private static GradientStop GetStartStop(float offset, List <GradientStop> stops)
{
for (int i = stops.Count - 1; i >= 0; i--)
{
GradientStop stop = stops[i];
if (offset >= stop.Offset)
{
return(stop);
}
}
if (stops.Count != 0)
{
return(stops[0]);
}
return(null);
}
/// <summary>
/// Generates the linear gradient texture content
/// </summary>
/// <param name="lineStart">The line start.</param>
/// <param name="lineEnd">The line end.</param>
/// <param name="borderThickness">The border thickness.</param>
/// <param name="sortedStops">The sorted stops.</param>
/// <param name="spread">The spread.</param>
/// <param name="isBorder">if set to <c>true</c> [is border].</param>
public override void GenerateLinearGradient(PointF lineStart, PointF lineEnd, Thickness borderThickness, List <GradientStop> sortedStops,
GradientSpreadMethod spread, bool isBorder)
{
Color[] data = new Color[Width * Height];
Color startColor = Color.TransparentBlack;
Color endColor = Color.TransparentBlack;
PointF point = new PointF();
float length = GetLength(lineStart, lineEnd);
int index = 0;
for (int y = 0; y < Height; y++)
{
for (int x = 0; x < Width; x++)
{
point.Y = y;
point.X = x;
if ((borderThickness.Top > point.Y || borderThickness.Bottom >= Height - point.Y) ||
(borderThickness.Left > point.X || borderThickness.Right >= Width - point.X) ||
!isBorder)
{
PointF projectPoint = ProjectToLine(lineStart, lineEnd, point, Width);
float finalOffset = GetLength(projectPoint, lineStart) / length;
switch (spread)
{
case GradientSpreadMethod.Pad:
if (projectPoint.X <= lineStart.X && projectPoint.Y <= lineStart.Y)
{
finalOffset = 0;
}
if (projectPoint.X >= lineEnd.X && projectPoint.Y >= lineEnd.Y)
{
finalOffset = 1;
}
break;
case GradientSpreadMethod.Reflect:
if (projectPoint.X <= lineStart.X && projectPoint.Y <= lineStart.Y ||
projectPoint.X >= lineEnd.X && projectPoint.Y >= lineEnd.Y)
{
if (finalOffset > 1)
{
finalOffset = ((float)Math.Ceiling(finalOffset) - finalOffset);
}
}
break;
case GradientSpreadMethod.Repeat:
if (projectPoint.X <= lineStart.X && projectPoint.Y <= lineStart.Y)
{
if (finalOffset > 0)
{
finalOffset = ((float)Math.Ceiling(finalOffset) - finalOffset);
}
}
if (projectPoint.X >= lineEnd.X && projectPoint.Y >= lineEnd.Y)
{
if (finalOffset > 1)
{
finalOffset = (finalOffset - (float)Math.Floor(finalOffset));
}
}
break;
default:
Debug.Assert(false);
break;
}
GradientStop startStop = GetStartStop(finalOffset, sortedStops);
startColor = startStop != null ? new Color {
PackedValue = startStop.Color.PackedValue
} : Color.TransparentBlack;
GradientStop endStop = GetEndStop(finalOffset, sortedStops, spread);
endColor = endStop != null ? new Color {
PackedValue = endStop.Color.PackedValue
} : Color.TransparentBlack;
if (endStop != null && startStop != null)
{
finalOffset = (finalOffset - startStop.Offset) * (1f / (endStop.Offset - startStop.Offset));
}
if (float.IsInfinity(finalOffset))
{
finalOffset = 0;
}
if (float.IsNaN(finalOffset))
{
finalOffset = 1;
}
Color finalColor = Color.Lerp(startColor, endColor, finalOffset);
data[index] = finalColor;
}
else
{
data[index] = Color.TransparentBlack;
}
index++;
}
}
texture.SetData <Color>(data);
}
