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Move kimageformats code to the root directory.
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239
src/imageformats/exr.cpp
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239
src/imageformats/exr.cpp
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// -*- C++;indent-tabs-mode: t; tab-width: 4; c-basic-offset: 4; -*-
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/**
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* KImageIO Routines to read (and perhaps in the future, write) images
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* in the high dynamic range EXR format.
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* Copyright (c) 2003, Brad Hards <bradh@frogmouth.net>
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*
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* This library is distributed under the conditions of the GNU LGPL.
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*/
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#include "exr.h"
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#include <ImfRgbaFile.h>
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#include <ImfStandardAttributes.h>
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#include <ImathBox.h>
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#include <ImfInputFile.h>
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#include <ImfBoxAttribute.h>
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#include <ImfChannelListAttribute.h>
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#include <ImfCompressionAttribute.h>
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#include <ImfFloatAttribute.h>
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#include <ImfIntAttribute.h>
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#include <ImfLineOrderAttribute.h>
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#include <ImfStringAttribute.h>
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#include <ImfVecAttribute.h>
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#include <ImfArray.h>
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#include <ImfConvert.h>
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#include <ImfVersion.h>
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#include <IexThrowErrnoExc.h>
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#include <iostream>
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#include <QImage>
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#include <QDataStream>
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// #include <QDebug>
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#include <QImageIOPlugin>
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class K_IStream: public Imf::IStream
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{
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public:
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K_IStream(QIODevice *dev, const QByteArray& fileName):
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IStream(fileName.data()), m_dev(dev) {
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}
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virtual bool read(char c[], int n);
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virtual Imf::Int64 tellg();
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virtual void seekg(Imf::Int64 pos);
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virtual void clear();
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private:
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QIODevice *m_dev;
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};
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bool K_IStream::read(char c[], int n)
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{
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qint64 result = m_dev->read(c, n);
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if (result > 0) {
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return true;
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} else if (result == 0) {
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throw Iex::InputExc("Unexpected end of file");
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} else // negative value {
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Iex::throwErrnoExc("Error in read", result);
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return false;
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}
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Imf::Int64 K_IStream::tellg()
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{
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return m_dev->pos();
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}
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void K_IStream::seekg(Imf::Int64 pos)
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{
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m_dev->seek(pos);
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}
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void K_IStream::clear()
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{
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// TODO
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}
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/* this does a conversion from the ILM Half (equal to Nvidia Half)
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* format into the normal 32 bit pixel format. Process is from the
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* ILM code.
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*/
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QRgb RgbaToQrgba(struct Imf::Rgba imagePixel)
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{
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float r, g, b, a;
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// 1) Compensate for fogging by subtracting defog
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// from the raw pixel values.
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// Response: We work with defog of 0.0, so this is a no-op
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// 2) Multiply the defogged pixel values by
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// 2^(exposure + 2.47393).
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// Response: We work with exposure of 0.0.
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// (2^2.47393) is 5.55555
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r = imagePixel.r * 5.55555;
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g = imagePixel.g * 5.55555;
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b = imagePixel.b * 5.55555;
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a = imagePixel.a * 5.55555;
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// 3) Values, which are now 1.0, are called "middle gray".
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// If defog and exposure are both set to 0.0, then
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// middle gray corresponds to a raw pixel value of 0.18.
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// In step 6, middle gray values will be mapped to an
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// intensity 3.5 f-stops below the display's maximum
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// intensity.
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// Response: no apparent content.
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// 4) Apply a knee function. The knee function has two
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// parameters, kneeLow and kneeHigh. Pixel values
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// below 2^kneeLow are not changed by the knee
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// function. Pixel values above kneeLow are lowered
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// according to a logarithmic curve, such that the
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// value 2^kneeHigh is mapped to 2^3.5 (in step 6,
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// this value will be mapped to the display's
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// maximum intensity).
