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// // Copyright (c) Dr. Dirk Lellinger. All rights reserved.
// // Licensed under the MIT license. See LICENSE file in the project root for full license information.
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 CompoundLengthConverter : IMultiValueConverter
{
/// <summary>
/// Gets an instance of <see cref="CompoundLengthConverter"/>.
/// </summary>
/// <value>
/// The instance.
/// </value>
public static CompoundLengthConverter Instance { get; private set; } = new CompoundLengthConverter();
/// <summary>
/// Converts a reference length and a percentage value to an absolute length.
/// </summary>
/// <param name="values">An array of two values: the column width and the height of the document. This value is produced by a multibinding.</param>
/// <param name="targetType">The type of the binding target property.</param>
/// <param name="parameter">Enumerable, consisting of tuples. The first member of each tuple is the size type, the second is the value.</param>
/// <param name="culture">The culture to use in the converter.</param>
/// <returns>
/// The absolute length is pixels.
/// </returns>
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
// it is supposed that the values are two doubles, giving the column width and the height of the viewport
double viewPortWidth = (1920 / 2); // assume a typical page width of 1920/2;
if (values != null && values.Length > 0 && values[0] is double w && w > 0)
viewPortWidth = w;
double viewPortHeight = 1080 / 2;
if (values != null && values.Length > 1 && values[1] is double h && h > 0)
viewPortHeight = h;
// parameter is assumed to be an enumerable of tuples consisting of an integer and a double
if (parameter is IEnumerable<(int type, double value)> seq)
{
double result = 0;
foreach (var entry in seq)
{
switch (entry.type)
{
case 0: // absolute value in px
result += entry.value;
break;
case 1: // 100red of viewport width
result += entry.value * viewPortWidth / 100;
break;
case 2: // 100red of viewport height
result += entry.value * viewPortHeight / 100;
break;
case 3: // Vmin
result += entry.value * Math.Min(viewPortWidth, viewPortHeight) / 100;
break;
case 4: // VMax
result += entry.value * Math.Max(viewPortWidth, viewPortHeight) / 100;
break;
}
}
return result;
}
return 16; // fallback value
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
}
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