//C- -*- C++ -*-
//C- -------------------------------------------------------------------
//C- DjVuLibre-3.5
//C- Copyright (c) 2002 Leon Bottou and Yann Le Cun.
//C- Copyright (c) 2001 AT&T
//C-
//C- This software is subject to, and may be distributed under, the
//C- GNU General Public License, either Version 2 of the license,
//C- or (at your option) any later version. The license should have
//C- accompanied the software or you may obtain a copy of the license
//C- from the Free Software Foundation at http://www.fsf.org .
//C-
//C- This program is distributed in the hope that it will be useful,
//C- but WITHOUT ANY WARRANTY; without even the implied warranty of
//C- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
//C- GNU General Public License for more details.
//C-
//C- DjVuLibre-3.5 is derived from the DjVu(r) Reference Library from
//C- Lizardtech Software. Lizardtech Software has authorized us to
//C- replace the original DjVu(r) Reference Library notice by the following
//C- text (see doc/lizard2002.djvu and doc/lizardtech2007.djvu):
//C-
//C- ------------------------------------------------------------------
//C- | DjVu (r) Reference Library (v. 3.5)
//C- | Copyright (c) 1999-2001 LizardTech, Inc. All Rights Reserved.
//C- | The DjVu Reference Library is protected by U.S. Pat. No.
//C- | 6,058,214 and patents pending.
//C- |
//C- | This software is subject to, and may be distributed under, the
//C- | GNU General Public License, either Version 2 of the license,
//C- | or (at your option) any later version. The license should have
//C- | accompanied the software or you may obtain a copy of the license
//C- | from the Free Software Foundation at http://www.fsf.org .
//C- |
//C- | The computer code originally released by LizardTech under this
//C- | license and unmodified by other parties is deemed "the LIZARDTECH
//C- | ORIGINAL CODE." Subject to any third party intellectual property
//C- | claims, LizardTech grants recipient a worldwide, royalty-free,
//C- | non-exclusive license to make, use, sell, or otherwise dispose of
//C- | the LIZARDTECH ORIGINAL CODE or of programs derived from the
//C- | LIZARDTECH ORIGINAL CODE in compliance with the terms of the GNU
//C- | General Public License. This grant only confers the right to
//C- | infringe patent claims underlying the LIZARDTECH ORIGINAL CODE to
//C- | the extent such infringement is reasonably necessary to enable
//C- | recipient to make, have made, practice, sell, or otherwise dispose
//C- | of the LIZARDTECH ORIGINAL CODE (or portions thereof) and not to
//C- | any greater extent that may be necessary to utilize further
//C- | modifications or combinations.
//C- |
//C- | The LIZARDTECH ORIGINAL CODE is provided "AS IS" WITHOUT WARRANTY
//C- | OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
//C- | TO ANY WARRANTY OF NON-INFRINGEMENT, OR ANY IMPLIED WARRANTY OF
//C- | MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
//C- +------------------------------------------------------------------
#ifndef _GSCALER_H_
#define _GSCALER_H_
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#if NEED_GNUG_PRAGMAS
# pragma interface
#endif
// From: Leon Bottou, 1/31/2002
// Almost equal to my initial code.
#include "GException.h"
#include "GRect.h"
#include "GBitmap.h"
#include "GPixmap.h"
#ifdef HAVE_NAMESPACES
namespace DJVU {
# ifdef NOT_DEFINED // Just to fool emacs c++ mode
}
#endif
#endif
/** @name GScaler.h
Files #"GScaler.h"# and #"GScaler.cpp"# implement a fast bilinear
interpolation scheme to rescale a \Ref{GBitmap} or a \Ref{GPixmap}.
Common setup functions are implemented by the base class \Ref{GScaler}.
The actual function for rescaling a gray level image is implemented by
class \Ref{GBitmapScaler}. The actual function for rescaling a color
image is implemented by class \Ref{GPixmapScaler}.
{\bf Remark} --- The bilinear interpolation code relies on fixed precision
tables. It becomes suboptimal when upsampling (i.e. zooming into) an
image by a factor greater than eight. High contrast images displayed at
high magnification may contain visible jaggies.
@memo
Rescaling images with bilinear interpolation.
