Working with Clips in PostScript | C++

Add Clip in PS Document

A clip in a PS document is a path that bounds the content of the current graphics state that will be shown in the PS viewer or editor. The content that is left beyond the bounds will be cut off.

A clipping path in C++ can be assigned in three ways:

• by System.Drawing.Drawing2D.GraphicsPath that can contain any closed shapes;
• by text outline;
• by 1 bpp (bits per pixel) 2-color image as a stencil mask;

At this moment Aspose.Page for C++ library offers the first and the second ways of clipping. In the example below we obtain a circle System.Drawing.Drawing2D.GraphicsPath from a rectangle as a clipping path and cut off a blue-filled rectangle in the same graphics state.

In order to add a clip to the new PsDocument with Aspose.Page for C++ library in this example we do the following steps:

1. Create an output stream for the resulting PS file.
2. Create the PsSaveOptions object with default options.
3. Create a 1-paged PsDocument with an already created output stream and save options.
4. Create a new graphics state.
5. Create a circle System.Drawing.Drawing2D.GraphicsPath from the rectangle.
6. Set a clip with this path.
7. Set a paint to the current graphics state of PsDocument.
8. Fill the rectangle path with the current paint.
9. Exit from the current graphics state to upper level one.
10. Translate to the place of the filled rectangle.
11. Stroke with a dashed line the bounds of the same rectangle above the filled one to show the bounds of the clipped filled rectangle.
12. Close the page.
13. Save the document.

    // The path to the documents directory.
    System::String dataDir = RunExamples::GetDataDir_WorkingWithCanvas();
    
    //Create output stream for PostScript document
    {
        System::SharedPtr<System::IO::Stream> outPsStream = System::MakeObject<System::IO::FileStream>(dataDir + u"Clipping_outPS.ps", System::IO::FileMode::Create);
        // Clearing resources under 'using' statement
        System::Details::DisposeGuard<1> __dispose_guard_0({ outPsStream});
        // ------------------------------------------
        
        try
        {
            //Create save options with default values
            System::SharedPtr<PsSaveOptions> options = System::MakeObject<PsSaveOptions>();
            
            // Create new 1-paged PS Document
            System::SharedPtr<PsDocument> document = System::MakeObject<PsDocument>(outPsStream, options, false);
            
            //Create graphics path from the rectangle
            System::SharedPtr<System::Drawing::Drawing2D::GraphicsPath> rectanglePath = System::MakeObject<System::Drawing::Drawing2D::GraphicsPath>();
            rectanglePath->AddRectangle(System::Drawing::RectangleF(0.0f, 0.0f, 300.0f, 200.0f));
            
            ////////////////////////////////////// Clipping by shape //////////////////////////////////////////////////////////////////////
            
            //Save graphics state in order to return back to this state after transformation
            document->WriteGraphicsSave();
            
            //Displace current graphics state on 100 points to the right and 100 points to the bottom.
            document->Translate(100.0f, 100.0f);
            
            //Create graphics path from the circle
            System::SharedPtr<System::Drawing::Drawing2D::GraphicsPath> circlePath = System::MakeObject<System::Drawing::Drawing2D::GraphicsPath>();
            circlePath->AddEllipse(System::Drawing::RectangleF(50.0f, 0.0f, 200.0f, 200.0f));
            
            //Add clipping by circle to the current graphics state
            document->Clip(circlePath);
            
            //Set paint in the current graphics state
            document->SetPaint(System::MakeObject<System::Drawing::SolidBrush>(System::Drawing::Color::get_Blue()));
            
            //Fill the rectangle in the current graphics state (with clipping)
            document->Fill(rectanglePath);
            
            //Restore graphics state to the previus (upper) level
            document->WriteGraphicsRestore();
            
            //Displace upper level graphics state on 100 points to the right and 100 points to the bottom.
            document->Translate(100.0f, 100.0f);
            
            System::SharedPtr<System::Drawing::Pen> pen = System::MakeObject<System::Drawing::Pen>(System::MakeObject<System::Drawing::SolidBrush>(System::Drawing::Color::get_Blue()), 2.0f);
            pen->set_DashStyle(System::Drawing::Drawing2D::DashStyle::Dash);
            
            document->SetStroke(pen);
            
