Metafile.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.IO;
using System.ComponentModel;
using System.Drawing.Internal;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.Serialization;
using Gdip = System.Drawing.SafeNativeMethods.Gdip;

namespace System.Drawing.Imaging;

/// <summary>
/// Defines a graphic metafile. A metafile contains records that describe a sequence of graphics operations that
/// can be recorded and played back.
/// </summary>
[Editor($"System.Drawing.Design.MetafileEditor, {AssemblyRef.SystemDrawingDesign}",
        $"System.Drawing.Design.UITypeEditor, {AssemblyRef.SystemDrawing}")]
[Serializable]
[TypeForwardedFrom(AssemblyRef.SystemDrawing)]
public sealed class Metafile : Image
{
    // GDI+ doesn't handle filenames over MAX_PATH very well
    private const int MaxPath = 260;

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified handle and
    /// <see cref='WmfPlaceableFileHeader'/>.
    /// </summary>
    public Metafile(IntPtr hmetafile, WmfPlaceableFileHeader wmfHeader, bool deleteWmf)
    {
        Gdip.CheckStatus(Gdip.GdipCreateMetafileFromWmf(hmetafile, deleteWmf, wmfHeader, out IntPtr metafile));
        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified handle and
    /// <see cref='WmfPlaceableFileHeader'/>.
    /// </summary>
    public Metafile(IntPtr henhmetafile, bool deleteEmf)
    {
        Gdip.CheckStatus(Gdip.GdipCreateMetafileFromEmf(henhmetafile, deleteEmf, out IntPtr metafile));
        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified filename.
    /// </summary>
    public Metafile(string filename)
    {
        // Called in order to emulate exception behavior from .NET Framework related to invalid file paths.
        Path.GetFullPath(filename);
        Gdip.CheckStatus(Gdip.GdipCreateMetafileFromFile(filename, out IntPtr metafile));
        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified device context, bounded
    /// by the specified rectangle.
    /// </summary>
    public Metafile(IntPtr referenceHdc, Rectangle frameRect) :
        this(referenceHdc, frameRect, MetafileFrameUnit.GdiCompatible)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified handle to a device context.
    /// </summary>
    public Metafile(IntPtr referenceHdc, EmfType emfType) :
        this(referenceHdc, emfType, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified device context, bounded
    /// by the specified rectangle.
    /// </summary>
    public Metafile(IntPtr referenceHdc, RectangleF frameRect) :
        this(referenceHdc, frameRect, MetafileFrameUnit.GdiCompatible)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified device context, bounded
    /// by the specified rectangle.
    /// </summary>
    public Metafile(IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit) :
        this(referenceHdc, frameRect, frameUnit, EmfType.EmfPlusDual)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified device context, bounded
    /// by the specified rectangle.
    /// </summary>
    public Metafile(IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit, EmfType type) :
        this(referenceHdc, frameRect, frameUnit, type, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified device context, bounded
    /// by the specified rectangle.
    /// </summary>
    public Metafile(IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit, EmfType type, string? description)
    {
        Gdip.CheckStatus(Gdip.GdipRecordMetafile(
            referenceHdc,
            type,
            ref frameRect,
            frameUnit,
            description,
            out IntPtr metafile));

        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified device context, bounded
    /// by the specified rectangle.
    /// </summary>
    public Metafile(IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit) :
        this(referenceHdc, frameRect, frameUnit, EmfType.EmfPlusDual)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified device context, bounded
    /// by the specified rectangle.
    /// </summary>
    public Metafile(IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit, EmfType type) :
        this(referenceHdc, frameRect, frameUnit, type, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc) :
        this(fileName, referenceHdc, EmfType.EmfPlusDual, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, EmfType type) :
        this(fileName, referenceHdc, type, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, RectangleF frameRect) :
        this(fileName, referenceHdc, frameRect, MetafileFrameUnit.GdiCompatible)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit) :
        this(fileName, referenceHdc, frameRect, frameUnit, EmfType.EmfPlusDual)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit, EmfType type) :
        this(fileName, referenceHdc, frameRect, frameUnit, type, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit, string? desc) :
        this(fileName, referenceHdc, frameRect, frameUnit, EmfType.EmfPlusDual, desc)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit, EmfType type, string? description)
    {
        // Called in order to emulate exception behavior from .NET Framework related to invalid file paths.
        Path.GetFullPath(fileName);
        if (fileName.Length > MaxPath)
        {
            throw new PathTooLongException();
        }

