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//------------------------------------------------------------------------------
// <copyright file="ImageConverter.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
/*
*/
namespace System.Drawing {
using System.Runtime.Serialization.Formatters;
using System.Runtime.InteropServices;
using System.IO;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using Microsoft.Win32;
using System.Collections;
using System.ComponentModel;
using System.Globalization;
using System.Reflection;
using System.Drawing.Imaging;
using System.ComponentModel.Design.Serialization;
using System.Runtime.Versioning;
/// <include file='doc\ImageConverter.uex' path='docs/doc[@for="ImageConverter"]/*' />
/// <devdoc>
/// ImageConverter is a class that can be used to convert
/// Image from one data type to another. Access this
/// class through the TypeDescriptor.
/// </devdoc>
public class ImageConverter : TypeConverter {
Type iconType = typeof(Icon);
/// <include file='doc\ImageConverter.uex' path='docs/doc[@for="ImageConverter.CanConvertFrom1"]/*' />
/// <devdoc>
/// <para>Gets a value indicating whether this converter can
/// convert an object in the given source type to the native type of the converter
/// using the context.</para>
/// </devdoc>
public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) {
if (sourceType == iconType) {
return true;
}
if (sourceType == typeof(byte[])) {
return true;
}
if(sourceType == typeof(InstanceDescriptor)){
return false;
}
return base.CanConvertFrom(context, sourceType);
}
/// <include file='doc\ImageConverter.uex' path='docs/doc[@for="ImageConverter.CanConvertTo1"]/*' />
/// <devdoc>
/// <para>Gets a value indicating whether this converter can
/// convert an object to the given destination type using the context.</para>
/// </devdoc>
public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType) {
if (destinationType == typeof(byte[])) {
return true;
}
return base.CanConvertTo(context, destinationType);
}
/// <include file='doc\ImageConverter.uex' path='docs/doc[@for="ImageConverter.ConvertFrom"]/*' />
/// <devdoc>
/// <para>Converts the given object to the converter's native type.</para>
/// </devdoc>
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily")]
[ResourceExposure(ResourceScope.Machine)]
[ResourceConsumption(ResourceScope.Machine)]
public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) {
if (value is Icon) {
Icon icon = (Icon) value;
return icon.ToBitmap();
}
byte[] bytes = value as byte[];
if (bytes != null) {
Stream memStream = null;
// this might be a magical OLE thing, try that first.
//
memStream = GetBitmapStream(bytes);
if (memStream == null) {
// guess not. Try plain memory.
//
memStream = new MemoryStream(bytes);
}
// hopefully GDI+ knows what to do with this!
//
return Image.FromStream(memStream);
}
return base.ConvertFrom(context, culture, value);
}
/// <include file='doc\ImageConverter.uex' path='docs/doc[@for="ImageConverter.ConvertTo"]/*' />
/// <devdoc>
/// Converts the given object to another type. The most common types to convert
/// are to and from a string object. The default implementation will make a call
/// to ToString on the object if the object is valid and if the destination
/// type is string. If this cannot convert to the desitnation type, this will
/// throw a NotSupportedException.
/// </devdoc>
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily")]
[SuppressMessage("Microsoft.Reliability", "CA2000:DisposeObjectsBeforeLosingScope")]
[ResourceExposure(ResourceScope.Machine)]
[ResourceConsumption(ResourceScope.Machine)]
public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) {
if (destinationType == null) {
throw new ArgumentNullException("destinationType");
}
if (destinationType == typeof(string)) {
if (value != null) {
// should do something besides ToString() the image...go get the filename
Image image = (Image)value;
return image.ToString();
}
else {
return SR.GetString(SR.toStringNone);
}
}
else if (destinationType == typeof(byte[])) {
if (value != null) {
bool createdNewImage = false;
MemoryStream ms = null;
Image image = null;
try {
ms = new MemoryStream();
image = (Image) value;
//We don't want to serialize an icon - since we're not really working with
//icons, these are "Images". So, we'll force a new and valid bitmap to be
//created around our icon with the ideal size.
if (image.RawFormat.Equals(ImageFormat.Icon)) {
createdNewImage = true;
image = new Bitmap(image, image.Width, image.Height);
}
image.Save(ms);
}
finally {
if (ms != null) {
ms.Close();
}
if (createdNewImage && image != null) {
image.Dispose();
}
}
if (ms != null) {
return ms.ToArray();
}
else {
return null;
}
}
else {
return new byte[0];
}
}
return base.ConvertTo(context, culture, value, destinationType);
}
/// <devdoc>
/// Try to get a bitmap out of a byte array. This is an ole format that Access uses.
/// this fails very quickly so we can try this first without a big perf hit.
/// </devdoc>
[SuppressMessage("Microsoft.Performance", "CA1808:AvoidCallsThatBoxValueTypes")]
private unsafe Stream GetBitmapStream(byte[] rawData)
{
Debug.Assert( rawData != null, "rawData is null." );
try
{
fixed (byte* pByte = rawData)
{
IntPtr addr = (IntPtr)pByte;
if (addr == IntPtr.Zero)
{
return null;
}
// this will be pHeader.signature, but we try to
// do this first so we avoid building the structure when we shouldn't
//
if (rawData.Length <= sizeof(SafeNativeMethods.OBJECTHEADER) || Marshal.ReadInt16(addr) != 0x1c15)
{
return null;
}
// the data is one of these OBJECTHEADER dudes. It's an encoded format that Access uses to push images
// into the DB. It's not particularly documented, but I found a KB:
//
// http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q175261
//
SafeNativeMethods.OBJECTHEADER pHeader = (SafeNativeMethods.OBJECTHEADER)Marshal.PtrToStructure(addr, typeof(SafeNativeMethods.OBJECTHEADER));
// "PBrush" should be the 6 chars after position 12 as well.
//
if (rawData.Length <= pHeader.headersize + 18)
{
return null;
}
string strPBrush = System.Text.Encoding.ASCII.GetString(rawData, pHeader.headersize + 12, 6);
if (strPBrush != "PBrush")
{
return null;
}
// okay, now we can safely trust that we've got a bitmap.
byte[] searchArray = System.Text.Encoding.ASCII.GetBytes("BM");
// search for "BM" in the data which is the start of our bitmap data...
//
// 18 is from (12+6) above.
//
for (int i = pHeader.headersize + 18; i < pHeader.headersize + 510 && i+1 < rawData.Length; i++)
{
if (searchArray[0] == pByte[i] &&
searchArray[1] == pByte[i+1])
{
// found the bitmap data.
//
return new MemoryStream(rawData, i, rawData.Length - i);
}
}
}
}
catch (OutOfMemoryException) // this exception may be caused by creating a new MemoryStream
{
}
catch (ArgumentException) // may be caused by Marshal.PtrToStructure
{
}
// nevermind...
return null;
}
/// <include file='doc\ImageConverter.uex' path='docs/doc[@for="ImageConverter.GetProperties"]/*' />
/// <devdoc>
/// Retrieves the set of properties for this type. By default, a type has
/// does not return any properties. An easy implementation of this method
/// can just call TypeDescriptor.GetProperties for the correct data type.
/// </devdoc>
public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes) {
return TypeDescriptor.GetProperties(typeof(Image), attributes);
}
/// <include file='doc\ImageConverter.uex' path='docs/doc[@for="ImageConverter.GetPropertiesSupported"]/*' />
/// <devdoc>
/// Determines if this object supports properties. By default, this
/// is false.
/// </devdoc>
public override bool GetPropertiesSupported(ITypeDescriptorContext context) {
return true;
}
}
}
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