Symbian3/Examples/guid-6013a680-57f9-415b-8851-c4fa63356636/_p_n_g_codec_8cpp_source.html
Week 32 contribution of PDK documentation content. See release notes for details. Fixes bug Bug 3582
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<h1>examples/Multimedia/ICL/ICLCodec/PNGCodec.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// PngCodec.CPP</span>
<a name="l00002"></a>00002 <span class="comment">//</span>
<a name="l00003"></a>00003 <span class="comment">// Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).</span>
<a name="l00004"></a>00004 <span class="comment">// All rights reserved.</span>
<a name="l00005"></a>00005 <span class="comment">// This component and the accompanying materials are made available</span>
<a name="l00006"></a>00006 <span class="comment">// under the terms of "Eclipse Public License v1.0"</span>
<a name="l00007"></a>00007 <span class="comment">// which accompanies this distribution, and is available</span>
<a name="l00008"></a>00008 <span class="comment">// at the URL "http://www.eclipse.org/legal/epl-v10.html".</span>
<a name="l00009"></a>00009 <span class="comment">//</span>
<a name="l00010"></a>00010 <span class="comment">// Initial Contributors:</span>
<a name="l00011"></a>00011 <span class="comment">// Nokia Corporation - initial contribution.</span>
<a name="l00012"></a>00012 <span class="comment">//</span>
<a name="l00013"></a>00013 <span class="comment">// Contributors:</span>
<a name="l00014"></a>00014 <span class="comment">//</span>
<a name="l00015"></a>00015 <span class="comment">// Description:</span>
<a name="l00016"></a>00016 <span class="comment">//</span>
<a name="l00017"></a>00017 <span class="comment">//</span>
<a name="l00018"></a>00018
<a name="l00019"></a>00019 <span class="preprocessor">#include <fbs.h></span>
<a name="l00020"></a>00020
<a name="l00021"></a>00021 <span class="preprocessor">#include "ImageUtils.h"</span>
<a name="l00022"></a>00022 <span class="preprocessor">#include "PNGCodec.h"</span>
<a name="l00023"></a>00023
<a name="l00024"></a>00024 <span class="comment">// Constants.</span>
<a name="l00025"></a>00025 <span class="keyword">const</span> TInt KTwipsPerMeter = 56693;
<a name="l00026"></a>00026
<a name="l00027"></a>00027 <span class="comment">// </span>
<a name="l00028"></a>00028 <span class="comment">// TPngImageInformation: PNG image information</span>
<a name="l00029"></a>00029 <span class="comment">//</span>
<a name="l00030"></a>00030
<a name="l00031"></a>00031 <span class="comment">// Initialise default PNG image information</span>
<a name="l00032"></a>00032 TPngImageInformation::TPngImageInformation()
<a name="l00033"></a>00033 {
<a name="l00034"></a>00034 iSize.SetSize(0,0);
<a name="l00035"></a>00035 iBitDepth = 0;
<a name="l00036"></a>00036 iColorType = EGrayscale;
<a name="l00037"></a>00037 iCompressionMethod = EDeflateInflate32K;
<a name="l00038"></a>00038 iFilterMethod = EAdaptiveFiltering;
<a name="l00039"></a>00039 iInterlaceMethod = ENoInterlace;
<a name="l00040"></a>00040 iPalettePresent = EFalse;
<a name="l00041"></a>00041
<a name="l00042"></a>00042 <span class="preprocessor">#if defined(_DEBUG)</span>
