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Transparency groups

This commit is contained in:
Jakub Melka 2019-09-29 18:09:09 +02:00
parent c1dfe0280c
commit 024c613171
4 changed files with 212 additions and 14 deletions
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63
PdfForQtLib/sources/pdfpagecontentprocessor.cpp
View File

@ -374,6 +374,18 @@ void PDFPageContentProcessor::performSetCacheDevice(PDFReal wx, PDFReal wy, PDFR
Q_UNUSED(ury);
}
void PDFPageContentProcessor::performBeginTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup)
{
Q_UNUSED(order);
Q_UNUSED(transparencyGroup);
}
void PDFPageContentProcessor::performEndTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup)
{
Q_UNUSED(order);
Q_UNUSED(transparencyGroup);
}
bool PDFPageContentProcessor::isContentSuppressed() const
{
return std::any_of(m_markedContentStack.cbegin(), m_markedContentStack.cend(), [](const MarkedContentState& state) { return state.contentSuppressed; });
@ -554,10 +566,38 @@ void PDFPageContentProcessor::processContentStream(const PDFStream* stream)
}
}
void PDFPageContentProcessor::processForm(const QMatrix& matrix, const QRectF& boundingBox, const PDFObject& resources, const QByteArray& content)
void PDFPageContentProcessor::processForm(const QMatrix& matrix,
const QRectF& boundingBox,
const PDFObject& resources,
const PDFObject& transparencyGroup,
const QByteArray& content)
{
PDFPageContentProcessorStateGuard guard(this);
std::unique_ptr<PDFTransparencyGroupGuard> guard2;
if (transparencyGroup.isDictionary())
{
// Parse the transparency group
const PDFDictionary* transparencyDictionary = transparencyGroup.getDictionary();
PDFDocumentDataLoaderDecorator loader(m_document);
PDFTransparencyGroup group;
const PDFObject& colorSpaceObject = m_document->getObject(transparencyDictionary->get("CS"));
if (!colorSpaceObject.isNull())
{
group.colorSpacePointer = PDFAbstractColorSpace::createColorSpace(m_colorSpaceDictionary, m_document, colorSpaceObject);
}
group.isolated = loader.readBooleanFromDictionary(transparencyDictionary, "I", false);
group.knockout = loader.readBooleanFromDictionary(transparencyDictionary, "K", false);
guard2.reset(new PDFTransparencyGroupGuard(this, qMove(group)));
// If we are in transparency group, we must reset transparency settings in the graphic state.
// Graphic state is then updated in the lines below.
m_graphicState.setBlendMode(BlendMode::Normal);
m_graphicState.setAlphaFilling(1.0);
m_graphicState.setAlphaStroking(1.0);
}
QMatrix formMatrix = matrix * m_graphicState.getCurrentTransformationMatrix();
m_graphicState.setCurrentTransformationMatrix(formMatrix);
updateGraphicState();
@ -2640,7 +2680,10 @@ void PDFPageContentProcessor::operatorPaintXObject(PDFPageContentProcessor::PDFO
// Read resources
PDFObject resources = m_document->getObject(streamDictionary->get("Resources"));
processForm(transformationMatrix, boundingBox, resources, content);
// Transparency group
PDFObject transparencyGroup = m_document->getObject(streamDictionary->get("Group"));
processForm(transformationMatrix, boundingBox, resources, transparencyGroup, content);
}
else
{
@ -3298,4 +3341,20 @@ PDFPageContentProcessor::PDFPageContentProcessorStateGuard::~PDFPageContentProce
m_processor->operatorRestoreGraphicState();
}
PDFPageContentProcessor::PDFTransparencyGroupGuard::PDFTransparencyGroupGuard(PDFPageContentProcessor* processor, PDFTransparencyGroup&& group) :
m_processor(processor)
{
m_processor->performBeginTransparencyGroup(ProcessOrder::BeforeOperation, group);
m_processor->m_transparencyGroupStack.push(qMove(group));
m_processor->performBeginTransparencyGroup(ProcessOrder::AfterOperation, m_processor->m_transparencyGroupStack.top());
}
PDFPageContentProcessor::PDFTransparencyGroupGuard::~PDFTransparencyGroupGuard()
{
m_processor->performEndTransparencyGroup(ProcessOrder::BeforeOperation, m_processor->m_transparencyGroupStack.top());
PDFTransparencyGroup group = qMove(m_processor->m_transparencyGroupStack.top());
m_processor->m_transparencyGroupStack.pop();
m_processor->performEndTransparencyGroup(ProcessOrder::AfterOperation, group);
}
} // namespace pdf

