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using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;
namespace HtmlToFlowDocument.Rendering
{
/// <summary>
/// Converts a relative size in percent to an absolute size. The relative size is given in the converter parameter,
/// the reference size is the property bound.
/// </summary>
/// <seealso cref="System.Windows.Data.IValueConverter" />
public class RelativeSizeConverter : IValueConverter
{
/// <summary>
/// Gets an instance of <see cref="RelativeSizeConverter"/>.
/// </summary>
/// <value>
/// The instance.
/// </value>
public static RelativeSizeConverter Instance { get; private set; } = new RelativeSizeConverter();
/// <summary>
/// Converts a reference length and a percentage value to an absolute length.
/// </summary>
/// <param name="value">The reference length. This value is produced by the binding source.</param>
/// <param name="targetType">The type of the binding target property.</param>
/// <param name="parameter">The percentage value. This value is from the converter parameter.</param>
/// <param name="culture">The culture to use in the converter.</param>
/// <returns>
/// The absolute length as referenceLength*100/percentageValue.
/// If the reference length was not set, a value of (1920/2) is used for the reference length.
/// </returns>
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
double? w = null;
if (parameter is string s && double.TryParse(s, NumberStyles.Float, CultureInfo.CurrentCulture, out var asDouble))
w = asDouble;
else if (parameter is double d)
w = d;
else if (parameter is Int32 i32)
w = i32;
if (!w.HasValue)
w = 100;
if (value is double referenceSize)
{
return referenceSize * w / 100.0;
}
else // if the referenceSize is not set or the binding failed
{
// assume a typical page width of 1920/2;
return (1920 / 2) * w / 100.0;
}
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
}
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