GDI +不支持CF_DIBV5格式但是当几个应用程序将透明图像放到剪贴板时，他们使用CF_DIBV5（格式17）格式来维护Alpha通道。
.NET Framework无法处理CF_DIBV5格式，因此.NET应用程序无法在剪贴板中放入或检索alpha图像。
是否有任何c＃代码支持CF_DIBV5从剪贴板转换位图？
抱歉！我在回答我自己的问题：
[StructLayout(LayoutKind.Sequential)]
public struct BITMAPV5HEADER
{
public uint bV5Size;
public int bV5Width;
public int bV5Height;
public UInt16 bV5Planes;
public UInt16 bV5BitCount;
public uint bV5Compression;
public uint bV5SizeImage;
public int bV5XPelsPerMeter;
public int bV5YPelsPerMeter;
public UInt16 bV5ClrUsed;
public UInt16 bV5ClrImportant;
public UInt16 bV5RedMask;
public UInt16 bV5GreenMask;
public UInt16 bV5BlueMask;
public UInt16 bV5AlphaMask;
public UInt16 bV5CSType;
public IntPtr bV5Endpoints;
public UInt16 bV5GammaRed;
public UInt16 bV5GammaGreen;
public UInt16 bV5GammaBlue;
public UInt16 bV5Intent;
public UInt16 bV5ProfileData;
public UInt16 bV5ProfileSize;
public UInt16 bV5Reserved;
}
public static Bitmap CF_DIBV5ToBitmap(byte[] data)
{
GCHandle handle = GCHandle.Alloc(data, GCHandleType.Pinned);
var bmi = (BITMAPV5HEADER)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(BITMAPV5HEADER));
Bitmap bitmap = new Bitmap((int)bmi.bV5Width, (int)bmi.bV5Height, -
(int)(bmi.bV5SizeImage / bmi.bV5Height), PixelFormat.Format32bppArgb,
new IntPtr(handle.AddrOfPinnedObject().ToInt32()
+ bmi.bV5Size + (bmi.bV5Height - 1)
* (int)(bmi.bV5SizeImage / bmi.bV5Height)));
handle.Free();
return bitmap;
}
这个解决方案对我来说很好：Copying From and To Clipboard loses image transparency
public static Image GetImageFromClipboard()
{
Image img = null;
DataObject clipboard = Clipboard.GetDataObject() as DataObject;
if (clipboard != null)
{
img = GetClipboardImage(clipboard);
}
return img;
}
/// <summary>
/// Retrieves an image from the given clipboard data object, in the order PNG, DIB, Bitmap, Image object.
/// </summary>
/// <param name="retrievedData">The clipboard data.</param>
/// <returns>The extracted image, or null if no supported image type was found.</returns>
public static Bitmap GetClipboardImage(DataObject retrievedData)
{
Bitmap clipboardimage = null;
// Order: try PNG, move on to try 32-bit ARGB DIB, then try the normal Bitmap and Image types.
if (retrievedData.GetDataPresent("PNG"))
{
MemoryStream png_stream = retrievedData.GetData("PNG") as MemoryStream;
if (png_stream != null)
using (Bitmap bm = new Bitmap(png_stream))
clipboardimage = CloneImage(bm);
}
if (clipboardimage == null && retrievedData.GetDataPresent(DataFormats.Dib))
{
MemoryStream dib = retrievedData.GetData(DataFormats.Dib) as MemoryStream;
if (dib != null)
clipboardimage = ImageFromClipboardDib(dib.ToArray());
}
if (clipboardimage == null && retrievedData.GetDataPresent(DataFormats.Bitmap))
clipboardimage = new Bitmap(retrievedData.GetData(DataFormats.Bitmap) as Image);
if (clipboardimage == null && retrievedData.GetDataPresent(typeof(Image)))
clipboardimage = new Bitmap(retrievedData.GetData(typeof(Image)) as Image);
return clipboardimage;
}
private static Bitmap CloneImage(Bitmap bm)
{
int stride;
return BuildImage(GetImageData(bm, out stride), bm.Width, bm.Height, stride, bm.PixelFormat, null, null);
}
/// <summary>
/// Copies the given image to the clipboard as PNG, DIB and standard Bitmap format.
