public void Encode_WithPngTransparentColorBehaviorClear_Works(PngColorType colorType)
{
// arrange
var image = new Image <Rgba32>(50, 50);
var encoder = new PngEncoder()
{
TransparentColorMode = PngTransparentColorMode.Clear,
ColorType = colorType
};
Rgba32 rgba32 = Color.Blue;
for (int y = 0; y < image.Height; y++)
{
System.Span <Rgba32> rowSpan = image.GetPixelRowSpan(y);
// Half of the test image should be transparent.
if (y > 25)
{
rgba32.A = 0;
}
for (int x = 0; x < image.Width; x++)
{
rowSpan[x].FromRgba32(rgba32);
}
}
// act
using var memStream = new MemoryStream();
image.Save(memStream, encoder);
// assert
memStream.Position = 0;
using var actual = Image.Load <Rgba32>(memStream);
Rgba32 expectedColor = Color.Blue;
if (colorType == PngColorType.Grayscale || colorType == PngColorType.GrayscaleWithAlpha)
{
var luminance = ImageMaths.Get8BitBT709Luminance(expectedColor.R, expectedColor.G, expectedColor.B);
expectedColor = new Rgba32(luminance, luminance, luminance);
}
for (int y = 0; y < actual.Height; y++)
{
System.Span <Rgba32> rowSpan = actual.GetPixelRowSpan(y);
if (y > 25)
{
expectedColor = Color.Transparent;
}
for (int x = 0; x < actual.Width; x++)
{
Assert.Equal(expectedColor, rowSpan[x]);
}
}
}
/// <inheritdoc/>
protected override void OnFrameApply(ImageFrame <TPixel> source)
{
byte threshold = (byte)MathF.Round(this.Definition.Threshold * 255F);
bool isAlphaOnly = typeof(TPixel) == typeof(Alpha8);
var interest = Rectangle.Intersect(this.SourceRectangle, source.Bounds());
int startY = interest.Y;
int endY = interest.Bottom;
int startX = interest.X;
int endX = interest.Right;
// Collect the values before looping so we can reduce our calculation count for identical sibling pixels
TPixel sourcePixel = source[startX, startY];
TPixel previousPixel = sourcePixel;
PixelPair <TPixel> pair = this.GetClosestPixelPair(ref sourcePixel);
Rgba32 rgba = default;
sourcePixel.ToRgba32(ref rgba);
// Convert to grayscale using ITU-R Recommendation BT.709 if required
byte luminance = isAlphaOnly ? rgba.A : ImageMaths.Get8BitBT709Luminance(rgba.R, rgba.G, rgba.B);
for (int y = startY; y < endY; y++)
{
Span <TPixel> row = source.GetPixelRowSpan(y);
for (int x = startX; x < endX; x++)
{
sourcePixel = row[x];
// Check if this is the same as the last pixel. If so use that value
// rather than calculating it again. This is an inexpensive optimization.
if (!previousPixel.Equals(sourcePixel))
{
pair = this.GetClosestPixelPair(ref sourcePixel);
// No error to spread, exact match.
if (sourcePixel.Equals(pair.First))
{
continue;
}
sourcePixel.ToRgba32(ref rgba);
luminance = isAlphaOnly ? rgba.A : ImageMaths.Get8BitBT709Luminance(rgba.R, rgba.G, rgba.B);
// Setup the previous pointer
previousPixel = sourcePixel;
}
TPixel transformedPixel = luminance >= threshold ? pair.Second : pair.First;
this.Definition.Diffuser.Dither(source, sourcePixel, transformedPixel, x, y, startX, startY, endX, endY);
}
}
}
public void Gray8_FromRgba32(byte rgb)
{
// Arrange
Gray8 gray = default;
byte expected = ImageMaths.Get8BitBT709Luminance(rgb, rgb, rgb);
// Act
gray.FromRgba32(new Rgba32(rgb, rgb, rgb));
byte actual = gray.PackedValue;
// Assert
Assert.Equal(expected, actual);
}
public void La16_FromRgba32(byte rgb)
{
// Arrange
La16 gray = default;
byte expected = ImageMaths.Get8BitBT709Luminance(rgb, rgb, rgb);
// Act
gray.FromRgba32(new Rgba32(rgb, rgb, rgb));
byte actual = gray.L;
// Assert
Assert.Equal(expected, actual);
Assert.Equal(255, gray.A);
}
/// <inheritdoc/>
protected override void OnFrameApply(ImageFrame <TPixel> source)
{
IOrderedDither dither = this.definition.Dither;
TPixel upperColor = this.definition.UpperColor.ToPixel <TPixel>();
TPixel lowerColor = this.definition.LowerColor.ToPixel <TPixel>();
bool isAlphaOnly = typeof(TPixel) == typeof(A8);
var interest = Rectangle.Intersect(this.SourceRectangle, source.Bounds());
int startY = interest.Y;
int endY = interest.Bottom;
int startX = interest.X;
int endX = interest.Right;
// Collect the values before looping so we can reduce our calculation count for identical sibling pixels
TPixel sourcePixel = source[startX, startY];
TPixel previousPixel = sourcePixel;
Rgba32 rgba = default;
sourcePixel.ToRgba32(ref rgba);
// Convert to grayscale using ITU-R Recommendation BT.709 if required
byte luminance = isAlphaOnly ? rgba.A : ImageMaths.Get8BitBT709Luminance(rgba.R, rgba.G, rgba.B);
for (int y = startY; y < endY; y++)
{
Span <TPixel> row = source.GetPixelRowSpan(y);
for (int x = startX; x < endX; x++)
{
sourcePixel = row[x];
// Check if this is the same as the last pixel. If so use that value
// rather than calculating it again. This is an inexpensive optimization.
if (!previousPixel.Equals(sourcePixel))
{
sourcePixel.ToRgba32(ref rgba);
luminance = isAlphaOnly ? rgba.A : ImageMaths.Get8BitBT709Luminance(rgba.R, rgba.G, rgba.B);
// Setup the previous pointer
previousPixel = sourcePixel;
}
dither.Dither(source, sourcePixel, upperColor, lowerColor, luminance, x, y);
}
}
}
/// <inheritdoc/>
protected override void OnFrameApply(ImageFrame <TPixel> source)
{
byte threshold = (byte)MathF.Round(this.definition.Threshold * 255F);
TPixel upper = this.definition.UpperColor.ToPixel <TPixel>();
TPixel lower = this.definition.LowerColor.ToPixel <TPixel>();
Rectangle sourceRectangle = this.SourceRectangle;
Configuration configuration = this.Configuration;
var interest = Rectangle.Intersect(sourceRectangle, source.Bounds());
int startY = interest.Y;
int endY = interest.Bottom;
int startX = interest.X;
int endX = interest.Right;
bool isAlphaOnly = typeof(TPixel) == typeof(Alpha8);
var workingRect = Rectangle.FromLTRB(startX, startY, endX, endY);
ParallelHelper.IterateRows(
workingRect,
configuration,
rows =>
{
Rgba32 rgba = default;
for (int y = rows.Min; y < rows.Max; y++)
{
Span <TPixel> row = source.GetPixelRowSpan(y);
for (int x = startX; x < endX; x++)
{
ref TPixel color = ref row[x];
color.ToRgba32(ref rgba);
// Convert to grayscale using ITU-R Recommendation BT.709 if required
byte luminance = isAlphaOnly ? rgba.A : ImageMaths.Get8BitBT709Luminance(rgba.R, rgba.G, rgba.B);
color = luminance >= threshold ? upper : lower;
}
}
});
}