<a name="l00043"></a>00043 <span class="preprocessor"></span> <span class="comment">// as an optimisation, we are going to set iPalette to all zeros, instead of setting</span>
<a name="l00044"></a>00044 <span class="comment">// each element to KRgbBlack. This assumes that KRbgBlack is itself zero.</span>
<a name="l00045"></a>00045 ASSERT(<span class="keyword">sizeof</span>(TRgb)==<span class="keyword">sizeof</span>(TUint32)); <span class="comment">// ie no new fields</span>
<a name="l00046"></a>00046 ASSERT(KRgbBlack.Value()==0); <span class="comment">// ie the one value is zero</span>
<a name="l00047"></a>00047 <span class="preprocessor">#endif // defined(_DEBUG)</span>
<a name="l00048"></a>00048 <span class="preprocessor"></span>
<a name="l00049"></a>00049 Mem::FillZ(iPalette, KPngMaxPLTESize*<span class="keyword">sizeof</span>(TRgb));
<a name="l00050"></a>00050
<a name="l00051"></a>00051 iBackgroundPresent = EFalse;
<a name="l00052"></a>00052 iBackgroundColor = KRgbWhite;
<a name="l00053"></a>00053 iPhysicalPresent = EFalse;
<a name="l00054"></a>00054 iPhysicalUnits = EUnknownUnits;
<a name="l00055"></a>00055 iPhysicalSize.SetSize(0,0);
<a name="l00056"></a>00056 iTransparencyPresent = EFalse;
<a name="l00057"></a>00057 Mem::Fill(iTransparencyValue,KPngMaxPLTESize,0xff);
<a name="l00058"></a>00058 }
<a name="l00059"></a>00059
<a name="l00060"></a>00060
<a name="l00061"></a>00061 <span class="comment">//</span>
<a name="l00062"></a>00062 <span class="comment">// CPngReadCodec: reads a PNG image</span>
<a name="l00063"></a>00063 <span class="comment">//</span>
<a name="l00064"></a>00064
<a name="l00065"></a>00065 CPngReadCodec::~CPngReadCodec()
<a name="l00066"></a>00066 {
<a name="l00067"></a>00067 <span class="keyword">delete</span> iDecoder;
<a name="l00068"></a>00068 <span class="keyword">delete</span> iDecompressor;
<a name="l00069"></a>00069 }
<a name="l00070"></a>00070
<a name="l00071"></a>00071 <span class="comment">// Called by framework when a Convert operation begins</span>
<a name="l00072"></a>00072 <span class="keywordtype">void</span> CPngReadCodec::InitFrameL(TFrameInfo& <span class="comment">/*aFrameInfo*/</span>, CFrameImageData& <span class="comment">/*aFrameImageData*/</span>,
<a name="l00073"></a>00073 TBool aDisableErrorDiffusion, CFbsBitmap& aDestination, CFbsBitmap* aDestinationMask)
<a name="l00074"></a>00074 {
<a name="l00075"></a>00075 CFbsBitmap& newFrame = aDestination;
<a name="l00076"></a>00076
<a name="l00077"></a>00077 TPoint& pos = Pos();
<a name="l00078"></a>00078 pos.SetXY(0,0);
<a name="l00079"></a>00079 iChunkBytesRemaining = 0;
<a name="l00080"></a>00080
<a name="l00081"></a>00081 <span class="comment">// Use the supplied image processor</span>
<a name="l00082"></a>00082 CImageProcessor* imageProc = ImageProcessorUtility::NewImageProcessorL(newFrame, iImageInfo.iSize, ERgb, aDisableErrorDiffusion);
<a name="l00083"></a>00083 SetImageProcessor(imageProc);
<a name="l00084"></a>00084 imageProc->PrepareL(newFrame,iImageInfo.iSize);
<a name="l00085"></a>00085
<a name="l00086"></a>00086 CImageProcessor* maskProc = NULL;
