Detailed Description

Implement this interface if you want to have your own custom method called during build and rendering of page layout model.

The primary use for this interface is to allow application code to abort build process.

It is possible to build page layout model for only a few pages at start of the document then abort process and render only what has been built already.

Note, however, that rendering results may not match what would be rendered for each page if process would have finished.

This technique may not work for every document or may fail completely.

See also: Aspose::Words::Layout::LayoutOptions::get_Callback

Examples

Shows how to track layout changes with a layout callback.

void PageLayoutCallback()
{
    auto doc = MakeObject<Document>();
    doc->get_BuiltInDocumentProperties()->set_Title(u"My Document");
 
    auto builder = MakeObject<DocumentBuilder>(doc);
    builder->Writeln(u"Hello world!");
 
    doc->get_LayoutOptions()->set_Callback(MakeObject<ExLayout::RenderPageLayoutCallback>());
    doc->UpdatePageLayout();
 
    doc->Save(ArtifactsDir + u"Layout.PageLayoutCallback.pdf");
}
 
class RenderPageLayoutCallback : public IPageLayoutCallback
{
public:
    void Notify(SharedPtr<PageLayoutCallbackArgs> a) override
    {
        switch (a->get_Event())
        {
        case PageLayoutEvent::PartReflowFinished:
            NotifyPartFinished(a);
            break;
 
        case PageLayoutEvent::ConversionFinished:
            NotifyConversionFinished(a);
            break;
 
        default:
            break;
        }
    }
 
    RenderPageLayoutCallback() : mNum(0)
    {
    }
 
private:
    int mNum;
 
    void NotifyPartFinished(SharedPtr<PageLayoutCallbackArgs> a)
    {
        std::cout << "Part at page " << (a->get_PageIndex() + 1) << " reflow." << std::endl;
        RenderPage(a, a->get_PageIndex());
    }
 
    void NotifyConversionFinished(SharedPtr<PageLayoutCallbackArgs> a)
    {
        std::cout << "Document \"" << a->get_Document()->get_BuiltInDocumentProperties()->get_Title() << "\" converted to page format." << std::endl;
    }
 
    void RenderPage(SharedPtr<PageLayoutCallbackArgs> a, int pageIndex)
    {
        auto saveOptions = MakeObject<ImageSaveOptions>(SaveFormat::Png);
        saveOptions->set_PageSet(MakeObject<PageSet>(pageIndex));
 
        {
            auto stream = MakeObject<System::IO::FileStream>(ArtifactsDir + String::Format(u"PageLayoutCallback.page-{0} {1}.png", pageIndex + 1, ++mNum),
                                                             System::IO::FileMode::Create);
            a->get_Document()->Save(stream, saveOptions);
        }
    }
};

#include <Aspose.Words.Cpp/Layout/IPageLayoutCallback.h>

Inheritance diagram for Aspose::Words::Layout::IPageLayoutCallback:

Public Member Functions
virtual const TypeInfo &	GetType () const override

virtual bool	Is (const TypeInfo &target) const override

virtual void	Notify (SharedPtr< PageLayoutCallbackArgs > args)=0
	This is called to notify of layout build and rendering progress. More...

Static Public Member Functions
static const TypeInfo &	Type ()

Member Function Documentation

◆ GetType()

virtual const System::TypeInfo& Aspose::Words::Layout::IPageLayoutCallback::GetType ( ) const

overridevirtual

Reimplemented from System::Object.

◆ Is()

virtual bool Aspose::Words::Layout::IPageLayoutCallback::Is ( const System::TypeInfo & target ) const

overridevirtual

Reimplemented from System::Object.

◆ Notify()

virtual void Aspose::Words::Layout::IPageLayoutCallback::Notify ( System::SharedPtr< Aspose::Words::Layout::PageLayoutCallbackArgs > args )

pure virtual

This is called to notify of layout build and rendering progress.

Exception when thrown by implementation aborts layout build process.

Parameters

args	An argument of the event.

Examples

Shows how to track layout changes with a layout callback.

void PageLayoutCallback()
{
    auto doc = MakeObject<Document>();
    doc->get_BuiltInDocumentProperties()->set_Title(u"My Document");
 
    auto builder = MakeObject<DocumentBuilder>(doc);
    builder->Writeln(u"Hello world!");
 
    doc->get_LayoutOptions()->set_Callback(MakeObject<ExLayout::RenderPageLayoutCallback>());
    doc->UpdatePageLayout();
 
    doc->Save(ArtifactsDir + u"Layout.PageLayoutCallback.pdf");
}
 
class RenderPageLayoutCallback : public IPageLayoutCallback
{
public:
    void Notify(SharedPtr<PageLayoutCallbackArgs> a) override
    {
        switch (a->get_Event())
        {
        case PageLayoutEvent::PartReflowFinished:
            NotifyPartFinished(a);
            break;
 
        case PageLayoutEvent::ConversionFinished:
            NotifyConversionFinished(a);
            break;
 
        default:
            break;
        }
    }
 
    RenderPageLayoutCallback() : mNum(0)
    {
    }
 
private:
    int mNum;
 
    void NotifyPartFinished(SharedPtr<PageLayoutCallbackArgs> a)
    {
        std::cout << "Part at page " << (a->get_PageIndex() + 1) << " reflow." << std::endl;
        RenderPage(a, a->get_PageIndex());
    }
 
    void NotifyConversionFinished(SharedPtr<PageLayoutCallbackArgs> a)
    {
        std::cout << "Document \"" << a->get_Document()->get_BuiltInDocumentProperties()->get_Title() << "\" converted to page format." << std::endl;
    }
 
    void RenderPage(SharedPtr<PageLayoutCallbackArgs> a, int pageIndex)
    {
        auto saveOptions = MakeObject<ImageSaveOptions>(SaveFormat::Png);
        saveOptions->set_PageSet(MakeObject<PageSet>(pageIndex));
 
        {
            auto stream = MakeObject<System::IO::FileStream>(ArtifactsDir + String::Format(u"PageLayoutCallback.page-{0} {1}.png", pageIndex + 1, ++mNum),
                                                             System::IO::FileMode::Create);
            a->get_Document()->Save(stream, saveOptions);
        }
    }
};

◆ Type()

static const System::TypeInfo& Aspose::Words::Layout::IPageLayoutCallback::Type ( )

static