@author
L\'eon Bottou <leonb@research.att.com>
*/
//@{
/** Base class for GBitmapScaler and GPixmapScaler. This base class
implements the common elements of class \Ref{GBitmapScaler} and
\Ref{GPixmapScaler}. Functions \Ref{set_input_size} and
\Ref{set_output_size} are used to specify the size of the input image and
the size of the output image. Functions \Ref{set_horz_ratio} and
\Ref{set_vert_ratio} may be used to override the scaling ratios computed
from the image sizes. You can then call function \Ref{get_input_rect} to
know which pixels of the input image are necessary to compute a specified
rectangular zone of the output image. The actual computation is then
performed by calling function #scale# in class \Ref{GBitmapScaler} and
\Ref{GPixmapScaler}.
*/
class DJVUAPI GScaler : public GPEnabled
{
protected:
GScaler();
public:
virtual ~GScaler();
/** Sets the size of the input image. Argument #w# (resp. #h#) contains the
horizontal (resp. vertical) size of the input image. This size is used
to initialize the internal data structures of the scaler object. */
void set_input_size(int w, int h);
/** Sets the size of the output image. Argument #w# (resp. #h#) contains the
horizontal (resp. vertical) size of the output image. This size is used
to initialize the internal data structures of the scaler object. */
void set_output_size(int w, int h);
/** Sets the horizontal scaling ratio #numer/denom#. This function may be
used to force an exact scaling ratio. The scaling ratios are otherwise
derived from the sizes of the input and output images. */
void set_horz_ratio(int numer, int denom);
/** Sets the vertical scaling ratio to #numer/denom#. This function may be
used to force an exact scaling ratio. The scaling ratios are otherwise
derived from the sizes of the input and output images. */
void set_vert_ratio(int numer, int denom);
/** Computes which input pixels are required to compute specified output
pixels. Let us assume that we only need a part of the output
image. This part is defined by rectangle #desired_output#. Only a part
of the input image is necessary to compute the output pixels. Function
#get_input_rect# computes the coordinates of that part of the input
image, and stores them into rectangle #required_input#. */
void get_input_rect( const GRect &desired_output, GRect &required_input );
protected:
// The sizes
int inw, inh;
int xshift, yshift;
int redw, redh;
int outw, outh;
// Fixed point coordinates
int *vcoord;
GPBuffer<int> gvcoord;
int *hcoord;
GPBuffer<int> ghcoord;
// Helper
void make_rectangles(const GRect &desired, GRect &red, GRect &inp);
};
/** Fast rescaling code for gray level images. This class augments the base
class \Ref{GScaler} with a function for rescaling gray level
images. Function \Ref{GBitmapScaler::scale} computes an arbitrary segment
of the output image given the corresponding pixels in the input image.
{\bf Example} --- The following functions returns an gray level image
(sixteen gray levels, size #nw# by #nh#) containing a rescaled version of
the input image #in#.
\begin{verbatim}
GBitmap *rescale_bitmap(const GBitmap &in, int nw, int nh)
{
int w = in.columns(); // Get input width
int h = in.raws(); // Get output width
GBitmapScaler scaler(w,h,nw,nh); // Creates bitmap scaler
GRect desired(0,0,nw,nh); // Desired output = complete bitmap
GRect provided(0,0,w,h); // Provided input = complete bitmap
GBitmap *out = new GBitmap;
scaler.scale(provided, in, desired, *out); // Rescale
out->change_grays(16); // Reduce to 16 gray levels
return out;
}
\end{verbatim} */
class DJVUAPI GBitmapScaler : public GScaler
{
protected:
GBitmapScaler(void);
GBitmapScaler(int inw, int inh, int outw, int outh);
public:
/// Virtual destructor.
virtual ~GBitmapScaler();
/** Creates an empty GBitmapScaler. You must call functions
\Ref{GScaler::set_input_size} and \Ref{GScaler::set_output_size} before
calling any of the scaling functions. */
static GP<GBitmapScaler> create(void) {return new GBitmapScaler(); }
/** Creates a GBitmapScaler. The size of the input image is given by
#inw# and #inh#. This function internally calls
\Ref{GScaler::set_input_size} and \Ref{GScaler::set_output_size}. The
size of the output image is given by #outw# and #outh#. . */
static GP<GBitmapScaler> create(
const int inw, const int inh, const int outw, const int outh)
{ return new GBitmapScaler(inw,inh,outw,outh); }
/** Computes a segment of the rescaled output image. The GBitmap object
#output# is overwritten with the segment of the output image specified
by the rectangle #desired_output#. The rectangle #provided_input#
specifies which segment of the input image is provided by the GBitmap
object #input#. An exception \Ref{GException} is thrown if the
rectangle #provided_input# is smaller then the rectangle
#required_input# returned by function \Ref{GScaler::get_input_rect}.