/// </summary>
/// <param name="image">Image to put on the clipboard.</param>
/// <param name="imageNoTr">Optional specifically nontransparent version of the image to put on the clipboard.</param>
/// <param name="data">Clipboard data object to put the image into. Might already contain other stuff. Leave null to create a new one.</param>
public static void SetClipboardImage(Bitmap image, Bitmap imageNoTr, DataObject data)
{
Clipboard.Clear();
if (data == null)
data = new DataObject();
if (imageNoTr == null)
imageNoTr = image;
using (MemoryStream pngMemStream = new MemoryStream())
using (MemoryStream dibMemStream = new MemoryStream())
{
// As standard bitmap, without transparency support
data.SetData(DataFormats.Bitmap, true, imageNoTr);
// As PNG. Gimp will prefer this over the other two.
image.Save(pngMemStream, ImageFormat.Png);
data.SetData("PNG", false, pngMemStream);
// As DIB. This is (wrongly) accepted as ARGB by many applications.
Byte[] dibData = ConvertToDib(image);
dibMemStream.Write(dibData, 0, dibData.Length);
data.SetData(DataFormats.Dib, false, dibMemStream);
// The 'copy=true' argument means the MemoryStreams can be safely disposed after the operation.
Clipboard.SetDataObject(data, true);
}
}
/// <summary>
/// Converts the image to Device Independent Bitmap format of type BITFIELDS.
/// This is (wrongly) accepted by many applications as containing transparency,
/// so I'm abusing it for that.
/// </summary>
/// <param name="image">Image to convert to DIB</param>
/// <returns>The image converted to DIB, in bytes.</returns>
public static Byte[] ConvertToDib(Image image)
{
Byte[] bm32bData;
Int32 width = image.Width;
Int32 height = image.Height;
// Ensure image is 32bppARGB by painting it on a new 32bppARGB image.
using (Bitmap bm32b = new Bitmap(image.Width, image.Height, PixelFormat.Format32bppArgb))
{
using (Graphics gr = Graphics.FromImage(bm32b))
gr.DrawImage(image, new Rectangle(0, 0, bm32b.Width, bm32b.Height));
// Bitmap format has its lines reversed.
bm32b.RotateFlip(RotateFlipType.Rotate180FlipX);
Int32 stride;
bm32bData = GetImageData(bm32b, out stride);
}
// BITMAPINFOHEADER struct for DIB.
Int32 hdrSize = 0x28;
Byte[] fullImage = new Byte[hdrSize + 12 + bm32bData.Length];
//Int32 biSize;
WriteIntToByteArray(fullImage, 0x00, 4, true, (UInt32)hdrSize);
//Int32 biWidth;
WriteIntToByteArray(fullImage, 0x04, 4, true, (UInt32)width);
//Int32 biHeight;
WriteIntToByteArray(fullImage, 0x08, 4, true, (UInt32)height);
//Int16 biPlanes;
WriteIntToByteArray(fullImage, 0x0C, 2, true, 1);
//Int16 biBitCount;
WriteIntToByteArray(fullImage, 0x0E, 2, true, 32);
//BITMAPCOMPRESSION biCompression = BITMAPCOMPRESSION.BITFIELDS;
WriteIntToByteArray(fullImage, 0x10, 4, true, 3);
//Int32 biSizeImage;
WriteIntToByteArray(fullImage, 0x14, 4, true, (UInt32)bm32bData.Length);
// These are all 0. Since .net clears new arrays, don't bother writing them.
//Int32 biXPelsPerMeter = 0;
//Int32 biYPelsPerMeter = 0;
//Int32 biClrUsed = 0;
//Int32 biClrImportant = 0;
// The aforementioned "BITFIELDS": colour masks applied to the Int32 pixel value to get the R, G and B values.
