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322 lines
13 KiB
322 lines
13 KiB
//C- -*- C++ -*-
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//C- -------------------------------------------------------------------
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//C- DjVuLibre-3.5
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//C- Copyright (c) 2002 Leon Bottou and Yann Le Cun.
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//C- Copyright (c) 2001 AT&T
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//C-
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//C- This software is subject to, and may be distributed under, the
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//C- GNU General Public License, Version 2. The license should have
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//C- accompanied the software or you may obtain a copy of the license
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//C- from the Free Software Foundation at http://www.fsf.org .
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//C-
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//C- This program is distributed in the hope that it will be useful,
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//C- but WITHOUT ANY WARRANTY; without even the implied warranty of
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//C- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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//C- GNU General Public License for more details.
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//C-
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//C- DjVuLibre-3.5 is derived from the DjVu(r) Reference Library
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//C- distributed by Lizardtech Software. On July 19th 2002, Lizardtech
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//C- Software authorized us to replace the original DjVu(r) Reference
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//C- Library notice by the following text (see doc/lizard2002.djvu):
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//C-
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//C- ------------------------------------------------------------------
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//C- | DjVu (r) Reference Library (v. 3.5)
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//C- | Copyright (c) 1999-2001 LizardTech, Inc. All Rights Reserved.
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//C- | The DjVu Reference Library is protected by U.S. Pat. No.
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//C- | 6,058,214 and patents pending.
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//C- |
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//C- | This software is subject to, and may be distributed under, the
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//C- | GNU General Public License, Version 2. The license should have
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//C- | accompanied the software or you may obtain a copy of the license
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//C- | from the Free Software Foundation at http://www.fsf.org .
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//C- |
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//C- | The computer code originally released by LizardTech under this
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//C- | license and unmodified by other parties is deemed "the LIZARDTECH
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//C- | ORIGINAL CODE." Subject to any third party intellectual property
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//C- | claims, LizardTech grants recipient a worldwide, royalty-free,
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//C- | non-exclusive license to make, use, sell, or otherwise dispose of
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//C- | the LIZARDTECH ORIGINAL CODE or of programs derived from the
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//C- | LIZARDTECH ORIGINAL CODE in compliance with the terms of the GNU
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//C- | General Public License. This grant only confers the right to
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//C- | infringe patent claims underlying the LIZARDTECH ORIGINAL CODE to
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//C- | the extent such infringement is reasonably necessary to enable
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//C- | recipient to make, have made, practice, sell, or otherwise dispose
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//C- | of the LIZARDTECH ORIGINAL CODE (or portions thereof) and not to
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//C- | any greater extent that may be necessary to utilize further
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//C- | modifications or combinations.
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//C- |
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//C- | The LIZARDTECH ORIGINAL CODE is provided "AS IS" WITHOUT WARRANTY
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//C- | OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
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//C- | TO ANY WARRANTY OF NON-INFRINGEMENT, OR ANY IMPLIED WARRANTY OF
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//C- | MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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//C- +------------------------------------------------------------------
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//
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// $Id: GScaler.h,v 1.9 2003/11/07 22:08:21 leonb Exp $
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// $Name: release_3_5_15 $
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#ifndef _GSCALER_H_
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#define _GSCALER_H_
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#if NEED_GNUG_PRAGMAS
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# pragma interface
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#endif
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// From: Leon Bottou, 1/31/2002
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// Almost equal to my initial code.
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#include "GException.h"
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#include "GRect.h"
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#include "GBitmap.h"
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#include "GPixmap.h"
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#ifdef HAVE_NAMESPACES
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namespace DJVU {
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# ifdef NOT_DEFINED // Just to fool emacs c++ mode
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}
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#endif
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#endif
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/** @name GScaler.h
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Files #"GScaler.h"# and #"GScaler.cpp"# implement a fast bilinear
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interpolation scheme to rescale a \Ref{GBitmap} or a \Ref{GPixmap}.
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Common setup functions are implemented by the base class \Ref{GScaler}.
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The actual function for rescaling a gray level image is implemented by
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class \Ref{GBitmapScaler}. The actual function for rescaling a color
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image is implemented by class \Ref{GPixmapScaler}.
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{\bf Remark} --- The bilinear interpolation code relies on fixed precision
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tables. It becomes suboptimal when upsampling (i.e. zooming into) an
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image by a factor greater than eight. High contrast images displayed at
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high magnification may contain visible jaggies.
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@memo
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Rescaling images with bilinear interpolation.
