exr.cpp

 
#include "config.h"
 
#ifdef HAVE_EXR
 
#include <ImfRgbaFile.h>
#include <ImfStandardAttributes.h>
#include <ImathBox.h>
#include <ImfInputFile.h>
#include <ImfBoxAttribute.h>
#include <ImfChannelListAttribute.h>
#include <ImfCompressionAttribute.h>
#include <ImfFloatAttribute.h>
#include <ImfIntAttribute.h>
#include <ImfLineOrderAttribute.h>
#include <ImfStringAttribute.h>
#include <ImfVecAttribute.h>
#include <ImfArray.h>
#include <ImfConvert.h>
 
#include <iostream>
 
#include <stdlib.h>
 
#include <kurl.h>
#include <tdeprocess.h>
#include <tdelocale.h>
#include <kgenericfactory.h>
#include <kdebug.h>
 
#include <tqimage.h>
#include <tqcstring.h>
#include <tqfile.h>
#include <tqdatetime.h>
#include <tqdict.h>
#include <tqvalidator.h>
#include <tqcolor.h>
 
#include "exr.h"
 
using namespace Imf;
 
/* this does a conversion from the ILM Half (equal to Nvidia Half)
 * format into the normal 32 bit pixel format. Process is from the
 * ILM code.
 */
TQRgb RgbaToQrgba(struct Rgba imagePixel)
{
    float r,g,b,a;
    
    //  1) Compensate for fogging by subtracting defog
    //     from the raw pixel values.
    // Response: We work with defog of 0.0, so this is a no-op        
 
    //  2) Multiply the defogged pixel values by
    //     2^(exposure + 2.47393).
    // Response: We work with exposure of 0.0.
    // (2^2.47393) is 5.55555 
    r = imagePixel.r * 5.55555;
    g = imagePixel.g * 5.55555;
    b = imagePixel.b * 5.55555;
    a = imagePixel.a * 5.55555;
 
    //  3) Values, which are now 1.0, are called "middle gray".
    //     If defog and exposure are both set to 0.0, then
    //     middle gray corresponds to a raw pixel value of 0.18.
    //     In step 6, middle gray values will be mapped to an
    //     intensity 3.5 f-stops below the display's maximum
    //     intensity.
    // Response: no apparent content.
 
    //  4) Apply a knee function.  The knee function has two
    //     parameters, kneeLow and kneeHigh.  Pixel values
    //     below 2^kneeLow are not changed by the knee
    //     function.  Pixel values above kneeLow are lowered
    //     according to a logarithmic curve, such that the
    //     value 2^kneeHigh is mapped to 2^3.5 (in step 6,
    //     this value will be mapped to the the display's
    //     maximum intensity).
    // Response: kneeLow = 0.0 (2^0.0 => 1); kneeHigh = 5.0 (2^5 =>32)
    if (r > 1.0)
        r = 1.0 + Imath::Math<float>::log ((r-1.0) * 0.184874 + 1) / 0.184874;
    if (g > 1.0)
        g = 1.0 + Imath::Math<float>::log ((g-1.0) * 0.184874 + 1) / 0.184874;
    if (b > 1.0)
        b = 1.0 + Imath::Math<float>::log ((b-1.0) * 0.184874 + 1) / 0.184874;
    if (a > 1.0)
        a = 1.0 + Imath::Math<float>::log ((a-1.0) * 0.184874 + 1) / 0.184874;
//
//  5) Gamma-correct the pixel values, assuming that the
//     screen's gamma is 0.4545 (or 1/2.2).
    r = Imath::Math<float>::pow (r, 0.4545);
    g = Imath::Math<float>::pow (g, 0.4545);
    b = Imath::Math<float>::pow (b, 0.4545);
    a = Imath::Math<float>::pow (a, 0.4545);
 
//  6) Scale the values such that pixels middle gray
//     pixels are mapped to 84.66 (or 3.5 f-stops below
//     the display's maximum intensity).
//
//  7) Clamp the values to [0, 255].
    return tqRgba( char (Imath::clamp ( r * 84.66f, 0.f, 255.f ) ),
                  char (Imath::clamp ( g * 84.66f, 0.f, 255.f ) ),
                  char (Imath::clamp ( b * 84.66f, 0.f, 255.f ) ),
                  char (Imath::clamp ( a * 84.66f, 0.f, 255.f ) ) );
}
 
TDE_EXPORT void kimgio_exr_read( TQImageIO *io )
{
    try
    {
        int width, height;
 
        // This won't work if io is not TQFile !
        RgbaInputFile file (TQFile::encodeName(io->fileName()));
        Imath::Box2i dw = file.dataWindow();
 
        width  = dw.max.x - dw.min.x + 1;
        height = dw.max.y - dw.min.y + 1;
 
        Array2D<Rgba> pixels;
        pixels.resizeErase (height, width);
 
        file.setFrameBuffer (&pixels[0][0] - dw.min.x - dw.min.y * width, 1, width);
        file.readPixels (dw.min.y, dw.max.y);
 
        TQImage image(width, height, 32, 0, TQImage::BigEndian);
        if( image.isNull())
            return;
 
        // somehow copy pixels into image
        for ( int y=0; y < height; y++ ) {
            for ( int x=0; x < width; x++ ) {
                // copy pixels(x,y) into image(x,y)
                image.setPixel( x, y, RgbaToQrgba( pixels[y][x] ) );
            }
        }
 
        io->setImage( image );
        io->setStatus( 0 );
    }
    catch (const std::exception &exc)
    {
        kdDebug(399) << exc.what() << endl;
        return;
    }
}
 
 
TDE_EXPORT void kimgio_exr_write(TQImageIO *)
{
    // TODO: stub
}
 
 
#endif