        Gdip.CheckStatus(Gdip.GdipRecordMetafileFileName(
            fileName,
            referenceHdc,
            type,
            ref frameRect,
            frameUnit,
            description,
            out IntPtr metafile));

        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, Rectangle frameRect) :
        this(fileName, referenceHdc, frameRect, MetafileFrameUnit.GdiCompatible)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit) :
        this(fileName, referenceHdc, frameRect, frameUnit, EmfType.EmfPlusDual)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit, EmfType type) :
        this(fileName, referenceHdc, frameRect, frameUnit, type, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit, string? description) :
        this(fileName, referenceHdc, frameRect, frameUnit, EmfType.EmfPlusDual, description)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified data stream.
    /// </summary>
    public Metafile(Stream stream, IntPtr referenceHdc) :
        this(stream, referenceHdc, EmfType.EmfPlusDual, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified data stream.
    /// </summary>
    public Metafile(Stream stream, IntPtr referenceHdc, EmfType type) :
        this(stream, referenceHdc, type, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified data stream.
    /// </summary>
    public Metafile(Stream stream, IntPtr referenceHdc, RectangleF frameRect) :
        this(stream, referenceHdc, frameRect, MetafileFrameUnit.GdiCompatible)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(Stream stream, IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit) :
        this(stream, referenceHdc, frameRect, frameUnit, EmfType.EmfPlusDual)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(Stream stream, IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit, EmfType type) :
        this(stream, referenceHdc, frameRect, frameUnit, type, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified data stream.
    /// </summary>
    public Metafile(Stream stream, IntPtr referenceHdc, Rectangle frameRect) :
        this(stream, referenceHdc, frameRect, MetafileFrameUnit.GdiCompatible)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(Stream stream, IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit) :
        this(stream, referenceHdc, frameRect, frameUnit, EmfType.EmfPlusDual)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(Stream stream, IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit, EmfType type) :
        this(stream, referenceHdc, frameRect, frameUnit, type, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified handle and
    /// <see cref='WmfPlaceableFileHeader'/>.
    /// </summary>
    public Metafile(IntPtr hmetafile, WmfPlaceableFileHeader wmfHeader) :
        this(hmetafile, wmfHeader, false)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified stream.
    /// </summary>
    public unsafe Metafile(Stream stream)
    {
        ArgumentNullException.ThrowIfNull(stream);

        using DrawingCom.IStreamWrapper streamWrapper = DrawingCom.GetComWrapper(new GPStream(stream));

        IntPtr metafile = IntPtr.Zero;
        Gdip.CheckStatus(Gdip.GdipCreateMetafileFromStream(streamWrapper.Ptr, &metafile));

        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified handle to a device context.
    /// </summary>
    public Metafile(IntPtr referenceHdc, EmfType emfType, string? description)
    {
        Gdip.CheckStatus(Gdip.GdipRecordMetafile(
            referenceHdc,
            emfType,
            IntPtr.Zero,
            MetafileFrameUnit.GdiCompatible,
            description,
            out IntPtr metafile));

        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified device context, bounded
    /// by the specified rectangle.
    /// </summary>
    public Metafile(IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit, EmfType type, string? desc)
    {
        IntPtr metafile;

        if (frameRect.IsEmpty)
        {
            Gdip.CheckStatus(Gdip.GdipRecordMetafile(
                referenceHdc,
                type,
                IntPtr.Zero,
                MetafileFrameUnit.GdiCompatible,
                desc,
                out metafile));
        }
        else
        {
            Gdip.CheckStatus(Gdip.GdipRecordMetafileI(
                referenceHdc,
                type,
                ref frameRect,
                frameUnit,
                desc,
                out metafile));
        }

        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, EmfType type, string? description)
    {
        // Called in order to emulate exception behavior from .NET Framework related to invalid file paths.
        Path.GetFullPath(fileName);

        Gdip.CheckStatus(Gdip.GdipRecordMetafileFileName(
            fileName,
            referenceHdc,
            type,
            IntPtr.Zero,
            MetafileFrameUnit.GdiCompatible,
            description,
            out IntPtr metafile));

        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public Metafile(string fileName, IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit, EmfType type, string? description)
    {
        // Called in order to emulate exception behavior from .NET Framework related to invalid file paths.
        Path.GetFullPath(fileName);

