mirror of https://github.com/SixLabors/ImageSharp
Anton Firszov
9 years ago
4 changed files with 164 additions and 90 deletions
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namespace ImageSharp.Processing.Processors |
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{ |
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using System; |
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using System.Numerics; |
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using System.Runtime.CompilerServices; |
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/// <content>
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/// Conains the definition of <see cref="WeightsWindow"/> and <see cref="WeightsBuffer"/>.
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/// </content>
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internal abstract partial class ResamplingWeightedProcessor<TColor> |
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{ |
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/// <summary>
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/// Points to a collection of of weights allocated in <see cref="WeightsBuffer"/>.
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/// </summary>
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protected unsafe struct WeightsWindow |
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{ |
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/// <summary>
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/// The local left index position
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/// </summary>
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public int Left; |
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/// <summary>
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/// The span of weights pointing to <see cref="WeightsBuffer"/>.
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/// </summary>
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public BufferSpan<float> Span; |
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/// <summary>
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/// Initializes a new instance of the <see cref="WeightsWindow"/> struct.
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/// </summary>
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/// <param name="left">The local left index</param>
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/// <param name="span">The span</param>
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[MethodImpl(MethodImplOptions.AggressiveInlining)] |
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internal WeightsWindow(int left, BufferSpan<float> span) |
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{ |
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this.Left = left; |
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this.Span = span; |
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} |
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/// <summary>
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/// Gets an unsafe float* pointer to the beginning of <see cref="Span"/>.
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/// </summary>
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public float* Ptr => (float*)this.Span.PointerAtOffset; |
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/// <summary>
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/// Gets the lenghth of the weights window
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/// </summary>
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public int Length => this.Span.Length; |
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/// <summary>
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/// Computes the sum of vectors in 'rowSpan' weighted by weight values, pointed by this <see cref="WeightsWindow"/> instance.
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/// </summary>
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/// <param name="rowSpan">The input span of vectors</param>
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/// <returns>The weighted sum</returns>
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public Vector4 ComputeWeightedRowSum(BufferSpan<Vector4> rowSpan) |
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{ |
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float* horizontalValues = this.Ptr; |
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int left = this.Left; |
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// Destination color components
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Vector4 result = Vector4.Zero; |
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for (int i = 0; i < this.Length; i++) |
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{ |
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float xw = horizontalValues[i]; |
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int index = left + i; |
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result += rowSpan[index] * xw; |
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} |
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return result; |
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} |
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/// <summary>
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/// Computes the sum of vectors in 'firstPassPixels' at a column pointed by 'x',
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/// weighted by weight values, pointed by this <see cref="WeightsWindow"/> instance.
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/// </summary>
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/// <param name="firstPassPixels">The buffer of input vectors in row first order</param>
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/// <param name="x">The column position</param>
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/// <returns>The weighted sum</returns>
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public Vector4 ComputeWeightedColumnSum(PinnedImageBuffer<Vector4> firstPassPixels, int x) |
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{ |
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float* verticalValues = this.Ptr; |
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int left = this.Left; |
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// Destination color components
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Vector4 result = Vector4.Zero; |
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for (int i = 0; i < this.Length; i++) |
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{ |
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float yw = verticalValues[i]; |
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int index = left + i; |
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result += firstPassPixels[x, index] * yw; |
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} |
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return result; |
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} |
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} |
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/// <summary>
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/// Holds the <see cref="WeightsWindow"/> values in an optimized contigous memory region.
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/// </summary>
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protected class WeightsBuffer : IDisposable |
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{ |
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private PinnedImageBuffer<float> dataBuffer; |
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/// <summary>
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/// Initializes a new instance of the <see cref="WeightsBuffer"/> class.
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/// </summary>
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/// <param name="sourceSize">The size of the source window</param>
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/// <param name="destinationSize">The size of the destination window</param>
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public WeightsBuffer(int sourceSize, int destinationSize) |
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{ |
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this.dataBuffer = new PinnedImageBuffer<float>(sourceSize, destinationSize); |
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this.dataBuffer.Clear(); |
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this.Weights = new WeightsWindow[destinationSize]; |
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} |
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/// <summary>
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/// Gets the calculated <see cref="Weights"/> values.
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/// </summary>
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public WeightsWindow[] Weights { get; } |
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/// <summary>
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/// Disposes <see cref="WeightsBuffer"/> instance releasing it's backing buffer.
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/// </summary>
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public void Dispose() |
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{ |
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this.dataBuffer.Dispose(); |
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} |
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/// <summary>
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/// Slices a weights value at the given positions.
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/// </summary>
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/// <param name="destIdx">The index in destination buffer</param>
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/// <param name="leftIdx">The local left index value</param>
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/// <param name="rightIdx">The local right index value</param>
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/// <returns>The weights</returns>
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public WeightsWindow GetWeightsWindow(int destIdx, int leftIdx, int rightIdx) |
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{ |
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BufferSpan<float> span = this.dataBuffer.GetRowSpan(destIdx).Slice(leftIdx, rightIdx - leftIdx); |
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return new WeightsWindow(leftIdx, span); |
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} |
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} |
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} |
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} |
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