//---------------------------------------------------------------------------
//
// File: HtmlFromXamlConverter.cs
//
// Copyright (C) Microsoft Corporation. All rights reserved.
//
// Description: Prototype for Xaml - Html conversion
//
//---------------------------------------------------------------------------
namespace GoalBook.Public.HtmlConverter
{
using System;
using System.Diagnostics;
using System.Text;
using System.IO;
using System.Xml;
/// <summary>
/// HtmlToXamlConverter is a static class that takes an HTML string
/// and converts it into XAML
/// </summary>
public static class HtmlFromXamlConverter
{
// ---------------------------------------------------------------------
//
// Internal Methods
//
// ---------------------------------------------------------------------
#region Public Methods
/// <summary>
/// Main entry point for Xaml-to-Html converter.
/// Converts a xaml string into html string.
/// </summary>
/// <param name="xamlString">
/// Xaml strinng to convert.
/// </param>
/// <returns>
/// Html string produced from a source xaml.
/// </returns>
public static string ConvertXamlToHtml(string xamlString)
{
if (string.IsNullOrEmpty(xamlString))
{
return string.Empty;
}
XmlTextReader xamlReader;
StringBuilder htmlStringBuilder;
XmlTextWriter htmlWriter;
xamlReader = new XmlTextReader(new StringReader(xamlString));
htmlStringBuilder = new StringBuilder(100);
htmlWriter = new XmlTextWriter(new StringWriter(htmlStringBuilder));
if (!WriteFlowDocument(xamlReader, htmlWriter))
{
return string.Empty;
}
string htmlString = htmlStringBuilder.ToString();
return htmlString;
}
#endregion Public Methods
// ---------------------------------------------------------------------
//
// Private Methods
//
// ---------------------------------------------------------------------
#region Private Methods
/// <summary>
/// Processes a root level element of XAML (normally it's FlowDocument element).
/// </summary>
/// <param name="xamlReader">
/// XmlTextReader for a source xaml.
/// </param>
/// <param name="htmlWriter">
/// XmlTextWriter producing resulting html
/// </param>
private static bool WriteFlowDocument(XmlTextReader xamlReader, XmlTextWriter htmlWriter)
{
if (!ReadNextToken(xamlReader))
{
// Xaml content is empty - nothing to convert
return false;
}
if (xamlReader.NodeType != XmlNodeType.Element || xamlReader.Name != "FlowDocument")
{
// Root FlowDocument elemet is missing
return false;
}
// Create a buffer StringBuilder for collecting css properties for inline STYLE attributes
// on every element level (it will be re-initialized on every level).
StringBuilder inlineStyle = new StringBuilder();
htmlWriter.WriteStartElement("HTML");
htmlWriter.WriteStartElement("BODY");
WriteFormattingProperties(xamlReader, htmlWriter, inlineStyle);
WriteElementContent(xamlReader, htmlWriter, inlineStyle);
htmlWriter.WriteEndElement();
htmlWriter.WriteEndElement();
return true;
}
/// <summary>
/// Reads attributes of the current xaml element and converts
/// them into appropriate html attributes or css styles.
/// </summary>
/// <param name="xamlReader">
/// XmlTextReader which is expected to be at XmlNodeType.Element
/// (opening element tag) position.
/// The reader will remain at the same level after function complete.
/// </param>
/// <param name="htmlWriter">
/// XmlTextWriter for output html, which is expected to be in
/// after WriteStartElement state.
/// </param>
/// <param name="inlineStyle">
/// String builder for collecting css properties for inline STYLE attribute.
