hdr.cpp
/* This file is part of the KDE project
Copyright (C) 2005 Christoph Hormann <chris_hormann@gmx.de>
Copyright (C) 2005 Ignacio Castaņo <castanyo@yahoo.es>
This program is free software; you can redistribute it and/or
modify it under the terms of the Lesser GNU General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
*/
#include "hdr.h"
#include <qimage.h>
#include <qdatastream.h>
#include <kdebug.h>
#include <kglobal.h>
typedef Q_UINT8 uchar;
namespace { // Private.
#define MAXLINE 1024
#define MINELEN 8 // minimum scanline length for encoding
#define MAXELEN 0x7fff // maximum scanline length for encoding
static inline uchar ClipToByte(float value)
{
if (value > 255.0f) return 255;
//else if (value < 0.0f) return 0; // we know value is positive.
return uchar(value);
}
// read an old style line from the hdr image file
// if 'first' is true the first byte is already read
static bool Read_Old_Line (uchar * image, int width, QDataStream & s)
{
int rshift = 0;
int i;
while (width > 0)
{
s >> image[0];
s >> image[1];
s >> image[2];
s >> image[3];
if (s.atEnd()) return false;
if ((image[0] == 1) && (image[1] == 1) && (image[2] == 1))
{
for (i = image[3] << rshift; i > 0; i--)
{
//memcpy(image, image-4, 4);
(uint &)image[0] = (uint &)image[0-4];
image += 4;
width--;
}
rshift += 8;
}
else
{
image += 4;
width--;
rshift = 0;
}
}
return true;
}
static void RGBE_To_QRgbLine(uchar * image, QRgb * scanline, int width)
{
for (int j = 0; j < width; j++)
{
// v = ldexp(1.0, int(image[3]) - 128);
float v;
int e = int(image[3]) - 128;
if( e > 0 )
{
v = float(1 << e);
}
else
{
v = 1.0f / float(1 << -e);
}
scanline[j] = qRgb( ClipToByte(float(image[0]) * v),
ClipToByte(float(image[1]) * v),
ClipToByte(float(image[2]) * v) );
image += 4;
}
}
// Load the HDR image.
static bool LoadHDR( QDataStream & s, const int width, const int height, QImage & img )
{
uchar val, code;
// Create dst image.
if( !img.create( width, height, 32 ) )
{
return false;
}
QMemArray<uchar> image( width * 4 );
for (int cline = 0; cline < height; cline++)
{
QRgb * scanline = (QRgb *) img.scanLine( cline );
// determine scanline type
if ((width < MINELEN) || (MAXELEN < width))
{
Read_Old_Line(image.data(), width, s);
RGBE_To_QRgbLine(image.data(), scanline, width);
continue;
}
s >> val;
if (s.atEnd())
{
return true;
}
if (val != 2)
{
s.device()->at( s.device()->at() - 1 );
Read_Old_Line(image.data(), width, s);
RGBE_To_QRgbLine(image.data(), scanline, width);
continue;
}
s >> image[1];
s >> image[2];
s >> image[3];
if (s.atEnd())
{
return true;
}
if ((image[1] != 2) || (image[2] & 128))
{
image[0] = 2;
Read_Old_Line(image.data()+4, width-1, s);
RGBE_To_QRgbLine(image.data(), scanline, width);
continue;
}
if ((image[2] << 8 | image[3]) != width)
{
return false;
}
// read each component
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < width; )
{
s >> code;
if (s.atEnd())
{
return false;
}
if (code > 128)
{
// run
code &= 127;
s >> val;
while( code != 0 )
{
image[i + j * 4] = val;
j++;
code--;
}
}
else
{
// non-run
while( code != 0 )
{
s >> image[i + j * 4];
j++;
code--;
}
}
}
}
RGBE_To_QRgbLine(image.data(), scanline, width);
}
return true;
}
} // namespace
KDE_EXPORT void kimgio_hdr_read( QImageIO * io )
{
int len;
char line[MAXLINE];
//bool validHeader = false;
bool validFormat = false;
// Parse header
do {
len = io->ioDevice()->readLine(line, MAXLINE);
/*if (strcmp(line, "#?RADIANCE\n") == 0 || strcmp(line, "#?RGBE\n") == 0)
{
validHeader = true;
}*/
if (strcmp(line, "FORMAT=32-bit_rle_rgbe\n") == 0)
{
validFormat = true;
}
} while((len > 0) && (line[0] != '\n'));
if( !validFormat )
{
kdDebug(399) << "Unknown HDR format." << endl;
io->setImage( 0 );
io->setStatus( -1 );
return;
}
io->ioDevice()->readLine(line, MAXLINE);
char s1[3], s2[3];
int width, height;
if (sscanf(line, "%2[+-XY] %d %2[+-XY] %d\n", s1, &height, s2, &width) != 4)
//if( sscanf(line, "-Y %d +X %d", &height, &width) < 2 )
{
kdDebug(399) << "Invalid HDR file." << endl;
io->setImage( 0 );
io->setStatus( -1 );
return;
}
QDataStream s( io->ioDevice() );
QImage img;
if( !LoadHDR(s, width, height, img) )
{
kdDebug(399) << "Error loading HDR file." << endl;
io->setImage( 0 );
io->setStatus( -1 );
return;
}
io->setImage( img );
io->setStatus( 0 );
}
KDE_EXPORT void kimgio_hdr_write( QImageIO * )
{
// intentionally not implemented (since writing low dynamic range data to a HDR file is nonsense.)
}

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