308 lines
8.4 KiB
C
308 lines
8.4 KiB
C
/* 2D reduce ... call reduceh and reducev
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*
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* 27/1/16
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* - from shrink.c
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* 15/8/16
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* - rename xshrink -> hshrink for greater consistency
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* 9/9/16
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* - add @centre option
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* 6/6/20 kleisauke
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* - deprecate @centre option, it's now always on
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* 22/4/22 kleisauke
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* - add @gap option
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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 <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/debug.h>
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#include <vips/internal.h>
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#include "presample.h"
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/**
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* VipsKernel:
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* @VIPS_KERNEL_NEAREST: The nearest pixel to the point.
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* @VIPS_KERNEL_LINEAR: Convolve with a triangle filter.
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* @VIPS_KERNEL_CUBIC: Convolve with a cubic filter.
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* @VIPS_KERNEL_MITCHELL: Convolve with a Mitchell kernel.
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* @VIPS_KERNEL_LANCZOS2: Convolve with a two-lobe Lanczos kernel.
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* @VIPS_KERNEL_LANCZOS3: Convolve with a three-lobe Lanczos kernel.
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*
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* The resampling kernels vips supports. See vips_reduce(), for example.
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*/
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/* gtk-doc does not see comments in C++ files, so we have these docs here.
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*/
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/**
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* vips_reducev: (method)
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* @in: input image
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* @out: (out): output image
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* @vshrink: vertical reduce
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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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* * @kernel: #VipsKernel to use to interpolate (default: lanczos3)
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* * @gap: reducing gap to use (default: 0.0)
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*
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* Reduce @in vertically by a float factor. The pixels in @out are
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* interpolated with a 1D mask generated by @kernel.
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*
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* Set @gap to speed up reducing by having vips_shrinkv() to shrink
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* with a box filter first. The bigger @gap, the closer the result
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* to the fair resampling. The smaller @gap, the faster resizing.
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* The default value is 0.0 (no optimization).
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*
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* This is a very low-level operation: see vips_resize() for a more
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* convenient way to resize images.
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*
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* This operation does not change xres or yres. The image resolution needs to
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* be updated by the application.
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*
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* See also: vips_shrink(), vips_resize(), vips_affine().
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*
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* Returns: 0 on success, -1 on error
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*/
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/**
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* vips_reduceh: (method)
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* @in: input image
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* @out: (out): output image
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* @hshrink: horizontal reduce
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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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* * @kernel: #VipsKernel to use to interpolate (default: lanczos3)
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* * @gap: reducing gap to use (default: 0.0)
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*
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* Reduce @in horizontally by a float factor. The pixels in @out are
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* interpolated with a 1D mask generated by @kernel.
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*
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* Set @gap to speed up reducing by having vips_shrinkh() to shrink
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* with a box filter first. The bigger @gap, the closer the result
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* to the fair resampling. The smaller @gap, the faster resizing.
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* The default value is 0.0 (no optimization).
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*
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* This is a very low-level operation: see vips_resize() for a more
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* convenient way to resize images.
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*
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* This operation does not change xres or yres. The image resolution needs to
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* be updated by the application.
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*
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* See also: vips_shrink(), vips_resize(), vips_affine().
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*
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* Returns: 0 on success, -1 on error
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*/
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typedef struct _VipsReduce {
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VipsResample parent_instance;
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double hshrink; /* Shrink factors */
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double vshrink;
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double gap; /* Reduce gap */
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/* The thing we use to make the kernel.
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*/
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VipsKernel kernel;
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/* Deprecated.
