public GradientBrushTexture(GradientStopCollection stops)
{
_assetId++;
_stops = new List <GradientStopData>(stops.Count);
foreach (GradientStop stop in stops)
{
_stops.Add(GradientStopData.FromGradientStop(stop));
}
_name = String.Format("GradientBrushTexture#{0}", _assetId);
Allocate();
}
private static void CreatePartialGradient(byte[] data, GradientStopData stopBegin, GradientStopData stopEnd)
{
const float width = GRADIENT_TEXTURE_WIDTH;
const int offY = GRADIENT_TEXTURE_WIDTH * 4;
Color4 colorStart = ColorConverter.FromColor(stopBegin.Color);
Color4 colorEnd = ColorConverter.FromColor(stopEnd.Color);
int offsetStart = (int)(stopBegin.Offset * width);
int offsetEnd = (int)(stopEnd.Offset * width);
int clampedStart = Math.Max(0, offsetStart);
int clampedEnd = Math.Min(GRADIENT_TEXTURE_WIDTH, offsetEnd);
float distance = offsetEnd - offsetStart;
for (int x = clampedStart; x < clampedEnd; ++x)
{
float step = (x - offsetStart) / distance;
float r = step * (colorEnd.Red - colorStart.Red);
r += colorStart.Red;
float g = step * (colorEnd.Green - colorStart.Green);
g += colorStart.Green;
float b = step * (colorEnd.Blue - colorStart.Blue);
b += colorStart.Blue;
float a = step * (colorEnd.Alpha - colorStart.Alpha);
a += colorStart.Alpha;
a *= 255;
r *= 255;
g *= 255;
b *= 255;
int offx = x * 4;
data[offx] = (byte)b;
data[offx + 1] = (byte)g;
data[offx + 2] = (byte)r;
data[offx + 3] = (byte)a;
data[offY + offx] = (byte)b;
data[offY + offx + 1] = (byte)g;
data[offY + offx + 2] = (byte)r;
data[offY + offx + 3] = (byte)a;
}
}
private static void CreatePartialGradient(byte[] data, GradientStopData stopBegin, GradientStopData stopEnd)
{
const float width = GRADIENT_TEXTURE_WIDTH;
const int offY = GRADIENT_TEXTURE_WIDTH * 4;
Color4 colorStart = ColorConverter.FromColor(stopBegin.Color);
Color4 colorEnd = ColorConverter.FromColor(stopEnd.Color);
int offsetStart = (int) (stopBegin.Offset * width);
int offsetEnd = (int) (stopEnd.Offset * width);
int clampedStart = Math.Max(0, offsetStart);
int clampedEnd = Math.Min(GRADIENT_TEXTURE_WIDTH, offsetEnd);
float distance = offsetEnd - offsetStart;
for (int x = clampedStart; x < clampedEnd; ++x)
{
float step = (x - offsetStart) / distance;
float r = step * (colorEnd.Red - colorStart.Red);
r += colorStart.Red;
float g = step * (colorEnd.Green - colorStart.Green);
g += colorStart.Green;
float b = step * (colorEnd.Blue - colorStart.Blue);
b += colorStart.Blue;
float a = step * (colorEnd.Alpha - colorStart.Alpha);
a += colorStart.Alpha;
a *= 255;
r *= 255;
g *= 255;
b *= 255;
int offx = x * 4;
data[offx] = (byte) b;
data[offx + 1] = (byte) g;
data[offx + 2] = (byte) r;
data[offx + 3] = (byte) a;
data[offY + offx] = (byte) b;
data[offY + offx + 1] = (byte) g;
data[offY + offx + 2] = (byte) r;
data[offY + offx + 3] = (byte) a;
}
}