Issue #10: Ability to cancel the operation

Pdf4QtLib/Pdf4QtLib.pro

@@ -142,6 +142,7 @@ HEADERS += \
     sources/pdfobjecteditorwidget.h \
     sources/pdfobjecteditorwidget_impl.h \
     sources/pdfobjectutils.h \
+    sources/pdfoperationcontrol.h \
     sources/pdfoptimizer.h \
     sources/pdfoptionalcontent.h \
     sources/pdfoutline.h \

Pdf4QtLib/sources/pdfcolorspaces.cpp

@@ -218,7 +218,8 @@ QImage PDFAbstractColorSpace::getImage(const PDFImageData& imageData,
                                        const PDFImageData& softMask,
                                        const PDFCMS* cms,
                                        RenderingIntent intent,
-                                       PDFRenderErrorReporter* reporter) const
+                                       PDFRenderErrorReporter* reporter,
+                                       const PDFOperationControl* operationControl) const
 {
     if (imageData.isValid())
     {
@@ -249,6 +250,12 @@ QImage PDFAbstractColorSpace::getImage(const PDFImageData& imageData,
 
                 auto transformPixelLine = [&](unsigned int i)
                 {
+                    // Is operation being cancelled?
+                    if (PDFOperationControl::isOperationCancelled(operationControl))
+                    {
+                        return;
+                    }
+
                     try
                     {
                         PDFBitReader reader(&imageData.getData(), imageData.getBitsPerComponent());
@@ -260,21 +267,27 @@ QImage PDFAbstractColorSpace::getImage(const PDFImageData& imageData,
 
                         std::vector<float> inputColors(imageWidth * componentCount, 0.0f);
                         auto itInputColor = inputColors.begin();
-                        for (unsigned int j = 0; j < imageData.getWidth(); ++j)
-                        {
-                            for (unsigned int k = 0; k < componentCount; ++k)
-                            {
-                                PDFReal value = reader.read();
 
-                                // Interpolate value, if it is not empty
+                        if (!decode.empty())
-                                if (!decode.empty())
+                        {
+                            // Interpolate value
+                            for (unsigned int j = 0; j < imageData.getWidth(); ++j)
+                            {
+                                for (unsigned int k = 0; k < componentCount; ++k)
                                 {
+                                    PDFReal value = reader.read();
                                     *itInputColor++ = interpolate(value, 0.0, max, decode[2 * k], decode[2 * k + 1]);
                                 }
-                                else
+                            }
-                                {
+                        }
-                                    *itInputColor++ = value * coefficient;
+                        else
-                                }
+                        {
+                            // Just read all values and multiply them with coefficient
+                            const unsigned int pixelCount = imageData.getWidth() * componentCount;
+                            for (unsigned int j = 0; j < pixelCount; ++j)
+                            {
+                                PDFReal value = reader.read();
+                                *itInputColor++ = value * coefficient;
                             }
                         }
 
@@ -334,6 +347,12 @@ QImage PDFAbstractColorSpace::getImage(const PDFImageData& imageData,
 
                 auto transformPixelLine = [&](unsigned int i)
                 {
+                    // Is operation being cancelled?
+                    if (PDFOperationControl::isOperationCancelled(operationControl))
+                    {
+                        return;
+                    }
+
                     try
                     {
                         PDFBitReader reader(&imageData.getData(), imageData.getBitsPerComponent());
@@ -1872,7 +1891,8 @@ QImage PDFIndexedColorSpace::getImage(const PDFImageData& imageData,
                                       const PDFImageData& softMask,
                                       const PDFCMS* cms,
                                       RenderingIntent intent,
-                                      PDFRenderErrorReporter* reporter) const
+                                      PDFRenderErrorReporter* reporter,
+                                      const PDFOperationControl* operationControl) const
 {
     if (imageData.isValid())
     {
@@ -1898,6 +1918,12 @@ QImage PDFIndexedColorSpace::getImage(const PDFImageData& imageData,
 
                 for (unsigned int i = 0, rowCount = imageData.getHeight(); i < rowCount; ++i)
                 {
+                    // Is operation being cancelled?
+                    if (PDFOperationControl::isOperationCancelled(operationControl))
+                    {
+                        throw PDFRendererException(RenderErrorType::Error, PDFTranslationContext::tr("Operation cancelled!"));
+                    }
+
                     reader.seek(i * imageData.getStride());
                     unsigned char* outputLine = image.scanLine(i);
 