            //Draw the rectangle in the current graphics state (has no clipping) above clipped rectangle
            document->Draw(rectanglePath);
            
            ////////////////////////////////////// Clipping by text //////////////////////////////////////////////////////////////////////
            
            //Save graphics state in order to return back to this state after transformation
            document->WriteGraphicsSave();
            
            //Displace current graphics state on 100 points to the right and 100 points to the bottom.
            document->Translate(0.0f, 350.0f);
            
            int32_t fontSize = 120;
            System::SharedPtr<System::Drawing::Font> font = System::MakeObject<System::Drawing::Font>(u"Arial", static_cast<float>(fontSize), System::Drawing::FontStyle::Bold);
            
            //Clip rectangle by text's outline
            document->ClipText(u"ABC", font, 20.0f, static_cast<float>(fontSize + 10));
            document->Fill(rectanglePath);
            
            document->WriteGraphicsRestore();
            
            document->Translate(0.0f, 350.0f);
            
            document->SetStroke(pen);
            //Draw the rectangle in the current graphics state (has no clipping) above clipped rectangle
            document->Draw(rectanglePath);
            
            //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
            
            //Close current page
            document->ClosePage();
            
            //Save the document
            document->Save();
        }
        catch(...)
        {
            __dispose_guard_0.SetCurrentException(std::current_exception());
        }
    }

See working with clips in PS documents in Java.

The result of running this code is appeared as

In the next example, we obtain a font that to clip a blue-filled rectangle with the text’s outline.

In order to add a clipping by text to the new PsDocument with Aspose.Page for C++ library in this example we do the following steps:

1. Create an output stream for the resulting PS file.
2. Create a PsSaveOptions object with default options.
3. Create a 1-paged PsDocument with an already created output stream and save options.
4. Create a new graphics state.
5. Create a font.
6. Set a clip with text and the font.
7. Set a paint to the current graphics state of PsDocument.
8. Fill the rectangle path with the current paint.
9. Exit from the current graphics state to upper level one.
10. Translate to the place of the filled rectangle.
11. Stroke with a dashed line the bounds of the same rectangle above the filled one to show the bounds of the clipped filled rectangle.
12. Close the page.
13. Save the document.

//Create an output stream for the PostScript document
using (Stream outPsStream = new FileStream(dataDir + "Clipping_outPS.ps", FileMode.Create))
{
    //Create save options with default values
    PsSaveOptions options = new PsSaveOptions();

    // Create a new 1-paged PS Document
    PsDocument document = new PsDocument(outPsStream, options, false);

    //Create a graphics path from the rectangle
    GraphicsPath rectangePath = new GraphicsPath();
    rectangePath.AddRectangle(new RectangleF(0, 0, 300, 200));

    //Save the graphics state in order to return back to this state after transformation
    document.WriteGraphicsSave();

    //Displace the current graphics state on 100 points to the right and 100 points to the bottom.
    document.Translate(100, 100);
    
    //Set the paint in the current graphics state
    document.SetPaint(new SolidBrush(Color.Blue));

    //Create a font
    int fontSize = 120;
    Font font = new Font("Arial", fontSize, FontStyle.Bold);

    //Clip the rectangle by text's outline
    document.ClipText("ABC", font, 20, fontSize + 10);
    document.Fill(rectanglePath);

    //Restore the graphics state to the previus (upper) level
    document.WriteGraphicsRestore();

		//Displace the upper level graphics state on 100 points to the right and 100 points to the bottom.
    document.Translate(100, 100);

		Pen pen = new Pen(new SolidBrush(Color.Blue), 2);
    pen.DashStyle = DashStyle.Dash;

    document.SetStroke(pen);
    
    //Draw the rectangle in the current graphics state (has no clipping) above the clipped rectangle
    document.Draw(rectanglePath);

    //Close the current page
    document.ClosePage();

    //Save the document
    document.Save();
}

See working with clips in PS documents in .NET or Java.

The result of running this code is appeared as

You can download examples and data files from GitHub.