// Copyright (C) 2021 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 PDFTRANSPARENCYRENDERER_H
#define PDFTRANSPARENCYRENDERER_H
#include "pdfglobal.h"
#include "pdfcolorspaces.h"
#include "pdfpagecontentprocessor.h"
#include "pdfconstants.h"
#include "pdfutils.h"
namespace pdf
{
/// Pixel format, describes color channels, both process colors (for example,
/// R, G, B, Gray, C, M, Y, K) or spot colors. Also, describes, if pixel
/// has shape channel and opacity channel. Two auxiliary channels are possible,
/// shape channel and opacity channel. Shape channel defines the shape (so, for
/// example, if we draw a rectangle onto the bitmap, shape value is 1.0 inside the
/// rectangle and 0.0 outside the rectangle). PDF transparency processing requires
/// shape and opacity values separated.
class PDFPixelFormat
{
public:
inline explicit constexpr PDFPixelFormat() = default;
constexpr static uint8_t INVALID_CHANNEL_INDEX = 0xFF;
constexpr bool operator==(const PDFPixelFormat&) const = default;
constexpr bool operator!=(const PDFPixelFormat&) const = default;
constexpr bool hasProcessColors() const { return m_processColors > 0; }
constexpr bool hasSpotColors() const { return m_spotColors > 0; }
constexpr bool hasShapeChannel() const { return m_flags & FLAG_HAS_SHAPE_CHANNEL; }
constexpr bool hasOpacityChannel() const { return m_flags & FLAG_HAS_OPACITY_CHANNEL; }
constexpr bool hasProcessColorsSubtractive() const { return m_flags & FLAG_PROCESS_COLORS_SUBTRACTIVE; }
constexpr bool hasSpotColorsSubtractive() const { return true; }
constexpr uint8_t getFlags() const { return m_flags; }
constexpr uint8_t getMaximalColorChannelCount() const { return 32; }
constexpr uint8_t getProcessColorChannelCount() const { return m_processColors; }
constexpr uint8_t getSpotColorChannelCount() const { return m_spotColors; }
constexpr uint8_t getColorChannelCount() const { return getProcessColorChannelCount() + getSpotColorChannelCount(); }
constexpr uint8_t getShapeChannelCount() const { return hasShapeChannel() ? 1 : 0; }
constexpr uint8_t getOpacityChannelCount() const { return hasOpacityChannel() ? 1 : 0; }
constexpr uint8_t getAuxiliaryChannelCount() const { return getShapeChannelCount() + getOpacityChannelCount(); }
constexpr uint8_t getChannelCount() const { return getColorChannelCount() + getAuxiliaryChannelCount(); }
constexpr uint8_t getProcessColorChannelIndexStart() const { return hasProcessColors() ? 0 : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getProcessColorChannelIndexEnd() const { return hasProcessColors() ? getProcessColorChannelCount() : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getSpotColorChannelIndexStart() const { return hasSpotColors() ? getProcessColorChannelCount() : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getSpotColorChannelIndexEnd() const { return hasSpotColors() ? getSpotColorChannelIndexStart() + getSpotColorChannelCount() : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getColorChannelIndexStart() const { return (hasProcessColors() || hasSpotColors()) ? 0 : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getColorChannelIndexEnd() const { return (hasProcessColors() || hasSpotColors()) ? (m_processColors + m_spotColors) : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getShapeChannelIndex() const { return hasShapeChannel() ? getProcessColorChannelCount() + getSpotColorChannelCount() : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getOpacityChannelIndex() const { return hasOpacityChannel() ? getProcessColorChannelCount() + getSpotColorChannelCount() + getShapeChannelCount() : INVALID_CHANNEL_INDEX; }
