199 lines
5.8 KiB
C
199 lines
5.8 KiB
C
/* base class for all resample operations
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*
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* properties:
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* - one in, one out
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* - not point-to-point
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* - size can change in any way
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* - bands, type, format etc. all fixed
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*/
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/*
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Copyright (C) 1991-2005 The National Gallery
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; 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 <glib/gi18n-lib.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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#include <vips/internal.h>
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#include "presample.h"
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/**
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* SECTION: resample
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* @short_description: resample images in various ways
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* @stability: Stable
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* @include: vips/vips.h
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*
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* These operations build on each other in a set of layers.
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*
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* First, vips_affine() applies an affine transform to an image. This is any
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* sort of 2D transform which preserves straight lines; so any combination of
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* stretch, sheer, rotate and translate. You supply an interpolator for it to
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* use to generate pixels, see vips_interpolate_new(). It will not produce
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* good results for very large shrinks: you'll see aliasing.
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*
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* vips_reduce() is like vips_affine(), but it can only shrink images, it can't
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* enlarge, rotate, or skew. It's very fast and uses an adaptive kernel for
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* interpolation.
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*
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* vips_shrink() is a fast block shrinker. It can quickly reduce images by
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* large integer factors. It will give poor results for small size reductions:
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* again, you'll see aliasing.
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*
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* Next, vips_resize() specialises in the common task of image reduce and
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* enlarge. It strings together combinations of vips_shrink(), vips_reduce(),
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* vips_affine() and others to implement a general, high-quality image
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* resizer.
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*
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* Finally, vips_thumbnail() combines load and resize in one operation, and adds
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* colour management and correct handling of alpha transparency. Because load
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* and resize happen together, it can exploit tricks like JPEG and TIFF
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* shrink-on-load, giving a (potentially) huge speedup. vips_thumbnail_image()
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* is only there for emergencies, don't use it unless you really have to.
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*
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* As a separate thing, `vips_mapim() can apply arbitrary 2D image transforms
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* to an image.
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*/
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/**
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* VipsSize:
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* @VIPS_SIZE_BOTH: size both up and down
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* @VIPS_SIZE_UP: only upsize
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* @VIPS_SIZE_DOWN: only downsize
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* @VIPS_SIZE_FORCE: force size, that is, break aspect ratio
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*
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* Controls whether an operation should upsize, downsize, both up and
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* downsize, or force a size.
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*
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* See also: vips_thumbnail().
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*/
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G_DEFINE_ABSTRACT_TYPE( VipsResample, vips_resample, VIPS_TYPE_OPERATION );
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static int
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vips_resample_build( VipsObject *object )
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{
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VipsResample *resample = VIPS_RESAMPLE( object );
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#ifdef DEBUG
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printf( "vips_resample_build: " );
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vips_object_print_name( object );
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printf( "\n" );
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#endif /*DEBUG*/
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g_object_set( resample, "out", vips_image_new(), NULL );
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if( VIPS_OBJECT_CLASS( vips_resample_parent_class )->build( object ) )
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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_resample_class_init( VipsResampleClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( 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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vobject_class->nickname = "resample";
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vobject_class->description = _( "resample operations" );
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vobject_class->build = vips_resample_build;
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VIPS_ARG_IMAGE( class, "in", 1,
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_( "Input" ),
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_( "Input image argument" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsResample, 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( VipsResample, out ) );
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}
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static void
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vips_resample_init( VipsResample *resample )
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{
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}
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/* Called from iofuncs to init all operations in this dir. Use a plugin system
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* instead?
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*/
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void
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vips_resample_operation_init( void )
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{
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extern GType vips_thumbnail_file_get_type( void );
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extern GType vips_thumbnail_buffer_get_type( void );
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extern GType vips_thumbnail_image_get_type( void );
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extern GType vips_thumbnail_source_get_type( void );
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extern GType vips_mapim_get_type( void );
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extern GType vips_shrink_get_type( void );
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extern GType vips_shrinkh_get_type( void );
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extern GType vips_shrinkv_get_type( void );
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extern GType vips_reduce_get_type( void );
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extern GType vips_reduceh_get_type( void );
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extern GType vips_reducev_get_type( void );
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extern GType vips_quadratic_get_type( void );
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extern GType vips_affine_get_type( void );
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extern GType vips_similarity_get_type( void );
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extern GType vips_rotate_get_type( void );
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extern GType vips_resize_get_type( void );
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vips_thumbnail_file_get_type();
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vips_thumbnail_buffer_get_type();
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vips_thumbnail_image_get_type();
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vips_thumbnail_source_get_type();
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vips_mapim_get_type();
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vips_shrink_get_type();
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vips_shrinkh_get_type();
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vips_shrinkv_get_type();
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vips_reduceh_get_type();
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vips_reducev_get_type();
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vips_reduce_get_type();
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vips_quadratic_get_type();
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vips_affine_get_type();
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vips_similarity_get_type();
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vips_rotate_get_type();
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vips_resize_get_type();
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}
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