Library renamed to Pdf4Qt

Pdf4QtLib/sources/pdfblendfunction.h

@@ -0,0 +1,93 @@
+//    Copyright (C) 2019-2020 Jakub Melka
+//
+//    This file is part of Pdf4Qt.
+//
+//    Pdf4Qt 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.
+//
+//    Pdf4Qt 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 Pdf4Qt.  If not, see <https://www.gnu.org/licenses/>.
+
+#ifndef PDFBLENDFUNCTION_H
+#define PDFBLENDFUNCTION_H
+
+#include "pdfglobal.h"
+
+#include <QPainter>
+
+namespace pdf
+{
+
+enum class BlendMode
+{
+    // Separable blending modes
+    Normal,     ///< Select source color, backdrop is ignored: B(source, dest) = source
+    Multiply,   ///< Backdrop and source colors are multiplied: B(source, dest) = source * dest
+    Screen,     ///< B(source, dest) = 1.0 - (1.0 - source) * (1.0 - dest) + source + dest - source * dest
+    Overlay,    ///< B(source, dest) = HardLight(dest, source)
+    Darken,     ///< Selects the darker of the colors. B(source, dest) = qMin(source, dest)
+    Lighten,    ///< Selects the lighter of the colors. B(source, dest) = qMax(source, dest)
+    ColorDodge, ///< Brightens the backdrop color reflecting the source color. B(source, dest) = qMin(1.0, dest / (1.0 - source)), or 1.0, if source is 1.0
+    ColorBurn,  ///< Darkens the backdrop color reflecting the source color. B(source, dest) = 1.0 - qMin(1.0, (1.0 - dest) / source), or 0.0, if source is 0.0
+    HardLight,  ///< Multiply or screen the color, depending on the source value.
+    SoftLight,  ///< Darkens or lightens the color, depending on the source value.
+    Difference, ///< Subtract the darker of colors from the lighter color. B(source, dest) = qAbs(source - dest)
+    Exclusion,  ///< B(source, dest) = source + dest - 2 * source * dest
+
+    // Non-separable blending modes
+    Hue,
+    Saturation,
+    Color,
+    Luminosity,
+
+    // For compatibility - older PDF specification specifies Compatible mode, which is equal
+    // to normal. It should be recognized for sake of compatibility.
+    Compatible, ///< Equals to normal
+
+    // Invalid blending mode - for internal purposes only
+    Invalid
+};
+
+class PDFBlendModeInfo
+{
+public:
+    PDFBlendModeInfo() = delete;
+
+    /// Returns blend mode from the specified string. If string is invalid,
+    /// then \p Invalid blend mode is returned.
+    /// \param name Name of the blend mode
+    static BlendMode getBlendMode(const QByteArray& name);
+
+    /// Returns true, if blend mode is supported by Qt drawing subsystem
+    /// \param mode Blend mode
+    static bool isSupportedByQt(BlendMode mode);
+
+    /// Returns composition mode for Qt drawing subsystem from blend mode defined
+    /// in PDF standard. If blend mode is not supported by Qt drawing subsystem, then default
+    /// composition mode is returned.
+    /// \param mode Blend mode
+    static QPainter::CompositionMode getCompositionModeFromBlendMode(BlendMode mode);
+
+    /// Returns blend mode name
+    /// \param mode Blend mode
+    static QString getBlendModeName(BlendMode mode);
+
+    /// Returns blend mode translated name
+    /// \param mode Blend mode
+    static QString getBlendModeTranslatedName(BlendMode mode);
+
+    /// Returns vector of all blend modes, excluding duplicate ones (for example,
+    /// Compatible mode is equal to Normal blend mode)
+    static std::vector<BlendMode> getBlendModes();
+};
+
+}   // namespace pdf
+
+#endif // PDFBLENDFUNCTION_H