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//------------------------------------------------------------------------------
// Microsoft Avalon
// Copyright (c) Microsoft Corporation, All rights reserved.
//
// File: BitmapPalette.cs
//
//------------------------------------------------------------------------------
using System;
using System.Security;
using System.Security.Permissions;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Reflection;
using MS.Internal;
using MS.Win32.PresentationCore;
using MS.Internal.PresentationCore; //SecurityHelper
using System.Diagnostics;
using System.Windows.Threading;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Globalization;
using System.Runtime.InteropServices;
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID;
namespace System.Windows.Media.Imaging
{
/// <summary>
/// BitmapPalette class
/// </summary>
public sealed class BitmapPalette : DispatcherObject
{
#region Constructors
/// <summary>
/// No public default constructor
/// </summary>
private BitmapPalette()
{
}
/// <summary>
/// Create a palette from the list of colors.
/// </summary>
public BitmapPalette(IList<Color> colors)
{
if (colors == null)
{
throw new ArgumentNullException("colors");
}
int count = colors.Count;
if (count < 1 || count > 256)
{
throw new InvalidOperationException(SR.Get(SRID.Image_PaletteZeroColors, null));
}
Color[] colorArray = new Color[count];
for (int i = 0; i < count; ++i)
{
colorArray[i] = colors[i];
}
_colors = new PartialList<Color>(colorArray);
_palette = CreateInternalPalette();
UpdateUnmanaged();
}
/// <summary>
/// Construct BitmapPalette from a BitmapSource.
///
/// If the BitmapSource is already palettized, the corresponding
/// palette is returned. Otherwise, a new palette is constructed from
/// an analysis of the bitmap.
/// </summary>
/// <param name="bitmapSource">Bitmap to use for analysis</param>
/// <param name="maxColorCount">Maximum number of colors</param>
/// <SecurityNote>
/// SecurityCritical: Accesses unmanaged resources (_wicSource)
/// PublicOk: Inputs are verified and _wicSource and the get is Critical
/// </SecurityNote>
[SecurityCritical]
public BitmapPalette(BitmapSource bitmapSource, int maxColorCount)
{
// Note: we will never return a palette from BitmapPalettes.
if (bitmapSource == null)
{
throw new ArgumentNullException("bitmapSource");
}
SafeMILHandle unmanagedBitmap = bitmapSource.WicSourceHandle;
_palette = CreateInternalPalette();
lock (bitmapSource.SyncObject)
{
HRESULT.Check(UnsafeNativeMethods.WICPalette.InitializeFromBitmap(
_palette,
unmanagedBitmap,
maxColorCount,
false));
}
UpdateManaged();
}
/// <summary>
/// Constructs a bitmap from a known WICPaletteType (does not perform
/// caching).
///
/// Note: It is an error to modify the Color property of the
/// constructed BitmapPalette. Indeed, the returned BitmapPalette
/// should probably be immediately frozen. Additionally, outside users
/// will have no knowledge that this is a predefined palette (or which
/// predefined palette it is). It is thus highly recommended that only
/// the BitmapPalettes class use this constructor.
/// </summary>
/// <SecurityNote>
/// Critical - Calls into an unsafe native method InitializePredefined().
/// Safe - we sanitize the input and only call into WIC with
/// acceptable palette types.
/// </SecurityNote>
[SecuritySafeCritical]
internal BitmapPalette(WICPaletteType paletteType,
bool addtransparentColor)
{
switch (paletteType)
{
case WICPaletteType.WICPaletteTypeFixedBW:
case WICPaletteType.WICPaletteTypeFixedHalftone8:
case WICPaletteType.WICPaletteTypeFixedHalftone27:
case WICPaletteType.WICPaletteTypeFixedHalftone64:
case WICPaletteType.WICPaletteTypeFixedHalftone125:
case WICPaletteType.WICPaletteTypeFixedHalftone216:
case WICPaletteType.WICPaletteTypeFixedHalftone252:
case WICPaletteType.WICPaletteTypeFixedHalftone256:
case WICPaletteType.WICPaletteTypeFixedGray4:
case WICPaletteType.WICPaletteTypeFixedGray16:
case WICPaletteType.WICPaletteTypeFixedGray256:
break;
default:
throw new System.ArgumentException(SR.Get(SRID.Image_PaletteFixedType, paletteType));
}
_palette = CreateInternalPalette();
HRESULT.Check(UnsafeNativeMethods.WICPalette.InitializePredefined(
_palette,
paletteType,
addtransparentColor));
// Fill in the Colors property.
UpdateManaged();
}
internal BitmapPalette(SafeMILHandle unmanagedPalette)
{
_palette = unmanagedPalette;
// Fill in the Colors property.
UpdateManaged();
}
#endregion // Constructors
#region Factory Methods
/// <summary>
/// Create a BitmapPalette from an unmanaged BitmapSource. If the
/// bitmap is not paletteized, we return BitmapPalette.Empty. If the
/// palette is of a known type, we will use BitmapPalettes.
