public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
{
string strValue = value as string;
if (strValue != null)
{
object obj = null;
string text = strValue.Trim();
if (text.Length == 0)
{
obj = Color.Empty;
}
else
{
// First, check to see if this is a standard name.
//
obj = GetNamedColor(text);
if (obj == null)
{
if (culture == null)
{
culture = CultureInfo.CurrentCulture;
}
char sep = culture.TextInfo.ListSeparator[0];
bool tryMappingToKnownColor = true;
TypeConverter intConverter = TypeDescriptor.GetConverter(typeof(int));
// If the value is a 6 digit hex number only, then
// we want to treat the Alpha as 255, not 0
//
if (text.IndexOf(sep) == -1)
{
// text can be '' (empty quoted string)
if (text.Length >= 2 && (text[0] == '\'' || text[0] == '"') && text[0] == text[text.Length - 1])
{
// In quotes means a named value
string colorName = text.Substring(1, text.Length - 2);
obj = Color.FromName(colorName);
tryMappingToKnownColor = false;
}
else if ((text.Length == 7 && text[0] == '#') ||
(text.Length == 8 && (text.StartsWith("0x") || text.StartsWith("0X"))) ||
(text.Length == 8 && (text.StartsWith("&h") || text.StartsWith("&H"))))
{
// Note: ConvertFromString will raise exception if value cannot be converted.
obj = Color.FromArgb(unchecked ((int)(0xFF000000 | (uint)(int)intConverter.ConvertFromString(context, culture, text))));
}
}
// Nope. Parse the RGBA from the text.
//
if (obj == null)
{
string[] tokens = text.Split(new char[] { sep });
int[] values = new int[tokens.Length];
for (int i = 0; i < values.Length; i++)
{
values[i] = unchecked ((int)intConverter.ConvertFromString(context, culture, tokens[i]));
}
// We should now have a number of parsed integer values.
// We support 1, 3, or 4 arguments:
//
// 1 -- full ARGB encoded
// 3 -- RGB
// 4 -- ARGB
//
switch (values.Length)
{
case 1:
obj = Color.FromArgb(values[0]);
break;
case 3:
obj = Color.FromArgb(values[0], values[1], values[2]);
break;
case 4:
obj = Color.FromArgb(values[0], values[1], values[2], values[3]);
break;
}
tryMappingToKnownColor = true;
}
if ((obj != null) && tryMappingToKnownColor)
{
// Now check to see if this color matches one of our known colors.
// If it does, then substitute it. We can only do this for "Colors"
// because system colors morph with user settings.
//
int targetARGB = ((Color)obj).ToArgb();
foreach (Color c in Colors.Values)
{
if (c.ToArgb() == targetARGB)
{
obj = c;
break;
}
}
}
}
if (obj == null)
{
throw new ArgumentException(SR.Format(SR.InvalidColor, text));
}
}
return(obj);
}
return(base.ConvertFrom(context, culture, value));
}
// Initializes this Image object. This is identical to calling the image's
// constructor with picture, but this allows non-constructor initialization,
// which may be necessary in some instances.
private unsafe void Initialize(int width, int height)
{
if (_iconData == null || _handle != IntPtr.Zero)
{
throw new InvalidOperationException(SR.Format(SR.IllegalState, GetType().Name));
}
if (_iconData.Length < sizeof(SafeNativeMethods.ICONDIR))
{
throw new ArgumentException(SR.Format(SR.InvalidPictureType, "picture", nameof(Icon)));
}
// Get the correct width and height.
if (width == 0)
{
width = UnsafeNativeMethods.GetSystemMetrics(SafeNativeMethods.SM_CXICON);
}
if (height == 0)
{
height = UnsafeNativeMethods.GetSystemMetrics(SafeNativeMethods.SM_CYICON);
}
if (s_bitDepth == 0)
{
IntPtr dc = Interop.User32.GetDC(IntPtr.Zero);
s_bitDepth = Interop.Gdi32.GetDeviceCaps(dc, Interop.Gdi32.DeviceCapability.BITSPIXEL);
s_bitDepth *= Interop.Gdi32.GetDeviceCaps(dc, Interop.Gdi32.DeviceCapability.PLANES);
Interop.User32.ReleaseDC(IntPtr.Zero, dc);
// If the bitdepth is 8, make it 4 because windows does not
// choose a 256 color icon if the display is running in 256 color mode
// due to palette flicker.
