456 lines
11 KiB
C
456 lines
11 KiB
C
/* Cored sharpen of LABQ image.
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*
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* Usage:
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*
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* int im_sharpen( IMAGE *in, IMAGE *out,
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* int mask_size,
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* int x1, int x2,
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* double m1, double m2 )
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*
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* Returns 0 on success and -1 on error
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*
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* Copyright: 1995 A. Abbood
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* Author: A. Abbood
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* Written on: 30/01/1995
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* 15/5/95 JC
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* - updated for latest 7.3 mods
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* - m3 parameter removed
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* - bug fixes and speed-ups
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* 4/7/95 JC
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* - x3 parameter added
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* - xs are now double
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* 6/7/95 JC
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* - xs are now ys
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* - better LUT generation
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* 12/3/01 JC
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* - uses seperable convolution for umask
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* - tiny clean ups
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* 23/7/01 JC
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* - fix for band extract index changed
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* 21/4/04
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* - switched to gaussian mask and radius
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* 20/11/04
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* - uses extract_bands() to remove and reattach ab for slight speedup
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* - accepts LabS as well as LabQ for slight speedup
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* - small code tidies
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* - ~15% speed up in total
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* 29/11/06
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* - convolve first to help region sharing
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* 3/2/10
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* - gtkdoc
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* - cleanups
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* 13/11/13
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* - redo as a class
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* - does any type, any number of bands
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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/*
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#define DEBUG
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <vips/intl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <vips/vips.h>
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typedef struct _VipsSharpen {
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VipsOperation parent_instance;
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VipsImage *in;
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VipsImage *out;
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int radius;
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double x1;
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double y2;
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double y3;
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double m1;
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double m2;
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double x2;
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double x3;
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/* Parameters scaled up to int.
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*
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* We need indexes in the range [-x3,x2], so add x3 to
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* indexes before starting to index table.
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*/
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int ix1;
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int ix2;
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int ix3;
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/* The lut we build.
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*/
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int *lut;
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} VipsSharpen;
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typedef VipsOperationClass VipsSharpenClass;
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G_DEFINE_TYPE( VipsSharpen, vips_sharpen, VIPS_TYPE_OPERATION );
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static int
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vips_sharpen_generate( VipsRegion *or,
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void *vseq, void *a, void *b, gboolean *stop )
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{
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VipsRegion **in = (VipsRegion **) vseq;
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VipsSharpen *sharpen = (VipsSharpen *) b;
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VipsRect *r = &or->valid;
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int ix3 = sharpen->ix3;
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int range = sharpen->ix2 + sharpen->ix3;
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int *lut = sharpen->lut;
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int x, y;
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if( vips_region_prepare( in[0], r ) ||
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vips_region_prepare( in[1], r ) )
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return( -1 );
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for( y = 0; y < r->height; y++ ) {
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short *p1 = (short *)
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VIPS_REGION_ADDR( in[0], r->left, r->top + y );
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short *p2 = (short *)
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VIPS_REGION_ADDR( in[1], r->left, r->top + y );
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short *q = (short *)
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VIPS_REGION_ADDR( or, r->left, r->top + y );
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for( x = 0; x < r->width; x++ ) {
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int v1 = p1[x];
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int v2 = p2[x];
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/* v2 is the area average. If this is zero, then we
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* pass the original image through unaltered.
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*/
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if( v2 == 0 )
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q[x] = v1;
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else {
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/* Find difference. Offset by x3 to get the
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* expected range of values.
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*/
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int s1 = ix3 + (v1 - v2);
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int s2;
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if( s1 < 0 )
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s1 = 0;
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else if( s1 > range )
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s1 = range;
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s2 = v1 + lut[s1];
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if( s2 < 0 )
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s2 = 0;
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else if( s2 > 32767 )
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s2 = 32767;
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q[x] = s2;
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}
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}
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}
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return( 0 );
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}
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static int
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vips_sharpen_build( VipsObject *object )
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{
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VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
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VipsSharpen *sharpen = (VipsSharpen *) object;
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VipsImage **t = (VipsImage **) vips_object_local_array( object, 7 );
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VipsImage **args = (VipsImage **) vips_object_local_array( object, 2 );
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VipsImage *in;
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int ix1, ix2, ix3;
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int i;
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if( VIPS_OBJECT_CLASS( vips_sharpen_parent_class )->build( object ) )
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return( -1 );
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/* Turn y parameters into xs.
