/*
* This region is a C++ -> C# conversion from the original sources of Pascal Getreuer <*****@*****.**>
*/
/// <summary>
/// Resizes the image to the specified dimensions using the given kernel type.
/// </summary>
/// <param name="destWidth">Width of the destination.</param>
/// <param name="destHeight">Height of the destination.</param>
/// <param name="interpolationInfo">The interpolation method info.</param>
/// <param name="centeredGrid">if set to <c>true</c> using a centered grid; otherwise, using top-left aligned.</param>
/// <returns>
/// The resized image
/// </returns>
private FloatImage _Resize(int destWidth, int destHeight, Kernels.FixedRadiusKernelInfo interpolationInfo, bool centeredGrid)
{
var xScale = (float)destWidth / this.Width;
var yScale = (float)destHeight / this.Height;
var xStep = 1 / xScale;
var yStep = 1 / yScale;
float xStart, yStart;
if (centeredGrid)
{
xStart = (xStep - 1) / 2;
yStart = (yStep - 1) / 2;
}
else
{
xStart = yStart = 0;
}
var result = new FloatImage(destWidth, destHeight, this._horizontalOutOfBoundsMode, this._verticalOutOfBoundsMode);
// prefilter image if necessary
if (interpolationInfo.PrefilterAlpha != null && interpolationInfo.PrefilterAlpha.Length > 0)
{
this._PrefilterImage(interpolationInfo.PrefilterAlpha, interpolationInfo.PrefilterScale);
}
// resample
this._LinScale2D(
result,
xStart,
xStep,
yStart,
yStep,
interpolationInfo.Kernel,
interpolationInfo.KernelRadius,
interpolationInfo.KernelNormalize,
OutOfBoundsUtils.GetHandlerOrCrash(this.HorizontalOutOfBoundsMode),
OutOfBoundsUtils.GetHandlerOrCrash(this.VerticalOutOfBoundsMode)
);
return(result);
}
/// <summary>
/// Converts a given image into a floating point one.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="filterRegion">The filter region.</param>
/// <returns></returns>
public static FloatImage FromImage(cImage image, Rectangle?filterRegion)
{
Contract.Requires(image != null);
var startX = filterRegion == null ? 0 : Math.Max(0, filterRegion.Value.Left);
var startY = filterRegion == null ? 0 : Math.Max(0, filterRegion.Value.Top);
var endX = filterRegion == null ? image.Width : Math.Min(image.Width, filterRegion.Value.Right);
var endY = filterRegion == null ? image.Height : Math.Min(image.Height, filterRegion.Value.Bottom);
var width = endX - startX;
var height = endY - startY;
var result = new FloatImage(width, height, image.HorizontalOutOfBoundsMode, image.VerticalOutOfBoundsMode);
// copy image data
Parallel.ForEach(
Partitioner.Create(startY, endY),
() => 0,
(range, _, threadStorage) => {
var i = (range.Item1 - startY) * width;
for (var y = range.Item1; y < range.Item2; ++y)
{
for (var x = startX; x < endX; ++x)
{
var color = image[x, y];
result._redPlane[i] = color.SingleRed;
result._greenPlane[i] = color.SingleGreen;
result._bluePlane[i] = color.SingleBlue;
result._alphaPlane[i] = color.SingleAlpha;
++i;
}
}
return(threadStorage);
},
_ => { }
);
return(result);
}
/*
* This region is a C++ -> C# conversion from the original sources of Pascal Getreuer <*****@*****.**>
*/
/// <summary>
/// Resizes the image to the specified dimensions using the given kernel type.
/// </summary>
/// <param name="destWidth">Width of the destination.</param>
/// <param name="destHeight">Height of the destination.</param>
/// <param name="interpolationInfo">The interpolation method info.</param>
/// <param name="centeredGrid">if set to <c>true</c> using a centered grid; otherwise, using top-left aligned.</param>
/// <returns>
/// The resized image
/// </returns>
private FloatImage _Resize(int destWidth, int destHeight, Kernels.FixedRadiusKernelInfo interpolationInfo, bool centeredGrid) {
var xScale = (float)destWidth / this.Width;
var yScale = (float)destHeight / this.Height;
var xStep = 1 / xScale;
var yStep = 1 / yScale;
float xStart, yStart;
if (centeredGrid) {
xStart = (xStep - 1) / 2;
yStart = (yStep - 1) / 2;
} else {
xStart = yStart = 0;
}
var result = new FloatImage(destWidth, destHeight, this._horizontalOutOfBoundsMode, this._verticalOutOfBoundsMode);
// prefilter image if necessary
if (interpolationInfo.PrefilterAlpha != null && interpolationInfo.PrefilterAlpha.Length > 0)
this._PrefilterImage(interpolationInfo.PrefilterAlpha, interpolationInfo.PrefilterScale);
// resample
this._LinScale2D(
result,
xStart,
xStep,
yStart,
yStep,
interpolationInfo.Kernel,
interpolationInfo.KernelRadius,
interpolationInfo.KernelNormalize,
OutOfBoundsUtils.GetHandlerOrCrash(this.HorizontalOutOfBoundsMode),
OutOfBoundsUtils.GetHandlerOrCrash(this.VerticalOutOfBoundsMode)
);
return (result);
}
/// <summary>
/// Scale image with a compact support interpolation kernel
/// This is a generic linear interpolation routine to scale an image using any
/// compactly supported interpolation kernel. The kernel is applied separably
/// along both dimensions. Half-sample even symmetric extension is used to
/// handle the boundaries.