@@ -1945,6 +1971,12 @@ QImage PDFIndexedColorSpace::getImage(const PDFImageData& imageData,
 
                 for (unsigned int i = 0, rowCount = imageData.getHeight(); i < rowCount; ++i)
                 {
+                    // Is operation being cancelled?
+                    if (PDFOperationControl::isOperationCancelled(operationControl))
+                    {
+                        throw PDFRendererException(RenderErrorType::Error, PDFTranslationContext::tr("Operation cancelled!"));
+                    }
+
                     reader.seek(i * imageData.getStride());
                     unsigned char* outputLine = image.scanLine(i);
                     unsigned char* alphaLine = alphaMask.scanLine(i);

Pdf4QtLib/sources/pdfcolorspaces.h

@@ -21,6 +21,7 @@
 #include "pdfflatarray.h"
 #include "pdffunction.h"
 #include "pdfutils.h"
+#include "pdfoperationcontrol.h"
 
 #include <QColor>
 #include <QImage>
@@ -365,11 +366,13 @@ public:
     /// \param cms Color management system
     /// \param intent Rendering intent
     /// \param reporter Error reporter
+    /// \param operationControl Operation control
     virtual QImage getImage(const PDFImageData& imageData,
                             const PDFImageData& softMask,
                             const PDFCMS* cms,
                             RenderingIntent intent,
-                            PDFRenderErrorReporter* reporter) const;
+                            PDFRenderErrorReporter* reporter,
+                            const PDFOperationControl* operationControl) const;
 
     /// Fills RGB buffer using colors from \p colors. Colors are transformed
     /// by this color space (or color management system is used). Buffer
@@ -755,7 +758,8 @@ public:
                             const PDFImageData& softMask,
                             const PDFCMS* cms,
                             RenderingIntent intent,
-                            PDFRenderErrorReporter* reporter) const override;
+                            PDFRenderErrorReporter* reporter,
+                            const PDFOperationControl* operationControl) const override;
 
     /// Creates indexed color space from provided values.
     /// \param colorSpaceDictionary Color space dictionary

Pdf4QtLib/sources/pdfcompiler.cpp

@@ -64,11 +64,12 @@ void PDFAsynchronousPageCompilerWorkerThread::run()
                     auto proxy = m_compiler->getProxy();
                     proxy->getFontCache()->setCacheShrinkEnabled(this, false);
 
-                    auto compilePage = [proxy](PDFAsynchronousPageCompiler::CompileTask& task) -> PDFPrecompiledPage
+                    auto compilePage = [this, proxy](PDFAsynchronousPageCompiler::CompileTask& task) -> PDFPrecompiledPage
                     {
                         PDFPrecompiledPage compiledPage;
                         PDFCMSPointer cms = proxy->getCMSManager()->getCurrentCMS();
                         PDFRenderer renderer(proxy->getDocument(), proxy->getFontCache(), cms.data(), proxy->getOptionalContentActivity(), proxy->getFeatures(), proxy->getMeshQualitySettings());
+                        renderer.setOperationControl(m_compiler);
                         renderer.compile(&task.precompiledPage, task.pageIndex);
                         task.finished = true;
                         return compiledPage;
@@ -122,6 +123,11 @@ PDFAsynchronousPageCompiler::~PDFAsynchronousPageCompiler()
     stop(true);
 }
 
+bool PDFAsynchronousPageCompiler::isOperationCancelled() const
+{
+    return m_state == State::Stopping;
+}
+
 void PDFAsynchronousPageCompiler::start()
 {
     switch (m_state)

Pdf4QtLib/sources/pdfcompiler.h

@@ -54,7 +54,7 @@ private:
 /// Asynchronous page compiler compiles pages asynchronously, and stores them in the
 /// cache. Cache size can be set. This object is designed to cooperate with
 /// draw widget proxy.
-class PDFAsynchronousPageCompiler : public QObject
+class PDFAsynchronousPageCompiler : public QObject, public PDFOperationControl
 {
     Q_OBJECT
 
@@ -106,6 +106,9 @@ public:
     /// \param compile Compile the page, if it is not found in the cache
     const PDFPrecompiledPage* getCompiledPage(PDFInteger pageIndex, bool compile);
 
+    /// Is operation being cancelled?
+    virtual bool isOperationCancelled() const override;
+
 signals:
     void pageImageChanged(bool all, const std::vector<pdf::PDFInteger>& pages);
     void renderingError(pdf::PDFInteger pageIndex, const QList<pdf::PDFRenderError>& errors);

Pdf4QtLib/sources/pdfimage.cpp

@@ -745,12 +745,14 @@ PDFImage PDFImage::createImage(const PDFDocument* document,
     return image;
 }
 
