libopenexr-dev 1.6.1-4.1 / usr / share / doc / libopenexr6 / examples / generalInterfaceExamples.cpp

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// Copyright (c) 2004, Industrial Light & Magic, a division of Lucas
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//-----------------------------------------------------------------------------
//
//	Code examples that show how class InputFile and class OutputFile
//	can be used to read and write OpenEXR image files with an arbitrary
//	set of channels.
//
//-----------------------------------------------------------------------------


#include <ImfOutputFile.h>
#include <ImfInputFile.h>
#include <ImfChannelList.h>
#include <ImfStringAttribute.h>
#include <ImfMatrixAttribute.h>
#include <ImfArray.h>
#include <drawImage.h>

#include <iostream>

using namespace std;
using namespace Imf;
using namespace Imath;


void
writeGZ1 (const char fileName[],
	  const half *gPixels,
	  const float *zPixels,
	  int width,
	  int height)
{
    //
    // Write an image with only a G (green) and a Z (depth) channel,
    // using class OutputFile.
    //
    //	- create a file header
    //	- add G and Z channels to the header
    //	- open the file, and store the header in the file
    //	- describe the memory layout of the G anx Z pixels
    //	- store the pixels in the file
    //

    Header header (width, height);
    header.channels().insert ("G", Channel (HALF));
    header.channels().insert ("Z", Channel (FLOAT));

    OutputFile file (fileName, header);

    FrameBuffer frameBuffer;

    frameBuffer.insert ("G",					// name
		        Slice (HALF,				// type
			       (char *) gPixels,		// base
			       sizeof (*gPixels) * 1,		// xStride
			       sizeof (*gPixels) * width));	// yStride

    frameBuffer.insert ("Z",					// name
			Slice (FLOAT,				// type
			       (char *) zPixels,		// base
			       sizeof (*zPixels) * 1,		// xStride
			       sizeof (*zPixels) * width));	// yStride

    file.setFrameBuffer (frameBuffer);
    file.writePixels (height);
}


void
writeGZ2 (const char fileName[],
	  const half *gPixels,
	  const float *zPixels,
	  int width,
	  int height,
	  const Box2i &dataWindow)
{
    //
    // Write an image with only a G (green) and a Z (depth) channel,
    // using class OutputFile.  Don't store the whole image in the
    // file, but crop it according to the given data window.
    //
    //	- create a file header
    //	- set the header's data window
    //	- add G and Z channels to the header
    //	- open the file, and store the header in the file
    //	- describe the memory layout of the G anx Z pixels
    //	- store the pixels in the file
    //

    Header header (width, height);
    header.dataWindow() = dataWindow;
    header.channels().insert ("G", Channel (HALF));
    header.channels().insert ("Z", Channel (FLOAT));

    OutputFile file (fileName, header);

    FrameBuffer frameBuffer;

    frameBuffer.insert ("G",					// name
			Slice (HALF,				// type
			       (char *) gPixels,		// base
			       sizeof (*gPixels) * 1,		// xStride
			       sizeof (*gPixels) * width));	// yStride

    frameBuffer.insert ("Z",					// name
			Slice (FLOAT,				// type
			       (char *) zPixels,		// base
			       sizeof (*zPixels) * 1,		// xStride
			       sizeof (*zPixels) * width));	// yStride

    file.setFrameBuffer (frameBuffer);
    file.writePixels (dataWindow.max.y - dataWindow.min.y + 1);
}


void
readGZ1 (const char fileName[],
	 Array2D<half> &rPixels,
	 Array2D<half> &gPixels,
	 Array2D<float> &zPixels,
	 int &width, int &height)
{
    //
    // Read an image using class InputFile.  Try to read two
    // channels, R and G, of type HALF, and one channel, Z,
    // of type FLOAT.  Store the R, G, and Z pixels in three
    // separate memory buffers.
    // If a channel is missing in the file, the buffer for that
    // channel will be filled with an appropriate default value.
    //
    //	- open the file
    //	- allocate memory for the pixels
    //	- describe the layout of the R, G, and Z pixel buffers
    //	- read the pixels from the file
    //

    InputFile file (fileName);

