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Improve Image save performance (dotnet#10784)
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Getting the array of encoder ImageCodeInfo is expensive and unnecessary to do repeatedly. Cache the guids for internal use without converting to managed classes and jagged arrays.
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@JeremyKuhne
JeremyKuhne authored Feb 1, 2024
1 parent 869e40e commit 27713b2
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Showing 5 changed files with 132 additions and 108 deletions.
71 changes: 36 additions & 35 deletions src/System.Drawing.Common/src/System/Drawing/Image.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,9 +8,6 @@
using System.Runtime.Serialization;
using Windows.Win32.System.Com;

#if DEBUG
#endif

namespace System.Drawing;

/// <summary>
Expand Down Expand Up @@ -259,18 +256,29 @@ public void Save(string filename, ImageFormat format)
{
ArgumentNullException.ThrowIfNull(format);

ImageCodecInfo codec = format.FindEncoder() ?? ImageFormat.Png.FindEncoder()!;
Guid encoder = format.Encoder;
if (encoder == Guid.Empty)
{
encoder = ImageCodecInfo.GetEncoderClsid(PInvokeCore.ImageFormatPNG);
}

Save(filename, codec, null);
Save(filename, encoder, null);
}

/// <summary>
/// Saves this <see cref='Image'/> to the specified file in the specified format and with the specified encoder parameters.
/// </summary>
public void Save(string filename, ImageCodecInfo encoder, Imaging.EncoderParameters? encoderParams)
=> Save(filename, encoder.Clsid, encoderParams);

private void Save(string filename, Guid encoder, Imaging.EncoderParameters? encoderParams)
{
ArgumentNullException.ThrowIfNull(filename);
ArgumentNullException.ThrowIfNull(encoder);
if (encoder == Guid.Empty)
{
throw new ArgumentNullException(nameof(encoder));
}

ThrowIfDirectoryDoesntExist(filename);

GdiPlus.EncoderParameters* nativeParameters = null;
Expand All @@ -283,22 +291,17 @@ public void Save(string filename, ImageCodecInfo encoder, Imaging.EncoderParamet

try
{
Guid guid = encoder.Clsid;
bool saved = false;

if (_animatedGifRawData is not null && RawFormat.FindEncoder() is { } rawEncoder && rawEncoder.Clsid == guid)
if (_animatedGifRawData is not null && RawFormat.Encoder == encoder)
{
// Special case for animated gifs. We don't have an encoder for them, so we just write the raw data.
using var fs = File.OpenWrite(filename);
fs.Write(_animatedGifRawData, 0, _animatedGifRawData.Length);
saved = true;
return;
}

if (!saved)
fixed (char* fn = filename)
{
fixed (char* fn = filename)
{
PInvoke.GdipSaveImageToFile(_nativeImage, fn, &guid, nativeParameters).ThrowIfFailed();
}
PInvoke.GdipSaveImageToFile(_nativeImage, fn, &encoder, nativeParameters).ThrowIfFailed();
}
}
finally
Expand All @@ -315,15 +318,18 @@ public void Save(string filename, ImageCodecInfo encoder, Imaging.EncoderParamet

private void Save(MemoryStream stream)
{
// Jpeg loses data, so we don't want to use it to serialize...
ImageFormat dest = RawFormat;
if (dest.Guid == ImageFormat.Jpeg.Guid)
dest = ImageFormat.Png;
Guid format = RawFormat.Guid;
Guid encoder = ImageCodecInfo.GetEncoderClsid(format);

// If we don't find an Encoder (for things like Icon), we just switch back to PNG...
ImageCodecInfo codec = dest.FindEncoder() ?? ImageFormat.Png.FindEncoder()!;
// Jpeg loses data, so we don't want to use it to serialize. We'll use PNG instead.
// If we don't find an Encoder (for things like Icon), we just switch back to PNG.
if (format == PInvokeCore.ImageFormatJPEG || encoder == Guid.Empty)
{
format = PInvokeCore.ImageFormatPNG;
encoder = ImageCodecInfo.GetEncoderClsid(format);
}

