public void ConversionTest <TSrcPixel, TDstPixel>()
where TSrcPixel : unmanaged, Pixel.IConvertTo, Pixel.IValueSetter <Pixel.BGRA32>
where TDstPixel : unmanaged, Pixel.IConvertTo, Pixel.IValueSetter <Pixel.BGRA32>
{
var srcFmt = PixelFormat.TryIdentifyFormat <TSrcPixel>();
var dstFmt = PixelFormat.TryIdentifyFormat <TDstPixel>();
var src = new TSrcPixel[5];
var dst = new TDstPixel[5];
for (int i = 0; i < 5; ++i)
{
src[i].SetValue(new Pixel.BGRA32(i * 50, 255 - i * 50, i * 30, 20 + i * 30));
}
Pixel.GetPixelCopyConverter <TSrcPixel, TDstPixel>().Invoke(src, dst);
for (int i = 0; i < 5; ++i)
{
var srcP = src[i].To <Pixel.BGRA32>();
var dstP = dst[i].To <Pixel.BGRA32>();
if (!srcFmt.HasUnpremulAlpha || !dstFmt.HasUnpremulAlpha)
{
srcP = new Pixel.BGRA32(srcP.R, srcP.G, srcP.B, (Byte)255);
dstP = new Pixel.BGRA32(dstP.R, dstP.G, dstP.B, (Byte)255);
}
Assert.AreEqual(srcP, dstP);
}
}
// 7.508 ns
public static Pixel.BGRP32 ToPremulReference(Pixel.BGRA32 src)
{
uint aa = src.A;
return(new Pixel.BGRP32
(
(Byte)((src.R * aa) / 255u),
(Byte)((src.G * aa) / 255u),
(Byte)((src.B * aa) / 255u),
src.A));
}
// 7.163 ns
public Pixel.BGRP32 ToPremulFast(Pixel.BGRA32 src)
{
var aa = (uint)257 * (uint)src.A;
return(new Pixel.BGRP32
(
(Byte)((src.R * aa + 255u) >> 16),
(Byte)((src.G * aa + 255u) >> 16),
(Byte)((src.B * aa + 255u) >> 16),
src.A));
}
private static void TestPremultiply <TPixel>(int a, int r)
where TPixel : unmanaged
, Pixel.IValueSetter <Pixel.BGRA32>
, Pixel.IValueSetter <Pixel.BGRP32>
, Pixel.IConvertTo
{
// color
var src = new Pixel.BGRA32(r, 1, 255, a);
var color = default(TPixel);
color.SetValue(src);
// references
var premulRef0 = color.GetReferenceBGRP32();
var rndtrpRef0 = premulRef0.GetReferenceBGRP32 <TPixel>();
// premul
var premul1 = color.To <Pixel.BGRP32>();
var premul2 = Pixel.BGRP32.From(color);
var premul3 = default(Pixel.BGRP32);
color.CopyTo(ref premul3);
Assert.AreEqual(premulRef0, premul1);
Assert.AreEqual(premulRef0, premul2);
Assert.AreEqual(premulRef0, premul3);
// unpremul
TPixel color1 = default;
color1.SetValue(premul1);
var color2 = premul1.To <TPixel>();
Assert.AreEqual(rndtrpRef0, color1);
Assert.AreEqual(rndtrpRef0, color2);
}