/// Pixel format is valid, if we have at least one color channel
/// (it doesn't matter, if it is process color, or spot color)
constexpr bool isValid() const { return getChannelCount() > 0; }
inline void setProcessColors(const uint8_t& processColors) { m_processColors = processColors; }
inline void setSpotColors(const uint8_t& spotColors) { m_spotColors = spotColors; }
inline void setProcessColorsSubtractive(bool subtractive)
{
if (subtractive)
{
m_flags |= FLAG_PROCESS_COLORS_SUBTRACTIVE;
}
else
{
m_flags &= ~FLAG_PROCESS_COLORS_SUBTRACTIVE;
}
}
static constexpr PDFPixelFormat createOpacityMask() { return PDFPixelFormat(0, 0, FLAG_HAS_OPACITY_CHANNEL); }
static constexpr PDFPixelFormat createFormatDefaultGray(uint8_t spotColors) { return createFormat(1, spotColors, true, false); }
static constexpr PDFPixelFormat createFormatDefaultRGB(uint8_t spotColors) { return createFormat(3, spotColors, true, false); }
static constexpr PDFPixelFormat createFormatDefaultCMYK(uint8_t spotColors) { return createFormat(4, spotColors, true, true); }
static constexpr PDFPixelFormat removeProcessColors(PDFPixelFormat format) { return PDFPixelFormat(0, format.getSpotColorChannelCount(), format.getFlags()); }
static constexpr PDFPixelFormat removeSpotColors(PDFPixelFormat format) { return PDFPixelFormat(format.getProcessColorChannelCount(), 0, format.getFlags()); }
static constexpr PDFPixelFormat removeShapeAndOpacity(PDFPixelFormat format) { return PDFPixelFormat(format.getProcessColorChannelCount(), format.getSpotColorChannelCount(), format.hasProcessColorsSubtractive() ? FLAG_PROCESS_COLORS_SUBTRACTIVE : 0); }
static constexpr PDFPixelFormat createFormat(uint8_t processColors, uint8_t spotColors, bool withShapeAndOpacity, bool processColorSubtractive)
{
return PDFPixelFormat(processColors, spotColors, (withShapeAndOpacity ? FLAG_HAS_SHAPE_CHANNEL + FLAG_HAS_OPACITY_CHANNEL : 0) + (processColorSubtractive ? FLAG_PROCESS_COLORS_SUBTRACTIVE : 0));
}
/// Calculates bitmap data length required to store bitmapt with given pixel format.
/// \param width Bitmap width
/// \param height Bitmap height
size_t calculateBitmapDataLength(size_t width, size_t height) const { return width * height * size_t(getChannelCount()); }
private:
inline explicit constexpr PDFPixelFormat(uint8_t processColors, uint8_t spotColors, uint8_t flags) :
m_processColors(processColors),
m_spotColors(spotColors),
m_flags(flags)
{
}
constexpr static uint8_t FLAG_HAS_SHAPE_CHANNEL = 0x01;
constexpr static uint8_t FLAG_HAS_OPACITY_CHANNEL = 0x02;
constexpr static uint8_t FLAG_PROCESS_COLORS_SUBTRACTIVE = 0x04;
uint8_t m_processColors = 0;
uint8_t m_spotColors = 0;
uint8_t m_flags = 0;
};
/// Represents float bitmap with arbitrary color channel count. Bitmap can also
/// have auxiliary channels, such as shape and opacity channels.
class PDFFloatBitmap
{
public:
explicit PDFFloatBitmap();
explicit PDFFloatBitmap(size_t width, size_t height, PDFPixelFormat format);
/// Returns buffer with pixel channels
PDFColorBuffer getPixel(size_t x, size_t y);
/// Returns constant buffer with pixel channels
PDFConstColorBuffer getPixel(size_t x, size_t y) const;
/// Returns buffer with all pixels
PDFColorBuffer getPixels();
const PDFColorComponent* begin() const;
const PDFColorComponent* end() const;
PDFColorComponent* begin();
PDFColorComponent* end();
size_t getWidth() const { return m_width; }
size_t getHeight() const { return m_height; }
size_t getPixelSize() const { return m_pixelSize; }
PDFPixelFormat getPixelFormat() const { return m_format; }
/// Fills both shape and opacity channel with zero value.
