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Refactored LinearGradientBrush

This commit is contained in:
Darth Affe 2015-09-24 21:42:29 +02:00
parent d80d454d43
commit ca65581f6d
2 changed files with 42 additions and 52 deletions

View File

@ -4,7 +4,6 @@ namespace CUE.NET.Devices.Keyboard.Brushes
{
public class GradientStop
{
#region Properties & Fields
public float Offset { get; set; }

View File

@ -42,89 +42,80 @@ namespace CUE.NET.Devices.Keyboard.Brushes
#endregion
#region Methods
public Color GetColorAtPoint(RectangleF rectangle, PointF point)
{
if (!GradientStops.Any()) return Color.Transparent;
if (GradientStops.Count == 1) return GradientStops.First().Color;
// Taken from https://dotupdate.wordpress.com/2008/01/28/find-the-color-of-a-point-in-a-lineargradientbrush/
// Based on https://dotupdate.wordpress.com/2008/01/28/find-the-color-of-a-point-in-a-lineargradientbrush/
float x3 = point.X;
float y3 = point.Y;
PointF startPoint = new PointF(StartPoint.X * rectangle.Width, StartPoint.Y * rectangle.Height);
PointF endPoint = new PointF(EndPoint.X * rectangle.Width, EndPoint.Y * rectangle.Height);
float x1 = StartPoint.X * rectangle.Width;
float y1 = StartPoint.Y * rectangle.Height;
PointF p1 = new PointF(x1, y1); // Starting point
PointF intersectingPoint;
if (startPoint.Y.Equals(endPoint.Y)) // Horizontal case
intersectingPoint = new PointF(point.X, startPoint.Y);
float x2 = EndPoint.X * rectangle.Width;
float y2 = EndPoint.Y * rectangle.Height;
PointF p2 = new PointF(x2, y2); //End point
// Calculate intersecting points
PointF p4;
if (y1.Equals(y2)) // Horizontal case
p4 = new PointF(x3, y1);
else if (x1.Equals(x2)) // Vertical case
p4 = new PointF(x1, y3);
else if (startPoint.X.Equals(endPoint.X)) // Vertical case
intersectingPoint = new PointF(startPoint.X, point.Y);
else // Diagnonal case
{
float m = (y2 - y1) / (x2 - x1);
float m2 = -1 / m;
float b = y1 - m * x1;
float c = y3 - m2 * x3;
float slope = (endPoint.Y - startPoint.Y) / (endPoint.X - startPoint.X);
float orthogonalSlope = -1 / slope;
float startYIntercept = startPoint.Y - slope * startPoint.X;
float pointYIntercept = point.Y - orthogonalSlope * point.X;
float x4 = (c - b) / (m - m2);
float y4 = m * x4 + b;
p4 = new PointF(x4, y4);
float intersectingPointX = (pointYIntercept - startYIntercept) / (slope - orthogonalSlope);
float intersectingPointY = slope * intersectingPointX + startYIntercept;
intersectingPoint = new PointF(intersectingPointX, intersectingPointY);
}
// Calculate distances relative to the vector start
float d4 = Dist(p4, p1, p2);
float d2 = Dist(p2, p1, p2);
float intersectDistance = CalculateDistance(intersectingPoint, startPoint, endPoint);
float gradientLength = CalculateDistance(endPoint, startPoint, endPoint);
float x = d4 / d2;
float offset = intersectDistance / gradientLength;
// Clip the input if before or after the max/min offset values
float max = GradientStops.Max(n => n.Offset);
if (x > max)
x = max;
if (offset > max)
offset = max;
float min = GradientStops.Min(n => n.Offset);
if (x < min)
x = min;
if (offset < min)
offset = min;
// Find gradient stops that surround the input value
GradientStop gs0 = GradientStops.Where(n => n.Offset <= x).OrderBy(n => n.Offset).Last();
GradientStop gs1 = GradientStops.Where(n => n.Offset >= x).OrderBy(n => n.Offset).First();
GradientStop gsBefore = GradientStops.Where(n => n.Offset <= offset).OrderBy(n => n.Offset).Last();
GradientStop gsAfter = GradientStops.Where(n => n.Offset >= offset).OrderBy(n => n.Offset).First();
float y = 0f;
if (!gs0.Offset.Equals(gs1.Offset))
y = ((x - gs0.Offset) / (gs1.Offset - gs0.Offset));
float blendFactor = 0f;
if (!gsBefore.Offset.Equals(gsAfter.Offset))
blendFactor = ((offset - gsBefore.Offset) / (gsAfter.Offset - gsBefore.Offset));
byte colA = (byte)((gs1.Color.A - gs0.Color.A) * y + gs0.Color.A);
byte colR = (byte)((gs1.Color.R - gs0.Color.R) * y + gs0.Color.R);
byte colG = (byte)((gs1.Color.G - gs0.Color.G) * y + gs0.Color.G);
byte colB = (byte)((gs1.Color.B - gs0.Color.B) * y + gs0.Color.B);
byte colA = (byte)((gsAfter.Color.A - gsBefore.Color.A) * blendFactor + gsBefore.Color.A);
byte colR = (byte)((gsAfter.Color.R - gsBefore.Color.R) * blendFactor + gsBefore.Color.R);
byte colG = (byte)((gsAfter.Color.G - gsBefore.Color.G) * blendFactor + gsBefore.Color.G);
byte colB = (byte)((gsAfter.Color.B - gsBefore.Color.B) * blendFactor + gsBefore.Color.B);
return Color.FromArgb(colA, colR, colG, colB);
}
// Taken from https://dotupdate.wordpress.com/2008/01/28/find-the-color-of-a-point-in-a-lineargradientbrush/
// Based on https://dotupdate.wordpress.com/2008/01/28/find-the-color-of-a-point-in-a-lineargradientbrush/
/// <summary>
/// Returns the signed magnitude of a point on a vector with origin po and pointing to pf
/// Returns the signed magnitude of a point on a vector
/// </summary>
private float Dist(PointF px, PointF po, PointF pf)
private float CalculateDistance(PointF point, PointF origin, PointF direction)
{
float d = (float)Math.Sqrt((px.Y - po.Y) * (px.Y - po.Y) + (px.X - po.X) * (px.X - po.X));
float distance = (float)Math.Sqrt((point.Y - origin.Y) * (point.Y - origin.Y) + (point.X - origin.X) * (point.X - origin.X));
return (((px.Y < po.Y) && (pf.Y > po.Y)) ||
((px.Y > po.Y) && (pf.Y < po.Y)) ||
((px.Y.Equals(po.Y)) && (px.X < po.X) && (pf.X > po.X)) ||
((px.Y.Equals(po.Y)) && (px.X > po.X) && (pf.X < po.X)))
? -d : d;
return (((point.Y < origin.Y) && (direction.Y > origin.Y)) ||
((point.Y > origin.Y) && (direction.Y < origin.Y)) ||
((point.Y.Equals(origin.Y)) && (point.X < origin.X) && (direction.X > origin.X)) ||
((point.Y.Equals(origin.Y)) && (point.X > origin.X) && (direction.X < origin.X)))
? -distance : distance;
}
#endregion