WriteIntToByteArray(fullImage, hdrSize + 0, 4, true, 0x00FF0000);
WriteIntToByteArray(fullImage, hdrSize + 4, 4, true, 0x0000FF00);
WriteIntToByteArray(fullImage, hdrSize + 8, 4, true, 0x000000FF);
Array.Copy(bm32bData, 0, fullImage, hdrSize + 12, bm32bData.Length);
return fullImage;
}
public static Bitmap ImageFromClipboardDib(Byte[] dibBytes)
{
if (dibBytes == null || dibBytes.Length < 4)
return null;
try
{
Int32 headerSize = (Int32)ReadIntFromByteArray(dibBytes, 0, 4, true);
// Only supporting 40-byte DIB from clipboard
if (headerSize != 40)
return null;
Byte[] header = new Byte[40];
Array.Copy(dibBytes, header, 40);
Int32 imageIndex = headerSize;
Int32 width = (Int32)ReadIntFromByteArray(header, 0x04, 4, true);
Int32 height = (Int32)ReadIntFromByteArray(header, 0x08, 4, true);
Int16 planes = (Int16)ReadIntFromByteArray(header, 0x0C, 2, true);
Int16 bitCount = (Int16)ReadIntFromByteArray(header, 0x0E, 2, true);
//Compression: 0 = RGB; 3 = BITFIELDS.
Int32 compression = (Int32)ReadIntFromByteArray(header, 0x10, 4, true);
// Not dealing with non-standard formats.
if (planes != 1 || (compression != 0 && compression != 3))
return null;
PixelFormat fmt;
switch (bitCount)
{
case 32:
fmt = PixelFormat.Format32bppRgb;
break;
case 24:
fmt = PixelFormat.Format24bppRgb;
break;
case 16:
fmt = PixelFormat.Format16bppRgb555;
break;
default:
return null;
}
if (compression == 3)
imageIndex += 12;
if (dibBytes.Length < imageIndex)
return null;
Byte[] image = new Byte[dibBytes.Length - imageIndex];
Array.Copy(dibBytes, imageIndex, image, 0, image.Length);
// Classic stride: fit within blocks of 4 bytes.
Int32 stride = (((((bitCount * width) + 7) / 8) + 3) / 4) * 4;
if (compression == 3)
{
UInt32 redMask = ReadIntFromByteArray(dibBytes, headerSize + 0, 4, true);
UInt32 greenMask = ReadIntFromByteArray(dibBytes, headerSize + 4, 4, true);
UInt32 blueMask = ReadIntFromByteArray(dibBytes, headerSize + 8, 4, true);
// Fix for the undocumented use of 32bppARGB disguised as BITFIELDS. Despite lacking an alpha bit field,
// the alpha bytes are still filled in, without any header indication of alpha usage.
// Pure 32-bit RGB: check if a switch to ARGB can be made by checking for non-zero alpha.
// Admitted, this may give a mess if the alpha bits simply aren't cleared, but why the hell wouldn't it use 24bpp then?
if (bitCount == 32 && redMask == 0xFF0000 && greenMask == 0x00FF00 && blueMask == 0x0000FF)
{
// Stride is always a multiple of 4; no need to take it into account for 32bpp.
for (Int32 pix = 3; pix < image.Length; pix += 4)
{
// 0 can mean transparent, but can also mean the alpha isn't filled in, so only check for non-zero alpha,
// which would indicate there is actual data in the alpha bytes.
if (image[pix] == 0)
continue;
fmt = PixelFormat.Format32bppPArgb;
break;
}
}
else
// Could be supported with a system that parses the colour masks,
// but I don't think the clipboard ever uses these anyway.
return null;
}
Bitmap bitmap = BuildImage(image, width, height, stride, fmt, null, null);
// This is bmp; reverse image lines.
bitmap.RotateFlip(RotateFlipType.Rotate180FlipX);
return bitmap;
}
catch
{
return null;
}
}
/// <summary>
/// Gets the raw bytes from an image.