Save(stream, codec);
Save(this, stream, encoder, format, null);
}

/// <summary>
Expand All @@ -332,23 +338,18 @@ private void Save(MemoryStream stream)
public void Save(Stream stream, ImageFormat format)
{
ArgumentNullException.ThrowIfNull(format);

ImageCodecInfo codec = format.FindEncoder()!;
Save(stream, codec);
Save(this, stream, format.Encoder, format.Guid, null);
}

internal void Save(Stream stream, ImageCodecInfo encoder) =>
Save(stream, encoder, encoderParameters: null);

internal void Save(Stream stream, ImageCodecInfo encoder, GdiPlus.EncoderParameters* encoderParameters) =>
Save(this, stream, encoder.Clsid, encoder.FormatID, encoderParameters);

internal static void Save(IImage image, Stream stream, Guid encoder, Guid format, GdiPlus.EncoderParameters* encoderParameters)
{
ArgumentNullException.ThrowIfNull(stream);
ArgumentNullException.ThrowIfNull(encoder);
if (encoder == Guid.Empty)
{
throw new ArgumentNullException(nameof(encoder));
}

if (format == ImageFormat.Gif.Guid && image.Data is { } rawData && rawData.Length > 0)
if (format == PInvokeCore.ImageFormatGIF && image.Data is { } rawData && rawData.Length > 0)
{
stream.Write(rawData);
return;
Expand Down Expand Up @@ -376,7 +377,7 @@ public void Save(Stream stream, ImageCodecInfo encoder, Imaging.EncoderParameter

try
{
Save(stream, encoder, nativeParameters);
Save(this, stream, encoder.Clsid, encoder.FormatID, nativeParameters);
}
finally
{
Expand Down
33 changes: 10 additions & 23 deletions src/System.Drawing.Common/src/System/Drawing/ImageConverter.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,6 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.ComponentModel;
using System.Drawing.Imaging;
using System.Globalization;
using System.IO;

Expand Down Expand Up @@ -40,7 +39,7 @@ public override bool CanConvertTo(ITypeDescriptorContext? context, [NotNullWhen(
}
}

public override object ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType)
public unsafe override object ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType)
{
if (destinationType == typeof(string))
{
Expand All @@ -63,37 +62,25 @@ public override object ConvertTo(ITypeDescriptorContext? context, CultureInfo? c
{
using MemoryStream ms = new();

ImageFormat dest = image.RawFormat;
// Jpeg loses data, so we don't want to use it to serialize.
if (dest == ImageFormat.Jpeg)
Guid format = image.RawFormat.Guid;
Guid encoder = ImageCodecInfo.GetEncoderClsid(format);

// Jpeg loses data, so we don't want to use it to serialize. We'll use PNG instead.
// If we don't find an Encoder (for things like Icon), we just switch back to PNG.
if (format == PInvokeCore.ImageFormatJPEG || encoder == Guid.Empty)
{
dest = ImageFormat.Png;
format = PInvokeCore.ImageFormatPNG;
encoder = ImageCodecInfo.GetEncoderClsid(format);
}

// If we don't find an Encoder (for things like Icon), we
// just switch back to PNG.
ImageCodecInfo codec = FindEncoder(dest) ?? FindEncoder(ImageFormat.Png)!;
image.Save(ms, codec);
Image.Save(image, ms, encoder, format, null);
return ms.ToArray();
}
}

throw GetConvertFromException(value);
}

// Find any random encoder which supports this format.
private static ImageCodecInfo? FindEncoder(ImageFormat imageformat)
{
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
foreach (ImageCodecInfo codec in codecs)
{
if (codec.FormatID.Equals(imageformat.Guid))
return codec;
}

return null;
}

[RequiresUnreferencedCode("The Type of value cannot be statically discovered. The public parameterless constructor or the 'Default' static field may be trimmed from the Attribute's Type.")]
public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext? context, object? value, Attribute[]? attributes)
{
Expand Down
52 changes: 52 additions & 0 deletions src/System.Drawing.Common/src/System/Drawing/Imaging/ImageCodecInfo.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,58 @@ internal ImageCodecInfo()