-QImage PDFImage::getImage(const PDFCMS* cms, PDFRenderErrorReporter* reporter) const
+QImage PDFImage::getImage(const PDFCMS* cms,
+                          PDFRenderErrorReporter* reporter,
+                          const PDFOperationControl* operationControl) const
 {
     const bool isImageMask = m_imageData.getMaskingType() == PDFImageData::MaskingType::ImageMask;
     if (m_colorSpace && !isImageMask)
     {
-        return m_colorSpace->getImage(m_imageData, m_softMask, cms, m_renderingIntent, reporter);
+        return m_colorSpace->getImage(m_imageData, m_softMask, cms, m_renderingIntent, reporter, operationControl);
     }
     else if (isImageMask)
     {

Pdf4QtLib/sources/pdfimage.h

@@ -20,6 +20,7 @@
 
 #include "pdfobject.h"
 #include "pdfcolorspaces.h"
+#include "pdfoperationcontrol.h"
 
 #include <QByteArray>
 
@@ -73,7 +74,9 @@ public:
                                 PDFRenderErrorReporter* errorReporter);
 
     /// Returns image transformed from image data and color space
-    QImage getImage(const PDFCMS* cms, PDFRenderErrorReporter* reporter) const;
+    QImage getImage(const PDFCMS* cms,
+                    PDFRenderErrorReporter* reporter,
+                    const PDFOperationControl* operationControl) const;
 
     /// Returns rendering intent of the image
     RenderingIntent getRenderingIntent() const { return m_renderingIntent; }

Pdf4QtLib/sources/pdfoperationcontrol.h

@@ -0,0 +1,51 @@
+//    Copyright (C) 2022 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
+//    with the written consent of the copyright owner, 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 PDFOPERATIONCONTROL_H
+#define PDFOPERATIONCONTROL_H
+
+#include "pdfglobal.h"
+
+namespace pdf
+{
+
+/// Operation controller. This interface can be used for
+/// long operation interruption - so operation is cancelled
+/// immediately.
+class PDFOperationControl
+{
+public:
+    constexpr PDFOperationControl() = default;
+    virtual ~PDFOperationControl() = default;
+
+    /// Returns true, if operation is cancelled and
+    /// processed data should be abandoned. It is safe
+    /// to call this function in another thread, implementators
+    /// of this interface must ensure thread safety.
+    /// If this function returns true, it must return true until
+    /// all operations are stopped and correctly handled.
+    virtual bool isOperationCancelled() const = 0;
+
+    static inline bool isOperationCancelled(const PDFOperationControl* operationControl)
+    {
+        return operationControl && operationControl->isOperationCancelled();
+    }
+};
+
+}
+
+#endif // PDFOPERATIONCONTROL_H

Pdf4QtLib/sources/pdfpagecontentprocessor.cpp

@@ -232,6 +232,7 @@ PDFPageContentProcessor::PDFPageContentProcessor(const PDFPage* page,
     m_fontCache(fontCache),
     m_CMS(CMS),
     m_optionalContentActivity(optionalContentActivity),
+    m_operationControl(nullptr),
     m_colorSpaceDictionary(nullptr),
     m_fontDictionary(nullptr),
     m_xobjectDictionary(nullptr),
@@ -311,6 +312,12 @@ QList<PDFRenderError> PDFPageContentProcessor::processContents()
 
         for (size_t i = 0; i < count; ++i)
         {
+            if (isProcessingCancelled())
+            {
+                // Break, if processing is being cancelled
+                break;
+            }
+
             const PDFObject& streamObject = m_document->getObject(array->getItem(i));
             if (streamObject.isStream())
             {
@@ -523,7 +530,7 @@ void PDFPageContentProcessor::processContent(const QByteArray& content)
 {
     PDFLexicalAnalyzer parser(content.constBegin(), content.constEnd());
 
-    while (!parser.isAtEnd())
+    while (!parser.isAtEnd() && !isProcessingCancelled())
     {
         bool tokenFetched = false;
         PDFInteger oldParserPosition = parser.pos();
@@ -844,7 +851,7 @@ void PDFPageContentProcessor::processPathPainting(const QPainterPath& path, bool
 
                         if (!performPathPaintingUsingShading(path, false, true, shadingPattern))
                         {
-                            PDFMesh mesh = shadingPattern->createMesh(settings, m_CMS, m_graphicState.getRenderingIntent(), this);
+                            PDFMesh mesh = shadingPattern->createMesh(settings, m_CMS, m_graphicState.getRenderingIntent(), this, m_operationControl);
 
                             // Now, merge the current path to the mesh clipping path
                             QPainterPath boundingPath = mesh.getBoundingPath();
@@ -961,7 +968,7 @@ void PDFPageContentProcessor::processPathPainting(const QPainterPath& path, bool
 