/// </summary>
/// <SecurityNote>
/// Critical - access unmanaged code
/// TreatAsSafe - Creating a palette from a Source is OK
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
static internal BitmapPalette CreateFromBitmapSource(BitmapSource source)
{
Debug.Assert(source != null);
SafeMILHandle bitmapSource = source.WicSourceHandle;
Debug.Assert(bitmapSource != null && !bitmapSource.IsInvalid);
SafeMILHandle unmanagedPalette = CreateInternalPalette();
BitmapPalette palette;
// Don't throw on the HRESULT from this method. If it returns failure,
// that likely means that the source doesn't have a palette.
lock (source.SyncObject)
{
int hr = UnsafeNativeMethods.WICBitmapSource.CopyPalette(
bitmapSource,
unmanagedPalette);
if (hr != HRESULT.S_OK)
{
return null;
}
}
WICPaletteType paletteType;
bool hasAlpha;
HRESULT.Check(UnsafeNativeMethods.WICPalette.GetType(unmanagedPalette, out paletteType));
HRESULT.Check(UnsafeNativeMethods.WICPalette.HasAlpha(unmanagedPalette, out hasAlpha));
if (paletteType == WICPaletteType.WICPaletteTypeCustom ||
paletteType == WICPaletteType.WICPaletteTypeOptimal)
{
palette = new BitmapPalette(unmanagedPalette);
}
else
{
palette = BitmapPalettes.FromMILPaletteType(paletteType, hasAlpha);
Debug.Assert(palette != null);
}
return palette;
}
#endregion // Factory Methods
#region Properties
/// <summary>
/// The contents of the palette.
/// </summary>
public IList<Color> Colors
{
get
{
return _colors;
}
}
#endregion // Properties
#region Internal Properties
/// <SecurityNote>
/// Critical: Exposes critical safe handle
/// </SecurityNote>
internal SafeMILHandle InternalPalette
{
[SecurityCritical]
get
{
if (_palette == null || _palette.IsInvalid)
{
_palette = CreateInternalPalette();
}
return _palette;
}
}
#endregion // Internal Properties
#region Static / Private Methods
/// Returns if the Palette has any alpha within its colors
internal static bool DoesPaletteHaveAlpha(BitmapPalette palette)
{
if (palette != null)
{
foreach (Color color in palette.Colors)
{
if (color.A != 255)
{
return true;
}
}
}
return false;
}
/// <SecurityNote>
/// Critical - calls unmanaged code
/// TreatAsSafe - only thing you can do with this is allocate some memory
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
static internal SafeMILHandle CreateInternalPalette()
{
SafeMILHandle palette = null;
using (FactoryMaker myFactory = new FactoryMaker())
{
HRESULT.Check(UnsafeNativeMethods.WICImagingFactory.CreatePalette(
myFactory.ImagingFactoryPtr,
out palette));
Debug.Assert(palette != null && !palette.IsInvalid);
}
return palette;
}
/// <summary>
/// Copy Colors down into the IMILPalette.
/// </summary>
/// Critical - is an unsafe method, calls into native code
/// TreatAsSafe - No inputs are provided, no information is exposed.
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
unsafe private void UpdateUnmanaged()
{
Debug.Assert(_palette != null && !_palette.IsInvalid);
int numColors = Math.Min(256, _colors.Count);
ImagePaletteColor[] paletteColorArray = new ImagePaletteColor[numColors];
for (int i = 0; i < numColors; ++i)
{
Color color = _colors[i];
paletteColorArray[i].B = color.B;
paletteColorArray[i].G = color.G;
paletteColorArray[i].R = color.R;
paletteColorArray[i].A = color.A;
}
fixed (void* paletteColorArrayPinned = paletteColorArray)
{
HRESULT.Check(UnsafeNativeMethods.WICPalette.InitializeCustom(
_palette,
(IntPtr)paletteColorArrayPinned,
numColors));
}
}
/// <summary>
/// Copy the colors from IMILBitmapPalette into Colors.
/// </summary>
/// <SecurityNote>
/// Critical - access unmanaged code
/// TreatAsSafe - No inputs are provided and only gets the color count and colors from a palette
/// </SecurityNote>
[SecurityCritical, SecurityTreatAsSafe]
private void UpdateManaged()
{
Debug.Assert(_palette != null && !_palette.IsInvalid);
int numColors = 0;
int cActualColors = 0;
HRESULT.Check(UnsafeNativeMethods.WICPalette.GetColorCount(_palette,
out numColors));
List<Color> colors = new List<Color>();
if (numColors < 1 || numColors > 256)
{
throw new InvalidOperationException(SR.Get(SRID.Image_PaletteZeroColors, null));
}
else
{
ImagePaletteColor[] paletteColorArray = new ImagePaletteColor[numColors];
unsafe
{
fixed(void* paletteColorArrayPinned = paletteColorArray)
{
HRESULT.Check(UnsafeNativeMethods.WICPalette.GetColors(
_palette,
numColors,
(IntPtr)paletteColorArrayPinned,
out cActualColors));
Debug.Assert(cActualColors == numColors);
}
}
for (int i = 0; i < numColors; ++i)
{
ImagePaletteColor c = paletteColorArray[i];
colors.Add(Color.FromArgb(c.A, c.R, c.G, c.B));
}
}
_colors = new PartialList<Color>(colors);
}
#endregion // Private Methods
/// <summary>
/// ImagePaletteColor structure -- convenience for Interop
/// </summary>
[StructLayout(LayoutKind.Sequential)]
private struct ImagePaletteColor
{
/// <summary>
/// blue channel: 0 - 255
/// </summary>
public byte B;
/// <summary>
/// green channel: 0 - 255
/// </summary>
public byte G;
/// <summary>
/// red channel: 0 - 255
/// </summary>
public byte R;
/// <summary>
/// alpha channel: 0 - 255
/// </summary>
public byte A;
};
// Note: We have a little trickery going on here. When a new BitmapPalette is
// cloned, _palette isn't copied and so is reset to null. This means that the
// next call to InternalPalette will create a new IWICPalette, which is exactly
// the behavior that we want.
private SafeMILHandle _palette = null; // IWICPalette*
private IList<Color> _colors = new PartialList<Color>(new List<Color>());
}
}
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