ImfPreviewImage.h

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//
// SPDX-License-Identifier: BSD-3-Clause
// Copyright (c) Contributors to the OpenEXR Project.
//

#ifndef INCLUDED_IMF_PREVIEW_IMAGE_H
#define INCLUDED_IMF_PREVIEW_IMAGE_H

#include "ImfForward.h"

//-----------------------------------------------------------------------------
//
//      class PreviewImage -- a usually small, low-dynamic range image,
//      that is intended to be stored in an image file's header.
//
//      struct PreviewRgba -- holds the value of a PreviewImage pixel.
//
//-----------------------------------------------------------------------------

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER

struct IMF_EXPORT_TYPE PreviewRgba
{
    unsigned char r; // Red, green and blue components of
    unsigned char g; // the pixel's color; intensity is
    unsigned char b; // proportional to pow (x/255, 2.2),
        // where x is r, g, or b.

    unsigned char a; // The pixel's alpha; 0 == transparent,
        // 255 == opaque.

    PreviewRgba (
        unsigned char r = 0,
        unsigned char g = 0,
        unsigned char b = 0,
        unsigned char a = 255)
        : r (r), g (g), b (b), a (a)
    {}
};

class IMF_EXPORT_TYPE PreviewImage
{
public:
    //--------------------------------------------------------------------
    // Constructor:
    //
    // PreviewImage(w,h,p) constructs a preview image with w by h pixels
    // whose initial values are specified in pixel array p.  The x and y
    // coordinates of the pixels in p go from 0 to w-1, and from 0 to h-1.
    // The pixel with coordinates (x, y) is at address p + y*w + x.
    // Pixel (0, 0) is in the upper left corner of the preview image.
    // If p is zero, the pixels in the preview image are initialized with
    // (r = 0, b = 0, g = 0, a = 255).
    //
    //--------------------------------------------------------------------

    IMF_EXPORT
    PreviewImage (
        unsigned int      width    = 0,
        unsigned int      height   = 0,
        const PreviewRgba pixels[] = 0);

    //-----------------------------------------------------
    // Copy constructor, destructor and assignment operator
    //-----------------------------------------------------

    IMF_EXPORT
    PreviewImage (const PreviewImage& other);
    IMF_EXPORT
    ~PreviewImage ();

    IMF_EXPORT
    PreviewImage& operator= (const PreviewImage& other);

    //-----------------------------------------------
    // Access to width, height and to the pixel array
    //-----------------------------------------------

    inline unsigned int width () const { return _width; }
    inline unsigned int height () const { return _height; }

    inline PreviewRgba*       pixels () { return _pixels; }
    inline const PreviewRgba* pixels () const { return _pixels; }

    //----------------------------
    // Access to individual pixels
    //----------------------------

    inline PreviewRgba& pixel (unsigned int x, unsigned int y)
    {
        return _pixels[y * _width + x];
    }

    inline const PreviewRgba& pixel (unsigned int x, unsigned int y) const
    {
        return _pixels[y * _width + x];
    }

private:
    unsigned int _width;
    unsigned int _height;
    PreviewRgba* _pixels;
};

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT

#endif