                         if (!performPathPaintingUsingShading(strokedPath, true, false, shadingPattern))
                         {
-                            PDFMesh mesh = shadingPattern->createMesh(settings, m_CMS, m_graphicState.getRenderingIntent(), this);
+                            PDFMesh mesh = shadingPattern->createMesh(settings, m_CMS, m_graphicState.getRenderingIntent(), this, m_operationControl);
 
                             QPainterPath boundingPath = mesh.getBoundingPath();
                             if (boundingPath.isEmpty())
@@ -1095,6 +1102,16 @@ void PDFPageContentProcessor::processTillingPatternPainting(const PDFTilingPatte
 
             performClipping(boundingPath, boundingPath.fillRule());
             processContent(content);
+
+            if (isProcessingCancelled())
+            {
+                break;
+            }
+        }
+
+        if (isProcessingCancelled())
+        {
+            break;
         }
     }
 }
@@ -1831,6 +1848,16 @@ void PDFPageContentProcessor::finishMarkedContent()
     }
 }
 
+void PDFPageContentProcessor::setOperationControl(const PDFOperationControl* newOperationControl)
+{
+    m_operationControl = newOperationControl;
+}
+
+bool PDFPageContentProcessor::isProcessingCancelled() const
+{
+    return m_operationControl && m_operationControl->isOperationCancelled();
+}
+
 void PDFPageContentProcessor::reportRenderErrorOnce(RenderErrorType type, QString message)
 {
     if (!m_onceReportedErrors.count(message))
@@ -2952,24 +2979,27 @@ void PDFPageContentProcessor::paintXObjectImage(const PDFStream* stream)
 
     if (!performOriginalImagePainting(pdfImage))
     {
-        QImage image = pdfImage.getImage(m_CMS, this);
+        QImage image = pdfImage.getImage(m_CMS, this, m_operationControl);
 
-        if (image.format() == QImage::Format_Alpha8)
+        if (!isProcessingCancelled())
         {
-            QSize size = image.size();
+            if (image.format() == QImage::Format_Alpha8)
-            QImage unmaskedImage(size, QImage::Format_ARGB32_Premultiplied);
+            {
-            unmaskedImage.fill(m_graphicState.getFillColor());
+                QSize size = image.size();
-            unmaskedImage.setAlphaChannel(image);
+                QImage unmaskedImage(size, QImage::Format_ARGB32_Premultiplied);
-            image = qMove(unmaskedImage);
+                unmaskedImage.fill(m_graphicState.getFillColor());
-        }
+                unmaskedImage.setAlphaChannel(image);
+                image = qMove(unmaskedImage);
+            }
 
-        if (!image.isNull())
+            if (!image.isNull())
-        {
+            {
-            performImagePainting(image);
+                performImagePainting(image);
-        }
+            }
-        else
+            else
-        {
+            {
-            throw PDFRendererException(RenderErrorType::Error, PDFTranslationContext::tr("Can't decode the image."));
+                throw PDFRendererException(RenderErrorType::Error, PDFTranslationContext::tr("Can't decode the image."));
+            }
         }
     }
 }

Pdf4QtLib/sources/pdfpagecontentprocessor.h

@@ -26,6 +26,7 @@
 #include "pdfmeshqualitysettings.h"
 #include "pdfblendfunction.h"
 #include "pdftextlayout.h"
+#include "pdfoperationcontrol.h"
 
 #include <QMatrix>
 #include <QPainterPath>
@@ -237,6 +238,15 @@ public:
     /// or true, if it is suppressed.
     virtual bool isContentSuppressedByOC(PDFObjectReference ocgOrOcmd);
 
+    /// Sets operation control object which can decide, if operation should
+    /// be cancelled. If this is the case, page content processor stops
+    /// processing page contents.
+    /// \param newOperationControl Operation control object
+    void setOperationControl(const PDFOperationControl* newOperationControl);
+
+    /// Returns true, if page content processing is being cancelled
+    bool isProcessingCancelled() const;
+
 protected:
 
     struct PDFTransparencyGroup
@@ -1009,6 +1019,7 @@ private:
     const PDFFontCache* m_fontCache;
     const PDFCMS* m_CMS;
     const PDFOptionalContentActivity* m_optionalContentActivity;
+    const PDFOperationControl* m_operationControl;
     const PDFDictionary* m_colorSpaceDictionary;
     const PDFDictionary* m_fontDictionary;
     const PDFDictionary* m_xobjectDictionary;

Pdf4QtLib/sources/pdfpattern.cpp

@@ -608,10 +608,16 @@ ShadingType PDFFunctionShading::getShadingType() const
     return ShadingType::Function;
 }
 