// Encoder/Decoder selection APIs

// Getting the entire array of ImageCodecInfo objects is expensive and not necessary when all we need are the
// encoder CLSIDs. There are only 5 encoders: PNG, JPEG, GIF, BMP, and TIFF. We'll just build the small cache
// here to avoid all of the overhead. (We could probably just hard-code the values, but on the very small chance
// that the list of encoders changes, we'll keep it dynamic.)
private static (Guid Format, Guid Encoder)[]? s_encoders;

/// <summary>
/// Get the encoder guid for the given image format guid.
/// </summary>
internal static Guid GetEncoderClsid(Guid format)
{
foreach ((Guid Format, Guid Encoder) in Encoders)
{
if (Format == format)
{
return Encoder;
}
}

return Guid.Empty;
}

private static (Guid Format, Guid Encoder)[] Encoders
{
get
{
if (s_encoders is null)
{
uint numEncoders;
uint size;

PInvoke.GdipGetImageEncodersSize(&numEncoders, &size).ThrowIfFailed();

using BufferScope<byte> buffer = new((int)size);

fixed (byte* b = buffer)
{
PInvoke.GdipGetImageEncoders(numEncoders, size, (GdiPlus.ImageCodecInfo*)b).ThrowIfFailed();
ReadOnlySpan<GdiPlus.ImageCodecInfo> codecInfo = new((GdiPlus.ImageCodecInfo*)b, (int)numEncoders);
s_encoders = new (Guid Format, Guid Encoder)[codecInfo.Length];

for (int i = 0; i < codecInfo.Length; i++)
{
s_encoders[i] = (codecInfo[i].FormatID, codecInfo[i].Clsid);
}
}
}

return s_encoders;
}
}

public static ImageCodecInfo[] GetImageDecoders()
{
ImageCodecInfo[] imageCodecs;
Expand Down
83 changes: 33 additions & 50 deletions src/System.Drawing.Common/src/System/Drawing/Imaging/ImageFormat.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,18 +14,18 @@ public sealed class ImageFormat
{
// Format IDs
// private static ImageFormat undefined = new ImageFormat(new Guid("{b96b3ca9-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_memoryBMP = new(new Guid("{b96b3caa-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_bmp = new(new Guid("{b96b3cab-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_emf = new(new Guid("{b96b3cac-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_wmf = new(new Guid("{b96b3cad-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_jpeg = new(new Guid("{b96b3cae-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_png = new(new Guid("{b96b3caf-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_gif = new(new Guid("{b96b3cb0-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_tiff = new(new Guid("{b96b3cb1-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_exif = new(new Guid("{b96b3cb2-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_icon = new(new Guid("{b96b3cb5-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_heif = new(new Guid("{b96b3cb6-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_webp = new(new Guid("{b96b3cb7-0728-11d3-9d7b-0000f81ef32e}"));
private static readonly ImageFormat s_memoryBMP = new(PInvokeCore.ImageFormatMemoryBMP);
private static readonly ImageFormat s_bmp = new(PInvokeCore.ImageFormatBMP);
private static readonly ImageFormat s_emf = new(PInvokeCore.ImageFormatEMF);
private static readonly ImageFormat s_wmf = new(PInvokeCore.ImageFormatWMF);
private static readonly ImageFormat s_jpeg = new(PInvokeCore.ImageFormatJPEG);
private static readonly ImageFormat s_png = new(PInvokeCore.ImageFormatPNG);
private static readonly ImageFormat s_gif = new(PInvokeCore.ImageFormatGIF);
private static readonly ImageFormat s_tiff = new(PInvokeCore.ImageFormatTIFF);
private static readonly ImageFormat s_exif = new(PInvokeCore.ImageFormatEXIF);
private static readonly ImageFormat s_icon = new(PInvokeCore.ImageFormatIcon);
private static readonly ImageFormat s_heif = new(PInvokeCore.ImageFormatHEIF);
private static readonly ImageFormat s_webp = new(PInvokeCore.ImageFormatWEBP);

private readonly Guid _guid;

