Working with Transparency | C++

Set Opacity Mask

Set Opacity Mask Object

It is possible to set opacity mask on an XPS document. Aspose.Page for C++ can be used to create/read an XPS document and set Opacity mask on such documents. The API uses image as an opacity mask where the Alpha component of each pixel is used to apply over underlying fill. The resultant XPS document will show slanting gradient stripes as present over source image file. To set the opacity mask on an XPS document, the following steps can be used.

1. Create a new object of XpsDocument class
2. Add a canvas to the document object using the XpsCanvas class
3. Create an object XpsPath class with required parameters
4. Set the opacity mask on the path
5. Create an XpsImageBrush class object
6. Save the document to disc using Save method

For complete examples and data files, please go to https://github.com/aspose-page/Aspose.Page-for-C
// Create new XPS Document
System::SharedPtr<XpsDocument> doc = System::MakeObject<XpsDocument>();
//Add Canvas to XpsDocument instance
System::SharedPtr<XpsCanvas> canvas = doc->AddCanvas();
// Rectangle with opacity masked by ImageBrush
System::SharedPtr<XpsPath> path = canvas->AddPath(doc->CreatePathGeometry(u"M 10,180 L 228,180 228,285 10,285"));
path->set_Fill(doc->CreateSolidColorBrush(doc->CreateColor(1.0f, 0.0f, 0.0f)));
path->set_OpacityMask(doc->CreateImageBrush(dataDir() + u"R08SY_NN.tif", System::Drawing::RectangleF(0.f, 0.f, 128.f, 192.f), System::Drawing::RectangleF(0.f, 0.f, 64.f, 96.f)));
(System::DynamicCast<Aspose::Page::Xps::XpsModel::XpsImageBrush>(path->get_OpacityMask()))->set_TileMode(Aspose::Page::Xps::XpsModel::XpsTileMode::Tile);
// Save resultant XPS document
doc->Save(outDir() + u"OpacityMask_out.xps");

Add Transparent Object inside XPS Document

Add Transparent Object

Aspose.Page for C++ lets you add transparent objects to an XPS document in your applications. The XpsPath class is used to achieve this using simple code. In order to add a transparent object to the XPS document, the following steps can be used.

1. Create a new object using the XpsDocument class
2. Create an XpsPath object with required parameters
3. Set rendering transformation information for the path
4. Use the set_Opacity method to specify the opacity value
5. Save the XPS document using the Save method.

For complete examples and data files, please go to https://github.com/aspose-page/Aspose.Page-for-C
// Create new XPS Document
auto doc = System::MakeObject<XpsDocument>();

// Just to demonstrate transparency
doc->AddPath(doc->CreatePathGeometry(u"M120,0 H400 v1000 H120"))->set_Fill(doc->CreateSolidColorBrush(System::Drawing::Color::get_Gray()));
doc->AddPath(doc->CreatePathGeometry(u"M300,120 h600 V420 h-600"))->set_Fill(doc->CreateSolidColorBrush(System::Drawing::Color::get_Gray()));

// Create path with closed rectangle geometry
System::SharedPtr<XpsPath> path1 = doc->CreatePath(doc->CreatePathGeometry(u"M20,20 h200 v200 h-200 z"));
// Set blue solid brush to fill path1
path1->set_Fill(doc->CreateSolidColorBrush(System::Drawing::Color::get_Blue()));
// Add it to the current page
System::SharedPtr<XpsPath> path2 = doc->Add(path1);

// path1 and path2 are the same as soon as path1 hasn't been placed inside any other element
// (which means that path1 had no parent element).
// Because of that rectangle's color on the page effectively turns to green
path2->set_Fill(doc->CreateSolidColorBrush(System::Drawing::Color::get_Green()));

// Now add path2 once again. Now path2 has parent. So path3 won't be the same as path2.
// Thus a new rectangle is painted on the page ...
System::SharedPtr<XpsPath> path3 = doc->Add(path2);
// ... and we shift it 300 units lower ...
path3->set_RenderTransform(doc->CreateMatrix(1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 300.0f));
// ... and set red solid brush to fill it
path3->set_Fill(doc->CreateSolidColorBrush(System::Drawing::Color::get_Red()));

// Create new path4 with path2's geometry ...
System::SharedPtr<XpsPath> path4 = doc->AddPath(path2->get_Data());
// ... shift it 300 units to the right ...
path4->set_RenderTransform(doc->CreateMatrix(1.0f, 0.0f, 0.0f, 1.0f, 300.0f, 0.0f));
// ... and set blue solid fill
path4->set_Fill(doc->CreateSolidColorBrush(System::Drawing::Color::get_Blue()));

// Add path4 once again.
System::SharedPtr<XpsPath> path5 = doc->Add(path4);
// path4 and path5 are not the same again ...
// (move path5 300 units lower)
path5->set_RenderTransform(path5->get_RenderTransform()->Clone());
// to disconnect RenderTransform value from path4 (see next comment about Fill property)
path5->get_RenderTransform()->Translate(0.0f, 300.0f);
// ... but if we set the opacity of Fill property, it will take effect on both path5 and path4
// because brush is a complex property value which remains the same for path5 and path4
path5->get_Fill()->set_Opacity(0.8f);

// Create new path6 with path2's geometry ...
System::SharedPtr<XpsPath> path6 = doc->AddPath(path2->get_Data());
// ... shift it 600 units to the right ...
path6->set_RenderTransform(doc->CreateMatrix(1.0f, 0.0f, 0.0f, 1.0f, 600.0f, 0.0f));
// ... and set yellow solid fill
path6->set_Fill(doc->CreateSolidColorBrush(System::Drawing::Color::get_Yellow()));

// Now add path6's clone ...
System::SharedPtr<XpsPath> path7 = doc->Add(path6->Clone());
// (move path5 300 units lower)
path7->set_RenderTransform(path7->get_RenderTransform()->Clone());
path7->get_RenderTransform()->Translate(0.0f, 300.0f);
// ... and set opacity for path7
path7->get_Fill()->set_Opacity(0.8f);
// Now opacity effects independantly as soon as property values are cloned along with the element

// The following code block is equivalent to the previous one.
// Add path6 itself. path6 and path7 are not the same. Although their Fill property values are the same 
//XpsPath path7 = doc.Add(path6);
//path7.RenderTransform = path7.RenderTransform.Clone();
//path7.RenderTransform.Translate(0, 300);
// To "disconnect" path7's Fill property from path6's Fill property reassign it to its clone (or path6's Fill clone)
//path7.Fill = ((XpsSolidColorBrush)path7.Fill).Clone();
//path7.Fill.Opacity = 0.8f;

// Save resultant XPS document
doc->Save(outDir() + u"WorkingWithTransparency_out.xps");

The result like this