Implementing the preview writer

This article shows how to implement the writer that generates the HTML displayed in the internal web browser preview control.

Add the preview writer class

Add a class such as InternalPreviewWriter.cs to your project. The class must implement the same interfaces and members as the file writer class that generates native target files. See Implementing the File Writer.

The following example shows the minimum code required for an internal preview writer:

using System.IO;
using Sdl.FileTypeSupport.Framework.BilingualApi;
using Sdl.FileTypeSupport.Framework.NativeApi;

namespace Sdk.Snippets.Native
{
    class InternalPreviewWriter : AbstractNativeFileWriter, INativeContentCycleAware
    {
        StreamWriter _preview = null;

        public void SetFileProperties(IFileProperties properties)
        {
        }

        public void StartOfInput()
        {
        }

        public void EndOfInput()
        {
        }
    }
}

Start the preview output

Generate a simplified HTML document for the preview output. Start by writing the opening HTML markup:

// start the preview output
public void StartOfInput()
{
    _preview = new StreamWriter(OutputProperties.OutputFilePath);
    _preview.WriteLine("<html><body>");
}

Output text and tags

Override the Text() method to write translatable strings:

// output the translatable strings
public override void Text(ITextProperties textInfo)
{
    _preview.Write(textInfo.Text);
}

If you want to insert a line break after each paragraph unit, override the following methods and wrap each paragraph in a DIV tag pair:

// each paragraph unit should appear in a new line
// therefore use a DIV element
public override void ParagraphUnitStart(IParagraphUnitProperties properties)
{
    _preview.WriteLine("<div>");
}

public override void ParagraphUnitEnd()
{
    _preview.Write("</div>");
}

Wrap each segment in a SPAN tag pair. This step is not required yet, but this structure becomes useful later when you implement the real-time preview. See Enhancing the Preview File Writer.

// enclose each segment in a SPAN tag pair
public override void SegmentStart(ISegmentPairProperties properties)
{
    _preview.Write("<span>");
}

public override void SegmentEnd()
{
    _preview.Write("</span>");
}

Next, override the following methods to write inline tag content. When you emit the HTML tags, the web browser preview control also applies the corresponding character formatting.

// output any inline tags,
// which will also apply the corresponding character formatting
public override void InlineStartTag(IStartTagProperties tagInfo)
{
    _preview.Write(tagInfo.TagContent);
}

public override void InlineEndTag(IEndTagProperties tagInfo)
{
    _preview.Write(tagInfo.TagContent);
}

This preview does not write any structure tag content.

Close the preview output

Finally, close the preview output:

// end the preview output
public void EndOfInput()
{
    _preview.WriteLine("</body></html>");
    _preview.Close();
}

The static HTML preview looks like this:

StaticHTMLPreview

Put it all together

The complete preview writer class looks like this:

using System.IO;
using Sdl.FileTypeSupport.Framework.BilingualApi;
using Sdl.FileTypeSupport.Framework.NativeApi;

namespace Sdk.Snippets.Native
{
    class InternalPreviewWriter1 : AbstractNativeFileWriter, INativeContentCycleAware
    {
        StreamWriter _preview = null;

        public void SetFileProperties(IFileProperties properties)
        {
            // not used in this implementation
        }

        // start the preview output
        public void StartOfInput()
        {
            _preview = new StreamWriter(OutputProperties.OutputFilePath);
            _preview.WriteLine("<html><body>");
        }

        // output the translatable strings
        public override void Text(ITextProperties textInfo)
        {
            _preview.Write(textInfo.Text);
        }

        // each paragraph unit should appear in a new line
        // therefore use a DIV element
        public override void ParagraphUnitStart(IParagraphUnitProperties properties)
        {
            _preview.WriteLine("<div>");
        }

        public override void ParagraphUnitEnd()
        {
            _preview.Write("</div>");
        }

        // enclose each segment in a SPAN tag pair
        public override void SegmentStart(ISegmentPairProperties properties)
        {
            _preview.Write("<span>");
        }

        public override void SegmentEnd()
        {
            _preview.Write("</span>");
        }

        // output any inline tags,
        // which will also apply the corresponding character formatting
        public override void InlineStartTag(IStartTagProperties tagInfo)
        {
            _preview.Write(tagInfo.TagContent);
        }

        public override void InlineEndTag(IEndTagProperties tagInfo)
        {
            _preview.Write(tagInfo.TagContent);
        }

        // end the preview output
        public void EndOfInput()
        {
            _preview.WriteLine("</body></html>");
            _preview.Close();
        }
    }
}