-PDFMesh PDFFunctionShading::createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const
+PDFMesh PDFFunctionShading::createMesh(const PDFMeshQualitySettings& settings,
+                                       const PDFCMS* cms,
+                                       RenderingIntent intent,
+                                       PDFRenderErrorReporter* reporter,
+                                       const PDFOperationControl* operationControl) const
 {
     PDFMesh mesh;
 
+    Q_UNUSED(operationControl);
+
     QMatrix patternSpaceToDeviceSpaceMatrix = getPatternSpaceToDeviceSpaceMatrix(settings);
     QMatrix domainToDeviceSpaceMatrix = m_domainToTargetTransform * patternSpaceToDeviceSpaceMatrix;
     QLineF topLine(m_domain.topLeft(), m_domain.topRight());
@@ -916,10 +922,16 @@ PDFShadingSampler* PDFFunctionShading::createSampler(QMatrix userSpaceToDeviceSp
     return new PDFFunctionShadingSampler(this, userSpaceToDeviceSpaceMatrix);
 }
 
-PDFMesh PDFAxialShading::createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const
+PDFMesh PDFAxialShading::createMesh(const PDFMeshQualitySettings& settings,
+                                    const PDFCMS* cms,
+                                    RenderingIntent intent,
+                                    PDFRenderErrorReporter* reporter,
+                                    const PDFOperationControl* operationControl) const
 {
     PDFMesh mesh;
 
+    Q_UNUSED(operationControl);
+
     QMatrix patternSpaceToDeviceSpaceMatrix = getPatternSpaceToDeviceSpaceMatrix(settings);
     QPointF p1 = patternSpaceToDeviceSpaceMatrix.map(m_startPoint);
     QPointF p2 = patternSpaceToDeviceSpaceMatrix.map(m_endPoint);
@@ -1423,10 +1435,16 @@ ShadingType PDFRadialShading::getShadingType() const
     return ShadingType::Radial;
 }
 
-PDFMesh PDFRadialShading::createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const
+PDFMesh PDFRadialShading::createMesh(const PDFMeshQualitySettings& settings,
+                                     const PDFCMS* cms,
+                                     RenderingIntent intent,
+                                     PDFRenderErrorReporter* reporter,
+                                     const PDFOperationControl* operationControl) const
 {
     PDFMesh mesh;
 
+    Q_UNUSED(operationControl);
+
     QMatrix patternSpaceToDeviceSpaceMatrix = getPatternSpaceToDeviceSpaceMatrix(settings);
     QPointF p1 = patternSpaceToDeviceSpaceMatrix.map(m_startPoint);
     QPointF p2 = patternSpaceToDeviceSpaceMatrix.map(m_endPoint);
@@ -2239,10 +2257,16 @@ bool PDFFreeFormGouradTriangleShading::processTriangles(InitializeFunction initi
     return true;
 }
 
-PDFMesh PDFFreeFormGouradTriangleShading::createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const
+PDFMesh PDFFreeFormGouradTriangleShading::createMesh(const PDFMeshQualitySettings& settings,
+                                                     const PDFCMS* cms,
+                                                     RenderingIntent intent,
+                                                     PDFRenderErrorReporter* reporter,
+                                                     const PDFOperationControl* operationControl) const
 {
     PDFMesh mesh;
 
+    Q_UNUSED(operationControl);
+
     auto addTriangle = [this, &settings, &mesh, cms, intent, reporter](const VertexData* va, const VertexData* vb, const VertexData* vc)
     {
         const uint32_t via = va->index;
@@ -2401,10 +2425,16 @@ bool PDFLatticeFormGouradTriangleShading::processTriangles(InitializeFunction in
     return true;
 }
 
-PDFMesh PDFLatticeFormGouradTriangleShading::createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const
+PDFMesh PDFLatticeFormGouradTriangleShading::createMesh(const PDFMeshQualitySettings& settings,
+                                                        const PDFCMS* cms,
+                                                        RenderingIntent intent,
+                                                        PDFRenderErrorReporter* reporter,
+                                                        const PDFOperationControl* operationControl) const
 {
     PDFMesh mesh;
 
+    Q_UNUSED(operationControl);
+
     auto addTriangle = [this, &settings, &mesh, cms, intent, reporter](const VertexData* va, const VertexData* vb, const VertexData* vc)
     {
         const uint32_t via = va->index;
@@ -3071,7 +3101,11 @@ PDFTensorPatches PDFTensorProductPatchShading::createPatches(QMatrix userSpaceTo
     return patches;
 }
 