37
PdfForQtLib/sources/pdfpagecontentprocessor.h
View File

@ -198,6 +198,13 @@ protected:
PDFReal m_dashOffset = 0.0;
};
struct PDFTransparencyGroup
{
PDFColorSpacePointer colorSpacePointer;
bool isolated = false;
bool knockout = false;
};
/// Represents graphic state of the PDF (holding current graphic state parameters).
/// Please see PDF Reference 1.7, Chapter 4.3 "Graphic State"
class PDFPageContentProcessorState
@ -435,6 +442,16 @@ protected:
/// Implement to react on set cache device request
virtual void performSetCacheDevice(PDFReal wx, PDFReal wy, PDFReal llx, PDFReal lly, PDFReal urx, PDFReal ury);
/// Implement to begin new transparency group
/// \param Order, in which is function called (before/after setting new transparency group)
/// \param transparencyGroup Transparency group
virtual void performBeginTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup);
/// Implement to end current transparency group
/// \param Order, in which is function called (before/after setting new transparency group)
/// \param transparencyGroup Transparency group
virtual void performEndTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup);
/// Returns current graphic state
const PDFPageContentProcessorState* getGraphicState() const { return &m_graphicState; }
@ -478,8 +495,9 @@ private:
/// \param Matrix Transformation matrix from form coordinate system to page coordinate system
/// \param boundingBox Bounding box, to which is drawed content clipped
/// \param resources Resources, assigned to the form
/// \param transparencyGroup Transparency group object
/// \param content Content stream of the form
void processForm(const QMatrix& matrix, const QRectF& boundingBox, const PDFObject& resources, const QByteArray& content);
void processForm(const QMatrix& matrix, const QRectF& boundingBox, const PDFObject& resources, const PDFObject& transparencyGroup, const QByteArray& content);
/// Performs path painting
/// \param path Path, which should be drawn (can be emtpy - in that case nothing happens)
@ -525,7 +543,7 @@ private:
bool contentSuppressed = false;
};
struct PDFPageContentProcessorStateGuard
class PDFPageContentProcessorStateGuard
{
public:
explicit PDFPageContentProcessorStateGuard(PDFPageContentProcessor* processor);
@ -544,7 +562,7 @@ private:
const PDFDictionary* m_patternDictionary;
};
struct PDFPageContentProcessorGraphicStateSaveRestoreGuard
class PDFPageContentProcessorGraphicStateSaveRestoreGuard
{
public:
inline explicit PDFPageContentProcessorGraphicStateSaveRestoreGuard(PDFPageContentProcessor* processor) :
@ -561,6 +579,16 @@ private:
PDFPageContentProcessor* m_processor;
};
class PDFTransparencyGroupGuard
{
public:
explicit PDFTransparencyGroupGuard(PDFPageContentProcessor* processor, PDFTransparencyGroup&& group);
~PDFTransparencyGroupGuard();
private:
PDFPageContentProcessor* m_processor;
};
/// Wrapper for PDF Name
struct PDFOperandName
{
@ -797,6 +825,9 @@ private:
/// Stack with saved graphic states
std::stack<PDFPageContentProcessorState> m_stack;
/// Stack with transparency groups
std::stack<PDFTransparencyGroup> m_transparencyGroupStack;
/// Stack with marked content
std::vector<MarkedContentState> m_markedContentStack;