/// If bitmap doesn't have shape/opacity channel, nothing happens.
void makeTransparent();
/// Fills both shape and opacity channel with 1.0 value.
/// If bitmap doesn't have shape/opacity channel, nothing happens.
void makeOpaque();
/// Fillss process color channels to a value, that corresponds to black,
/// so 0.0 for additive colors, 1.0 for subtractive colors.
void makeColorBlack();
/// Fillss process color channels to a value, that corresponds to white,
/// so 1.0 for additive colors, 0.0 for subtractive colors.
void makeColorWhite();
/// Returns index where given pixel starts in the data block
/// \param x Horizontal coordinate of the pixel
/// \param y Vertical coordinate of the pixel
size_t getPixelIndex(size_t x, size_t y) const;
/// Extract process colors into another bitmap
PDFFloatBitmap extractProcessColors();
enum class OverprintMode
{
NoOveprint, ///< No oveprint performed
Overprint_Mode_0, ///< Overprint performed (either backdrop or source color is selected)
Overprint_Mode_1, ///< Overprint performed (only nonzero source color is selected, otherwise backdrop)
};
/// Performs bitmap blending, pixel format of source and target must be the same.
/// Blending algorithm uses the one from chapter 11.4.8 in the PDF 2.0 specification.
/// Bitmap size must be equal for all three bitmaps (source, target and soft mask).
/// Oveprinting is also handled. You can specify a mask with active color channels.
/// If n-th bit in \p activeColorChannels variable is 1, then color channel is active;
/// otherwise backdrop color is selected (if overprint is active).
/// \param source Source bitmap
/// \param target Target bitmap
/// \param backdrop Backdrop
/// \param initialBackdrop Initial backdrop
/// \param softMask Soft mask
/// \param alphaIsShape Both soft mask and constant alpha are shapes and not opacity?
/// \param constantAlpha Constant alpha, can mean shape or opacity
/// \param mode Blend mode
/// \param activeColorChannels Active color channels
/// \param overprintMode Overprint mode
static void blend(const PDFFloatBitmap& source,
PDFFloatBitmap& target,
const PDFFloatBitmap& backdrop,
const PDFFloatBitmap& initialBackdrop,
PDFFloatBitmap& softMask,
bool alphaIsShape,
PDFColorComponent constantAlpha,
BlendMode mode,
bool knockoutGroup,
uint32_t activeColorChannels,
OverprintMode overprintMode);
private:
void fillProcessColorChannels(PDFColorComponent value);
void fillChannel(size_t channel, PDFColorComponent value);
PDFPixelFormat m_format;
std::size_t m_width;
std::size_t m_height;
std::size_t m_pixelSize;
std::vector<PDFColorComponent> m_data;
};
/// Float bitmap with color space
class PDFFloatBitmapWithColorSpace : public PDFFloatBitmap
{
public:
explicit PDFFloatBitmapWithColorSpace();
explicit PDFFloatBitmapWithColorSpace(size_t width, size_t height, PDFPixelFormat format);
explicit PDFFloatBitmapWithColorSpace(size_t width, size_t height, PDFPixelFormat format, PDFColorSpacePointer blendColorSpace);
PDFColorSpacePointer getColorSpace() const;
void setColorSpace(const PDFColorSpacePointer& colorSpace);
/// Converts bitmap to target color space
/// \param cms Color management system
/// \param targetColorSpace Target color space
void convertToColorSpace(const PDFCMS* cms,
RenderingIntent intent,
const PDFColorSpacePointer& targetColorSpace,
PDFRenderErrorReporter* reporter);
private:
PDFColorSpacePointer m_colorSpace;
};
/// Ink mapping
struct PDFInkMapping
{
inline bool isValid() const { return !mapping.empty(); }
inline void reserve(size_t size) { mapping.reserve(size); }
inline void map(uint8_t source, uint8_t target) { mapping.emplace_back(Mapping{ source, target, Pass}); activeChannels |= 1 << target; }
enum Type
{
Pass
};
struct Mapping
{
uint8_t source = 0;
uint8_t target = 0;
Type type = Pass;
};
std::vector<Mapping> mapping;
uint32_t activeChannels = 0;
};
/// Ink mapper for mapping device inks (device colors) and spot inks (spot colors).
