internal static Bitmap ResizeLanczos(Bitmap source, int width, int height, Rectangle destinationRectangle, bool fixGamma = true)
{
int sourceWidth = source.Width;
int sourceHeight = source.Height;
int startX = destinationRectangle.X;
int startY = destinationRectangle.Y;
int endX = destinationRectangle.Width + startX;
int endY = destinationRectangle.Height + startY;
Bitmap destination = new Bitmap(width, height, PixelFormat.Format32bppPArgb);
destination.SetResolution(source.HorizontalResolution, source.VerticalResolution);
using (FastBitmap sourceBitmap = new FastBitmap(source))
{
using (FastBitmap destinationBitmap = new FastBitmap(destination))
{
// Scaling factors
double widthFactor = sourceWidth / (double)destinationRectangle.Width;
double heightFactor = sourceHeight / (double)destinationRectangle.Height;
// Width and height decreased by 1
int maxHeight = sourceHeight - 1;
int maxWidth = sourceWidth - 1;
// For each column
Parallel.For(
startY,
endY,
y =>
{
if (y >= 0 && y < height)
{
// Y coordinates of source points.
double originY = ((y - startY) * heightFactor) - 0.5;
int originY1 = (int)originY;
double dy = originY - originY1;
// For each row.
for (int x = startX; x < endX; x++)
{
if (x >= 0 && x < width)
{
// X coordinates of source points.
double originX = ((x - startX) * widthFactor) - 0.5f;
int originX1 = (int)originX;
double dx = originX - originX1;
// Destination color components
double r = 0;
double g = 0;
double b = 0;
double a = 0;
for (int n = -3; n < 6; n++)
{
// Get Y cooefficient
double k1 = Interpolation.LanczosKernel3(dy - n);
int originY2 = originY1 + n;
if (originY2 < 0)
{
originY2 = 0;
}
if (originY2 > maxHeight)
{
originY2 = maxHeight;
}
for (int m = -3; m < 6; m++)
{
// Get X cooefficient
double k2 = k1 * Interpolation.LanczosKernel3(m - dx);
int originX2 = originX1 + m;
if (originX2 < 0)
{
originX2 = 0;
}
if (originX2 > maxWidth)
{
originX2 = maxWidth;
}
// ReSharper disable once AccessToDisposedClosure
Color sourceColor = sourceBitmap.GetPixel(originX2, originY2);
if (fixGamma)
{
sourceColor = PixelOperations.ToLinear(sourceColor);
}
r += k2 * sourceColor.R;
g += k2 * sourceColor.G;
b += k2 * sourceColor.B;
a += k2 * sourceColor.A;
}
}
Color destinationColor = Color.FromArgb(
a.ToByte(),
r.ToByte(),
g.ToByte(),
b.ToByte());
if (fixGamma)
{
destinationColor = PixelOperations.ToSRGB(destinationColor);
}
// ReSharper disable once AccessToDisposedClosure
destinationBitmap.SetPixel(x, y, destinationColor);
}
}
}
});
}
}
source.Dispose();
return(destination);
}
public static Bitmap ResizeBicubicHighQuality(Bitmap source, int width, int height, Rectangle destinationRectangle, bool fixGamma)
{
int sourceWidth = source.Width;
int sourceHeight = source.Height;
int startX = destinationRectangle.X;
int startY = destinationRectangle.Y;
int endX = destinationRectangle.Width + startX;
int endY = destinationRectangle.Height + startY;
// Scaling factors
double widthFactor = sourceWidth / (double)destinationRectangle.Width;
double heightFactor = sourceHeight / (double)destinationRectangle.Height;
// Width and height decreased by 1
int maxHeight = sourceHeight - 1;
int maxWidth = sourceWidth - 1;
Bitmap destination = new Bitmap(width, height, PixelFormat.Format32bppPArgb);
destination.SetResolution(source.HorizontalResolution, source.VerticalResolution);
// The radius for pre blurring the images.
// We only apply this for very small images.
int radius = 0;
if (width <= 150 && height <= 150)
{
radius = 4;
}
using (FastBitmap sourceBitmap = new FastBitmap(source))
{
using (FastBitmap destinationBitmap = new FastBitmap(destination))
{
// For each column
Parallel.For(
startY,
endY,
y =>
{
if (y >= 0 && y < height)
{
// Y coordinates of source points.
double originY = ((y - startY) * heightFactor) - 0.5;
int originY1 = (int)originY;
double dy = originY - originY1;
// Houses colors for blurring.
Color[,] sourceColors = new Color[4, 4];
// For each row.
for (int x = startX; x < endX; x++)
{
if (x >= 0 && x < width)
{
// X coordinates of source points.
double originX = ((x - startX) * widthFactor) - 0.5f;
int originX1 = (int)originX;
double dx = originX - originX1;
// Destination color components
double r = 0;
double g = 0;
double b = 0;
double a = 0;
for (int yy = -1; yy < 3; yy++)
{
int originY2 = originY1 + yy;
if (originY2 < 0)
{
originY2 = 0;
}
if (originY2 > maxHeight)
{
originY2 = maxHeight;
}
for (int xx = -1; xx < 3; xx++)
{
int originX2 = originX1 + xx;
if (originX2 < 0)
{
originX2 = 0;
}
if (originX2 > maxWidth)
{
originX2 = maxWidth;
}
Color sourceColor = sourceBitmap.GetPixel(originX2, originY2);
sourceColors[xx + 1, yy + 1] = sourceColor;
}
}
// Blur the colors.
if (radius > 0)
{
sourceColors = BoxBlur(sourceColors, radius, fixGamma);
}
// Do the resize.
for (int yy = -1; yy < 3; yy++)
{
// Get Y cooefficient
double kernel1 = Interpolation.BiCubicBSplineKernel(dy - yy);
for (int xx = -1; xx < 3; xx++)
{
// Get X cooefficient
double kernel2 = kernel1 * Interpolation.BiCubicBSplineKernel(xx - dx);
Color sourceColor = sourceColors[xx + 1, yy + 1];
if (fixGamma)
{
sourceColor = PixelOperations.ToLinear(sourceColor);
}
r += kernel2 * sourceColor.R;
g += kernel2 * sourceColor.G;
b += kernel2 * sourceColor.B;
a += kernel2 * sourceColor.A;
}
}
Color destinationColor = Color.FromArgb(
a.ToByte(),
r.ToByte(),
g.ToByte(),
b.ToByte());
if (fixGamma)
{
destinationColor = PixelOperations.ToSRGB(destinationColor);
}
destinationBitmap.SetPixel(x, y, destinationColor);
}
}
}
});
}
}
source.Dispose();
return(destination);
}