104
PdfForQtLib/sources/pdfpainter.cpp
View File

@ -154,7 +154,7 @@ void PDFPainter::performMeshPainting(const PDFMesh& mesh)
{
m_painter->save();
m_painter->setWorldMatrix(QMatrix());
mesh.paint(m_painter, getGraphicState()->getAlphaFilling());
mesh.paint(m_painter, getEffectiveFillingAlpha());
m_painter->restore();
}
@ -188,15 +188,26 @@ void PDFPainter::performUpdateGraphicsState(const PDFPageContentProcessorState&
// If current blend mode has changed, then update it
if (flags.testFlag(PDFPageContentProcessorState::StateBlendMode))
{
// Try to simulate transparency groups. Use only first composition mode,
// outside the transparency groups (so we are on pages main transparency
// groups).
const BlendMode blendMode = state.getBlendMode();
const QPainter::CompositionMode compositionMode = PDFBlendModeInfo::getCompositionModeFromBlendMode(blendMode);
if (!PDFBlendModeInfo::isSupportedByQt(blendMode))
if (canSetBlendMode(blendMode))
{
reportRenderError(RenderErrorType::NotImplemented, PDFTranslationContext::tr("Blend mode '%1' not supported.").arg(PDFBlendModeInfo::getBlendModeName(blendMode)));
}
const QPainter::CompositionMode compositionMode = PDFBlendModeInfo::getCompositionModeFromBlendMode(blendMode);
m_painter->setCompositionMode(compositionMode);
if (!PDFBlendModeInfo::isSupportedByQt(blendMode))
{
reportRenderError(RenderErrorType::NotSupported, PDFTranslationContext::tr("Blend mode '%1' not supported.").arg(PDFBlendModeInfo::getBlendModeName(blendMode)));
}
m_painter->setCompositionMode(compositionMode);
}
else if (blendMode != BlendMode::Normal && blendMode != BlendMode::Compatible)
{
reportRenderError(RenderErrorType::NotSupported, PDFTranslationContext::tr("Blend mode '%1' is in transparency group, which is not supported.").arg(PDFBlendModeInfo::getBlendModeName(blendMode)));
}
}
PDFPageContentProcessor::performUpdateGraphicsState(state);
@ -218,6 +229,29 @@ void PDFPainter::performRestoreGraphicState(ProcessOrder order)
}
}
void PDFPainter::performBeginTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup)
{
if (order == ProcessOrder::BeforeOperation)
{
PDFTransparencyGroupPainterData data;
data.group = transparencyGroup;
data.alphaFill = getGraphicState()->getAlphaFilling();
data.alphaStroke = getGraphicState()->getAlphaStroking();
data.blendMode = getGraphicState()->getBlendMode();
m_transparencyGroupDataStack.emplace_back(qMove(data));
}
}
void PDFPainter::performEndTransparencyGroup(PDFPageContentProcessor::ProcessOrder order, const PDFPageContentProcessor::PDFTransparencyGroup& transparencyGroup)
{
Q_UNUSED(transparencyGroup);
if (order == ProcessOrder::AfterOperation)
{
m_transparencyGroupDataStack.pop_back();
}
}
bool PDFPainter::isContentSuppressedByOC(PDFObjectReference ocgOrOcmd)
{
if (m_features.testFlag(PDFRenderer::IgnoreOptionalContent))
@ -231,9 +265,10 @@ bool PDFPainter::isContentSuppressedByOC(PDFObjectReference ocgOrOcmd)
QPen PDFPainter::getCurrentPenImpl() const
{
const PDFPageContentProcessorState* graphicState = getGraphicState();
const QColor& color = graphicState->getStrokeColorWithAlpha();
QColor color = graphicState->getStrokeColor();
if (color.isValid())
{
color.setAlphaF(getEffectiveStrokingAlpha());
const PDFReal lineWidth = graphicState->getLineWidth();
Qt::PenCapStyle penCapStyle = graphicState->getLineCapStyle();
Qt::PenJoinStyle penJoinStyle = graphicState->getLineJoinStyle();
@ -269,9 +304,10 @@ QPen PDFPainter::getCurrentPenImpl() const
QBrush PDFPainter::getCurrentBrushImpl() const
{
const PDFPageContentProcessorState* graphicState = getGraphicState();
const QColor& color = graphicState->getFillColorWithAlpha();
QColor color = graphicState->getFillColor();
if (color.isValid())
{
color.setAlphaF(getEffectiveFillingAlpha());
return QBrush(color, Qt::SolidPattern);
}
else
@ -280,4 +316,54 @@ QBrush PDFPainter::getCurrentBrushImpl() const
}
}
PDFReal PDFPainter::getEffectiveStrokingAlpha() const
{
PDFReal alpha = getGraphicState()->getAlphaStroking();
auto it = m_transparencyGroupDataStack.crbegin();
auto itEnd = m_transparencyGroupDataStack.crend();
for (; it != itEnd; ++it)
{
const PDFTransparencyGroupPainterData& transparencyGroup = *it;
alpha *= transparencyGroup.alphaStroke;
if (transparencyGroup.group.isolated)
{
break;
}
}
return alpha;
}
PDFReal PDFPainter::getEffectiveFillingAlpha() const
{
PDFReal alpha = getGraphicState()->getAlphaFilling();
auto it = m_transparencyGroupDataStack.crbegin();
auto itEnd = m_transparencyGroupDataStack.crend();
for (; it != itEnd; ++it)
{
const PDFTransparencyGroupPainterData& transparencyGroup = *it;
alpha *= transparencyGroup.alphaFill;
if (transparencyGroup.group.isolated)
{
break;
}
}
return alpha;
}
bool PDFPainter::canSetBlendMode(BlendMode mode) const
{
// We will assume, that we can set blend mode, when
// all other blend modes on transparency stack are normal,
// or compatible. It should work.
Q_UNUSED(mode);
return std::all_of(m_transparencyGroupDataStack.cbegin(), m_transparencyGroupDataStack.cend(), [](const PDFTransparencyGroupPainterData& group) { return group.blendMode == BlendMode::Normal || group.blendMode == BlendMode::Compatible; });
}
} // namespace pdf