/// </param>
private static void WriteFormattingProperties(XmlTextReader xamlReader, XmlTextWriter htmlWriter, StringBuilder inlineStyle)
{
Debug.Assert(xamlReader.NodeType == XmlNodeType.Element);
// Clear string builder for the inline style
inlineStyle.Remove(0, inlineStyle.Length);
if (!xamlReader.HasAttributes)
{
return;
}
bool borderSet = false;
while (xamlReader.MoveToNextAttribute())
{
string css = null;
switch (xamlReader.Name)
{
// Character fomatting properties
// ------------------------------
case "Background":
css = "background-color:" + ParseXamlColor(xamlReader.Value) + ";";
break;
case "FontFamily":
css = "font-family:" + xamlReader.Value + ";";
break;
case "FontStyle":
css = "font-style:" + xamlReader.Value.ToLower() + ";";
break;
case "FontWeight":
css = "font-weight:" + xamlReader.Value.ToLower() + ";";
break;
case "FontStretch":
break;
case "FontSize":
css = "font-size:" + xamlReader.Value + ";";
break;
case "Foreground":
css = "color:" + ParseXamlColor(xamlReader.Value) + ";";
break;
case "TextDecorations":
css = "text-decoration:underline;";
break;
case "TextEffects":
break;
case "Emphasis":
break;
case "StandardLigatures":
break;
case "Variants":
break;
case "Capitals":
break;
case "Fraction":
break;
// Paragraph formatting properties
// -------------------------------
case "Padding":
css = "padding:" + ParseXamlThickness(xamlReader.Value) + ";";
break;
case "Margin":
css = "margin:" + ParseXamlThickness(xamlReader.Value) + ";";
break;
case "BorderThickness":
css = "border-width:" + ParseXamlThickness(xamlReader.Value) + ";";
borderSet = true;
break;
case "BorderBrush":
css = "border-color:" + ParseXamlColor(xamlReader.Value) + ";";
borderSet = true;
break;
case "LineHeight":
break;
case "TextIndent":
css = "text-indent:" + xamlReader.Value + ";";
break;
case "TextAlignment":
css = "text-align:" + xamlReader.Value + ";";
break;
case "IsKeptTogether":
break;
case "IsKeptWithNext":
break;
case "ColumnBreakBefore":
break;
case "PageBreakBefore":
break;
case "FlowDirection":
break;
// Table attributes
// ----------------
case "Width":
css = "width:" + xamlReader.Value + ";";
break;
case "ColumnSpan":
htmlWriter.WriteAttributeString("COLSPAN", xamlReader.Value);
break;
case "RowSpan":
htmlWriter.WriteAttributeString("ROWSPAN", xamlReader.Value);
break;
case "NavigateUri":
htmlWriter.WriteAttributeString("href", xamlReader.Value);
break;
}
if (css != null)
{
inlineStyle.Append(css);
}
}
if (borderSet)
{
inlineStyle.Append("border-style:solid;mso-element:para-border-div;");
}
// Return the xamlReader back to element level
xamlReader.MoveToElement();
Debug.Assert(xamlReader.NodeType == XmlNodeType.Element);
}
private static string ParseXamlColor(string color)
{
if (color.StartsWith("#"))
{
// Remove transparancy value
color = "#" + color.Substring(3);
}
return color;
}
private static string ParseXamlThickness(string thickness)
{
string[] values = thickness.Split(',');
for (int i = 0; i < values.Length; i++)
{
double value;
if (double.TryParse(values[i], out value))
{
values[i] = Math.Ceiling(value).ToString();
}
else
{
values[i] = "1";
}
}
string cssThickness;
switch (values.Length)
{
case 1:
cssThickness = thickness;
break;
case 2:
cssThickness = values[1] + " " + values[0];
break;
case 4:
cssThickness = values[1] + " " + values[2] + " " + values[3] + " " + values[0];
break;
default:
cssThickness = values[0];
break;
}
return cssThickness;
}
/// <summary>
/// Reads a content of current xaml element, converts it
/// </summary>
/// <param name="xamlReader">
/// XmlTextReader which is expected to be at XmlNodeType.Element
/// (opening element tag) position.
/// </param>
/// <param name="htmlWriter">
/// May be null, in which case we are skipping the xaml element;
/// witout producing any output to html.