/// </summary>
/// <param name="sourceImage">The image to get the bytes from.</param>
/// <param name="stride">Stride of the retrieved image data.</param>
/// <returns>The raw bytes of the image</returns>
public static Byte[] GetImageData(Bitmap sourceImage, out Int32 stride)
{
BitmapData sourceData = sourceImage.LockBits(new Rectangle(0, 0, sourceImage.Width, sourceImage.Height), ImageLockMode.ReadOnly, sourceImage.PixelFormat);
stride = sourceData.Stride;
Byte[] data = new Byte[stride * sourceImage.Height];
Marshal.Copy(sourceData.Scan0, data, 0, data.Length);
sourceImage.UnlockBits(sourceData);
return data;
}
/// <summary>
/// Creates a bitmap based on data, width, height, stride and pixel format.
/// </summary>
/// <param name="sourceData">Byte array of raw source data</param>
/// <param name="width">Width of the image</param>
/// <param name="height">Height of the image</param>
/// <param name="stride">Scanline length inside the data</param>
/// <param name="pixelFormat">Pixel format</param>
/// <param name="palette">Color palette</param>
/// <param name="defaultColor">Default color to fill in on the palette if the given colors don't fully fill it.</param>
/// <returns>The new image</returns>
public static Bitmap BuildImage(Byte[] sourceData, Int32 width, Int32 height, Int32 stride, PixelFormat pixelFormat, Color[] palette, Color? defaultColor)
{
Bitmap newImage = new Bitmap(width, height, pixelFormat);
BitmapData targetData = newImage.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.WriteOnly, newImage.PixelFormat);
CopyToMemory(targetData.Scan0, sourceData, 0, sourceData.Length, stride, targetData.Stride);
newImage.UnlockBits(targetData);
// For indexed images, set the palette.
if ((pixelFormat & PixelFormat.Indexed) != 0 && palette != null)
{
ColorPalette pal = newImage.Palette;
for (Int32 i = 0; i < pal.Entries.Length; i++)
{
if (i < palette.Length)
pal.Entries[i] = palette[i];
else if (defaultColor.HasValue)
pal.Entries[i] = defaultColor.Value;
else
break;
}
newImage.Palette = pal;
}
return newImage;
}
public static void CopyToMemory(IntPtr target, Byte[] bytes, Int32 startPos, Int32 length, Int32 origStride, Int32 targetStride)
{
Int32 sourcePos = startPos;
IntPtr destPos = target;
Int32 minStride = Math.Min(origStride, targetStride);
while (length >= targetStride)
{
Marshal.Copy(bytes, sourcePos, destPos, minStride);
length -= origStride;
sourcePos += origStride;
destPos = new IntPtr(destPos.ToInt64() + targetStride);
}
if (length > 0)
{
Marshal.Copy(bytes, sourcePos, destPos, length);
}
}
public static void WriteIntToByteArray(Byte[] data, Int32 startIndex, Int32 bytes, Boolean littleEndian, UInt32 value)
{
Int32 lastByte = bytes - 1;
if (data.Length < startIndex + bytes)
throw new ArgumentOutOfRangeException("startIndex", "Data array is too small to write a " + bytes + "-byte value at offset " + startIndex + ".");
for (Int32 index = 0; index < bytes; index++)
{
Int32 offs = startIndex + (littleEndian ? index : lastByte - index);
data[offs] = (Byte)(value >> (8 * index) & 0xFF);
}
}
public static UInt32 ReadIntFromByteArray(Byte[] data, Int32 startIndex, Int32 bytes, Boolean littleEndian)
{
Int32 lastByte = bytes - 1;
if (data.Length < startIndex + bytes)
throw new ArgumentOutOfRangeException("startIndex", "Data array is too small to read a " + bytes + "-byte value at offset " + startIndex + ".");
UInt32 value = 0;
for (Int32 index = 0; index < bytes; index++)
{
Int32 offs = startIndex + (littleEndian ? index : lastByte - index);
value += (UInt32)(data[offs] << (8 * index));
}
return value;
}