SvgStyleableElement.cs :  » GUI » SharpVectorGraphics » SharpVectors » Dom » Svg » C# / CSharp Open Source

using System;
using System.Xml;
using System.Collections;
using System.Text.RegularExpressions;
using System.Diagnostics;
using SharpVectors.Dom.Css;



namespace SharpVectors.Dom.Svg{
  /// <summary>
  /// SvgStyleableElement is an extension to the Svg DOM to create a class for all elements that are styleable.
  /// </summary>
  public class SvgStyleableElement : SvgElement, ISvgStylable
  {
    #region Private static fields
    private static Regex isImportant = new Regex(@"!\s*important$");
    #endregion

    #region Private Fields
    private Hashtable styleProperties = new Hashtable();
    
    #endregion

    #region Constructors
    internal SvgStyleableElement(string prefix, string localname, string ns, SvgDocument doc) : base(prefix, localname, ns, doc) 
    {
    }
    #endregion

    #region Implementation of ISvgStylable
    #region ClassName
    private ISvgAnimatedString className;
    public ISvgAnimatedString ClassName
    {
      get
      {
        if(className == null)
        {
          className = new SvgAnimatedString(GetAttribute("class", String.Empty));
        }
        return className;
      }
    }
    #endregion

    #region PresentationAttributes
    private Hashtable presentationAttributes = new Hashtable();
    public ICssValue GetPresentationAttribute(string name)
    {
      if(!presentationAttributes.ContainsKey(name))
      {
        ICssValue result;
        string attValue = GetAttribute(name, String.Empty).Trim();
        if(attValue != null && attValue.Length > 0)
        {
          if(isImportant.IsMatch(attValue))
          {
            result = null;
          }
          else
          {
            result = CssValue.GetCssValue(attValue, false);
          }
        }
        else
        {
          result = null;
        }
        presentationAttributes[name] = result;

      }
      return presentationAttributes[name] as ICssValue;
    }
    #endregion
    #endregion

    #region GetValues
    public string GetPropertyValue(string name)
    {
      return GetComputedStyle(String.Empty).GetPropertyValue(name);
    }

    public string GetPropertyValue(string name1, string name2)
    {
      string cssString = GetComputedStyle(String.Empty).GetPropertyValue(name1);
      if(cssString == null)
      {
        cssString = GetComputedStyle(String.Empty).GetPropertyValue(name2);
      }

      return cssString;
    }

    public override ICssStyleDeclaration GetComputedStyle(string pseudoElt)
    {
      if(cachedCSD == null)
      {
        CssCollectedStyleDeclaration csd = (CssCollectedStyleDeclaration)base.GetComputedStyle(pseudoElt);
        
        IEnumerator cssPropNames = OwnerDocument.CssPropertyProfile.GetAllPropertyNames().GetEnumerator();
        while(cssPropNames.MoveNext())
        {
          string cssPropName = (string)cssPropNames.Current;
          CssValue cssValue = (CssValue)GetPresentationAttribute(cssPropName);
          if(cssValue != null)
          {
            csd.CollectProperty(cssPropName, 0, cssValue, CssStyleSheetType.NonCssPresentationalHints, String.Empty);
          }
        }

        cachedCSD = csd;
      }
      return cachedCSD;
    }    
    
    #endregion

    #region Update handling
    public override void HandleAttributeChange(XmlAttribute attribute)
    {
      
      if(attribute.NamespaceURI.Length == 0)
      {
        string localName = attribute.LocalName;
        if(presentationAttributes.ContainsKey(localName))
        {
          presentationAttributes.Remove(localName);                    
        }

        switch(attribute.LocalName)
        {
          case "class":
            className = null;
            // class changes need to propogate to children and invalidate CSS
            break;
        }
      }
      base.HandleAttributeChange(attribute);
    }
    #endregion
  }
}