/// </param>
/// <param name="inlineStyle">
/// StringBuilder used for collecting css properties for inline STYLE attribute.
/// </param>
private static void WriteElementContent(XmlTextReader xamlReader, XmlTextWriter htmlWriter, StringBuilder inlineStyle)
{
Debug.Assert(xamlReader.NodeType == XmlNodeType.Element);
bool elementContentStarted = false;
if (xamlReader.IsEmptyElement)
{
if (htmlWriter != null && !elementContentStarted && inlineStyle.Length > 0)
{
// Output STYLE attribute and clear inlineStyle buffer.
htmlWriter.WriteAttributeString("STYLE", inlineStyle.ToString());
inlineStyle.Remove(0, inlineStyle.Length);
}
elementContentStarted = true;
}
else
{
while (ReadNextToken(xamlReader) && xamlReader.NodeType != XmlNodeType.EndElement)
{
switch (xamlReader.NodeType)
{
case XmlNodeType.Element:
if (xamlReader.Name.Contains("."))
{
AddComplexProperty(xamlReader, inlineStyle);
}
else
{
if (htmlWriter != null && !elementContentStarted && inlineStyle.Length > 0)
{
// Output STYLE attribute and clear inlineStyle buffer.
htmlWriter.WriteAttributeString("STYLE", inlineStyle.ToString());
inlineStyle.Remove(0, inlineStyle.Length);
}
elementContentStarted = true;
WriteElement(xamlReader, htmlWriter, inlineStyle);
}
Debug.Assert(xamlReader.NodeType == XmlNodeType.EndElement || xamlReader.NodeType == XmlNodeType.Element && xamlReader.IsEmptyElement);
break;
case XmlNodeType.Comment:
if (htmlWriter != null)
{
if (!elementContentStarted && inlineStyle.Length > 0)
{
htmlWriter.WriteAttributeString("STYLE", inlineStyle.ToString());
}
htmlWriter.WriteComment(xamlReader.Value);
}
elementContentStarted = true;
break;
case XmlNodeType.CDATA:
case XmlNodeType.Text:
case XmlNodeType.SignificantWhitespace:
if (htmlWriter != null)
{
if (!elementContentStarted && inlineStyle.Length > 0)
{
htmlWriter.WriteAttributeString("STYLE", inlineStyle.ToString());
}
htmlWriter.WriteString(xamlReader.Value);
}
elementContentStarted = true;
break;
}
}
Debug.Assert(xamlReader.NodeType == XmlNodeType.EndElement);
}
}
/// <summary>
/// Conberts an element notation of complex property into
/// </summary>
/// <param name="xamlReader">
/// On entry this XmlTextReader must be on Element start tag;
/// on exit - on EndElement tag.
/// </param>
/// <param name="inlineStyle">
/// StringBuilder containing a value for STYLE attribute.
/// </param>
private static void AddComplexProperty(XmlTextReader xamlReader, StringBuilder inlineStyle)
{
Debug.Assert(xamlReader.NodeType == XmlNodeType.Element);
if (inlineStyle != null && xamlReader.Name.EndsWith(".TextDecorations"))
{
inlineStyle.Append("text-decoration:underline;");
}
// Skip the element representing the complex property
WriteElementContent(xamlReader, /*htmlWriter:*/null, /*inlineStyle:*/null);
}
/// <summary>
/// Converts a xaml element into an appropriate html element.
/// </summary>
/// <param name="xamlReader">
/// On entry this XmlTextReader must be on Element start tag;
/// on exit - on EndElement tag.
/// </param>
/// <param name="htmlWriter">
/// May be null, in which case we are skipping xaml content
/// without producing any html output
/// </param>
/// <param name="inlineStyle">
/// StringBuilder used for collecting css properties for inline STYLE attributes on every level.