class Pdf4QtLIBSHARED_EXPORT PDFInkMapper
{
public:
explicit PDFInkMapper(const PDFDocument* document);
struct SpotColorInfo
{
QByteArray name;
uint32_t spotColorIndex = 0; ///< Index of this spot color
uint32_t colorSpaceIndex = 0; ///< Index into DeviceN color space (index of colorant)
PDFColorSpacePointer colorSpace;
bool active = false; ///< Is spot color active?
};
static constexpr const uint32_t MAX_COLOR_COMPONENTS = PDF_MAX_COLOR_COMPONENTS;
static constexpr const uint32_t MAX_DEVICE_COLOR_COMPONENTS = 4;
static constexpr const uint32_t MAX_SPOT_COLOR_COMPONENTS = MAX_COLOR_COMPONENTS - MAX_DEVICE_COLOR_COMPONENTS - 2;
/// Scan document for spot colors and fills color info
/// \param activate Set spot colors active?
void createSpotColors(bool activate);
/// Returns true, if mapper contains given spot color
/// \param colorName Color name
bool containsSpotColor(const QByteArray& colorName) const;
/// Returns number of active spot colors
size_t getActiveSpotColorCount() const { return m_activeSpotColors; }
/// Returns spot color information (or nullptr, if spot color is not present)
/// \param colorName Color name
const SpotColorInfo* getSpotColor(const QByteArray& colorName) const;
/// Creates color mapping from source color space to the target color space.
/// If mapping cannot be created, then invalid mapping is returned. Target
/// color space must be blending color space and must correspond to active
/// blending space, if used when painting.
/// \param sourceColorSpace Source color space
/// \param targetColorSpace Target color space
/// \param targetPixelFormat
PDFInkMapping createMapping(const PDFAbstractColorSpace* sourceColorSpace,
const PDFAbstractColorSpace* targetColorSpace,
PDFPixelFormat targetPixelFormat) const;
private:
const PDFDocument* m_document;
std::vector<SpotColorInfo> m_spotColors;
size_t m_activeSpotColors = 0;
};
/// Renders PDF pages with transparency, using 32-bit floating point precision.
/// Both device color space and blending color space can be defined. It implements
/// page blending space and device blending space. So, painted graphics is being
/// blended to the page blending space, and then converted to the device blending
/// space.
class Pdf4QtLIBSHARED_EXPORT PDFTransparencyRenderer : public PDFPageContentProcessor
{
private:
using BaseClass = PDFPageContentProcessor;
public:
PDFTransparencyRenderer(const PDFPage* page,
const PDFDocument* document,
const PDFFontCache* fontCache,
const PDFCMS* cms,
const PDFOptionalContentActivity* optionalContentActivity,
const PDFInkMapper* inkMapper,
QMatrix pagePointToDevicePointMatrix);
/// Sets device color space. This is final color space, to which
/// is painted page transformed.
/// \param colorSpace Color space
void setDeviceColorSpace(PDFColorSpacePointer colorSpace);
/// Sets process color space. This color space is used for blending
/// and intermediate results. If page has transparency group, then
/// blending color space from transparency group is used.
