vendoring NetVips

vendor/NetVips/net6.0/Image.cs

@@ -0,0 +1,171 @@
+#if NET6_0_OR_GREATER
+
+using System;
+using System.Runtime.InteropServices;
+using NetVips.Internal;
+
+namespace NetVips;
+
+/// <summary>
+/// Wrap a <see cref="VipsImage"/> object.
+/// </summary>
+public partial class Image
+{
+    #region helpers
+
+    /// <summary>
+    /// Find the name of the load operation vips will use to load a buffer.
+    /// </summary>
+    /// <remarks>
+    /// For example "VipsForeignLoadJpegBuffer". You can use this to work out what
+    /// options to pass to <see cref="NewFromBuffer(ReadOnlySpan{byte}, string, Enums.Access?, Enums.FailOn?, VOption)"/>.
+    /// </remarks>
+    /// <param name="data">The buffer to test.</param>
+    /// <param name="size">Length of the buffer.</param>
+    /// <returns>The name of the load operation, or <see langword="null"/>.</returns>
+    private static unsafe string FindLoadBuffer(void* data, ulong size) =>
+        Marshal.PtrToStringAnsi(VipsForeign.FindLoadBuffer(data, size));
+
+    /// <summary>
+    /// Find the name of the load operation vips will use to load a buffer.
+    /// </summary>
+    /// <remarks>
+    /// For example "VipsForeignLoadJpegBuffer". You can use this to work out what
+    /// options to pass to <see cref="NewFromBuffer(ReadOnlySpan{byte}, string, Enums.Access?, Enums.FailOn?, VOption)"/>.
+    /// </remarks>
+    /// <param name="data">The buffer to test.</param>
+    /// <returns>The name of the load operation, or <see langword="null"/>.</returns>
+    public static unsafe string FindLoadBuffer(ReadOnlySpan<byte> data)
+    {
+        fixed (byte* dataFixed = data)
+        {
+            return FindLoadBuffer(dataFixed, (ulong)data.Length);
+        }
+    }
+
+    #endregion
+
+    #region constructors
+
+    /// <summary>
+    /// Load a formatted image from memory.
+    /// </summary>
+    /// <remarks>
+    /// This behaves exactly as <see cref="NewFromFile"/>, but the image is
+    /// loaded from the memory object rather than from a file. The memory
+    /// object can be a string or buffer.
+    /// </remarks>
+    /// <param name="data">The memory object to load the image from.</param>
+    /// <param name="strOptions">Load options as a string. Use <see cref="string.Empty"/> for no options.</param>
+    /// <param name="access">Hint the expected access pattern for the image.</param>
+    /// <param name="failOn">The type of error that will cause load to fail. By
+    /// default, loaders are permissive, that is, <see cref="Enums.FailOn.None"/>.</param>
+    /// <param name="kwargs">Optional options that depend on the load operation.</param>
+    /// <returns>A new <see cref="Image"/>.</returns>
+    /// <exception cref="VipsException">If unable to load from <paramref name="data"/>.</exception>
+    public static unsafe Image NewFromBuffer(
+        ReadOnlySpan<byte> data,
+        string strOptions = "",
+        Enums.Access? access = null,
+        Enums.FailOn? failOn = null,
+        VOption kwargs = null)
+    {
+        fixed (byte* dataFixed = data)
+        {
+            var operationName = FindLoadBuffer(dataFixed, (ulong)data.Length);
+            if (operationName == null)
+            {
+                throw new VipsException("unable to load from buffer");
+            }
+
+            var options = new VOption();
+            if (kwargs != null)
+            {
+                options.Merge(kwargs);
+            }
+
+            options.AddIfPresent(nameof(access), access);
+            options.AddFailOn(failOn);
+
+            options.Add("string_options", strOptions);
+
+            var ptr = Internal.VipsBlob.Copy(dataFixed, (nuint)data.Length);
+            if (ptr == IntPtr.Zero)
+            {
+                throw new VipsException("unable to load from buffer");
+            }
+
+            using var blob = new VipsBlob(ptr);
+            return Operation.Call(operationName, options, blob) as Image;
+        }
+    }
+
+    /// <summary>
+    /// Wrap an image around a memory array.
+    /// </summary>
+    /// <param name="data">A <see cref="ReadOnlyMemory{T}"/>.</param>
+    /// <param name="width">Image width in pixels.</param>
+    /// <param name="height">Image height in pixels.</param>
+    /// <param name="bands">Number of bands.</param>
+    /// <param name="format">Band format.</param>
+    /// <returns>A new <see cref="Image"/>.</returns>
+    /// <exception cref="VipsException">If unable to make image from <paramref name="data"/>.</exception>
+    public static unsafe Image NewFromMemory<T>(
+        ReadOnlyMemory<T> data,
+        int width,
+        int height,
+        int bands,
+        Enums.BandFormat format) where T : unmanaged
+    {
+        var handle = data.Pin();
+        var vi = VipsImage.NewFromMemory(handle.Pointer, (nuint)data.Length, width, height, bands,
+            format);
+        if (vi == IntPtr.Zero)
+        {
+            handle.Dispose();
+
+            throw new VipsException("unable to make image from memory");
+        }
+
+        var image = new Image(vi) { MemoryPressure = data.Length };
+
+        // Need to release the pinned MemoryHandle when the image is closed.
+        image.OnPostClose += () => handle.Dispose();
+
+        return image;
+    }
+
+    /// <summary>
+    /// Like <see cref="NewFromMemory{T}(ReadOnlyMemory{T}, int, int, int, Enums.BandFormat)"/>, but
+    /// for <see cref="ReadOnlySpan{T}"/>, so we must copy as it could be allocated on the stack.
+    /// </summary>
+    /// <param name="data">A <see cref="ReadOnlySpan{T}"/>.</param>
+    /// <param name="width">Image width in pixels.</param>
+    /// <param name="height">Image height in pixels.</param>
+    /// <param name="bands">Number of bands.</param>
+    /// <param name="format">Band format.</param>
+    /// <returns>A new <see cref="Image"/>.</returns>
+    /// <exception cref="VipsException">If unable to make image from <paramref name="data"/>.</exception>
+    public static unsafe Image NewFromMemoryCopy<T>(
+        ReadOnlySpan<T> data,
+        int width,
+        int height,
+        int bands,
+        Enums.BandFormat format) where T : unmanaged
+    {
+        fixed (T* dataFixed = data)
+        {
+            var vi = VipsImage.NewFromMemoryCopy(dataFixed, (nuint)data.Length, width, height, bands, format);
+            if (vi == IntPtr.Zero)
+            {
+                throw new VipsException("unable to make image from memory");
+            }
+
+            return new Image(vi) { MemoryPressure = data.Length };
+        }
+    }
+
+    #endregion
+}
+
+#endif