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libcamera: Add ColorSpace class
This class represents a color space by defining its color primaries, the transfer (gamma) function it uses, the YCbCr encoding and whether the output is full or limited range. Signed-off-by: David Plowman <david.plowman@raspberrypi.com> Reviewed-by: Naushir Patuck <naush@raspberrypi.com> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
This commit is contained in:
David Plowman
Laurent Pinchart
parent
015fa7f718
commit
ddb5e9d37e
4 changed files with 389 additions and 0 deletions
70
include/libcamera/color_space.h
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70
include/libcamera/color_space.h
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@ -0,0 +1,70 @@
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
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/*
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* Copyright (C) 2021, Raspberry Pi (Trading) Limited
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*
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* color_space.h - color space definitions
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*/
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#pragma once
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#include <optional>
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#include <string>
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namespace libcamera {
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class ColorSpace
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{
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public:
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enum class Primaries {
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Raw,
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Smpte170m,
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Rec709,
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Rec2020,
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};
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enum class TransferFunction {
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Linear,
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Srgb,
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Rec709,
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};
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enum class YcbcrEncoding {
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None,
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Rec601,
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Rec709,
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Rec2020,
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};
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enum class Range {
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Full,
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Limited,
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};
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constexpr ColorSpace(Primaries p, TransferFunction t, YcbcrEncoding e, Range r)
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: primaries(p), transferFunction(t), ycbcrEncoding(e), range(r)
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{
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}
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static const ColorSpace Raw;
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static const ColorSpace Jpeg;
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static const ColorSpace Srgb;
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static const ColorSpace Smpte170m;
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static const ColorSpace Rec709;
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static const ColorSpace Rec2020;
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Primaries primaries;
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TransferFunction transferFunction;
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YcbcrEncoding ycbcrEncoding;
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Range range;
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std::string toString() const;
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static std::string toString(const std::optional<ColorSpace> &colorSpace);
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};
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bool operator==(const ColorSpace &lhs, const ColorSpace &rhs);
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static inline bool operator!=(const ColorSpace &lhs, const ColorSpace &rhs)
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{
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return !(lhs == rhs);
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}
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} /* namespace libcamera */
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@ -5,6 +5,7 @@ libcamera_include_dir = 'libcamera' / 'libcamera'
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libcamera_public_headers = files([
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'camera.h',
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'camera_manager.h',
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'color_space.h',
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'controls.h',
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'fence.h',
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'framebuffer.h',
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317
src/libcamera/color_space.cpp
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317
src/libcamera/color_space.cpp
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
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/*
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* Copyright (C) 2021, Raspberry Pi (Trading) Limited
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*
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* color_space.cpp - color spaces.
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*/
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#include <libcamera/color_space.h>
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#include <algorithm>
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#include <array>
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#include <map>
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#include <sstream>
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#include <utility>
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/**
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* \file color_space.h
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* \brief Class and enums to represent color spaces
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*/
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namespace libcamera {
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/**
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* \class ColorSpace
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* \brief Class to describe a color space
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*
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* The ColorSpace class defines the color primaries, the transfer function,
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* the Y'CbCr encoding associated with the color space, and the range
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* (sometimes also referred to as the quantisation) of the color space.
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*
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* Certain combinations of these fields form well-known standard color
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* spaces such as "JPEG" or "REC709".
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*
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* In the strictest sense a "color space" formally only refers to the
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* color primaries and white point. Here, however, the ColorSpace class
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* adopts the common broader usage that includes the transfer function,
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* Y'CbCr encoding method and quantisation.