        IntPtr metafile;

        if (frameRect.IsEmpty)
        {
            Gdip.CheckStatus(Gdip.GdipRecordMetafileFileName(
                fileName,
                referenceHdc,
                type,
                IntPtr.Zero,
                frameUnit,
                description,
                out metafile));
        }
        else
        {
            Gdip.CheckStatus(Gdip.GdipRecordMetafileFileNameI(
                fileName,
                referenceHdc,
                type,
                ref frameRect,
                frameUnit,
                description,
                out metafile));
        }

        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class from the specified data stream.
    /// </summary>
    public unsafe Metafile(Stream stream, IntPtr referenceHdc, EmfType type, string? description)
    {
        using DrawingCom.IStreamWrapper streamWrapper = DrawingCom.GetComWrapper(new GPStream(stream));

        IntPtr metafile = IntPtr.Zero;
        Gdip.CheckStatus(Gdip.GdipRecordMetafileStream(
            streamWrapper.Ptr,
            referenceHdc,
            type,
            IntPtr.Zero,
            MetafileFrameUnit.GdiCompatible,
            description,
            &metafile));

        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public unsafe Metafile(Stream stream, IntPtr referenceHdc, RectangleF frameRect, MetafileFrameUnit frameUnit, EmfType type, string? description)
    {
        using DrawingCom.IStreamWrapper streamWrapper = DrawingCom.GetComWrapper(new GPStream(stream));

        IntPtr metafile = IntPtr.Zero;
        Gdip.CheckStatus(Gdip.GdipRecordMetafileStream(
            streamWrapper.Ptr,
            referenceHdc,
            type,
            &frameRect,
            frameUnit,
            description,
            &metafile));

        SetNativeImage(metafile);
    }

    /// <summary>
    /// Initializes a new instance of the <see cref='Metafile'/> class with the specified filename.
    /// </summary>
    public unsafe Metafile(Stream stream, IntPtr referenceHdc, Rectangle frameRect, MetafileFrameUnit frameUnit, EmfType type, string? description)
    {
        using DrawingCom.IStreamWrapper streamWrapper = DrawingCom.GetComWrapper(new GPStream(stream));

        IntPtr metafile = IntPtr.Zero;
        if (frameRect.IsEmpty)
        {
            Gdip.CheckStatus(Gdip.GdipRecordMetafileStream(
                streamWrapper.Ptr,
                referenceHdc,
                type,
                IntPtr.Zero,
                frameUnit,
                description,
                &metafile));
        }
        else
        {
            Gdip.CheckStatus(Gdip.GdipRecordMetafileStreamI(
                streamWrapper.Ptr,
                referenceHdc,
                type,
                &frameRect,
                frameUnit,
                description,
                &metafile));
        }

        SetNativeImage(metafile);
    }

    private Metafile(SerializationInfo info, StreamingContext context) : base(info, context)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="Metafile"/> class from a native metafile handle.
    /// </summary>
    internal Metafile(IntPtr ptr) => SetNativeImage(ptr);

    /// <summary>
    /// Plays an EMF+ file.
    /// </summary>
    public void PlayRecord(EmfPlusRecordType recordType, int flags, int dataSize, byte[] data)
    {
        // Used in conjunction with Graphics.EnumerateMetafile to play an EMF+
        // The data must be DWORD aligned if it's an EMF or EMF+.  It must be
        // WORD aligned if it's a WMF.

        Gdip.CheckStatus(Gdip.GdipPlayMetafileRecord(
            new HandleRef(this, _nativeImage),
            recordType,
            flags,
            dataSize,
            data));
    }

    /// <summary>
    /// Returns the <see cref='MetafileHeader'/> associated with the specified <see cref='Metafile'/>.
    /// </summary>
    public static MetafileHeader GetMetafileHeader(IntPtr hmetafile, WmfPlaceableFileHeader wmfHeader)
    {
        MetafileHeader header = new MetafileHeader
        {
            wmf = new MetafileHeaderWmf()
        };

        Gdip.CheckStatus(Gdip.GdipGetMetafileHeaderFromWmf(hmetafile, wmfHeader, header.wmf));
        return header;
    }

    /// <summary>
    /// Returns the <see cref='MetafileHeader'/> associated with the specified <see cref='Metafile'/>.
    /// </summary>
    public static MetafileHeader GetMetafileHeader(IntPtr henhmetafile)
    {
        MetafileHeader header = new MetafileHeader
        {
            emf = new MetafileHeaderEmf()
        };