if (s_bitDepth == 8)
{
s_bitDepth = 4;
}
}
fixed(byte *b = _iconData)
{
SafeNativeMethods.ICONDIR *dir = (SafeNativeMethods.ICONDIR *)b;
if (dir->idReserved != 0 || dir->idType != 1 || dir->idCount == 0)
{
throw new ArgumentException(SR.Format(SR.InvalidPictureType, "picture", nameof(Icon)));
}
byte bestWidth = 0;
byte bestHeight = 0;
if (sizeof(SafeNativeMethods.ICONDIRENTRY) * (dir->idCount - 1) + sizeof(SafeNativeMethods.ICONDIR)
> _iconData.Length)
{
throw new ArgumentException(SR.Format(SR.InvalidPictureType, "picture", nameof(Icon)));
}
var entries = new ReadOnlySpan <SafeNativeMethods.ICONDIRENTRY>(&dir->idEntries, dir->idCount);
foreach (SafeNativeMethods.ICONDIRENTRY entry in entries)
{
bool fUpdateBestFit = false;
uint iconBitDepth;
if (entry.bColorCount != 0)
{
iconBitDepth = 4;
if (entry.bColorCount < 0x10)
{
iconBitDepth = 1;
}
}
else
{
iconBitDepth = entry.wBitCount;
}
// If it looks like if nothing is specified at this point then set the bits per pixel to 8.
if (iconBitDepth == 0)
{
iconBitDepth = 8;
}
// Windows rules for specifing an icon:
//
// 1. The icon with the closest size match.
// 2. For matching sizes, the image with the closest bit depth.
// 3. If there is no color depth match, the icon with the closest color depth that does not exceed the display.
// 4. If all icon color depth > display, lowest color depth is chosen.
// 5. color depth of > 8bpp are all equal.
// 6. Never choose an 8bpp icon on an 8bpp system.
if (_bestBytesInRes == 0)
{
fUpdateBestFit = true;
}
else
{
int bestDelta = Math.Abs(bestWidth - width) + Math.Abs(bestHeight - height);
int thisDelta = Math.Abs(entry.bWidth - width) + Math.Abs(entry.bHeight - height);
if ((thisDelta < bestDelta) ||
(thisDelta == bestDelta && (iconBitDepth <= s_bitDepth && iconBitDepth > _bestBitDepth || _bestBitDepth > s_bitDepth && iconBitDepth < _bestBitDepth)))
{
fUpdateBestFit = true;
}
}
if (fUpdateBestFit)
{
bestWidth = entry.bWidth;
bestHeight = entry.bHeight;
_bestImageOffset = entry.dwImageOffset;
_bestBytesInRes = entry.dwBytesInRes;
_bestBitDepth = iconBitDepth;
}
}
if (_bestImageOffset > int.MaxValue)
{
throw new ArgumentException(SR.Format(SR.InvalidPictureType, "picture", nameof(Icon)));
}
if (_bestBytesInRes > int.MaxValue)
{
throw new Win32Exception(SafeNativeMethods.ERROR_INVALID_PARAMETER);
}
uint endOffset;
try
{
endOffset = checked (_bestImageOffset + _bestBytesInRes);
}
catch (OverflowException)
{
throw new Win32Exception(SafeNativeMethods.ERROR_INVALID_PARAMETER);
}
if (endOffset > _iconData.Length)
{
throw new ArgumentException(SR.Format(SR.InvalidPictureType, "picture", nameof(Icon)));
}
// Copy the bytes into an aligned buffer if needed.
if ((_bestImageOffset % IntPtr.Size) != 0)
{
// Beginning of icon's content is misaligned.
byte[] alignedBuffer = ArrayPool <byte> .Shared.Rent((int)_bestBytesInRes);
Array.Copy(_iconData, _bestImageOffset, alignedBuffer, 0, _bestBytesInRes);
fixed(byte *pbAlignedBuffer = alignedBuffer)
{
_handle = SafeNativeMethods.CreateIconFromResourceEx(pbAlignedBuffer, _bestBytesInRes, true, 0x00030000, 0, 0, 0);
}
ArrayPool <byte> .Shared.Return(alignedBuffer);
}
else
{
try
{
_handle = SafeNativeMethods.CreateIconFromResourceEx(checked (b + _bestImageOffset), _bestBytesInRes, true, 0x00030000, 0, 0, 0);
}
catch (OverflowException)
{
throw new Win32Exception(SafeNativeMethods.ERROR_INVALID_PARAMETER);
}
}
if (_handle == IntPtr.Zero)
{
throw new Win32Exception();
}
}
}