<a name="l00087"></a>00087 SetMaskProcessor(NULL);
<a name="l00088"></a>00088
<a name="l00089"></a>00089 <span class="comment">// If transparency is being used, create a bitmap mask as well</span>
<a name="l00090"></a>00090 <span class="keywordflow">if</span> ((iImageInfo.iTransparencyPresent || (iImageInfo.iColorType & TPngImageInformation::EAlphaChannelUsed))
<a name="l00091"></a>00091 && aDestinationMask)
<a name="l00092"></a>00092 {
<a name="l00093"></a>00093 maskProc = ImageProcessorUtility::NewImageProcessorL(*aDestinationMask, iImageInfo.iSize, ERgb, aDisableErrorDiffusion);
<a name="l00094"></a>00094 SetMaskProcessor(maskProc);
<a name="l00095"></a>00095 maskProc->PrepareL(*aDestinationMask,iImageInfo.iSize);
<a name="l00096"></a>00096 <span class="comment">// set mask to black so that unknown parts on streamed image are not drawn</span>
<a name="l00097"></a>00097 ClearBitmapL(*aDestinationMask, KRgbBlack);
<a name="l00098"></a>00098 }
<a name="l00099"></a>00099
<a name="l00100"></a>00100 <span class="comment">// Create a helper to read the scan lines</span>
<a name="l00101"></a>00101 <span class="keyword">delete</span> iDecoder;
<a name="l00102"></a>00102 iDecoder = NULL;
<a name="l00103"></a>00103 iDecoder = CPngReadSubCodec::NewL(imageProc,maskProc,iImageInfo);
<a name="l00104"></a>00104
<a name="l00105"></a>00105 <span class="comment">// And a unzipper to decompress image data</span>
<a name="l00106"></a>00106 <span class="keywordflow">if</span> (!iDecompressor)
<a name="l00107"></a>00107 iDecompressor = CEZDecompressor::NewL(*<span class="keyword">this</span>);
<a name="l00108"></a>00108 <span class="keywordflow">else</span>
<a name="l00109"></a>00109 iDecompressor->ResetL(*<span class="keyword">this</span>);
<a name="l00110"></a>00110
<a name="l00111"></a>00111 <span class="keywordflow">if</span> (maskProc==NULL)
<a name="l00112"></a>00112 {
<a name="l00113"></a>00113 <span class="comment">// if no mask, clear destination for sensible behaviour on streamed partial images</span>
<a name="l00114"></a>00114 TRgb background = iImageInfo.iBackgroundPresent ? iImageInfo.iBackgroundColor : KRgbWhite;
<a name="l00115"></a>00115 ClearBitmapL(aDestination, background);
<a name="l00116"></a>00116 }
<a name="l00117"></a>00117 }
<a name="l00118"></a>00118
<a name="l00119"></a>00119 <span class="comment">// Called by framework to initialise image frame header</span>
<a name="l00120"></a>00120 <span class="keywordtype">void</span> CPngReadCodec::InitFrameHeader(TFrameInfo& aFrameSettings, CFrameImageData& <span class="comment">/* aFrameImageData */</span>)
<a name="l00121"></a>00121 {
<a name="l00122"></a>00122 ASSERT(aFrameSettings.CurrentFrameState() == TFrameInfo::EFrameInfoUninitialised);
<a name="l00123"></a>00123 iFrameInfo = &aFrameSettings;
<a name="l00124"></a>00124 iFrameInfo->SetCurrentFrameState(TFrameInfo::EFrameInfoProcessingFrameHeader);
<a name="l00125"></a>00125 }
<a name="l00126"></a>00126
<a name="l00127"></a>00127 <span class="comment">// Called by framework to process a header for a frame</span>
<a name="l00128"></a>00128 TFrameState CPngReadCodec::ProcessFrameHeaderL(TBufPtr8& aData)