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// Response: kneeLow = 0.0 (2^0.0 => 1); kneeHigh = 5.0 (2^5 =>32)
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if (r > 1.0)
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r = 1.0 + Imath::Math<float>::log((r - 1.0) * 0.184874 + 1) / 0.184874;
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if (g > 1.0)
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g = 1.0 + Imath::Math<float>::log((g - 1.0) * 0.184874 + 1) / 0.184874;
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if (b > 1.0)
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b = 1.0 + Imath::Math<float>::log((b - 1.0) * 0.184874 + 1) / 0.184874;
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if (a > 1.0)
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a = 1.0 + Imath::Math<float>::log((a - 1.0) * 0.184874 + 1) / 0.184874;
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//
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// 5) Gamma-correct the pixel values, assuming that the
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// screen's gamma is 0.4545 (or 1/2.2).
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r = Imath::Math<float>::pow(r, 0.4545);
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g = Imath::Math<float>::pow(g, 0.4545);
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b = Imath::Math<float>::pow(b, 0.4545);
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a = Imath::Math<float>::pow(a, 0.4545);
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// 6) Scale the values such that pixels middle gray
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// pixels are mapped to 84.66 (or 3.5 f-stops below
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// the display's maximum intensity).
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//
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// 7) Clamp the values to [0, 255].
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return qRgba((unsigned char)(Imath::clamp(r * 84.66f, 0.f, 255.f)),
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(unsigned char)(Imath::clamp(g * 84.66f, 0.f, 255.f)),
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(unsigned char)(Imath::clamp(b * 84.66f, 0.f, 255.f)),
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(unsigned char)(Imath::clamp(a * 84.66f, 0.f, 255.f)));
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}
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EXRHandler::EXRHandler()
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{
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}
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bool EXRHandler::canRead() const
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{
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if (canRead(device())) {
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setFormat("exr");
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return true;
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}
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return false;
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}
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bool EXRHandler::read(QImage *outImage)
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{
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try {
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int width, height;
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K_IStream istr(device(), QByteArray());
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Imf::RgbaInputFile file(istr);
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Imath::Box2i dw = file.dataWindow();
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width = dw.max.x - dw.min.x + 1;
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height = dw.max.y - dw.min.y + 1;
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Imf::Array2D<Imf::Rgba> pixels;
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pixels.resizeErase(height, width);
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file.setFrameBuffer(&pixels[0][0] - dw.min.x - dw.min.y * width, 1, width);
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file.readPixels(dw.min.y, dw.max.y);
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QImage image(width, height, QImage::Format_RGB32);
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if (image.isNull())
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return false;
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// somehow copy pixels into image
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for (int y = 0; y < height; y++) {
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for (int x = 0; x < width; x++) {
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// copy pixels(x,y) into image(x,y)
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image.setPixel(x, y, RgbaToQrgba(pixels[y][x]));
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}
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}
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*outImage = image;
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return true;
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} catch (const std::exception &exc) {
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// qDebug() << exc.what();
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return false;
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}
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}
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bool EXRHandler::write(const QImage &image)
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{
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// TODO: stub
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Q_UNUSED(image);
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return false;
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}
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bool EXRHandler::canRead(QIODevice *device)
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{
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if (!device) {
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qWarning("EXRHandler::canRead() called with no device");
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return false;
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}
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const QByteArray head = device->peek(4);
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return Imf::isImfMagic(head.data());
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}
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QImageIOPlugin::Capabilities EXRPlugin::capabilities(QIODevice *device, const QByteArray &format) const
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{
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if (format == "exr")
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return Capabilities(CanRead);
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if (!format.isEmpty())
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return 0;
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if (!device->isOpen())
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return 0;
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Capabilities cap;
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if (device->isReadable() && EXRHandler::canRead(device))
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cap |= CanRead;
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return cap;
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}
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QImageIOHandler *EXRPlugin::create(QIODevice *device, const QByteArray &format) const
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{
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QImageIOHandler *handler = new EXRHandler;
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handler->setDevice(device);
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handler->setFormat(format);
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return handler;
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}
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