #include #include #include "binary.h" typedef VipsBinary VipsSubtract; typedef VipsBinaryClass VipsSubtractClass; G_DEFINE_TYPE( VipsSubtract, vips_subtract, VIPS_TYPE_BINARY ); #define LOOP( IN, OUT ) { \ IN * restrict left = (IN *) in[0]; \ IN * restrict right = (IN *) in[1]; \ OUT * restrict q = (OUT *) out; \ \ for( x = 0; x < sz; x++ ) \ q[x] = left[x] - right[x]; \ } static void vips_subtract_buffer( VipsArithmetic *arithmetic, VipsPel *out, VipsPel **in, int width ) { VipsImage *im = arithmetic->ready[0]; /* Complex just doubles the size. */ const int sz = width * vips_image_get_bands( im ) * (vips_band_format_iscomplex( vips_image_get_format( im ) ) ? 2 : 1); int x; /* Keep types here in sync with bandfmt_subtract[] * below. */ switch( vips_image_get_format( im ) ) { case VIPS_FORMAT_CHAR: LOOP( signed char, signed short ); break; case VIPS_FORMAT_UCHAR: LOOP( unsigned char, signed short ); break; case VIPS_FORMAT_SHORT: LOOP( signed short, signed int ); break; case VIPS_FORMAT_USHORT:LOOP( unsigned short, signed int ); break; case VIPS_FORMAT_INT: LOOP( signed int, signed int ); break; case VIPS_FORMAT_UINT: LOOP( unsigned int, signed int ); break; case VIPS_FORMAT_FLOAT: case VIPS_FORMAT_COMPLEX: LOOP( float, float ); break; case VIPS_FORMAT_DOUBLE: case VIPS_FORMAT_DPCOMPLEX: LOOP( double, double ); break; default: g_assert_not_reached(); } } /* Save a bit of typing. */ #define UC VIPS_FORMAT_UCHAR #define C VIPS_FORMAT_CHAR #define US VIPS_FORMAT_USHORT #define S VIPS_FORMAT_SHORT #define UI VIPS_FORMAT_UINT #define I VIPS_FORMAT_INT #define F VIPS_FORMAT_FLOAT #define X VIPS_FORMAT_COMPLEX #define D VIPS_FORMAT_DOUBLE #define DX VIPS_FORMAT_DPCOMPLEX /* Type promotion for subtraction. Sign and value preserving. Make sure these * match the case statement in vips_subtract_buffer() above. */ static const VipsBandFormat vips_subtract_format_table[10] = { /* Band format: UC C US S UI I F X D DX */ /* Promotion: */ S, S, I, I, I, I, F, X, D, DX }; static void vips_subtract_class_init( VipsSubtractClass *class ) { VipsObjectClass *object_class = (VipsObjectClass *) class; VipsArithmeticClass *aclass = VIPS_ARITHMETIC_CLASS( class ); object_class->nickname = "subtract"; object_class->description = _( "subtract two images" ); aclass->process_line = vips_subtract_buffer; vips_arithmetic_set_format_table( aclass, vips_subtract_format_table ); } static void vips_subtract_init( VipsSubtract *subtract ) { } /** * vips_subtract: * @in1: input image * @in2: input image * @out: (out): output image * @...: %NULL-terminated list of optional named arguments * * This operation calculates @in1 - @in2 and writes the result to @out. * * If the images differ in size, the smaller image is enlarged to match the * larger by adding zero pixels along the bottom and right. * * If the number of bands differs, one of the images * must have one band. In this case, an n-band image is formed from the * one-band image by joining n copies of the one-band image together, and then * the two n-band images are operated upon. * * The two input images are cast up to the smallest common format (see table * Smallest common format in * arithmetic), then the * following table is used to determine the output type: * * * VipsSubtract type promotion * * * * input type * output type * * * * * uchar * short * * * char * short * * * ushort * int * * * short * int * * * uint * int * * * int * int * * * float * float * * * double * double * * * complex * complex * * * double complex * double complex * * * *
* * In other words, the output type is just large enough to hold the whole * range of possible values. * * See also: vips_add(), vips_linear(). * * Returns: 0 on success, -1 on error */ int vips_subtract( VipsImage *left, VipsImage *right, VipsImage **out, ... ) { va_list ap; int result; va_start( ap, out ); result = vips_call_split( "subtract", ap, left, right, out ); va_end( ap ); return( result ); }