<a name="l00129"></a>00129 {
<a name="l00130"></a>00130 <span class="keyword">const</span> TUint8* startDataPtr = aData.Ptr();
<a name="l00131"></a>00131 <span class="keyword">const</span> TUint8* dataPtr = startDataPtr;
<a name="l00132"></a>00132 <span class="keyword">const</span> TUint8* dataPtrLimit = startDataPtr + aData.Length();
<a name="l00133"></a>00133
<a name="l00134"></a>00134 <span class="comment">// Process the mandatory PNG header chunk: sets up iImageInfo</span>
<a name="l00135"></a>00135 <span class="keywordflow">if</span> (iFrameInfo->CurrentFrameState() == TFrameInfo::EFrameInfoProcessingFrameHeader)
<a name="l00136"></a>00136 {
<a name="l00137"></a>00137 <span class="keywordflow">if</span> (dataPtr + KPngChunkLengthSize + KPngChunkIdSize + KPngIHDRChunkSize + KPngChunkCRCSize > dataPtrLimit)
<a name="l00138"></a>00138 User::Leave(KErrUnderflow);
<a name="l00139"></a>00139
<a name="l00140"></a>00140 TInt chunkLength = PtrReadUtil::ReadBigEndianUint32Inc(dataPtr);
<a name="l00141"></a>00141 TPtrC8 chunkId(dataPtr,KPngChunkIdSize);
<a name="l00142"></a>00142
<a name="l00143"></a>00143 <span class="keywordflow">if</span> (chunkLength != KPngIHDRChunkSize || chunkId != KPngIHDRChunkId)
<a name="l00144"></a>00144 User::Leave(KErrNotFound);
<a name="l00145"></a>00145
<a name="l00146"></a>00146 dataPtr += KPngChunkIdSize;
<a name="l00147"></a>00147
<a name="l00148"></a>00148 DoProcessIHDRL(dataPtr,chunkLength);
<a name="l00149"></a>00149
<a name="l00150"></a>00150 dataPtr += KPngIHDRChunkSize + KPngChunkCRCSize;
<a name="l00151"></a>00151 }
<a name="l00152"></a>00152
<a name="l00153"></a>00153 <span class="comment">// Process any optional PNG header chunks</span>
<a name="l00154"></a>00154 TRAPD(err, DoProcessInfoL(dataPtr, dataPtrLimit));
<a name="l00155"></a>00155 <span class="keywordflow">if</span> (err != KErrNone)
<a name="l00156"></a>00156 {
<a name="l00157"></a>00157 <span class="keywordflow">if</span> (err == KErrNotFound)
<a name="l00158"></a>00158 <span class="keywordflow">return</span> EFrameComplete;
<a name="l00159"></a>00159
<a name="l00160"></a>00160 User::Leave(err); <span class="comment">// A real error occured</span>
<a name="l00161"></a>00161 }
<a name="l00162"></a>00162
<a name="l00163"></a>00163 <span class="comment">// Having read the header, can initialise the frame information</span>
<a name="l00164"></a>00164 aData.Shift(dataPtr - startDataPtr);
<a name="l00165"></a>00165
<a name="l00166"></a>00166 iFrameInfo->iFrameCoordsInPixels.SetRect(TPoint(0,0),iImageInfo.iSize);
<a name="l00167"></a>00167 iFrameInfo->iOverallSizeInPixels = iImageInfo.iSize;
<a name="l00168"></a>00168 <span class="keywordflow">if</span> (iImageInfo.iPhysicalPresent && iImageInfo.iPhysicalUnits == TPngImageInformation::EMeters)
<a name="l00169"></a>00169 iFrameInfo->iFrameSizeInTwips = iImageInfo.iPhysicalSize;
<a name="l00170"></a>00170 <span class="keywordflow">else</span>
<a name="l00171"></a>00171 iFrameInfo->iFrameSizeInTwips.SetSize(0,0);
<a name="l00172"></a>00172
<a name="l00173"></a>00173 iFrameInfo->iBitsPerPixel = iImageInfo.iBitDepth;