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*
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* For more information on the specific color spaces described here, please
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* see:
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*
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* - <a href="https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/colorspaces-details.html#col-srgb">sRGB</a>
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* - <a href="https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/colorspaces-details.html#col-jpeg">JPEG</a>
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* - <a href="https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/colorspaces-details.html#col-smpte-170m">SMPTE 170M</a>
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* - <a href="https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/colorspaces-details.html#col-rec709">Rec.709</a>
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* - <a href="https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/colorspaces-details.html#col-bt2020">Rec.2020</a>
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*/
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/**
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* \enum ColorSpace::Primaries
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* \brief The color primaries for this color space
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*
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* \var ColorSpace::Primaries::Raw
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* \brief These are raw colors directly from a sensor, the primaries are
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* unspecified
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*
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* \var ColorSpace::Primaries::Smpte170m
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* \brief SMPTE 170M color primaries
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*
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* \var ColorSpace::Primaries::Rec709
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* \brief Rec.709 color primaries
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*
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* \var ColorSpace::Primaries::Rec2020
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* \brief Rec.2020 color primaries
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*/
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/**
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* \enum ColorSpace::TransferFunction
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* \brief The transfer function used for this color space
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*
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* \var ColorSpace::TransferFunction::Linear
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* \brief This color space uses a linear (identity) transfer function
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*
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* \var ColorSpace::TransferFunction::Srgb
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* \brief sRGB transfer function
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*
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* \var ColorSpace::TransferFunction::Rec709
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* \brief Rec.709 transfer function
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*/
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/**
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* \enum ColorSpace::YcbcrEncoding
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* \brief The Y'CbCr encoding
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*
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* \var ColorSpace::YcbcrEncoding::None
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* \brief There is no defined Y'CbCr encoding (used for non-YUV formats)
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*
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* \var ColorSpace::YcbcrEncoding::Rec601
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* \brief Rec.601 Y'CbCr encoding
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*
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* \var ColorSpace::YcbcrEncoding::Rec709
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* \brief Rec.709 Y'CbCr encoding
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*
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* \var ColorSpace::YcbcrEncoding::Rec2020
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* \brief Rec.2020 Y'CbCr encoding
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*/
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/**
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* \enum ColorSpace::Range
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* \brief The range (sometimes "quantisation") for this color space
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*
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* \var ColorSpace::Range::Full
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* \brief This color space uses full range pixel values
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*
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* \var ColorSpace::Range::Limited
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* \brief This color space uses limited range pixel values, being
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* 16 to 235 for Y' and 16 to 240 for Cb and Cr (8 bits per sample)
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* or 64 to 940 for Y' and 16 to 960 for Cb and Cr (10 bits)
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*/
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/**
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* \fn ColorSpace::ColorSpace(Primaries p, TransferFunction t, Encoding e, Range r)
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* \brief Construct a ColorSpace from explicit values
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* \param[in] p The color primaries
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* \param[in] t The transfer function for the color space
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* \param[in] e The Y'CbCr encoding
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* \param[in] r The range of the pixel values in this color space
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*/
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/**
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* \brief Assemble and return a readable string representation of the
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* ColorSpace
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*
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* If the color space matches a standard ColorSpace (such as ColorSpace::Jpeg)
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* then the short name of the color space ("JPEG") is returned. Otherwise
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* the four constituent parts of the ColorSpace are assembled into a longer
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* string.
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*
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* \return A string describing the ColorSpace
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*/
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std::string ColorSpace::toString() const
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{
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/* Print out a brief name only for standard color spaces. */
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static const std::array<std::pair<ColorSpace, const char *>, 6> colorSpaceNames = { {
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{ ColorSpace::Raw, "RAW" },
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{ ColorSpace::Jpeg, "JPEG" },
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{ ColorSpace::Srgb, "sRGB" },
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{ ColorSpace::Smpte170m, "SMPTE170M" },
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{ ColorSpace::Rec709, "Rec709" },
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{ ColorSpace::Rec2020, "Rec2020" },
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} };
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auto it = std::find_if(colorSpaceNames.begin(), colorSpaceNames.end(),
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[this](const auto &item) {
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return *this == item.first;
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});
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if (it != colorSpaceNames.end())
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return std::string(it->second);
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/* Assemble a name made of the constituent fields. */
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static const std::map<Primaries, std::string> primariesNames = {
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{ Primaries::Raw, "RAW" },
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{ Primaries::Smpte170m, "SMPTE170M" },
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{ Primaries::Rec709, "Rec709" },
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{ Primaries::Rec2020, "Rec2020" },
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};
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static const std::map<TransferFunction, std::string> transferNames = {
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{ TransferFunction::Linear, "Linear" },
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{ TransferFunction::Srgb, "sRGB" },
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{ TransferFunction::Rec709, "Rec709" },
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};
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static const std::map<YcbcrEncoding, std::string> encodingNames = {
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{ YcbcrEncoding::None, "None" },
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{ YcbcrEncoding::Rec601, "Rec601" },
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{ YcbcrEncoding::Rec709, "Rec709" },
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{ YcbcrEncoding::Rec2020, "Rec2020" },
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};
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static const std::map<Range, std::string> rangeNames = {
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{ Range::Full, "Full" },
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{ Range::Limited, "Limited" },
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};
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auto itPrimaries = primariesNames.find(primaries);
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std::string primariesName =
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itPrimaries == primariesNames.end() ? "Invalid" : itPrimaries->second;
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auto itTransfer = transferNames.find(transferFunction);
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std::string transferName =
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itTransfer == transferNames.end() ? "Invalid" : itTransfer->second;
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auto itEncoding = encodingNames.find(ycbcrEncoding);
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std::string encodingName =
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itEncoding == encodingNames.end() ? "Invalid" : itEncoding->second;
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auto itRange = rangeNames.find(range);
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std::string rangeName =
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itRange == rangeNames.end() ? "Invalid" : itRange->second;
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std::stringstream ss;
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ss << primariesName << "/" << transferName << "/" << encodingName << "/" << rangeName;
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return ss.str();
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}
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/**
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* \brief Assemble and return a readable string representation of an
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* optional ColorSpace
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*
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* This is a convenience helper to easily obtain a string representation
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* for a ColorSpace in parts of the libcamera API where it is stored in a
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* std::optional<>. If the ColorSpace is set, this function returns
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* \a colorSpace.toString(), otherwise it returns "Unset".
