/// <summary>
/// Initializes a new instance of the GradientTheme class
/// </summary>
/// <remarks>
/// <para>The gradient theme interpolates linearly between two styles based on a numerical attribute in the datasource.
/// This is useful for scaling symbols, line widths, line and fill colors from numerical attributes.</para>
/// <para>Colors are interpolated between two colors, but if you want to interpolate through more colors (fx. a rainbow),
/// set the <see cref="TextColorBlend"/>, <see cref="LineColorBlend"/> and <see cref="FillColorBlend"/> properties
/// to a custom <see cref="ColorBlend"/>.
/// </para>
/// <para>The following properties are scaled (properties not mentioned here are not interpolated):
/// <list type="table">
/// <listheader><term>Property</term><description>Remarks</description></listheader>
/// <item><term><see cref="System.Drawing.Color"/></term><description>Red, Green, Blue and Alpha values are linearly interpolated.</description></item>
/// <item><term><see cref="System.Drawing.Pen"/></term><description>The color, width, color of pens are interpolated. MiterLimit,StartCap,EndCap,LineJoin,DashStyle,DashPattern,DashOffset,DashCap,CompoundArray, and Alignment are switched in the middle of the min/max values.</description></item>
/// <item><term><see cref="System.Drawing.SolidBrush"/></term><description>SolidBrush color are interpolated. Other brushes are not supported.</description></item>
/// <item><term><see cref="SharpMap.Styles.VectorStyle"/></term><description>MaxVisible, MinVisible, Line, Outline, Fill and SymbolScale are scaled linearly. Symbol, EnableOutline and Enabled switch in the middle of the min/max values.</description></item>
/// <item><term><see cref="SharpMap.Styles.LabelStyle"/></term><description>FontSize, BackColor, ForeColor, MaxVisible, MinVisible, Offset are scaled linearly. All other properties use min-style.</description></item>
/// </list>
/// </para>
/// <example>
/// Creating a rainbow colorblend showing colors from red, through yellow, green and blue depicting
/// the population density of a country.
/// <code lang="C#">
/// //Create two vector styles to interpolate between
/// SharpMap.Styles.VectorStyle min = new SharpMap.Styles.VectorStyle();
/// SharpMap.Styles.VectorStyle max = new SharpMap.Styles.VectorStyle();
/// min.Outline.Width = 1f; //Outline width of the minimum value
/// max.Outline.Width = 3f; //Outline width of the maximum value
/// //Create a theme interpolating population density between 0 and 400
/// SharpMap.Rendering.Thematics.GradientTheme popdens = new SharpMap.Rendering.Thematics.GradientTheme("PopDens", 0, 400, min, max);
/// //Set the fill-style colors to be a rainbow blend from red to blue.
/// popdens.FillColorBlend = SharpMap.Rendering.Thematics.ColorBlend.Rainbow5;
/// myVectorLayer.Theme = popdens;
/// </code>
/// </example>
/// </remarks>
/// <param name="columnName">Name of column to extract the attribute</param>
/// <param name="minValue">Minimum value</param>
/// <param name="maxValue">Maximum value</param>
/// <param name="minStyle">Color for minimum value</param>
/// <param name="maxStyle">Color for maximum value</param>
public GradientTheme(string columnName, double minValue, double maxValue, SharpMap.Styles.IStyle minStyle, SharpMap.Styles.IStyle maxStyle)
{
_ColumnName = columnName;
_min = minValue;
_max = maxValue;
_maxStyle = maxStyle;
_minStyle = minStyle;
}
/// <summary>
/// Returns the <see cref="System.Drawing.Color">color</see> based on an attribute value
/// </summary>
/// <returns>Style generated by GetStyle-Delegate</returns>
public SharpMap.Styles.IStyle GetStyle(IFeature feature)
{
if (_getStyleDelegate == null)
{
return(_DefaultStyle);
}
SharpMap.Styles.IStyle style = _getStyleDelegate(feature);
if (style != null)
{
return(style);
}
else
{
return(_DefaultStyle);
}
}
/// <summary>
/// Initializes a new instance of the GradientTheme class
/// </summary>
/// <remarks>
/// <para>The gradient theme interpolates linearly between two styles based on a numerical attribute in the datasource.
/// This is useful for scaling symbols, line widths, line and fill colors from numerical attributes.</para>
/// <para>Colors are interpolated between two colors, but if you want to interpolate through more colors (fx. a rainbow),
/// set the <see cref="TextColorBlend"/>, <see cref="LineColorBlend"/> and <see cref="FillColorBlend"/> properties
/// to a custom <see cref="ColorBlend"/>.
/// </para>
/// <para>The following properties are scaled (properties not mentioned here are not interpolated):
/// <list type="table">
/// <listheader><term>Property</term><description>Remarks</description></listheader>
/// <item><term><see cref="System.Drawing.Color"/></term><description>Red, Green, Blue and Alpha values are linearly interpolated.</description></item>
/// <item><term><see cref="System.Drawing.Pen"/></term><description>The color, width, color of pens are interpolated. MiterLimit,StartCap,EndCap,LineJoin,DashStyle,DashPattern,DashOffset,DashCap,CompoundArray, and Alignment are switched in the middle of the min/max values.</description></item>
/// <item><term><see cref="System.Drawing.SolidBrush"/></term><description>SolidBrush color are interpolated. Other brushes are not supported.</description></item>
/// <item><term><see cref="SharpMap.Styles.VectorStyle"/></term><description>MaxVisible, MinVisible, Line, Outline, Fill and SymbolScale are scaled linearly. Symbol, EnableOutline and Enabled switch in the middle of the min/max values.</description></item>
/// <item><term><see cref="SharpMap.Styles.LabelStyle"/></term><description>FontSize, BackColor, ForeColor, MaxVisible, MinVisible, Offset are scaled linearly. All other properties use min-style.</description></item>
/// </list>
/// </para>
/// <example>
/// Creating a rainbow colorblend showing colors from red, through yellow, green and blue depicting
/// the population density of a country.
/// <code lang="C#">
/// //Create two vector styles to interpolate between
/// SharpMap.Styles.VectorStyle min = new SharpMap.Styles.VectorStyle();
/// SharpMap.Styles.VectorStyle max = new SharpMap.Styles.VectorStyle();
/// min.Outline.Width = 1f; //Outline width of the minimum value
/// max.Outline.Width = 3f; //Outline width of the maximum value
/// //Create a theme interpolating population density between 0 and 400
/// SharpMap.Rendering.Thematics.GradientTheme popdens = new SharpMap.Rendering.Thematics.GradientTheme("PopDens", 0, 400, min, max);
/// //Set the fill-style colors to be a rainbow blend from red to blue.
/// popdens.FillColorBlend = SharpMap.Rendering.Thematics.ColorBlend.Rainbow5;
/// myVectorLayer.Theme = popdens;
/// </code>
/// </example>
/// </remarks>
/// <param name="columnName">Name of column to extract the attribute</param>
/// <param name="minValue">Minimum value</param>
/// <param name="maxValue">Maximum value</param>
/// <param name="minStyle">Color for minimum value</param>
/// <param name="maxStyle">Color for maximum value</param>
public GradientTheme(string columnName, double minValue, double maxValue, SharpMap.Styles.IStyle minStyle, SharpMap.Styles.IStyle maxStyle)
{
_ColumnName = columnName;
_min = minValue;
_max = maxValue;
_maxStyle = maxStyle;
_minStyle = minStyle;
}