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@author
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L\'eon Bottou <leonb@research.att.com>
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@version
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#$Id: GScaler.h,v 1.9 2003/11/07 22:08:21 leonb Exp $# */
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//@{
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/** Base class for GBitmapScaler and GPixmapScaler. This base class
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implements the common elements of class \Ref{GBitmapScaler} and
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\Ref{GPixmapScaler}. Functions \Ref{set_input_size} and
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\Ref{set_output_size} are used to specify the size of the input image and
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the size of the output image. Functions \Ref{set_horz_ratio} and
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\Ref{set_vert_ratio} may be used to override the scaling ratios computed
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from the image sizes. You can then call function \Ref{get_input_rect} to
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know which pixels of the input image are necessary to compute a specified
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rectangular zone of the output image. The actual computation is then
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performed by calling function #scale# in class \Ref{GBitmapScaler} and
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\Ref{GPixmapScaler}.
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*/
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class GScaler : public GPEnabled
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{
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protected:
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GScaler();
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public:
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virtual ~GScaler();
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/** Sets the size of the input image. Argument #w# (resp. #h#) contains the
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horizontal (resp. vertical) size of the input image. This size is used
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to initialize the internal data structures of the scaler object. */
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void set_input_size(int w, int h);
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/** Sets the size of the output image. Argument #w# (resp. #h#) contains the
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horizontal (resp. vertical) size of the output image. This size is used
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to initialize the internal data structures of the scaler object. */
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void set_output_size(int w, int h);
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/** Sets the horizontal scaling ratio #numer/denom#. This function may be
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used to force an exact scaling ratio. The scaling ratios are otherwise
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derived from the sizes of the input and output images. */
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void set_horz_ratio(int numer, int denom);
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/** Sets the vertical scaling ratio to #numer/denom#. This function may be
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used to force an exact scaling ratio. The scaling ratios are otherwise
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derived from the sizes of the input and output images. */
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void set_vert_ratio(int numer, int denom);
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/** Computes which input pixels are required to compute specified output
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pixels. Let us assume that we only need a part of the output
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image. This part is defined by rectangle #desired_output#. Only a part
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of the input image is necessary to compute the output pixels. Function
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#get_input_rect# computes the coordinates of that part of the input
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image, and stores them into rectangle #required_input#. */
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void get_input_rect( const GRect &desired_output, GRect &required_input );
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protected:
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// The sizes
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int inw, inh;
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int xshift, yshift;
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int redw, redh;
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int outw, outh;
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// Fixed point coordinates
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int *vcoord;
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GPBuffer<int> gvcoord;
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int *hcoord;
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GPBuffer<int> ghcoord;
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// Helper
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void make_rectangles(const GRect &desired, GRect &red, GRect &inp);
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};
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/** Fast rescaling code for gray level images. This class augments the base
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class \Ref{GScaler} with a function for rescaling gray level
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images. Function \Ref{GBitmapScaler::scale} computes an arbitrary segment
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of the output image given the corresponding pixels in the input image.
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{\bf Example} --- The following functions returns an gray level image
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(sixteen gray levels, size #nw# by #nh#) containing a rescaled version of
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the input image #in#.
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\begin{verbatim}
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GBitmap *rescale_bitmap(const GBitmap &in, int nw, int nh)
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{
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int w = in.columns(); // Get input width
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int h = in.raws(); // Get output width
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GBitmapScaler scaler(w,h,nw,nh); // Creates bitmap scaler
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GRect desired(0,0,nw,nh); // Desired output = complete bitmap
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GRect provided(0,0,w,h); // Provided input = complete bitmap
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GBitmap *out = new GBitmap;
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scaler.scale(provided, in, desired, *out); // Rescale
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out->change_grays(16); // Reduce to 16 gray levels
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return out;
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}
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\end{verbatim} */
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class GBitmapScaler : public GScaler
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{
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protected:
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GBitmapScaler(void);
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GBitmapScaler(int inw, int inh, int outw, int outh);
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public:
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/// Virtual destructor.