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*
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* \return A string describing the optional ColorSpace
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*/
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std::string ColorSpace::toString(const std::optional<ColorSpace> &colorSpace)
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{
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if (!colorSpace)
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return "Unset";
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return colorSpace->toString();
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}
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/**
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* \var ColorSpace::primaries
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* \brief The color primaries of this color space
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*/
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/**
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* \var ColorSpace::transferFunction
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* \brief The transfer function used by this color space
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*/
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/**
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* \var ColorSpace::ycbcrEncoding
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* \brief The Y'CbCr encoding used by this color space
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*/
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/**
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* \var ColorSpace::range
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* \brief The pixel range used with by color space
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*/
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/**
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* \brief A constant representing a raw color space (from a sensor)
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*/
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const ColorSpace ColorSpace::Raw = {
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Primaries::Raw,
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TransferFunction::Linear,
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YcbcrEncoding::None,
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Range::Full
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};
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/**
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* \brief A constant representing the JPEG color space used for
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* encoding JPEG images
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*/
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const ColorSpace ColorSpace::Jpeg = {
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Primaries::Rec709,
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TransferFunction::Srgb,
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YcbcrEncoding::Rec601,
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Range::Full
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};
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/**
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* \brief A constant representing the sRGB color space
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*
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* This is identical to the JPEG color space except that the Y'CbCr
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* range is limited rather than full.
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*/
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const ColorSpace ColorSpace::Srgb = {
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Primaries::Rec709,
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TransferFunction::Srgb,
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YcbcrEncoding::Rec601,
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Range::Limited
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};
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/**
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* \brief A constant representing the SMPTE170M color space
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*/
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const ColorSpace ColorSpace::Smpte170m = {
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Primaries::Smpte170m,
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TransferFunction::Rec709,
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YcbcrEncoding::Rec601,
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Range::Limited
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};
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/**
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* \brief A constant representing the Rec.709 color space
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*/
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const ColorSpace ColorSpace::Rec709 = {
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Primaries::Rec709,
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TransferFunction::Rec709,
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YcbcrEncoding::Rec709,
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Range::Limited
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};
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/**
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* \brief A constant representing the Rec.2020 color space
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*/
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const ColorSpace ColorSpace::Rec2020 = {
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Primaries::Rec2020,
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TransferFunction::Rec709,
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YcbcrEncoding::Rec2020,
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Range::Limited
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};
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/**
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* \brief Compare color spaces for equality
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* \return True if the two color spaces are identical, false otherwise
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*/
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bool operator==(const ColorSpace &lhs, const ColorSpace &rhs)
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{
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return lhs.primaries == rhs.primaries &&
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lhs.transferFunction == rhs.transferFunction &&
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lhs.ycbcrEncoding == rhs.ycbcrEncoding &&
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lhs.range == rhs.range;
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}
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/**
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* \fn bool operator!=(const ColorSpace &lhs, const ColorSpace &rhs)
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* \brief Compare color spaces for inequality
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* \return True if the two color spaces are not identical, false otherwise
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*/
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} /* namespace libcamera */
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@ -9,6 +9,7 @@ libcamera_sources = files([
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'camera_manager.cpp',
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'camera_sensor.cpp',
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'camera_sensor_properties.cpp',
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'color_space.cpp',
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'controls.cpp',
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'control_serializer.cpp',
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'control_validator.cpp',
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