PSD格式文件的读取

本文主要是介绍PSD格式文件的读取，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

介绍*.PSD文件的读取方法，并提供完整读取函数。其中：m_Rect为目标区域，m_lpDDS7为目标DirectDraw表面，m_pbAlphaMask为目标Aplha通告指针。Read16函数为从指定文件当前位置读取一个WORD，Read32函数为从指定文件当前位置读取一个DWORD。MAX_PSD_CHANNELS为24。以下就是*.PSD文件的读取方法，有兴趣的朋友可以继续深入研究，到时可别忘了发我一份。

HRESULT LoadPSD( LPSTR strFilename ) // 读取PSD文件{DWORD dwWidth, dwHeight; // 宽高long lSurfWidth = m_Rect.right - m_Rect.left;long lSurfHeight = m_Rect.bottom - m_Rect.top;WORD CompressionType; // 压缩类型HDC hDC;FILE *fpPSD;WORD ChannelCount; // 通道数 // 打开PSD文件if ( ( fpPSD = fopen ( strFilename, "rb" ) ) == NULL ) {return E_FAIL;}// 头四个字节为"8BPS"char signature[5];signature[0] = fgetc( fpPSD );signature[1] = fgetc( fpPSD );signature[2] = fgetc( fpPSD );signature[3] = fgetc( fpPSD );signature[4] = '/0';if ( strcmp( signature,"8BPS" ) != 0 ) {return E_FAIL;}// 版本必须为1if ( Read16( fpPSD ) != 1 ) {return E_FAIL;}// 跳过一些数据 (总是0)Read32( fpPSD );Read16( fpPSD );// 读取通道数ChannelCount = Read16( fpPSD );// 确定至少有一个通道if ( ( ChannelCount < 0 ) || ( ChannelCount > MAX_PSD_CHANNELS ) ) {return E_FAIL;}// 读入宽和高dwHeight = Read32( fpPSD );dwWidth = Read32( fpPSD );if ( dwWidth != ( DWORD )lSurfWidth || dwHeight != ( DWORD )lSurfHeight ) {return E_FAIL;}// 只读入8位通道if ( Read16( fpPSD ) != 8 ) {return E_FAIL;}// 确定模式为RGB.// 可能值：// 0: 位图// 1: 灰阶// 2: 索引// 3: RGB// 4: CMYK// 7: Multichannel// 8: Duotone// 9: Labif ( Read16( fpPSD ) != 3 ) {return E_FAIL;}// 跳过数据（如调色板）int ModeDataCount = Read32( fpPSD );if ( ModeDataCount )fseek( fpPSD, ModeDataCount, SEEK_CUR );// 跳过数据（如：pen tool paths, etc）int ResourceDataCount = Read32( fpPSD );if ( ResourceDataCount )fseek( fpPSD, ResourceDataCount, SEEK_CUR );// 条过保留数据int ReservedDataCount = Read32( fpPSD );if ( ReservedDataCount )fseek( fpPSD, ReservedDataCount, SEEK_CUR );// 0: 非压缩// 1: RLE压缩CompressionType = Read16( fpPSD );if ( CompressionType > 1 ) {return E_FAIL;}BYTE* PSDPixels = new BYTE[ ( lSurfWidth * lSurfHeight ) * 4 ];// 解包数据UnPackPSD( fpPSD, lSurfWidth, lSurfHeight, PSDPixels, ChannelCount, CompressionType );fclose( fpPSD );// 复制信息BITMAPINFO BitmapInfo;ZeroMemory( &BitmapInfo, sizeof( BitmapInfo ) );BitmapInfo.bmiHeader.biSize = sizeof( BitmapInfo.bmiHeader );BitmapInfo.bmiHeader.biWidth = lSurfWidth;BitmapInfo.bmiHeader.biHeight = -lSurfHeight;BitmapInfo.bmiHeader.biPlanes = 1;BitmapInfo.bmiHeader.biBitCount = 32;m_lpDDS7->GetDC( &hDC );int rc = StretchDIBits( hDC,0,0,lSurfWidth,lSurfHeight,0,0,lSurfWidth,lSurfHeight,PSDPixels,&BitmapInfo,DIB_RGB_COLORS,SRCCOPY );m_lpDDS7->ReleaseDC( hDC );if ( rc == GDI_ERROR ) {H_ARRAY_DELETE( PSDPixels );#ifdef _DEBUGg_pHERR->OutDebugMsg( 3, H2DSERR_INVALID_PSD );#endifreturn E_FAIL;}// 是否读取Alpha混合通道if( ChannelCount > 3 ) {m_pbAlphaMask = new BYTE[ lSurfWidth * lSurfHeight ];for ( int x = 0; x < lSurfWidth; x++ )for ( int y = 0; y < lSurfHeight; y++ ) {m_pbAlphaMask[ ( y * lSurfWidth ) + x ] =　PSDPixels[ ( ( ( y * lSurfHeight ) + x ) * 4 ) + 3 ];}}else {m_pbAlphaMask = NULL;}H_ARRAY_DELETE( PSDPixels );return DD_OK;}// PSD文件解包　void CHades2DSurface::UnPackPSD( FILE *fp,　// fp为PSD文件指针，DWORD dwWidth, // dwWidth、dwHeight为宽高，DWORD dwHeight,BYTE* pixels,　// pixels为解包目标指针，WORD ChannelCnt,　 // ChannelCnt为通道数，WORD Compression ) // Compression位压缩类型。 {int Default[4] = { 0, 0, 0, 255 };int chn[4] = { 2, 1, 0, 3};int PixelCount = dwWidth * dwHeight;if ( Compression ) {fseek( fp, dwHeight * ChannelCnt * 2, SEEK_CUR );for ( int c = 0; c < 4; c++ ) {int pn = 0;int channel = chn[c];if ( channel >= ChannelCnt ) {for ( pn=0; pn < PixelCount ;pn++ ) {pixels[ ( pn * 4 ) + channel ] = Default[ channel ];}}else // 非压缩{int count = 0;while( count < PixelCount ) {int len = fgetc( fp );if( len == 128 ) { }else if ( len < 128 ) // 非RLE{len++;count += len;while(len) {pixels[ ( pn * 4 ) + channel ] = fgetc( fp );pn++;len--;}}　 else if ( len > 128 ) // RLE打包{len ^= 0x0FF;len += 2;unsigned char val = fgetc( fp );count += len;while( len ) {pixels[ ( pn * 4 ) + channel ] = val;pn++;len--;}}}}}}else{for ( int c=0; c < 4; c++ ) {int channel = chn[c];if ( channel > ChannelCnt ) {for( int pn = 0; pn < PixelCount; pn++ ) {pixels[ ( pn * 4 ) + channel ] = Default[ channel ];}}else {for( int n = 0; n < PixelCount; n++ ) {pixels[ ( n * 4 ) + channel ] = fgetc( fp );}}}}}

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