<a name="l00174"></a>00174 <span class="keywordflow">if</span> (iImageInfo.iColorType & TPngImageInformation::EColorUsed)
<a name="l00175"></a>00175 iFrameInfo->iBitsPerPixel *= 3;
<a name="l00176"></a>00176
<a name="l00177"></a>00177 iFrameInfo->iDelay = 0;
<a name="l00178"></a>00178 iFrameInfo->iFlags = TFrameInfo::ECanDither;
<a name="l00179"></a>00179
<a name="l00180"></a>00180 <span class="keywordflow">if</span> (iImageInfo.iColorType & (TPngImageInformation::EPaletteUsed | TPngImageInformation::EColorUsed))
<a name="l00181"></a>00181 iFrameInfo->iFlags |= TFrameInfo::EColor;
<a name="l00182"></a>00182
<a name="l00183"></a>00183 <span class="keywordflow">if</span> (iImageInfo.iColorType & TPngImageInformation::EAlphaChannelUsed)
<a name="l00184"></a>00184 {
<a name="l00185"></a>00185 iFrameInfo->iFlags |= TFrameInfo::ETransparencyPossible;
<a name="l00186"></a>00186 iFrameInfo->iFlags |= TFrameInfo::EAlphaChannel;
<a name="l00187"></a>00187 }
<a name="l00188"></a>00188 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (iImageInfo.iTransparencyPresent)
<a name="l00189"></a>00189 iFrameInfo->iFlags |= TFrameInfo::ETransparencyPossible;
<a name="l00190"></a>00190
<a name="l00191"></a>00191 <span class="keywordflow">switch</span> (iFrameInfo->iBitsPerPixel)
<a name="l00192"></a>00192 {
<a name="l00193"></a>00193 <span class="keywordflow">case</span> 1:
<a name="l00194"></a>00194 iFrameInfo->iFrameDisplayMode = EGray2;
<a name="l00195"></a>00195 <span class="keywordflow">break</span>;
<a name="l00196"></a>00196
<a name="l00197"></a>00197 <span class="keywordflow">case</span> 2:
<a name="l00198"></a>00198 iFrameInfo->iFrameDisplayMode = EGray4;
<a name="l00199"></a>00199 <span class="keywordflow">break</span>;
<a name="l00200"></a>00200
<a name="l00201"></a>00201 <span class="keywordflow">case</span> 4:
<a name="l00202"></a>00202 iFrameInfo->iFrameDisplayMode = (iFrameInfo->iFlags & TFrameInfo::EColor) ? EColor16 : EGray16;
<a name="l00203"></a>00203 <span class="keywordflow">break</span>;
<a name="l00204"></a>00204
<a name="l00205"></a>00205 <span class="keywordflow">case</span> 8:
<a name="l00206"></a>00206 iFrameInfo->iFrameDisplayMode = (iFrameInfo->iFlags & TFrameInfo::EColor) ? EColor256 : EGray256;
<a name="l00207"></a>00207 <span class="keywordflow">break</span>;
<a name="l00208"></a>00208
<a name="l00209"></a>00209 <span class="keywordflow">case</span> 12:
<a name="l00210"></a>00210 iFrameInfo->iFrameDisplayMode = EColor4K;
<a name="l00211"></a>00211 <span class="keywordflow">break</span>;
<a name="l00212"></a>00212
<a name="l00213"></a>00213 <span class="keywordflow">case</span> 16:
<a name="l00214"></a>00214 iFrameInfo->iFrameDisplayMode = EColor64K;
<a name="l00215"></a>00215 <span class="keywordflow">break</span>;
<a name="l00216"></a>00216
<a name="l00217"></a>00217 <span class="keywordflow">case</span> 24:
<a name="l00218"></a>00218 iFrameInfo->iFrameDisplayMode = EColor16M;
<a name="l00219"></a>00219 <span class="keywordflow">break</span>;
<a name="l00220"></a>00220
<a name="l00221"></a>00221 <span class="keywordflow">default</span>:
<a name="l00222"></a>00222 User::Leave(KErrCorrupt);