22
PdfForQtLib/sources/pdfpainter.h
View File

@ -30,6 +30,8 @@ namespace pdf
/// Processor, which processes PDF's page commands on the QPainter. It works with QPainter
/// and with transformation matrix, which translates page points to the device points.
/// Only basic transparency is supported, advanced transparency, such as transparency groups,
/// are not supported. Painter will try to emulate them so painting will not fail completely.
class PDFPainter : public PDFPageContentProcessor
{
public:
@ -60,6 +62,8 @@ protected:
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);
virtual void performEndTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup);
virtual bool isContentSuppressedByOC(PDFObjectReference ocgOrOcmd) override;
private:
@ -75,10 +79,28 @@ private:
/// Returns current brush (implementation)
QBrush getCurrentBrushImpl() const;
/// Returns effective stroking alpha from transparency groups and current graphic state
PDFReal getEffectiveStrokingAlpha() const;
/// Returns effective filling alpha from transparency groups and current graphic state
PDFReal getEffectiveFillingAlpha() const;
/// Returns true, if blend mode can be set according the transparency group stack
bool canSetBlendMode(BlendMode mode) const;
struct PDFTransparencyGroupPainterData
{
PDFTransparencyGroup group;
PDFReal alphaStroke = 1.0;
PDFReal alphaFill = 1.0;
BlendMode blendMode = BlendMode::Normal;
};
QPainter* m_painter;
PDFRenderer::Features m_features;
PDFCachedItem<QPen> m_currentPen;
PDFCachedItem<QBrush> m_currentBrush;
std::vector<PDFTransparencyGroupPainterData> m_transparencyGroupDataStack;
};
} // namespace pdf