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*/
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sharpen->x2 = (sharpen->y2 -
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sharpen->x1 * (sharpen->m1 - sharpen->m2)) / sharpen->m2;
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sharpen->x3 = (sharpen->y3 -
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sharpen->x1 * (sharpen->m1 - sharpen->m2)) / sharpen->m2;
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in = sharpen->in;
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if( vips_colourspace( in, &t[0], VIPS_INTERPRETATION_LABS, NULL ) )
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return( -1 );
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in = t[0];
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if( vips_check_uncoded( class->nickname, in ) ||
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vips_check_bands_atleast( class->nickname, in, 3 ) ||
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vips_check_format( class->nickname, in, VIPS_FORMAT_SHORT ) )
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return( -1 );
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if( sharpen->x1 < 0 || sharpen->x1 > 99 ||
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sharpen->x2 < 0 || sharpen->x2 > 99 ||
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sharpen->x1 > sharpen->x2 ||
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sharpen->x3 < 0 || sharpen->x3 > 99 ||
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sharpen->x1 > sharpen->x3 ) {
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vips_error( class->nickname,
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"%s", _( "parameters out of range" ) );
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return( -1 );
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}
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/* Stop at 20% of max ... bit mean, but means mask radius is roughly
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* right. We always sharpen a short, so no point using a float mask.
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*/
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if( vips_gaussmat( &t[1], sharpen->radius / 2, 0.2,
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"separable", TRUE,
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"integer", TRUE,
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NULL ) )
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return( -1 );
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#ifdef DEBUG
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printf( "sharpen: blurring with:\n" );
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vips_matrixprint( t[1], NULL );
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#endif /*DEBUG*/
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/* Build the int lut.
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*/
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sharpen->ix1 = ix1 = sharpen->x1 * 327.67;
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sharpen->ix2 = ix2 = sharpen->x2 * 327.67;
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sharpen->ix3 = ix3 = sharpen->x3 * 327.67;
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if( !(sharpen->lut = VIPS_ARRAY( sharpen->out, ix2 + ix3 + 1, int )) )
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return( -1 );
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for( i = 0; i < ix1; i++ ) {
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sharpen->lut[ix3 + i] = i * sharpen->m1;
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sharpen->lut[ix3 - i] = -i * sharpen->m1;
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}
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for( i = ix1; i <= ix2; i++ )
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sharpen->lut[ix3 + i] =
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ix1 * sharpen->m1 + (i - ix1) * sharpen->m2;
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for( i = ix1; i <= ix3; i++ )
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sharpen->lut[ix3 - i] =
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-(ix1 * sharpen->m1 + (i - ix1) * sharpen->m2);
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/* Extract L and the rest, convolve L.
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*/
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if( vips_extract_band( in, &args[0], 0, NULL ) ||
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vips_extract_band( in, &t[3], 1, "n", in->Bands - 1, NULL ) ||
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vips_convsep( args[0], &args[1], t[1], NULL ) )
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return( -1 );
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/* Set demand hints. FATSTRIP is good for us, as THINSTRIP will cause
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* too many recalculations on overlaps.
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*/
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t[5] = vips_image_new();
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if( vips_image_pipeline_array( t[5],
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VIPS_DEMAND_STYLE_FATSTRIP, args ) )
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return( -1 );
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if( vips_image_generate( t[5],
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vips_start_many, vips_sharpen_generate, vips_stop_many,
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args, sharpen ) )
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return( -1 );
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g_object_set( object, "out", vips_image_new(), NULL );
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/* Reattach the rest.