    Box2i dw = file.header().dataWindow();
    width  = dw.max.x - dw.min.x + 1;
    height = dw.max.y - dw.min.y + 1;

    rPixels.resizeErase (height, width);
    gPixels.resizeErase (height, width);
    zPixels.resizeErase (height, width);

    FrameBuffer frameBuffer;

    frameBuffer.insert ("R",					// name
			Slice (HALF,				// type
			       (char *) (&rPixels[0][0] -	// base
					 dw.min.x -
					 dw.min.y * width),
			       sizeof (rPixels[0][0]) * 1,	// xStride
			       sizeof (rPixels[0][0]) * width,	// yStride
			       1, 1,				// x/y sampling
			       0.0));				// fillValue

    frameBuffer.insert ("G",					// name
			Slice (HALF,				// type
			       (char *) (&gPixels[0][0] -	// base
					 dw.min.x -
					 dw.min.y * width),
			       sizeof (gPixels[0][0]) * 1,	// xStride
			       sizeof (gPixels[0][0]) * width,	// yStride
			       1, 1,				// x/y sampling
			       0.0));				// fillValue

    frameBuffer.insert ("Z",					// name
			Slice (FLOAT,				// type
			       (char *) (&zPixels[0][0] -	// base
					 dw.min.x -
					 dw.min.y * width),
			       sizeof (zPixels[0][0]) * 1,	 // xStride
			       sizeof (zPixels[0][0]) * width,	// yStride
			       1, 1,				// x/y sampling
			       FLT_MAX));			// fillValue

    file.setFrameBuffer (frameBuffer);
    file.readPixels (dw.min.y, dw.max.y);
}


void
readGZ2 (const char fileName[],
	 Array2D<GZ> &pixels,
	 int &width, int &height)
{
    //
    // Read an image using class InputFile.  Try to read one channel,
    // G, of type HALF, and one channel, Z, of type FLOAT.  In memory,
    // the G and Z channels will be interleaved in a single buffer.
    //
    //	- open the file
    //	- allocate memory for the pixels
    //	- describe the layout of the GZ pixel buffer
    //	- read the pixels from the file
    //

    InputFile file (fileName);

    Box2i dw = file.header().dataWindow();
    width  = dw.max.x - dw.min.x + 1;
    height = dw.max.y - dw.min.y + 1;
    int dx = dw.min.x;
    int dy = dw.min.y;

    pixels.resizeErase (height, width);

    FrameBuffer frameBuffer;

    frameBuffer.insert ("G",					 // name
                        Slice (HALF,				 // type
			       (char *) &pixels[-dy][-dx].g,	 // base
				sizeof (pixels[0][0]) * 1,	 // xStride
				sizeof (pixels[0][0]) * width)); // yStride

    frameBuffer.insert ("Z",					 // name
                        Slice (FLOAT,				 // type
			       (char *) &pixels[-dy][-dx].z,	 // base
				sizeof (pixels[0][0]) * 1,	 // xStride
				sizeof (pixels[0][0]) * width)); // yStride

    file.setFrameBuffer (frameBuffer);
    file.readPixels (dw.min.y, dw.max.y);
}


void
generalInterfaceExamples ()
{
    cout << "\nGZ (green, depth) images\n" << endl;
    cout << "drawing image" << endl;

    int w = 800;
    int h = 600;

    Array2D<half>  gp (h, w);
    Array2D<float> zp (h, w);
    drawImage2 (gp, zp, w, h);

    cout << "writing entire image" << endl;

    writeGZ1 ("gz1.exr", &gp[0][0], &zp[0][0], w, h);

    cout << "writing cropped image" << endl;

    writeGZ2 ("gz2.exr", &gp[0][0], &zp[0][0], w, h,
	      Box2i (V2i (w/6, h/6), V2i (w/2, h/2)));

    cout << "reading file into separate per-channel buffers" << endl;

    Array2D<half> rp (1, 1);
    readGZ1 ("gz2.exr", rp, gp, zp, w, h);

    cout << "reading file into interleaved multi-channel buffer" << endl;

    Array2D<GZ> gzp (1, 1);
    readGZ2 ("gz2.exr", gzp, w, h);
}