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*/
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gboolean centre;
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} VipsReduce;
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typedef VipsResampleClass VipsReduceClass;
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G_DEFINE_TYPE( VipsReduce, vips_reduce, VIPS_TYPE_RESAMPLE );
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static int
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vips_reduce_build( VipsObject *object )
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{
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VipsResample *resample = VIPS_RESAMPLE( object );
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VipsReduce *reduce = (VipsReduce *) object;
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VipsImage **t = (VipsImage **)
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vips_object_local_array( object, 2 );
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if( VIPS_OBJECT_CLASS( vips_reduce_parent_class )->build( object ) )
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return( -1 );
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if( vips_reducev( resample->in, &t[0], reduce->vshrink,
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"kernel", reduce->kernel,
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"gap", reduce->gap,
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NULL ) ||
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vips_reduceh( t[0], &t[1], reduce->hshrink,
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"kernel", reduce->kernel,
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"gap", reduce->gap,
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NULL ) ||
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vips_image_write( t[1], resample->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_reduce_class_init( VipsReduceClass *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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VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
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VIPS_DEBUG_MSG( "vips_reduce_class_init\n" );
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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 = "reduce";
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vobject_class->description = _( "reduce an image" );
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vobject_class->build = vips_reduce_build;
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operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
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VIPS_ARG_DOUBLE( class, "hshrink", 8,
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_( "Hshrink" ),
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_( "Horizontal shrink factor" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsReduce, hshrink ),
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1.0, 1000000.0, 1.0 );
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VIPS_ARG_DOUBLE( class, "vshrink", 9,
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_( "Vshrink" ),
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_( "Vertical shrink factor" ),
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VIPS_ARGUMENT_REQUIRED_INPUT,
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G_STRUCT_OFFSET( VipsReduce, vshrink ),
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1.0, 1000000.0, 1.0 );
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VIPS_ARG_ENUM( class, "kernel", 3,
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_( "Kernel" ),
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_( "Resampling kernel" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsReduce, kernel ),
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VIPS_TYPE_KERNEL, VIPS_KERNEL_LANCZOS3 );
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VIPS_ARG_DOUBLE( class, "gap", 4,
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_( "Gap" ),
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_( "Reducing gap" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT,
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G_STRUCT_OFFSET( VipsReduce, gap ),
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0.0, 1000000.0, 0.0 );
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/* The old names .. now use h and v everywhere.
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*/
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VIPS_ARG_DOUBLE( class, "xshrink", 8,
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_( "Xshrink" ),
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_( "Horizontal shrink factor" ),
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VIPS_ARGUMENT_REQUIRED_INPUT | VIPS_ARGUMENT_DEPRECATED,
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G_STRUCT_OFFSET( VipsReduce, hshrink ),
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1.0, 1000000.0, 1.0 );
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VIPS_ARG_DOUBLE( class, "yshrink", 9,
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_( "Yshrink" ),
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_( "Vertical shrink factor" ),
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VIPS_ARGUMENT_REQUIRED_INPUT | VIPS_ARGUMENT_DEPRECATED,
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G_STRUCT_OFFSET( VipsReduce, vshrink ),
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1.0, 1000000.0, 1.0 );
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/* We used to let people pick centre or corner, but it's automatic now.
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*/
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VIPS_ARG_BOOL( class, "centre", 7,
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_( "Centre" ),
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_( "Use centre sampling convention" ),
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VIPS_ARGUMENT_OPTIONAL_INPUT | VIPS_ARGUMENT_DEPRECATED,
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G_STRUCT_OFFSET( VipsReduce, centre ),
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FALSE );
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}
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static void
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vips_reduce_init( VipsReduce *reduce )
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{
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reduce->gap = 0.0;
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reduce->kernel = VIPS_KERNEL_LANCZOS3;
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}
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/**
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* vips_reduce: (method)
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* @in: input image
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* @out: (out): output image
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* @hshrink: horizontal shrink
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* @vshrink: vertical shrink
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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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* * @kernel: #VipsKernel to use to interpolate (default: lanczos3)
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* * @gap: reducing gap to use (default: 0.0)
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*
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* Reduce @in by a pair of factors with a pair of 1D kernels. This
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* will not work well for shrink factors greater than three.
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*
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* Set @gap to speed up reducing by having vips_shrink() to shrink
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* with a box filter first. The bigger @gap, the closer the result
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* to the fair resampling. The smaller @gap, the faster resizing.
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* The default value is 0.0 (no optimization).
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*
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* This is a very low-level operation: see vips_resize() for a more
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* convenient way to resize images.
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*
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* This operation does not change xres or yres. The image resolution needs to
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* be updated by the application.
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*
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* See also: vips_shrink(), vips_resize(), vips_affine().
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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_reduce( VipsImage *in, VipsImage **out,
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double hshrink, double vshrink, ... )
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{
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va_list ap;
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int result;
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va_start( ap, vshrink );
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result = vips_call_split( "reduce", ap, in, out, hshrink, vshrink );
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va_end( ap );
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return( result );
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}
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