static void GradientColour(double z, Gradient grad, out double r, out double g, out double b, out double a)
{
r = g = b = a = 0;
if (grad == null)
{
return;
}
z = Math.Min(1.0, Math.Max(0.0, z));
var seg = GetSegmentAt(grad, z);
double middle, factor = 0;
double seglen = seg.right - seg.left;
if (seglen < double.Epsilon)
{
middle = 0.5;
z = 0.5;
}
else
{
middle = (seg.middle - seg.left) / seglen;
z = (z - seg.left) / seglen;
}
switch (seg.type)
{
case GradType.Linear:
factor = CalcLinearFactor(middle, z);
break;
case GradType.Curved:
if (middle < double.Epsilon)
{
middle = double.Epsilon;
}
factor = Math.Pow(z, Math.Log(0.5) / Math.Log(middle));
break;
case GradType.Sine:
z = CalcLinearFactor(middle, z);
factor = (Math.Sin((-Math.PI / 2.0) + Math.PI * z) + 1.0) / 2.0;
break;
case GradType.SphereInc:
z = CalcLinearFactor(middle, z) - 1.0;
factor = Math.Sqrt(1.0 - z * z);
break;
case GradType.SphereDec:
z = CalcLinearFactor(middle, z);
factor = 1.0 - Math.Sqrt(1.0 - z * z);
break;
default:
throw new ArgumentException("Corrupt gradient");
}
a = seg.a0 + (seg.a1 - seg.a0) * factor;
if (seg.color == GradColor.RGB)
{
r = seg.r0 + (seg.r1 - seg.r0) * factor;
g = seg.g0 + (seg.g1 - seg.g0) * factor;
b = seg.b0 + (seg.b1 - seg.b0) * factor;
}
else
{
double h0, s0, v0;
ColorHelpers.RGBtoHSV(seg.r0, seg.g0, seg.b0, out h0, out s0, out v0);
double h1, s1, v1;
ColorHelpers.RGBtoHSV(seg.r1, seg.g1, seg.b1, out h1, out s1, out v1);
s0 = s0 + (s1 - s0) * factor;
v0 = v0 + (v1 - v0) * factor;
switch (seg.color)
{
case GradColor.HSVccw:
if (h0 < h1)
{
h0 = h0 + (h1 - h0) * factor;
}
else
{
h0 = h0 + (1.0 - (h0 - h1)) * factor;
if (h0 > 1.0)
{
h0 -= 1.0;
}
}
break;
case GradColor.HSVcw:
if (h1 < h0)
{
h0 = h0 - (h0 - h1) * factor;
}
else
{
h0 = h0 - (1.0 - (h1 - h0)) * factor;
if (h0 < 0.0)
{
h0 += 1.0;
}
}
break;
default:
throw new ArgumentException("unknown colour model");
}
ColorHelpers.HSVtoRGB(h0, s0, v0, out r, out g, out b);
}
}
static GradSegment ParseSeg(string line)
{
int element = 0;
StringBuilder chunk = new StringBuilder();
double num = double.NaN;
GradSegment seg = new GradSegment();
line += " ";
foreach (char c in line)
{
if (!char.IsWhiteSpace(c))
{
chunk.Append(c);
continue;
}
double.TryParse(chunk.ToString(), out num);
if (double.IsInfinity(num) || double.IsNaN(num))
{
throw new ArgumentOutOfRangeException("unexpected value found");
}
switch (element)
{
case 00: seg.left = num; break;
case 01: seg.middle = num; break;
case 02: seg.right = num; break;
case 03: seg.r0 = num; break;
case 04: seg.g0 = num; break;
case 05: seg.b0 = num; break;
case 06: seg.a0 = num; break;
case 07: seg.r1 = num; break;
case 08: seg.g1 = num; break;
case 09: seg.b1 = num; break;
case 10: seg.a1 = num; break;
case 11: seg.type = (GradType)((int)num); break;
case 12: seg.color = (GradColor)((int)num); break;
}
chunk.Clear();
element++;
}
if (seg.color == GradColor.HSVshort || seg.color == GradColor.HSVlong)
{
double h0, s0, v0, h1, s1, v1;
ColorHelpers.RGBtoHSV(seg.r0, seg.g0, seg.b0, out h0, out s0, out v0);
ColorHelpers.RGBtoHSV(seg.r1, seg.g1, seg.b1, out h1, out s1, out v1);
seg.color = GradHSVType(seg.color, h0, h1);
}
if (!Enum.IsDefined(typeof(GradColor), seg.color))
{
throw new ArgumentOutOfRangeException("unknown colour model");
}
return(seg);
}