-PDFMesh PDFTensorProductPatchShading::createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const
+PDFMesh PDFTensorProductPatchShading::createMesh(const PDFMeshQualitySettings& settings,
+                                                 const PDFCMS* cms,
+                                                 RenderingIntent intent,
+                                                 PDFRenderErrorReporter* reporter,
+                                                 const PDFOperationControl* operationControl) const
 {
     PDFMesh mesh;
 
@@ -3082,7 +3116,7 @@ PDFMesh PDFTensorProductPatchShading::createMesh(const PDFMeshQualitySettings& s
         throw PDFException(PDFTranslationContext::tr("Invalid data in tensor product patch shading."));
     }
 
-    fillMesh(mesh, getPatternSpaceToDeviceSpaceMatrix(settings.userSpaceToDeviceSpaceMatrix), settings, patches, cms, intent, reporter);
+    fillMesh(mesh, getPatternSpaceToDeviceSpaceMatrix(settings.userSpaceToDeviceSpaceMatrix), settings, patches, cms, intent, reporter, operationControl);
     return mesh;
 }
 
@@ -3228,7 +3262,8 @@ void PDFTensorProductPatchShadingBase::fillMesh(PDFMesh& mesh,
                                                 const PDFCMS* cms,
                                                 RenderingIntent intent,
                                                 PDFRenderErrorReporter* reporter,
-                                                bool fastAlgorithm) const
+                                                bool fastAlgorithm,
+                                                const PDFOperationControl* operationControl) const
 {
     // We implement algorithm similar to Ruppert's algorithm (see https://en.wikipedia.org/wiki/Ruppert%27s_algorithm), but
     // we do not need a mesh for FEM calculation, so we do not care about quality of the triangles (we can have triangles with
@@ -3301,6 +3336,13 @@ void PDFTensorProductPatchShadingBase::fillMesh(PDFMesh& mesh,
 
     while (!unfinishedTriangles.empty())
     {
+        // Mesh generation is cancelled
+        if (PDFOperationControl::isOperationCancelled(operationControl))
+        {
+            mesh = PDFMesh();
+            return;
+        }
+
         Triangle triangle = unfinishedTriangles.back();
         unfinishedTriangles.pop_back();
 
@@ -3417,12 +3459,13 @@ void PDFTensorProductPatchShadingBase::fillMesh(PDFMesh& mesh,
                                                 const PDFTensorPatches& patches,
                                                 const PDFCMS* cms,
                                                 RenderingIntent intent,
-                                                PDFRenderErrorReporter* reporter) const
+                                                PDFRenderErrorReporter* reporter,
+                                                const PDFOperationControl* operationControl) const
 {
     const bool fastAlgorithm = patches.size() > 16;
     for (const auto& patch : patches)
     {
-        fillMesh(mesh, settings, patch, cms, intent, reporter, fastAlgorithm);
+        fillMesh(mesh, settings, patch, cms, intent, reporter, fastAlgorithm, operationControl);
     }
 
     // Create bounding path
@@ -3655,7 +3698,11 @@ PDFTensorPatches PDFCoonsPatchShading::createPatches(QMatrix userSpaceToDeviceSp
     return patches;
 }
 
-PDFMesh PDFCoonsPatchShading::createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const
+PDFMesh PDFCoonsPatchShading::createMesh(const PDFMeshQualitySettings& settings,
+                                         const PDFCMS* cms,
+                                         RenderingIntent intent,
+                                         PDFRenderErrorReporter* reporter,
+                                         const PDFOperationControl* operationControl) const
 {
     PDFMesh mesh;
     PDFTensorPatches patches = createPatches(settings.userSpaceToDeviceSpaceMatrix, true);
@@ -3665,7 +3712,7 @@ PDFMesh PDFCoonsPatchShading::createMesh(const PDFMeshQualitySettings& settings,
         throw PDFException(PDFTranslationContext::tr("Invalid data in coons patch shading."));
     }
 
-    fillMesh(mesh, getPatternSpaceToDeviceSpaceMatrix(settings), settings, patches, cms, intent, reporter);
+    fillMesh(mesh, getPatternSpaceToDeviceSpaceMatrix(settings), settings, patches, cms, intent, reporter, operationControl);
     return mesh;
 }
 

Pdf4QtLib/sources/pdfpattern.h

@@ -311,7 +311,11 @@ public:
     /// \param cms Color management system
     /// \param intent Rendering intent
     /// \param reporter Error reporter
-    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const = 0;
+    /// \param operationControl Operation control
+    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings,
+                               const PDFCMS* cms, RenderingIntent intent,
+                               PDFRenderErrorReporter* reporter,
+                               const PDFOperationControl* operationControl) const = 0;
 