///
/// The interpolation is computed so that Dest[m + DestWidth*n] is the
/// interpolation of Src at sampling location
/// (XStart + m*XStep, YStart + n*YStep)
/// for m = 0, ..., DestWidth - 1, n = 0, ..., DestHeight - 1, where the
/// pixels of Src are located at the integers.
///
/// The implementation follows the approach taken in ffmpeg's swscale library.
/// First a "scanline filter" is constructed, a sparse matrix such that
/// multiplying with a row of the input image produces an interpolated row in
/// the output image. Similarly a second matrix is constructed for
/// interpolating columns. The interpolation itself is then essentially two
/// sparse matrix times dense matrix multiplies.
/// </summary>
/// <param name="destination">pointer to memory for holding the interpolated image</param>
/// <param name="xStart">leftmost sampling location (in input coordinates)</param>
/// <param name="xStep">the length between successive samples (in input coordinates)</param>
/// <param name="yStart">uppermost sampling location (in input coordinates)</param>
/// <param name="yStep">the length between successive samples (in input coordinates)</param>
/// <param name="kernel">interpolation kernel function to use</param>
/// <param name="kernelRadius">kernel support radius</param>
/// <param name="kernelNormalize">if set to <c>true</c> filter rows are normalized to sum to 1</param>
/// <param name="horizontalOutOfBoundsHandler">The horizontal out of bounds handler.</param>
/// <param name="verticalOutOfBoundsHandler">The vertical out of bounds handler.</param>
private void _LinScale2D(FloatImage destination, float xStart, float xStep, float yStart, float yStep, Kernels.FixedRadiusKernelMethod kernel, float kernelRadius, bool kernelNormalize, OutOfBoundsUtils.OutOfBoundsHandler horizontalOutOfBoundsHandler, OutOfBoundsUtils.OutOfBoundsHandler verticalOutOfBoundsHandler) {
Contract.Requires(destination != null);
Contract.Requires(kernel != null);
Contract.Requires(!(kernelRadius < 0));
var srcWidth = this.Width;
var srcHeight = this.Height;
var destHeight = destination.Height;
var destWidth = destination.Width;
var buffer = new float[srcWidth * destHeight];
var hFilter = _MakeScaleScanFilter(destWidth, xStart, xStep, srcWidth, kernel, kernelRadius, kernelNormalize, horizontalOutOfBoundsHandler);
var vFilter = _MakeScaleScanFilter(destHeight, yStart, yStep, srcHeight, kernel, kernelRadius, kernelNormalize, verticalOutOfBoundsHandler);
foreach (var plane in new[] {
Tuple.Create(this._redPlane,destination._redPlane),
Tuple.Create(this._greenPlane,destination._greenPlane),
Tuple.Create(this._bluePlane,destination._bluePlane),
Tuple.Create(this._alphaPlane,destination._alphaPlane),
}) {
for (var x = 0; x < srcWidth; x++)
_ScaleScan(buffer, x, srcWidth, destHeight, plane.Item1, x, srcWidth, vFilter);
for (var y = 0; y < destHeight; y++)
_ScaleScan(plane.Item2, y * destWidth, 1, destWidth, buffer, y * srcWidth, 1, hFilter);
}
}
/// <summary>
/// Converts a given image into a floating point one.
/// </summary>
/// <param name="image">The image.</param>
/// <param name="filterRegion">The filter region.</param>
/// <returns></returns>
public static FloatImage FromImage(cImage image, Rectangle? filterRegion) {
Contract.Requires(image != null);
var startX = filterRegion == null ? 0 : Math.Max(0, filterRegion.Value.Left);
var startY = filterRegion == null ? 0 : Math.Max(0, filterRegion.Value.Top);
var endX = filterRegion == null ? image.Width : Math.Min(image.Width, filterRegion.Value.Right);
var endY = filterRegion == null ? image.Height : Math.Min(image.Height, filterRegion.Value.Bottom);
var width = endX - startX;
var height = endY - startY;
var result = new FloatImage(width, height, image.HorizontalOutOfBoundsMode, image.VerticalOutOfBoundsMode);
// copy image data
Parallel.ForEach(
Partitioner.Create(startY, endY),
() => 0,
(range, _, threadStorage) => {
var i = (range.Item1 - startY) * width;
for (var y = range.Item1; y < range.Item2; ++y) {
for (var x = startX; x < endX; ++x) {
var color = image[x, y];
result._redPlane[i] = color.SingleRed;
result._greenPlane[i] = color.SingleGreen;
result._bluePlane[i] = color.SingleBlue;
result._alphaPlane[i] = color.SingleAlpha;
++i;
}
}
return (threadStorage);
},
_ => { }
);
return (result);
}
