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using System;
using System.Drawing;
namespace UVtools.Core.Extensions
{
public static class DrawingExtensions
{
public static Color FactorColor(this Color color, byte pixelColor, byte min = 0, byte max = byte.MaxValue) =>
FactorColor(color, pixelColor / 255f, min, max);
public static Color FactorColor(this Color color, float factor, byte min = 0, byte max = byte.MaxValue)
{
byte r = (byte)(color.R == 0 ? 0 :
Math.Min(Math.Max(min, color.R * factor), max));
byte g = (byte)(color.G == 0 ? 0 :
Math.Min(Math.Max(min, color.G * factor), max));
byte b = (byte)(color.B == 0 ? 0 :
Math.Min(Math.Max(min, color.B * factor), max));
return Color.FromArgb(r, g, b);
}
public static double CalculatePolygonSideLengthFromRadius(double radius, int sides)
{
return 2 * radius * Math.Sin(Math.PI / sides);
}
public static double CalculatePolygonVerticalLengthFromRadius(double radius, int sides)
{
return radius * Math.Cos(Math.PI / sides);
}
public static double CalculatePolygonRadiusFromSideLength(double length, int sides)
{
var theta = 360.0 / sides;
return length / (2 * Math.Cos((90 - theta / 2) * Math.PI / 180.0));
}
public static Point[] GetPolygonVertices(int sides, int radius, Point center, double startingAngle = 0, bool flipHorizontally = false, bool flipVertically = false)
{
if (sides < 3)
throw new ArgumentException("Polygons can't have less than 3 sides...", nameof(sides));
var vertices = new Point[sides];
double deg = 360.0 / sides;//calculate the rotation angle
var rad = Math.PI / 180.0;
var x0 = center.X + radius * Math.Cos(-(((180 - deg) / 2) + startingAngle) * rad);
var y0 = center.Y - radius * Math.Sin(-(((180 - deg) / 2) + startingAngle) * rad);
var x1 = center.X + radius * Math.Cos(-(((180 - deg) / 2) + deg + startingAngle) * rad);
var y1 = center.Y - radius * Math.Sin(-(((180 - deg) / 2) + deg + startingAngle) * rad);
vertices[0] = new(
(int) Math.Round(x0),
(int) Math.Round(y0)
);
vertices[1] = new(
(int) Math.Round(x1),
(int) Math.Round(y1)
);
for (int i = 0; i < sides - 2; i++)
{
double dsinrot = Math.Sin((deg * (i + 1)) * rad);
double dcosrot = Math.Cos((deg * (i + 1)) * rad);
vertices[i + 2] = new(
(int)Math.Round(center.X + dcosrot * (x1 - center.X) - dsinrot * (y1 - center.Y)),
(int)Math.Round(center.Y + dsinrot * (x1 - center.X) + dcosrot * (y1 - center.Y))
);
}
if (flipHorizontally)
{
var startX = center.X - radius;
var endX = center.X + radius;
for (int i = 0; i < sides; i++)
{
vertices[i].X = endX - (vertices[i].X - startX);
}
}
if (flipVertically)
{
var startY = center.Y - radius;
var endY = center.Y + radius;
for (int i = 0; i < sides; i++)
{
vertices[i].Y = endY - (vertices[i].Y - startY);
}
}
return vertices;
}
}
}
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