Color management system - base classes + settings

PdfForQtLib/sources/pdfcms.h

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+//    Copyright (C) 2019 Jakub Melka
+//
+//    This file is part of PdfForQt.
+//
+//    PdfForQt is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Lesser General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    PdfForQt is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Lesser General Public License for more details.
+//
+//    You should have received a copy of the GNU Lesser General Public License
+//    along with PDFForQt. If not, see <https://www.gnu.org/licenses/>.
+
+#ifndef PDFCMS_H
+#define PDFCMS_H
+
+#include "pdfglobal.h"
+#include "pdfcolorspaces.h"
+#include "pdfexception.h"
+#include "pdfutils.h"
+
+#include <QMutex>
+
+#include <compare>
+
+namespace pdf
+{
+
+/// This simple structure stores settings for color management system, and what
+/// color management system should be used. At default, two color management
+/// system are available - generic (which uses default imprecise color management),
+/// and CMS using engine LittleCMS2, which was written by Marti Maria, and is
+/// linked as separate library.
+struct PDFCMSSettings
+{
+    /// Type of color management system
+    enum class System
+    {
+        Generic,
+        LittleCMS2
+    };
+
+    /// Controls accuracy of the color transformations. High accuracy
+    /// could mean high memory consumption, but better color accuracy,
+    /// low accuracy means low memory consumption and low color accuracy.
+    enum class Accuracy
+    {
+        Low,
+        Medium,
+        High
+    };
+
+    bool operator==(const PDFCMSSettings&) const = default;
+
+    System system = System::Generic;
+    Accuracy accuracy = Accuracy::Medium;
+    RenderingIntent intent = RenderingIntent::Auto;
+    bool isBlackPointCompensationActive = true;
+    bool isWhitePaperColorTransformed = false;
+    QString outputCS;       ///< Output (rendering) color space
+    QString deviceGray;     ///< Identifiers for color space (device gray)
+    QString deviceRGB;      ///< Identifiers for color space (device RGB)
+    QString deviceCMYK;     ///< Identifiers for color space (device CMYK)
+};
+
+/// Color management system base class. It contains functions to transform
+/// colors from various color system to device color system. If color management
+/// system can't handle color transform, it should return invalid color.
+class PDFCMS
+{
+public:
+    explicit inline PDFCMS() = default;
+    virtual ~PDFCMS() = default;
+
+    /// This function should decide, if color management system is compatible with these
+    /// settings (so, it transforms colors according to this setting). If this
+    /// function returns false, then this color management system should be replaced
+    /// by newly created one, according these settings.
+    virtual bool isCompatible(const PDFCMSSettings& settings) const = 0;
+
+    /// Converts color in Device Gray color space to the target device
+    /// color space. If error occurs, then invalid color is returned.
+    /// Caller then should handle this - try to convert color as accurate
+    /// as possible.
+    /// \param color Single color channel value
+    /// \param intent Rendering intent
+    /// \param reporter Render error reporter (used, when color transform fails)
+    virtual QColor getColorFromDeviceGray(const PDFColor& color, RenderingIntent intent, PDFRenderErrorReporter* reporter) const = 0;
+
+    /// Converts color in Device RGB color space to the target device
+    /// color space. If error occurs, then invalid color is returned.
+    /// Caller then should handle this - try to convert color as accurate
+    /// as possible.
+    /// \param color Three color channel value (R,G,B channel)
+    /// \param intent Rendering intent
+    /// \param reporter Render error reporter (used, when color transform fails)
+    virtual QColor getColorFromDeviceRGB(const PDFColor& color, RenderingIntent intent, PDFRenderErrorReporter* reporter) const = 0;
+
+    /// Converts color in Device CMYK color space to the target device
+    /// color space. If error occurs, then invalid color is returned.
+    /// Caller then should handle this - try to convert color as accurate
+    /// as possible.
+    /// \param color Four color channel value (C,M,Y,K channel)
+    /// \param intent Rendering intent
+    /// \param reporter Render error reporter (used, when color transform fails)
+    virtual QColor getColorFromDeviceCMYK(const PDFColor& color, RenderingIntent intent, PDFRenderErrorReporter* reporter) const = 0;
+
+    /// Converts color in XYZ color space to the target device
+    /// color space. If error occurs, then invalid color is returned.
+    /// Caller then should handle this - try to convert color as accurate
+    /// as possible.