        Gdip.CheckStatus(Gdip.GdipGetMetafileHeaderFromEmf(henhmetafile, header.emf));
        return header;
    }

    /// <summary>
    /// Returns the <see cref='MetafileHeader'/> associated with the specified <see cref='Metafile'/>.
    /// </summary>
    public static MetafileHeader GetMetafileHeader(string fileName)
    {
        // Called in order to emulate exception behavior from .NET Framework related to invalid file paths.
        Path.GetFullPath(fileName);

        MetafileHeader header = new MetafileHeader();

        IntPtr memory = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeaderEmf>());

        try
        {
            Gdip.CheckStatus(Gdip.GdipGetMetafileHeaderFromFile(fileName, memory));

            int[] type = new int[] { 0 };

            Marshal.Copy(memory, type, 0, 1);

            MetafileType metafileType = (MetafileType)type[0];

            if (metafileType == MetafileType.Wmf ||
                metafileType == MetafileType.WmfPlaceable)
            {
                // WMF header
                header.wmf = Marshal.PtrToStructure<MetafileHeaderWmf>(memory)!;
                header.emf = null;
            }
            else
            {
                // EMF header
                header.wmf = null;
                header.emf = Marshal.PtrToStructure<MetafileHeaderEmf>(memory)!;
            }
        }
        finally
        {
            Marshal.FreeHGlobal(memory);
        }

        return header;
    }

    /// <summary>
    /// Returns the <see cref='MetafileHeader'/> associated with the specified <see cref='Metafile'/>.
    /// </summary>
    public static MetafileHeader GetMetafileHeader(Stream stream)
    {
        MetafileHeader header;

        IntPtr memory = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeaderEmf>());

        try
        {
            using DrawingCom.IStreamWrapper streamWrapper = DrawingCom.GetComWrapper(new GPStream(stream));
            Gdip.CheckStatus(Gdip.GdipGetMetafileHeaderFromStream(streamWrapper.Ptr, memory));

            int[] type = new int[] { 0 };

            Marshal.Copy(memory, type, 0, 1);

            MetafileType metafileType = (MetafileType)type[0];

            header = new MetafileHeader();

            if (metafileType == MetafileType.Wmf ||
                metafileType == MetafileType.WmfPlaceable)
            {
                // WMF header
                header.wmf = Marshal.PtrToStructure<MetafileHeaderWmf>(memory)!;
                header.emf = null;
            }
            else
            {
                // EMF header
                header.wmf = null;
                header.emf = Marshal.PtrToStructure<MetafileHeaderEmf>(memory)!;
            }
        }
        finally
        {
            Marshal.FreeHGlobal(memory);
        }

        return header;
    }

    /// <summary>
    /// Returns the <see cref='MetafileHeader'/> associated with this <see cref='Metafile'/>.
    /// </summary>
    public MetafileHeader GetMetafileHeader()
    {
        MetafileHeader header;

        IntPtr memory = Marshal.AllocHGlobal(Marshal.SizeOf<MetafileHeaderEmf>());

        try
        {
            Gdip.CheckStatus(Gdip.GdipGetMetafileHeaderFromMetafile(new HandleRef(this, _nativeImage), memory));

            int[] type = new int[] { 0 };

            Marshal.Copy(memory, type, 0, 1);

            MetafileType metafileType = (MetafileType)type[0];

            header = new MetafileHeader();

            if (metafileType == MetafileType.Wmf ||
                metafileType == MetafileType.WmfPlaceable)
            {
                // WMF header
                header.wmf = Marshal.PtrToStructure<MetafileHeaderWmf>(memory)!;
                header.emf = null;
            }
            else
            {
                // EMF header
                header.wmf = null;
                header.emf = Marshal.PtrToStructure<MetafileHeaderEmf>(memory)!;
            }
        }
        finally
        {
            Marshal.FreeHGlobal(memory);
        }

        return header;
    }

    /// <summary>
    /// Returns a Windows handle to an enhanced <see cref='Metafile'/>.
    /// </summary>
    public IntPtr GetHenhmetafile()
    {
        Gdip.CheckStatus(Gdip.GdipGetHemfFromMetafile(new HandleRef(this, _nativeImage), out IntPtr hEmf));
        return hEmf;
    }
}