Note that the output image always contain 256 gray levels. You may want
to use function \Ref{GBitmap::change_grays} to reduce the number of gray
levels. */
void scale( const GRect &provided_input, const GBitmap &input,
const GRect &desired_output, GBitmap &output );
protected:
// Helpers
unsigned char *get_line(int, const GRect &, const GRect &, const GBitmap &);
// Temporaries
unsigned char *lbuffer;
GPBuffer<unsigned char> glbuffer;
unsigned char *conv;
GPBuffer<unsigned char> gconv;
unsigned char *p1;
GPBuffer<unsigned char> gp1;
unsigned char *p2;
GPBuffer<unsigned char> gp2;
int l1;
int l2;
};
/** Fast rescaling code for color images. This class augments the base class
\Ref{GScaler} with a function for rescaling color images. Function
\Ref{GPixmapScaler::scale} computes an arbitrary segment of the output
image given the corresponding pixels in the input image.
{\bf Example} --- The following functions returns a color image
of size #nw# by #nh# containing a rescaled version of
the input image #in#.
\begin{verbatim}
GPixmap *rescale_pixmap(const GPixmap &in, int nw, int nh)
{
int w = in.columns(); // Get input width
int h = in.raws(); // Get output width
GPixmapScaler scaler(w,h,nw,nh); // Creates bitmap scaler
GRect desired(0,0,nw,nh); // Desired output = complete image
GRect provided(0,0,w,h); // Provided input = complete image
GPixmap *out = new GPixmap;
scaler.scale(provided, in, desired, *out); // Rescale
return out;
}
\end{verbatim}
*/
class DJVUAPI GPixmapScaler : public GScaler
{
protected:
GPixmapScaler(void);
GPixmapScaler(int inw, int inh, int outw, int outh);
public:
/// Virtual destructor.
virtual ~GPixmapScaler();
/** Creates an empty GPixmapScaler. You must call functions
\Ref{GScaler::set_input_size} and \Ref{GScaler::set_output_size} before
calling any of the scaling functions. */
static GP<GPixmapScaler> create(void) {return new GPixmapScaler(); }
/** Creates a GPixmapScaler. The size of the input image is given by
#inw# and #inh#. This function internally calls
\Ref{GScaler::set_input_size} and \Ref{GScaler::set_output_size}. The
size of the output image is given by #outw# and #outh#. . */
static GP<GPixmapScaler> create(
const int inw, const int inh, const int outw, const int outh)
{ return new GPixmapScaler(inw,inh,outw,outh); }
/** Computes a segment of the rescaled output image. The pixmap #output# is
overwritten with the segment of the output image specified by the
rectangle #desired_output#. The rectangle #provided_input# specifies
which segment of the input image is provided in the pixmap #input#. An
exception \Ref{GException} is thrown if the rectangle #provided_input#
is smaller then the rectangle #required_input# returned by function
\Ref{GScaler::get_input_rect}. */
void scale( const GRect &provided_input, const GPixmap &input,
const GRect &desired_output, GPixmap &output );
protected:
// Helpers
GPixel *get_line(int, const GRect &, const GRect &, const GPixmap &);
// Temporaries
GPixel *lbuffer;
GPBuffer<GPixel> glbuffer;
GPixel *p1;
GPBuffer<GPixel> gp1;
GPixel *p2;
GPBuffer<GPixel> gp2;
int l1;
int l2;
};
//@}
// -------- END
#ifdef HAVE_NAMESPACES
}
# ifndef NOT_USING_DJVU_NAMESPACE
using namespace DJVU;
# endif
#endif
#endif