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virtual ~GBitmapScaler();
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/** Creates an empty GBitmapScaler. You must call functions
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\Ref{GScaler::set_input_size} and \Ref{GScaler::set_output_size} before
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calling any of the scaling functions. */
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static GP<GBitmapScaler> create(void) {return new GBitmapScaler(); }
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/** Creates a GBitmapScaler. The size of the input image is given by
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#inw# and #inh#. This function internally calls
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\Ref{GScaler::set_input_size} and \Ref{GScaler::set_output_size}. The
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size of the output image is given by #outw# and #outh#. . */
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static GP<GBitmapScaler> create(
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const int inw, const int inh, const int outw, const int outh)
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{ return new GBitmapScaler(inw,inh,outw,outh); }
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/** Computes a segment of the rescaled output image. The GBitmap object
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#output# is overwritten with the segment of the output image specified
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by the rectangle #desired_output#. The rectangle #provided_input#
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specifies which segment of the input image is provided by the GBitmap
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object #input#. An exception \Ref{GException} is thrown if the
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rectangle #provided_input# is smaller then the rectangle
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#required_input# returned by function \Ref{GScaler::get_input_rect}.
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Note that the output image always contain 256 gray levels. You may want
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to use function \Ref{GBitmap::change_grays} to reduce the number of gray
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levels. */
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void scale( const GRect &provided_input, const GBitmap &input,
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const GRect &desired_output, GBitmap &output );
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protected:
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// Helpers
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unsigned char *get_line(int, const GRect &, const GRect &, const GBitmap &);
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// Temporaries
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unsigned char *lbuffer;
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GPBuffer<unsigned char> glbuffer;
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unsigned char *conv;
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GPBuffer<unsigned char> gconv;
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unsigned char *p1;
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GPBuffer<unsigned char> gp1;
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unsigned char *p2;
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GPBuffer<unsigned char> gp2;
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int l1;
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int l2;
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};
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/** Fast rescaling code for color images. This class augments the base class
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\Ref{GScaler} with a function for rescaling color images. Function
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\Ref{GPixmapScaler::scale} computes an arbitrary segment of the output
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image given the corresponding pixels in the input image.
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{\bf Example} --- The following functions returns a color image
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of size #nw# by #nh# containing a rescaled version of
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the input image #in#.
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\begin{verbatim}
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GPixmap *rescale_pixmap(const GPixmap &in, int nw, int nh)
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{
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int w = in.columns(); // Get input width
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int h = in.raws(); // Get output width
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GPixmapScaler scaler(w,h,nw,nh); // Creates bitmap scaler
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GRect desired(0,0,nw,nh); // Desired output = complete image
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GRect provided(0,0,w,h); // Provided input = complete image
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GPixmap *out = new GPixmap;
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scaler.scale(provided, in, desired, *out); // Rescale
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return out;
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}
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\end{verbatim}
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*/
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class GPixmapScaler : public GScaler
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{
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protected:
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GPixmapScaler(void);
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GPixmapScaler(int inw, int inh, int outw, int outh);
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public:
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/// Virtual destructor.
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virtual ~GPixmapScaler();
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/** Creates an empty GPixmapScaler. You must call functions
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\Ref{GScaler::set_input_size} and \Ref{GScaler::set_output_size} before
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calling any of the scaling functions. */
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static GP<GPixmapScaler> create(void) {return new GPixmapScaler(); }
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/** Creates a GPixmapScaler. The size of the input image is given by
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#inw# and #inh#. This function internally calls
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\Ref{GScaler::set_input_size} and \Ref{GScaler::set_output_size}. The
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size of the output image is given by #outw# and #outh#. . */
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static GP<GPixmapScaler> create(
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const int inw, const int inh, const int outw, const int outh)
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{ return new GPixmapScaler(inw,inh,outw,outh); }
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/** Computes a segment of the rescaled output image. The pixmap #output# is
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overwritten with the segment of the output image specified by the
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rectangle #desired_output#. The rectangle #provided_input# specifies
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which segment of the input image is provided in the pixmap #input#. An
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exception \Ref{GException} is thrown if the rectangle #provided_input#
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is smaller then the rectangle #required_input# returned by function
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\Ref{GScaler::get_input_rect}. */
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void scale( const GRect &provided_input, const GPixmap &input,
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const GRect &desired_output, GPixmap &output );
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protected:
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// Helpers
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GPixel *get_line(int, const GRect &, const GRect &, const GPixmap &);
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// Temporaries
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GPixel *lbuffer;
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GPBufferBase glbuffer;
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GPixel *p1;
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GPBufferBase gp1;
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GPixel *p2;
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GPBufferBase gp2;
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int l1;
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int l2;
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};
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//@}
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// -------- END
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#ifdef HAVE_NAMESPACES
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}
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# ifndef NOT_USING_DJVU_NAMESPACE
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using namespace DJVU;
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# endif
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#endif
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#endif
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