/// \param colorSpace Color space
void setProcessColorSpace(PDFColorSpacePointer colorSpace);
/// Starts painting on the device. This function must be called before page
/// content stream is being processed (and must be called exactly once).
void beginPaint(QSize pixelSize);
/// Finishes painting on the device. This function must be called after page
/// content stream is processed and all result graphics is being drawn. Page
/// transparency group collapses nad contents are draw onto device transparency
/// group.
const PDFFloatBitmap& endPaint();
/// This function should be called only after call to \p endPaint. After painting,
/// when it is finished, the result float image can be converted to QImage with
/// this function, but only, if the float image is RGB. If error occurs, empty
/// image is returned.
/// \param use16bit
QImage toImage(bool use16Bit) const;
virtual void performPathPainting(const QPainterPath& path, bool stroke, bool fill, bool text, Qt::FillRule fillRule) override;
virtual void performClipping(const QPainterPath& path, Qt::FillRule fillRule) override;
virtual void performUpdateGraphicsState(const PDFPageContentProcessorState& state) override;
virtual void performSaveGraphicState(ProcessOrder order) override;
virtual void performRestoreGraphicState(ProcessOrder order) override;
virtual void performBeginTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup) override;
virtual void performEndTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup) override;
private:
PDFReal getShapeStroking() const;
PDFReal getOpacityStroking() const;
PDFReal getShapeFilling() const;
PDFReal getOpacityFilling() const;
struct PDFTransparencyGroupPainterData
{
PDFTransparencyGroup group;
bool alphaIsShape = false;
PDFReal alphaStroke = 1.0;
PDFReal alphaFill = 1.0;
BlendMode blendMode = BlendMode::Normal;
BlackPointCompensationMode blackPointCompensationMode = BlackPointCompensationMode::Default;
RenderingIntent renderingIntent = RenderingIntent::RelativeColorimetric;
PDFFloatBitmapWithColorSpace initialBackdrop; ///< Initial backdrop
PDFFloatBitmapWithColorSpace immediateBackdrop; ///< Immediate backdrop
PDFFloatBitmap softMask; ///< Soft mask for this group
PDFColorSpacePointer blendColorSpace;
};
struct PDFTransparencyPainterState
{
QPainterPath clipPath; ///< Clipping path in device state coordinates
};
struct PDFMappedColor
{
PDFColor mappedColor;
uint32_t activeChannels = 0;
};
void invalidateCachedItems();
void removeInitialBackdrop();
void fillMappedColorUsingMapping(const PDFPixelFormat pixelFormat,
PDFMappedColor& result,
const PDFInkMapping& inkMapping,
const PDFColor& sourceColor);
PDFMappedColor createMappedColor(const PDFColor& sourceColor,
const PDFAbstractColorSpace* sourceColorSpace);
PDFFloatBitmapWithColorSpace* getInitialBackdrop();
PDFFloatBitmapWithColorSpace* getImmediateBackdrop();
PDFFloatBitmapWithColorSpace* getBackdrop();
const PDFColorSpacePointer& getBlendColorSpace() const;
PDFTransparencyPainterState* getPainterState() { return &m_painterStateStack.top(); }
bool isTransparencyGroupIsolated() const;
bool isTransparencyGroupKnockout() const;
const PDFMappedColor& getMappedStrokeColor();
const PDFMappedColor& getMappedFillColor();
PDFMappedColor getMappedStrokeColorImpl();
PDFMappedColor getMappedFillColorImpl();
PDFColorSpacePointer m_deviceColorSpace; ///< Device color space (color space for final result)
PDFColorSpacePointer m_processColorSpace; ///< Process color space (color space, in which is page graphic's blended)
std::unique_ptr<PDFTransparencyGroupGuard> m_pageTransparencyGroupGuard;
std::vector<PDFTransparencyGroupPainterData> m_transparencyGroupDataStack;
std::stack<PDFTransparencyPainterState> m_painterStateStack;
const PDFInkMapper* m_inkMapper;
bool m_active;
PDFCachedItem<PDFMappedColor> m_mappedStrokeColor;
PDFCachedItem<PDFMappedColor> m_mappedFillColor;
};
} // namespace pdf
#endif // PDFTRANSPARENCYRENDERER_H