Renk seçimi için kullanılabilecek, daire şeklinde bir renk seçme paleti oluşturan csharp sınıfı alternatifidir.
public class ColorWheel
{
/// <summary>
/// Draw a color wheel in the indicated area.
/// </summary>
/// <param name="gr"></param>
/// <param name="outline_color"></param>
/// <param name="xmin"></param>
/// <param name="ymin"></param>
/// <param name="wid"></param>
/// <param name="hgt"></param>
public static void Draw(Graphics gr, Color outline_color,
int xmin, int ymin, int wid, int hgt)
{
Rectangle rect = new Rectangle(xmin, ymin, wid, hgt);
GraphicsPath wheel_path = new GraphicsPath();
wheel_path.AddEllipse(rect);
wheel_path.Flatten();
float num_pts = (wheel_path.PointCount - 1) / 6;
Color[] surround_colors = new Color[wheel_path.PointCount];
int index = 0;
InterpolateColors(surround_colors, ref index,
1 * num_pts, 255, 255, 0, 0, 255, 255, 0, 255);
InterpolateColors(surround_colors, ref index,
2 * num_pts, 255, 255, 0, 255, 255, 0, 0, 255);
InterpolateColors(surround_colors, ref index,
3 * num_pts, 255, 0, 0, 255, 255, 0, 255, 255);
InterpolateColors(surround_colors, ref index,
4 * num_pts, 255, 0, 255, 255, 255, 0, 255, 0);
InterpolateColors(surround_colors, ref index,
5 * num_pts, 255, 0, 255, 0, 255, 255, 255, 0);
InterpolateColors(surround_colors, ref index,
wheel_path.PointCount, 255, 255, 255, 0, 255, 255, 0, 0);
using (PathGradientBrush path_brush =
new PathGradientBrush(wheel_path))
{
path_brush.CenterColor = Color.White;
path_brush.SurroundColors = surround_colors;
gr.FillPath(path_brush, wheel_path);
// It looks better if we outline the wheel.
using (Pen thick_pen = new Pen(outline_color, 2))
{
gr.DrawPath(thick_pen, wheel_path);
}
}
//// Uncomment the following to draw the path's points.
//for (int i = 0; i < wheel_path.PointCount; i++)
//{
// gr.FillEllipse(Brushes.Black,
// wheel_path.PathPoints[i].X - 2,
// wheel_path.PathPoints[i].Y - 2,
// 4, 4);
//}
}
/// <summary>
/// Fill in colors interpolating between the from and to values.
/// </summary>
/// <param name="surround_colors"></param>
/// <param name="index"></param>
/// <param name="stop_pt"></param>
/// <param name="from_a"></param>
/// <param name="from_r"></param>
/// <param name="from_g"></param>
/// <param name="from_b"></param>
/// <param name="to_a"></param>
/// <param name="to_r"></param>
/// <param name="to_g"></param>
/// <param name="to_b"></param>
public static void InterpolateColors(Color[] surround_colors,
ref int index, float stop_pt,
int from_a, int from_r, int from_g, int from_b,
int to_a, int to_r, int to_g, int to_b)
{
int num_pts = (int)stop_pt - index;
float a = from_a, r = from_r, g = from_g, b = from_b;
float da = (to_a - from_a) / (num_pts - 1);
float dr = (to_r - from_r) / (num_pts - 1);
float dg = (to_g - from_g) / (num_pts - 1);
float db = (to_b - from_b) / (num_pts - 1);
for (int i = 0; i < num_pts; i++)
{
surround_colors[index++] =
Color.FromArgb((int)a, (int)r, (int)g, (int)b);
a += da;
r += dr;
g += dg;
b += db;
}
}
}