protected internal override Shader GetShader(Size size)
{
if (GradientStops.Count == 0)
{
return(null);
}
var colors = GradientStops.SelectToList(s => ((Android.Graphics.Color)GetColorWithOpacity(s.Color)).ToArgb());
var locations = GradientStops.SelectToList(s => (float)s.Offset);
if (GradientStops.Count == 1)
{
// Android LinearGradient requires two ore more stop points.
// We work around this by duplicating the first gradient stop.
colors.Add(colors[0]);
locations.Add(locations[0]);
}
var width = size.Width;
var height = size.Height;
Android.Graphics.Matrix nativeTransformMatrix = null;
if (RelativeTransform != null)
{
var matrix = RelativeTransform.ToMatrix(Point.Zero, new Size(width, height));
matrix.M31 *= (float)width;
matrix.M32 *= (float)height;
nativeTransformMatrix = matrix.ToNative();
}
//Matrix .MapPoints takes an array of floats
var pts = MappingMode == BrushMappingMode.RelativeToBoundingBox
? new[]
{
(float)(StartPoint.X * width),
(float)(StartPoint.Y * height),
(float)(EndPoint.X * width),
(float)(EndPoint.Y * height)
}
: new[]
{
(float)ViewHelper.LogicalToPhysicalPixels(StartPoint.X),
(float)ViewHelper.LogicalToPhysicalPixels(StartPoint.Y),
(float)ViewHelper.LogicalToPhysicalPixels(EndPoint.X),
(float)ViewHelper.LogicalToPhysicalPixels(EndPoint.Y)
};
nativeTransformMatrix?.MapPoints(pts);
nativeTransformMatrix?.Dispose();
return(new LinearGradient(pts[0], pts[1], pts[2], pts[3], colors.ToArray(), locations.ToArray(), Shader.TileMode.Clamp));
}
public Vector2 RelativeToAbsolute(int x, int y)
{
var points = new float[] {x, y};
var inverse = new Matrix();
InverseMatrix.Invert(inverse);
inverse.MapPoints(points);
return new Vector2(points);
}