本文介绍了创建Compact Framework的单色位图的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我需要创建一个使用原始字节重新presenting单色位图数据的位图对象。在完整的框架，我做以下内容：
I need to create a Bitmap object using raw bytes representing monochrome bitmap data. On the full framework, I am doing the following:
Bitmap bmp = new Bitmap(width, height, PixelFormat.Format8bppIndexed)
BitmapData bmpData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.WriteOnly, bmp.PixelFormat);
// Write my data into bmpData.Scan0
bmp.UnlockBits(bmpData);
不幸的是，Compact Framework不具备 PixelFormat.Format8bppIndexed 枚举值。所以，我怎么能在CF做到这一点？我能想到的唯一的事情是手动创建位图文件头自己，并将其写入与数据一起到流然后构造一个位图与该对象流。
Unfortunately, the Compact Framework doesn't have the PixelFormat.Format8bppIndexed enum value. So how can I accomplish this on the CF? The only thing I can think of is to manually create the bitmap file header myself and write it along with the data into a Stream and then construct a Bitmap object with that Stream.
想法？
推荐答案
下面是一些code，可以帮助：
Here's some code that might help:
const int XPelsPerMeter = 0xb12; // 72 ppi, 96 would work well too
const int YPelsPerMeter = 0xb12;
const int Gptr = 0x40;
const int Srccopy = 0x00CC0020;
struct BITMAPFILEHEADER
{
public ushort bfType;
public uint bfSize;
public ushort bfReserved1;
public ushort bfReserved2;
public uint bfOffBits;
}
struct BITMAPINFOHEADER
{
public uint biSize;
public int biWidth;
public int biHeight;
public ushort biPlanes;
public ushort biBitCount;
public uint biCompression;
public uint biSizeImage;
public int biXPelsPerMeter;
public int biYPelsPerMeter;
public uint biClrUsed;
public uint biClrImportant;
}
public static byte[] GetByteArray(Bitmap bitmap)
{
IntPtr hbm = bitmap.GetHbitmap(); // this is step (1)
IntPtr sdc = GetDC( IntPtr.Zero ); // First we obtain the DC for the screen
// Next, create a DC for the original hbitmap
IntPtr hdc = CreateCompatibleDC( sdc );
SelectObject( hdc, hbm );
byte[] arrayBytes = CreateBinary(hdc, bitmap.Height, bitmap.Width);
// Finally some cleanup.
DeleteDC( hdc );
ReleaseDC( IntPtr.Zero, sdc );
DeleteObject( hbm );
return arrayBytes;
}
static int WIDTHBYTES( int bits )
{
return ( ( ( ( bits ) + 31 ) / 32 ) * 4 );
}
private static byte[] CreateBinary( IntPtr hDc, int height, int width )
{
IntPtr hMemDc = CreateCompatibleDC( hDc );
int cb = 0;
BITMAPINFOHEADER bi = new BITMAPINFOHEADER();
bi.biSize = ( uint )Marshal.SizeOf( bi );
bi.biBitCount = 1; // Creating RGB bitmap. The following three members don't matter
bi.biClrUsed = 2;
bi.biClrImportant = 2;
bi.biCompression = 0;
bi.biHeight = height;
bi.biWidth = width;
bi.biPlanes = 1;
cb = WIDTHBYTES( bi.biWidth * bi.biBitCount ) * bi.biHeight;
bi.biSizeImage = ( uint )cb;
bi.biXPelsPerMeter = XPelsPerMeter;
bi.biYPelsPerMeter = YPelsPerMeter;
IntPtr pBits = IntPtr.Zero;
//Allocate memory for bitmap bits
IntPtr pBi = LocalAlloc( Gptr, bi.biSize );
// Not sure if this needed - simply trying to keep marshaller happy
Marshal.StructureToPtr( bi, pBi, false );
//This will return IntPtr to actual DIB bits in pBits
IntPtr hBmp = CreateDIBSection( hDc, pBi, 0, ref pBits, IntPtr.Zero, 0 );
//Marshall back - now we have BITMAPINFOHEADER correctly filled in
//Marshal.PtrToStructure(pBI, bi);
BITMAPINFOHEADER biNew = ( BITMAPINFOHEADER )Marshal.PtrToStructure( pBi, typeof( BITMAPINFOHEADER ) );