+    /// \param whitePoint White point of source XYZ color space
+    /// \param Three color channel value (X,Y,Z channel)
+    /// \param intent Rendering intent
+    /// \param reporter Render error reporter (used, when color transform fails)
+    virtual QColor getColorFromXYZ(const PDFColor3& whitePoint, const PDFColor& color, RenderingIntent intent, PDFRenderErrorReporter* reporter) const = 0;
+};
+
+class PDFCMSGeneric : public PDFCMS
+{
+public:
+    explicit inline PDFCMSGeneric() = default;
+
+    virtual bool isCompatible(const PDFCMSSettings& settings) const override;
+    virtual QColor getColorFromDeviceGray(const PDFColor& color, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual QColor getColorFromDeviceRGB(const PDFColor& color, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual QColor getColorFromDeviceCMYK(const PDFColor& color, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual QColor getColorFromXYZ(const PDFColor3& whitePoint, const PDFColor& color, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+};
+
+struct PDFColorSpaceIdentifier
+{
+    enum class Type
+    {
+        Gray,
+        sRGB,
+        RGB,
+        CMYK
+    };
+
+    Type type = Type::sRGB;
+    QString name;
+    QString id;
+    PDFReal temperature = 6500.0;
+    QPointF primaryR;
+    QPointF primaryG;
+    QPointF primaryB;
+    PDFReal gamma = 1.0;
+
+    /// Creates gray color space identifier
+    /// \param name Name of color profile
+    /// \param id Identifier of color profile
+    /// \param temperature White point temperature
+    /// \param gamma Gamma correction
+    static PDFColorSpaceIdentifier createGray(QString name, QString id, PDFReal temperature, PDFReal gamma);
+
+    /// Creates sRGB color space identifier
+    static PDFColorSpaceIdentifier createSRGB();
+
+    /// Creates RGB color space identifier
+    /// \param name Name of color profile
+    /// \param id Identifier of color profile
+    /// \param temperature White point temperature
+    /// \param primaryR Primary red
+    /// \param primaryG Primary green
+    /// \param primaryB Primary blue
+    /// \param gamma Gamma correction
+    static PDFColorSpaceIdentifier createRGB(QString name, QString id, PDFReal temperature, QPointF primaryR, QPointF primaryG, QPointF primaryB, PDFReal gamma);
+};
+
+using PDFColorSpaceIdentifiers = std::vector<PDFColorSpaceIdentifier>;
+
+/// Manager, that manages current color management system and also list
+/// of usable input and output color profiles. It has color profiles
+/// for outout device, and color profiles for input (gray/RGB/CMYK).
+/// It also handles settings, and it's changes. Constant functions
+/// is save to call from multiple threads, this also holds for some
+/// non-constant functions - manager is protected by mutexes.
+class PDFFORQTLIBSHARED_EXPORT PDFCMSManager : public QObject
+{
+    Q_OBJECT
+
+private:
+    using BaseClass = QObject;
+
+public:
+    explicit PDFCMSManager(QObject* parent);
+
+    const PDFColorSpaceIdentifiers& getOutputProfiles() const;
+    const PDFColorSpaceIdentifiers& getGrayProfiles() const;
+    const PDFColorSpaceIdentifiers& getRGBProfiles() const;
+    const PDFColorSpaceIdentifiers& getCMYKProfiles() const;
+
+    /// Returns default color management settings
+    PDFCMSSettings getDefaultSettings() const;
+
+    /// Get translated name for color management system
+    /// \param system System
+    static QString getSystemName(PDFCMSSettings::System system);
+
+signals:
+    void colorManagementSystemChanged();
+
+private:
+    PDFColorSpaceIdentifiers getOutputProfilesImpl() const;
+    PDFColorSpaceIdentifiers getGrayProfilesImpl() const;
+    PDFColorSpaceIdentifiers getRGBProfilesImpl() const;
+    PDFColorSpaceIdentifiers getCMYKProfilesImpl() const;
+
+    PDFCMSSettings m_settings;
+
+    mutable QMutex m_mutex;
+    mutable PDFCachedItem<PDFColorSpaceIdentifiers> m_outputProfiles;
+    mutable PDFCachedItem<PDFColorSpaceIdentifiers> m_grayProfiles;
+    mutable PDFCachedItem<PDFColorSpaceIdentifiers> m_RGBProfiles;
+    mutable PDFCachedItem<PDFColorSpaceIdentifiers> m_CMYKProfiles;
+};
+
+}   // namespace pdf
+
+#endif // PDFCMS_H