/// </param>
private static void WriteElement(XmlTextReader xamlReader, XmlTextWriter htmlWriter, StringBuilder inlineStyle)
{
Debug.Assert(xamlReader.NodeType == XmlNodeType.Element);
if (htmlWriter == null)
{
// Skipping mode; recurse into the xaml element without any output
WriteElementContent(xamlReader, /*htmlWriter:*/null, null);
}
else
{
string htmlElementName = null;
switch (xamlReader.Name)
{
case "Run" :
case "Span":
htmlElementName = "SPAN";
break;
case "InlineUIContainer":
htmlElementName = "SPAN";
break;
case "Bold":
htmlElementName = "B";
break;
case "Italic" :
htmlElementName = "I";
break;
case "Paragraph" :
htmlElementName = "P";
break;
case "BlockUIContainer":
htmlElementName = "DIV";
break;
case "Section":
htmlElementName = "DIV";
break;
case "Table":
htmlElementName = "TABLE";
break;
case "TableColumn":
htmlElementName = "COL";
break;
case "TableRowGroup" :
htmlElementName = "TBODY";
break;
case "TableRow" :
htmlElementName = "TR";
break;
case "TableCell" :
htmlElementName = "TD";
break;
case "List" :
string marker = xamlReader.GetAttribute("MarkerStyle");
if (marker == null || marker == "None" || marker == "Disc" || marker == "Circle" || marker == "Square" || marker == "Box")
{
htmlElementName = "UL";
}
else
{
htmlElementName = "OL";
}
break;
case "ListItem" :
htmlElementName = "LI";
break;
case "Hyperlink":
htmlElementName = "A";
break;
case "LineBreak":
htmlElementName = "BR";
break;
default :
htmlElementName = null; // Ignore the element
break;
}
if (htmlWriter != null && htmlElementName != null)
{
htmlWriter.WriteStartElement(htmlElementName);
WriteFormattingProperties(xamlReader, htmlWriter, inlineStyle);
WriteElementContent(xamlReader, htmlWriter, inlineStyle);
htmlWriter.WriteEndElement();
}
else
{
// Skip this unrecognized xaml element
WriteElementContent(xamlReader, /*htmlWriter:*/null, null);
}
}
}
// Reader advance helpers
// ----------------------
/// <summary>
/// Reads several items from xamlReader skipping all non-significant stuff.
/// </summary>
/// <param name="xamlReader">
/// XmlTextReader from tokens are being read.
/// </param>
/// <returns>
/// True if new token is available; false if end of stream reached.
/// </returns>
private static bool ReadNextToken(XmlReader xamlReader)
{
while (xamlReader.Read())
{
Debug.Assert(xamlReader.ReadState == ReadState.Interactive, "Reader is expected to be in Interactive state (" + xamlReader.ReadState + ")");
switch (xamlReader.NodeType)
{
case XmlNodeType.Element:
case XmlNodeType.EndElement:
case XmlNodeType.None:
case XmlNodeType.CDATA:
case XmlNodeType.Text:
case XmlNodeType.SignificantWhitespace:
return true;
case XmlNodeType.Whitespace:
if (xamlReader.XmlSpace == XmlSpace.Preserve)
{
return true;
}
// ignore insignificant whitespace
break;
case XmlNodeType.EndEntity:
case XmlNodeType.EntityReference:
// Implement entity reading
//xamlReader.ResolveEntity();
//xamlReader.Read();
//ReadChildNodes( parent, parentBaseUri, xamlReader, positionInfo);
break; // for now we ignore entities as insignificant stuff
case XmlNodeType.Comment:
return true;
case XmlNodeType.ProcessingInstruction:
case XmlNodeType.DocumentType:
case XmlNodeType.XmlDeclaration:
default:
// Ignorable stuff
break;
}
}
return false;
}
#endregion Private Methods
// ---------------------------------------------------------------------
//
// Private Fields
//
// ---------------------------------------------------------------------
#region Private Fields
#endregion Private Fields
}
}
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