     /// Returns patterns graphic state. This state must be applied before
     /// the shading pattern is painted to the target device.
@@ -386,7 +390,11 @@ public:
     explicit PDFFunctionShading() = default;
 
     virtual ShadingType getShadingType() const override;
-    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings,
+                               const PDFCMS* cms,
+                               RenderingIntent intent,
+                               PDFRenderErrorReporter* reporter,
+                               const PDFOperationControl* operationControl) const override;
     virtual PDFShadingSampler* createSampler(QMatrix userSpaceToDeviceSpaceMatrix) const override;
 
     const QRectF& getDomain() const { return m_domain; }
@@ -407,7 +415,11 @@ public:
     explicit PDFAxialShading() = default;
 
     virtual ShadingType getShadingType() const override;
-    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings,
+                               const PDFCMS* cms,
+                               RenderingIntent intent,
+                               PDFRenderErrorReporter* reporter,
+                               const PDFOperationControl* operationControl) const override;
     virtual PDFShadingSampler* createSampler(QMatrix userSpaceToDeviceSpaceMatrix) const override;
 
 private:
@@ -420,7 +432,11 @@ public:
     explicit PDFRadialShading() = default;
 
     virtual ShadingType getShadingType() const override;
-    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings,
+                               const PDFCMS* cms,
+                               RenderingIntent intent,
+                               PDFRenderErrorReporter* reporter,
+                               const PDFOperationControl* operationControl) const override;
     virtual PDFShadingSampler* createSampler(QMatrix userSpaceToDeviceSpaceMatrix) const override;
 
     PDFReal getR0() const { return m_r0; }
@@ -480,7 +496,11 @@ public:
     explicit PDFFreeFormGouradTriangleShading() = default;
 
     virtual ShadingType getShadingType() const override;
-    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings,
+                               const PDFCMS* cms,
+                               RenderingIntent intent,
+                               PDFRenderErrorReporter* reporter,
+                               const PDFOperationControl* operationControl) const override;
     virtual PDFShadingSampler* createSampler(QMatrix userSpaceToDeviceSpaceMatrix) const override;
 
 private:
@@ -509,7 +529,11 @@ public:
     explicit PDFLatticeFormGouradTriangleShading() = default;
 
     virtual ShadingType getShadingType() const override;
-    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings,
+                               const PDFCMS* cms,
+                               RenderingIntent intent,
+                               PDFRenderErrorReporter* reporter,
+                               const PDFOperationControl* operationControl) const override;
     virtual PDFShadingSampler* createSampler(QMatrix userSpaceToDeviceSpaceMatrix) const override;
 
 private:
@@ -675,8 +699,8 @@ public:
 protected:
     struct Triangle;
 
-    void fillMesh(PDFMesh& mesh, const PDFMeshQualitySettings& settings, const PDFTensorPatch& patch, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter, bool fastAlgorithm) const;
+    void fillMesh(PDFMesh& mesh, const PDFMeshQualitySettings& settings, const PDFTensorPatch& patch, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter, bool fastAlgorithm, const PDFOperationControl* operationControl) const;
-    void fillMesh(PDFMesh& mesh, const QMatrix& patternSpaceToDeviceSpaceMatrix, const PDFMeshQualitySettings& settings, const PDFTensorPatches& patches, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const;
+    void fillMesh(PDFMesh& mesh, const QMatrix& patternSpaceToDeviceSpaceMatrix, const PDFMeshQualitySettings& settings, const PDFTensorPatches& patches, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter, const PDFOperationControl* operationControl) const;
     static void addTriangle(std::vector<Triangle>& triangles, const PDFTensorPatch& patch, std::array<QPointF, 3> uvCoordinates);
 
 private:
@@ -689,7 +713,11 @@ public:
     explicit PDFCoonsPatchShading() = default;
 
     virtual ShadingType getShadingType() const override;
-    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings,
+                               const PDFCMS* cms,
+                               RenderingIntent intent,
+                               PDFRenderErrorReporter* reporter,
+                               const PDFOperationControl* operationControl) const override;
     virtual PDFTensorPatches createPatches(QMatrix userSpaceToDeviceSpaceMatrix, bool transformColor) const override;
 
 private:
@@ -702,7 +730,11 @@ public:
     explicit PDFTensorProductPatchShading() = default;
 
     virtual ShadingType getShadingType() const override;
-    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings, const PDFCMS* cms, RenderingIntent intent, PDFRenderErrorReporter* reporter) const override;
+    virtual PDFMesh createMesh(const PDFMeshQualitySettings& settings,
+                               const PDFCMS* cms,
+                               RenderingIntent intent,
+                               PDFRenderErrorReporter* reporter,
+                               const PDFOperationControl* operationControl) const override;
     virtual PDFTensorPatches createPatches(QMatrix userSpaceToDeviceSpaceMatrix, bool transformColor) const override;
 
 private:

Pdf4QtLib/sources/pdfrenderer.cpp

@@ -43,6 +43,7 @@ PDFRenderer::PDFRenderer(const PDFDocument* document,
     m_fontCache(fontCache),
     m_cms(cms),
     m_optionalContentActivity(optionalContentActivity),
+    m_operationControl(nullptr),
     m_features(features),
     m_meshQualitySettings(meshQualitySettings)
 {
@@ -107,6 +108,16 @@ QMatrix PDFRenderer::createMediaBoxToDevicePointMatrix(const QRectF& mediaBox,
     return matrix;
 }
 
+const PDFOperationControl* PDFRenderer::getOperationControl() const
+{
+    return m_operationControl;
+}
+
+void PDFRenderer::setOperationControl(const PDFOperationControl* newOperationControl)
+{
+    m_operationControl = newOperationControl;
+}
+
 QList<PDFRenderError> PDFRenderer::render(QPainter* painter, const QRectF& rectangle, size_t pageIndex) const
 {
     const PDFCatalog* catalog = m_document->getCatalog();
@@ -122,6 +133,7 @@ QList<PDFRenderError> PDFRenderer::render(QPainter* painter, const QRectF& recta
     QMatrix matrix = createPagePointToDevicePointMatrix(page, rectangle);
 
     PDFPainter processor(painter, m_features, matrix, page, m_document, m_fontCache, m_cms, m_optionalContentActivity, m_meshQualitySettings);
+    processor.setOperationControl(m_operationControl);
     return processor.processContents();
 }
 
@@ -138,6 +150,7 @@ QList<PDFRenderError> PDFRenderer::render(QPainter* painter, const QMatrix& matr
     Q_ASSERT(page);
 
     PDFPainter processor(painter, m_features, matrix, page, m_document, m_fontCache, m_cms, m_optionalContentActivity, m_meshQualitySettings);
+    processor.setOperationControl(m_operationControl);
     return processor.processContents();
 }
 
@@ -158,6 +171,7 @@ void PDFRenderer::compile(PDFPrecompiledPage* precompiledPage, size_t pageIndex)
     timer.start();
 
     PDFPrecompiledPageGenerator generator(precompiledPage, m_features, page, m_document, m_fontCache, m_cms, m_optionalContentActivity, m_meshQualitySettings);
+    generator.setOperationControl(m_operationControl);
     QList<PDFRenderError> errors = generator.processContents();
 
     if (m_features.testFlag(InvertColors))

Pdf4QtLib/sources/pdfrenderer.h

@@ -20,6 +20,7 @@
 
 #include "pdfpage.h"
 #include "pdfexception.h"
+#include "pdfoperationcontrol.h"
 #include "pdfmeshqualitysettings.h"
 
 #include <QMutex>
@@ -113,11 +114,15 @@ public:
     /// Returns default renderer features
     static constexpr Features getDefaultFeatures() { return Features(Antialiasing | TextAntialiasing | ClipToCropBox | DisplayAnnotations); }
 
+    const PDFOperationControl* getOperationControl() const;
+    void setOperationControl(const PDFOperationControl* newOperationControl);
+
 private:
     const PDFDocument* m_document;
     const PDFFontCache* m_fontCache;
     const PDFCMS* m_cms;
     const PDFOptionalContentActivity* m_optionalContentActivity;
+    const PDFOperationControl* m_operationControl;
     Features m_features;
     PDFMeshQualitySettings m_meshQualitySettings;
 };

Pdf4QtViewerPlugins/ObjectInspectorPlugin/objectviewerwidget.cpp

@@ -228,7 +228,7 @@ void ObjectViewerWidget::updateUi()
 
                 pdf::PDFRenderErrorReporterDummy dummyErrorReporter;
                 pdf::PDFImage pdfImage = pdf::PDFImage::createImage(m_document, stream, qMove(colorSpace), false, pdf::RenderingIntent::Perceptual, &dummyErrorReporter);
-                QImage image = pdfImage.getImage(m_cms, &dummyErrorReporter);
+                QImage image = pdfImage.getImage(m_cms, &dummyErrorReporter, nullptr);
                 ui->stackedWidget->setCurrentWidget(ui->imageBrowserPage);
                 ui->imageBrowser->setPixmap(QPixmap::fromImage(image));