71 lines
No EOL
2.3 KiB
C#
71 lines
No EOL
2.3 KiB
C#
namespace Uwaa.PNG;
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/// <summary>
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/// The high level information about the image.
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/// </summary>
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public readonly struct ImageHeader
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{
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internal static readonly byte[] HeaderBytes = { 73, 72, 68, 82 };
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internal static readonly byte[] ValidationHeader = { 137, 80, 78, 71, 13, 10, 26, 10 };
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static readonly Dictionary<ColorType, HashSet<byte>> PermittedBitDepths = new Dictionary<ColorType, HashSet<byte>>
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{
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{ColorType.None, new HashSet<byte> {1, 2, 4, 8, 16}},
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{ColorType.ColorUsed, new HashSet<byte> {8, 16}},
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{ColorType.PaletteUsed | ColorType.ColorUsed, new HashSet<byte> {1, 2, 4, 8}},
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{ColorType.AlphaChannelUsed, new HashSet<byte> {8, 16}},
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{ColorType.AlphaChannelUsed | ColorType.ColorUsed, new HashSet<byte> {8, 16}},
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};
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/// <summary>
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/// The width of the image in pixels.
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/// </summary>
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public int Width { get; }
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/// <summary>
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/// The height of the image in pixels.
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/// </summary>
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public int Height { get; }
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/// <summary>
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/// The bit depth of the image.
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/// </summary>
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public byte BitDepth { get; }
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/// <summary>
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/// The color type of the image.
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/// </summary>
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public ColorType ColorType { get; }
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/// <summary>
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/// The interlace method used by the image..
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/// </summary>
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public InterlaceMethod InterlaceMethod { get; }
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/// <summary>
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/// Create a new <see cref="ImageHeader"/>.
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/// </summary>
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public ImageHeader(int width, int height, byte bitDepth, ColorType colorType, InterlaceMethod interlaceMethod)
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{
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if (width == 0)
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throw new ArgumentOutOfRangeException(nameof(width), "Invalid width (0) for image.");
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if (height == 0)
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throw new ArgumentOutOfRangeException(nameof(height), "Invalid height (0) for image.");
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if (!PermittedBitDepths.TryGetValue(colorType, out var permitted) || !permitted.Contains(bitDepth))
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throw new ArgumentException($"The bit depth {bitDepth} is not permitted for color type {colorType}.");
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Width = width;
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Height = height;
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BitDepth = bitDepth;
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ColorType = colorType;
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InterlaceMethod = interlaceMethod;
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}
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public override string ToString()
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{
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return $"w: {Width}, h: {Height}, bitDepth: {BitDepth}, colorType: {ColorType}, interlace: {InterlaceMethod}.";
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}
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} |