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*/
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if( vips_bandjoin2( t[5], t[3], &t[6], NULL ) ||
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vips_image_write( t[6], sharpen->out ) )
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return( -1 );
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return( 0 );
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}
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static void
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vips_sharpen_class_init( VipsSharpenClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *object_class = (VipsObjectClass *) class;
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gobject_class->set_property = vips_object_set_property;
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gobject_class->get_property = vips_object_get_property;
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object_class->nickname = "sharpen";
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object_class->description = _( "Unsharp masking for print" );
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object_class->build = vips_sharpen_build;
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VIPS_ARG_IMAGE( class, "in", 1,
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_( "Input" ),
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_( "Input image" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, in ) );
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VIPS_ARG_IMAGE( class, "out", 2,
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_( "Output" ),
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_( "Output image" ),
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VIPS_ARGUMENT_REQUIRED_OUTPUT,
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G_STRUCT_OFFSET( VipsSharpen, out ) );
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VIPS_ARG_INT( class, "radius", 3,
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_( "Radius" ),
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_( "Mask radius" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, radius ),
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1, 1000000, 3 );
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VIPS_ARG_DOUBLE( class, "x1", 5,
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_( "x1" ),
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_( "Flat/jaggy threshold" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, x1 ),
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1, 1000000, 1.5 );
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VIPS_ARG_DOUBLE( class, "y2", 6,
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_( "y2" ),
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_( "Maximum brightening" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, y2 ),
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1, 1000000, 20 );
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VIPS_ARG_DOUBLE( class, "y3", 7,
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_( "y3" ),
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_( "Maximum darkening" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, y3 ),
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1, 1000000, 50 );
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VIPS_ARG_DOUBLE( class, "m1", 8,
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_( "m1" ),
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_( "Slope for flat areas" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, m1 ),
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1, 1000000, 1 );
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VIPS_ARG_DOUBLE( class, "m2", 9,
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_( "m2" ),
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_( "Slope for jaggy areas" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsSharpen, m2 ),
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1, 1000000, 2 );
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}
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static void
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vips_sharpen_init( VipsSharpen *sharpen )
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{
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sharpen->radius = 3;
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sharpen->x1 = 1.5;
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sharpen->y2 = 20;
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sharpen->y3 = 50;
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sharpen->m1 = 1;
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sharpen->m2 = 2;
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}
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/**
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* vips_sharpen:
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* @in: input image
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* @out: output image
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* @...: %NULL-terminated list of optional named arguments
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*
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* Optional arguments:
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*
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* @radius: how large a mask to use
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* @x1: flat/jaggy threshold
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* @y2: maximum amount of brightening
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* @y3: maximum amount of darkening
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* @m1: slope for flat areas
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* @m2: slope for jaggy areas
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*
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* Selectively sharpen the L channel of a LAB image. The input image is
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* transformed to #VIPS_INTERPRETATION_LABS.
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*
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* The operation performs a gaussian blur of radius @radius and subtracts
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* from @in to generate a high-frequency signal. This signal is passed
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* through a lookup table formed from the five parameters and added back to
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* @in.
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*
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* The lookup table is formed like this:
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*
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* |[
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^
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y2 |- - - - - -----------
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| /
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| / slope m2
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| .../
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-x1 | ... |
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-------------------...---------------------->
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| ... | x1
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|... slope m1
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/ |
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/ m2 |
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/ |
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/ |
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/ |
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/ |
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______/ _ _ _ _ _ _ | -y3
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* ]|
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*
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* For printing, we recommend the following settings (the defaults):
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*
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* |[
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radius == 3
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x1 == 1.5
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y2 == 20 (don't brighten by more than 20 L*)
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y3 == 50 (can darken by up to 50 L*)
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m1 == 1 (some sharpening in flat areas)
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m2 == 2 (more sharpening in jaggy areas)
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* ]|
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*
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* If you want more or less sharpening, we suggest you just change the m1
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* and m2 parameters.
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*
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* The @radius parameter changes the width of the fringe and can be
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* adjusted according to the output printing resolution. As an approximate
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* guideline, use 1 for 4 pixels/mm (CRT display resolution), 2 for 8
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* pixels/mm, 3 for 12 pixels/mm and 4 for 16 pixels/mm (300 dpi == 12
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* pixels/mm). These figures refer to the image raster, not the half-tone
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* resolution.
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*
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* See also: im_conv().
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*
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* Returns: 0 on success, -1 on error.
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*/
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int
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vips_sharpen( VipsImage *in, VipsImage **out, ... )
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{
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va_list ap;
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int result;
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va_start( ap, out );
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result = vips_call_split( "sharpen", ap, in, out );
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va_end( ap );
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return( result );
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}
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