Expand Down Expand Up @@ -93,16 +93,16 @@ public sealed class ImageFormat
/// Specifies the High Efficiency Image Format (HEIF).
/// </summary>
/// <remarks>
/// This format is supported since Windows 10 1809.
/// <para>This format is supported since Windows 10 1809.</para>
/// </remarks>
[SupportedOSPlatform("windows10.0.17763.0")]
public static ImageFormat Heif => s_heif;

/// <summary>
/// Specifies the WebP image format.
/// Specifies the WebP image format.
/// </summary>
/// <remarks>
/// This format is supported since Windows 10 1809.
/// <para>This format is supported since Windows 10 1809.</para>
/// </remarks>
[SupportedOSPlatform("windows10.0.17763.0")]
public static ImageFormat Webp => s_webp;
Expand All @@ -111,52 +111,35 @@ public sealed class ImageFormat
/// Returns a value indicating whether the specified object is an <see cref='ImageFormat'/> equivalent to this
/// <see cref='ImageFormat'/>.
/// </summary>
public override bool Equals([NotNullWhen(true)] object? o)
{
ImageFormat? format = o as ImageFormat;
if (format is null)
return false;
return _guid == format._guid;
}
public override bool Equals([NotNullWhen(true)] object? o) => o is ImageFormat format && _guid == format._guid;

/// <summary>
/// Returns a hash code.
/// </summary>
public override int GetHashCode()
{
return _guid.GetHashCode();
}
public override int GetHashCode() => _guid.GetHashCode();

// Find any random encoder which supports this format
internal ImageCodecInfo? FindEncoder()
{
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
foreach (ImageCodecInfo codec in codecs)
{
if (codec.FormatID.Equals(_guid))
return codec;
}

return null;
}
/// <summary>
/// The encoder that supports this format, if any.
/// </summary>
internal Guid Encoder => ImageCodecInfo.GetEncoderClsid(_guid);

/// <summary>
/// Converts this <see cref='ImageFormat'/> to a human-readable string.
/// </summary>
public override string ToString()
{
if (Guid == s_memoryBMP.Guid) return "MemoryBMP";
if (Guid == s_bmp.Guid) return "Bmp";
if (Guid == s_emf.Guid) return "Emf";
if (Guid == s_wmf.Guid) return "Wmf";
if (Guid == s_gif.Guid) return "Gif";
if (Guid == s_jpeg.Guid) return "Jpeg";
if (Guid == s_png.Guid) return "Png";
if (Guid == s_tiff.Guid) return "Tiff";
if (Guid == s_exif.Guid) return "Exif";
if (Guid == s_icon.Guid) return "Icon";
if (Guid == s_heif.Guid) return "Heif";
if (Guid == s_webp.Guid) return "Webp";
if (Guid == PInvokeCore.ImageFormatMemoryBMP) return "MemoryBMP";
if (Guid == PInvokeCore.ImageFormatBMP) return "Bmp";
if (Guid == PInvokeCore.ImageFormatEMF) return "Emf";
if (Guid == PInvokeCore.ImageFormatWMF) return "Wmf";
if (Guid == PInvokeCore.ImageFormatGIF) return "Gif";
if (Guid == PInvokeCore.ImageFormatJPEG) return "Jpeg";
if (Guid == PInvokeCore.ImageFormatPNG) return "Png";
if (Guid == PInvokeCore.ImageFormatTIFF) return "Tiff";
if (Guid == PInvokeCore.ImageFormatEXIF) return "Exif";
if (Guid == PInvokeCore.ImageFormatIcon) return "Icon";
if (Guid == PInvokeCore.ImageFormatHEIF) return "Heif";
if (Guid == PInvokeCore.ImageFormatWEBP) return "Webp";
return $"[ImageFormat: {_guid}]";
}
}
1 change: 1 addition & 0 deletions src/System.Private.Windows.Core/src/NativeMethods.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -106,6 +106,7 @@ HWND_*
IDI_*
IEnumUnknown
IGlobalInterfaceTable
ImageFormat*
INPLACE_E_NOTOOLSPACE
IntersectClipRect
IStream
Expand Down

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