144 lines
4.4 KiB
C#
144 lines
4.4 KiB
C#
using System;
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using System.IO;
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using System.Runtime.InteropServices;
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namespace Quik.Stb
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{
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/// <summary>
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/// A class that encompasses all features of stb_image.h in a safe way.
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/// </summary>
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public unsafe class StbImage : IDisposable
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{
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private bool isDisposed = false;
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/// <summary>
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/// Pointer to the image.
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/// </summary>
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public IntPtr ImagePointer { get; }
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/// <summary>
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/// Width of the image.
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/// </summary>
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public int Width { get; }
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/// <summary>
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/// Height of the image.
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/// </summary>
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/// <value></value>
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public int Height { get; }
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/// <summary>
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/// Internal image format.
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/// </summary>
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public StbiImageFormat Format { get; }
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public bool IsFloat { get; }
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private StbImage(IntPtr image, int x, int y, StbiImageFormat format, bool isFloat)
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{
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ImagePointer = image;
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Width = x;
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Height = y;
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Format = format;
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IsFloat = isFloat;
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}
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~StbImage()
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{
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Dispose(false);
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}
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public void Dispose() => Dispose(true);
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private void Dispose(bool disposing)
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{
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if (isDisposed) return;
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if (disposing)
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{
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GC.SuppressFinalize(this);
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}
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Stbi.image_free(ImagePointer.ToPointer());
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isDisposed = true;
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}
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/// <summary>
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/// Set to flip the y-axis of loaded images on load.
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/// </summary>
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public static bool FlipVerticallyOnLoad { set => Stbi.set_flip_vertically_on_load(1); }
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/// <summary>
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/// Set to unpremultiply images on load.
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/// </summary>
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/// <remarks>
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/// According to the stb_image documentation, only iPhone PNG images
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/// can come with premultiplied alpha.
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/// </remarks>
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public static bool UnpremultiplyOnLoad { set => Stbi.set_unpremultiply_on_load(1); }
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/// <summary>
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/// Try loading an image, without raising exceptions.
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/// </summary>
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/// <param name="image">The resulting image.</param>
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/// <param name="stream">Source stream.</param>
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/// <param name="format">The desired image format.</param>
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/// <returns>True on success.</returns>
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public static bool TryLoad(out StbImage image, Stream stream, StbiImageFormat format = StbiImageFormat.Default, bool isFloat = false)
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{
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int x, y, iFormat;
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StbiStreamWrapper wrapper = new StbiStreamWrapper(stream, true);
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wrapper.CreateCallbacks(out stbi_io_callbacks cb);
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stream.Position = 0;
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IntPtr imagePtr;
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if (isFloat)
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{
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imagePtr = (IntPtr)Stbi.loadf_from_callbacks(&cb, null, &x, &y, &iFormat, (int)format);
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}
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else
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{
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imagePtr = (IntPtr)Stbi.load_from_callbacks(&cb, null, &x, &y, &iFormat, (int)format);
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}
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if (imagePtr != IntPtr.Zero)
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{
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image = new StbImage(imagePtr, x, y, (StbiImageFormat)iFormat, isFloat);
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return true;
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}
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else
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{
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image = null;
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return false;
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}
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}
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/// <summary>
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/// Load an image.
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/// </summary>
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/// <param name="stream">The stream to load from.</param>
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/// <param name="format">The desired image format.</param>
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/// <returns>The image object.</returns>
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public static StbImage Load(Stream stream, StbiImageFormat format = StbiImageFormat.Default, bool isFloat = false)
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{
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if (TryLoad(out StbImage image, stream, format, isFloat))
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{
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return image;
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}
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string reason = Marshal.PtrToStringUTF8((IntPtr)Stbi.failure_reason());
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throw new Exception($"Failed to load image: {reason}");
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}
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public bool IsLoadable(Stream stream)
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{
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int x, y, iFormat;
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StbiStreamWrapper wrapper = new StbiStreamWrapper(stream, true);
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wrapper.CreateCallbacks(out stbi_io_callbacks cb);
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stream.Position = 0;
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int result = Stbi.info_from_callbacks(&cb, null, &x, &y, &iFormat);
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return result != 0;
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}
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}
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} |