mirror of https://github.com/JakubMelka/PDF4QT.git
86 lines
3.5 KiB
C++
86 lines
3.5 KiB
C++
// Copyright (C) 2019-2020 Jakub Melka
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//
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// This file is part of PdfForQt.
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//
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// PdfForQt is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// PdfForQt is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with PDFForQt. If not, see <https://www.gnu.org/licenses/>.
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#ifndef PDFBLENDFUNCTION_H
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#define PDFBLENDFUNCTION_H
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#include "pdfglobal.h"
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#include <QPainter>
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namespace pdf
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{
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enum class BlendMode
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{
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// Separable blending modes
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Normal, ///< Select source color, backdrop is ignored: B(source, dest) = source
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Multiply, ///< Backdrop and source colors are multiplied: B(source, dest) = source * dest
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Screen, ///< B(source, dest) = 1.0 - (1.0 - source) * (1.0 - dest) + source + dest - source * dest
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Overlay, ///< B(source, dest) = HardLight(dest, source)
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Darken, ///< Selects the darker of the colors. B(source, dest) = qMin(source, dest)
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Lighten, ///< Selects the lighter of the colors. B(source, dest) = qMax(source, dest)
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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
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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
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HardLight, ///< Multiply or screen the color, depending on the source value.
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SoftLight, ///< Darkens or lightens the color, depending on the source value.
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Difference, ///< Subtract the darker of colors from the lighter color. B(source, dest) = qAbs(source - dest)
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Exclusion, ///< B(source, dest) = source + dest - 2 * source * dest
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// Non-separable blending modes
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Hue,
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Saturation,
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Color,
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Luminosity,
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// For compatibility - older PDF specification specifies Compatible mode, which is equal
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// to normal. It should be recognized for sake of compatibility.
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Compatible, ///< Equals to normal
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// Invalid blending mode - for internal purposes only
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Invalid
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};
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class PDFBlendModeInfo
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{
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public:
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PDFBlendModeInfo() = delete;
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/// Returns blend mode from the specified string. If string is invalid,
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/// then \p Invalid blend mode is returned.
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/// \param name Name of the blend mode
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static BlendMode getBlendMode(const QByteArray& name);
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/// Returns true, if blend mode is supported by Qt drawing subsystem
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/// \param mode Blend mode
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static bool isSupportedByQt(BlendMode mode);
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/// Returns composition mode for Qt drawing subsystem from blend mode defined
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/// in PDF standard. If blend mode is not supported by Qt drawing subsystem, then default
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/// composition mode is returned.
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/// \param mode Blend mode
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static QPainter::CompositionMode getCompositionModeFromBlendMode(BlendMode mode);
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/// Returns blend mode name
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/// \param mode Blend mode
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static QString getBlendModeName(BlendMode mode);
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};
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} // namespace pdf
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#endif // PDFBLENDFUNCTION_H
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