Current File : //usr/share/doc/OpenEXR/examples/rgbaInterfaceExamples.cpp
//
// SPDX-License-Identifier: BSD-3-Clause
// Copyright (c) Contributors to the OpenEXR Project.
//
//-----------------------------------------------------------------------------
//
// Code examples that show how class RgbaInputFile and
// class RgbaOutputFile can be used to read and write
// OpenEXR image files with 16-bit floating-point red,
// green, blue and alpha channels.
//
//-----------------------------------------------------------------------------
#include <ImfRgbaFile.h>
#include <ImfStringAttribute.h>
#include <ImfMatrixAttribute.h>
#include <ImfArray.h>
#include "drawImage.h"
#include <iostream>
#include <algorithm>
#include "namespaceAlias.h"
using namespace IMF;
using namespace std;
using namespace IMATH_NAMESPACE;
void
writeRgba1 (const char fileName[],
const Rgba *pixels,
int width,
int height)
{
//
// Write an RGBA image using class RgbaOutputFile.
//
// - open the file
// - describe the memory layout of the pixels
// - store the pixels in the file
//
RgbaOutputFile file (fileName, width, height, WRITE_RGBA);
file.setFrameBuffer (pixels, 1, width);
file.writePixels (height);
}
void
writeRgba2 (const char fileName[],
const Rgba *pixels,
int width,
int height,
const Box2i &dataWindow)
{
//
// Write an RGBA image using class RgbaOutputFile.
// Don't store the whole image in the file, but
// crop it according to the given data window.
//
// - open the file
// - describe the memory layout of the pixels
// - store the pixels in the file
//
Box2i displayWindow (V2i (0, 0), V2i (width - 1, height - 1));
RgbaOutputFile file (fileName, displayWindow, dataWindow, WRITE_RGBA);
file.setFrameBuffer (pixels, 1, width);
file.writePixels (dataWindow.max.y - dataWindow.min.y + 1);
}
void
writeRgba3 (const char fileName[],
const Rgba *pixels,
int width,
int height,
const char comments[],
const M44f &cameraTransform)
{
//
// Write an RGBA image using class RgbaOutputFile.
// Store two extra attributes in the image header:
// a string and a 4x4 transformation matrix.
//
// - open the file
// - describe the memory layout of the pixels
// - store the pixels in the file
//
Header header (width, height);
header.insert ("comments", StringAttribute (comments));
header.insert ("cameraTransform", M44fAttribute (cameraTransform));
RgbaOutputFile file (fileName, header, WRITE_RGBA);
file.setFrameBuffer (pixels, 1, width);
file.writePixels (height);
}
void
readRgba1 (const char fileName[],
Array2D<Rgba> &pixels,
int &width,
int &height)
{
//
// Read an RGBA image using class RgbaInputFile:
//
// - open the file
// - allocate memory for the pixels
// - describe the memory layout of the pixels
// - read the pixels from the file
//
RgbaInputFile file (fileName);
Box2i dw = file.dataWindow();
width = dw.max.x - dw.min.x + 1;
height = dw.max.y - dw.min.y + 1;
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);
}
void
readRgba2 (const char fileName[])
{
//
// Read an RGBA image using class RgbaInputFile.
// Read the pixels, 10 scan lines at a time, and
// store the pixel data in a buffer that is just
// large enough to hold 10 scan lines worth of data.
//
// - open the file
// - allocate memory for the pixels
// - for each block of 10 scan lines,
// describe the memory layout of the pixels,
// read the pixels from the file,
// process the pixels and discard them
//
RgbaInputFile file (fileName);
Box2i dw = file.dataWindow();
int width = dw.max.x - dw.min.x + 1;
Array2D<Rgba> pixels (10, width);
while (dw.min.y <= dw.max.y)
{
file.setFrameBuffer (&pixels[0][0] - dw.min.x - dw.min.y * width,
1, width);
file.readPixels (dw.min.y, min (dw.min.y + 9, dw.max.y));
// processPixels (pixels)
dw.min.y += 10;
}
}
void
readHeader (const char fileName[])
{
//
// Read an image's header from a file, and if the header
// contains comments and camera transformation attributes,
// print the values of those attributes.
//
// - open the file
// - get the file header
// - look for the attributes
//
RgbaInputFile file (fileName);
const StringAttribute *comments =
file.header().findTypedAttribute <StringAttribute> ("comments");
const M44fAttribute *cameraTransform =
file.header().findTypedAttribute <M44fAttribute> ("cameraTransform");
if (comments)
cout << "comments\n " << comments->value() << endl;
if (cameraTransform)
cout << "cameraTransform\n" << cameraTransform->value() << flush;
}
void
rgbaInterfaceExamples ()
{
cout << "\nRGBA images\n" << endl;
cout << "drawing image" << endl;
int w = 800;
int h = 600;
Array2D<Rgba> p (h, w);
drawImage1 (p, w, h);
cout << "writing entire image" << endl;
writeRgba1 ("rgba1.exr", &p[0][0], w, h);
cout << "writing cropped image" << endl;
writeRgba2 ("rgba2.exr", &p[0][0], w, h,
Box2i (V2i (w/6, h/6), V2i (w/2, h/2)));
cout << "writing image with extra header attributes" << endl;
writeRgba3 ("rgba3.exr", &p[0][0], w, h,
"may contain peanuts", M44f());
cout << "reading rgba file" << endl;
readRgba1 ("rgba2.exr", p, w, h);
cout << "reading rgba file into 10-scanline buffer" << endl;
readRgba2 ("rgba2.exr");
cout << "reading extra file header attributes" << endl;
readHeader ("rgba3.exr");
}
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