//Usual stuff
IntPtr hOldBitmap = SelectObject( hMemDc, hBmp );
//Grab bitmap
BitBlt( hMemDc, 0, 0, bi.biWidth, bi.biHeight, hDc, 0, 0, Srccopy );
// Allocate memory for a copy of bitmap bits
byte[] RealBits = new byte[cb];
// And grab bits from DIBSestion data
Marshal.Copy( pBits, RealBits, 0, cb );
// This simply creates valid bitmap file header, so it can be saved to disk
BITMAPFILEHEADER bfh = new BITMAPFILEHEADER();
uint colorSize = 2 * 4;//2 colors for B&W, 4 bytes (RGBQUAD)
uint sizeofBinfo = 0x36 + colorSize;//original
//sizeofBINFO = (uint)Marshal.SizeOf(bi);//sorin
//bfh.bfSize = ( uint )cb + 0x36; // Size of header + size of BITMAPINFOHEADER size of bitmap bits
bfh.bfSize = ( uint )( cb + sizeofBinfo );
bfh.bfType = 0x4d42; //BM
bfh.bfOffBits = sizeofBinfo; //
int HdrSize = 14;
byte[] header = new byte[HdrSize];
BitConverter.GetBytes( bfh.bfType ).CopyTo( header, 0 );
BitConverter.GetBytes( bfh.bfSize ).CopyTo( header, 2 );
BitConverter.GetBytes( bfh.bfOffBits ).CopyTo( header, 10 );
//Allocate enough memory for complete bitmap file
byte[] data = new byte[cb + bfh.bfOffBits];
//BITMAPFILEHEADER
header.CopyTo( data, 0 );
//BITMAPINFOHEADER
header = new byte[Marshal.SizeOf( bi )];
IntPtr pHeader = LocalAlloc( Gptr, ( uint )Marshal.SizeOf( bi ) );
Marshal.StructureToPtr( biNew, pHeader, false );
Marshal.Copy( pHeader, header, 0, Marshal.SizeOf( bi ) );
LocalFree( pHeader );
header.CopyTo( data, HdrSize );
//set black color as second color from color table
byte[] colors = new byte[10];
colors[4] = 255;
colors[5] = 255;
colors[6] = 255;
colors.CopyTo( data, ( int )bfh.bfOffBits - ( int )colorSize );
//Bitmap bits
RealBits.CopyTo( data, ( int )bfh.bfOffBits );
DeleteObject( SelectObject( hMemDc, hOldBitmap ) );
DeleteDC( hMemDc );
return data;
}
[DllImport( "coredll.dll" )]
public static extern bool DeleteObject( IntPtr hObject );
[DllImport( "coredll.dll" )]
public static extern int InvalidateRect( IntPtr hwnd, IntPtr rect, int bErase );
[DllImport( "coredll.dll" )]
public static extern IntPtr GetDC( IntPtr hwnd );
[DllImport( "coredll.dll" )]
public static extern IntPtr CreateCompatibleDC( IntPtr hdc );
[DllImport( "coredll.dll" )]
public static extern int ReleaseDC( IntPtr hwnd, IntPtr hdc );
[DllImport( "coredll.dll" )]
public static extern int DeleteDC( IntPtr hdc );
[DllImport( "coredll.dll" )]
public static extern IntPtr SelectObject( IntPtr hdc, IntPtr hgdiobj );
[DllImport( "coredll.dll" )]
public static extern int BitBlt( IntPtr hdcDst, int xDst, int yDst, int w, int h, IntPtr hdcSrc, int xSrc, int ySrc, int rop );
[DllImport( "coredll.dll" )]
private static extern IntPtr LocalAlloc( uint flags, uint cb );
[DllImport( "coredll.dll" )]
private static extern IntPtr LocalFree( IntPtr hMem );
[DllImport( "coredll.dll" )]
private static extern IntPtr CreateDIBSection( IntPtr hdc, IntPtr hdr, uint colors, ref IntPtr pBits, IntPtr hFile, uint offset );
}
要保存到一个文件中做到以下几点：
To save it to a file do the following:
byte[] data = BWImage.GetByteArray(bitmap);
FileStream fs = new FileStream( "BW.bmp", FileMode.Create );
fs.Write( data, 0, data.Length );
fs.Flush();
fs.Close();
这篇关于创建Compact Framework的单色位图的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！