<a name="l00223"></a>00223 }
<a name="l00224"></a>00224
<a name="l00225"></a>00225 <span class="keywordflow">if</span> (iImageInfo.iBackgroundPresent)
<a name="l00226"></a>00226 iFrameInfo->iBackgroundColor = iImageInfo.iBackgroundColor;
<a name="l00227"></a>00227
<a name="l00228"></a>00228 iFrameInfo->SetCurrentFrameState(TFrameInfo::EFrameInfoProcessingComplete);
<a name="l00229"></a>00229 <span class="keywordflow">return</span> EFrameComplete;
<a name="l00230"></a>00230 }
<a name="l00231"></a>00231
<a name="l00232"></a>00232 <span class="comment">// Called by the framework to process frame data</span>
<a name="l00233"></a>00233 TFrameState CPngReadCodec::ProcessFrameL(TBufPtr8& aSrc)
<a name="l00234"></a>00234 {
<a name="l00235"></a>00235 CImageProcessor*<span class="keyword">const</span> imageProc = ImageProcessor();
<a name="l00236"></a>00236 CImageProcessor*<span class="keyword">const</span> maskProc = MaskProcessor();
<a name="l00237"></a>00237
<a name="l00238"></a>00238 TUint8* startDataPtr = <span class="keyword">const_cast<</span>TUint8*<span class="keyword">></span>(aSrc.Ptr());
<a name="l00239"></a>00239 TUint8* dataPtr = startDataPtr;
<a name="l00240"></a>00240 <span class="keyword">const</span> TUint8* dataPtrLimit = dataPtr + aSrc.Length();
<a name="l00241"></a>00241 <span class="keywordflow">while</span> (dataPtr < dataPtrLimit)
<a name="l00242"></a>00242 {
<a name="l00243"></a>00243 <span class="comment">// If at the end of a PNG chunk</span>
<a name="l00244"></a>00244 <span class="keywordflow">if</span> (iChunkBytesRemaining == 0)
<a name="l00245"></a>00245 {
<a name="l00246"></a>00246 <span class="keywordflow">if</span> (iChunkId == KPngIDATChunkId) <span class="comment">// Need to skip IDAT chunk CRCs</span>
<a name="l00247"></a>00247 {
<a name="l00248"></a>00248 <span class="keywordflow">if</span> (dataPtr + KPngChunkCRCSize + KPngChunkLengthSize + KPngChunkIdSize > dataPtrLimit)
<a name="l00249"></a>00249 <span class="keywordflow">break</span>;
<a name="l00250"></a>00250
<a name="l00251"></a>00251 dataPtr += KPngChunkCRCSize;
<a name="l00252"></a>00252 }
<a name="l00253"></a>00253 <span class="keywordflow">else</span>
<a name="l00254"></a>00254 {
<a name="l00255"></a>00255 <span class="keywordflow">if</span> (dataPtr + KPngChunkLengthSize + KPngChunkIdSize > dataPtrLimit)
<a name="l00256"></a>00256 <span class="keywordflow">break</span>;
<a name="l00257"></a>00257 }
<a name="l00258"></a>00258
<a name="l00259"></a>00259 iChunkBytesRemaining = PtrReadUtil::ReadBigEndianUint32Inc(const_cast<const TUint8*&>(dataPtr));
<a name="l00260"></a>00260 iChunkId = TPtr8(dataPtr,KPngChunkIdSize,KPngChunkIdSize);
<a name="l00261"></a>00261 dataPtr += KPngChunkIdSize;
<a name="l00262"></a>00262 }
<a name="l00263"></a>00263 <span class="comment">// Process an image data chunk</span>
<a name="l00264"></a>00264 <span class="keywordflow">if</span> (iChunkId == KPngIDATChunkId)
<a name="l00265"></a>00265 DoProcessDataL(const_cast<const TUint8*&>(dataPtr),dataPtrLimit);
<a name="l00266"></a>00266 <span class="comment">// Process an END chunk -- frame is complete</span>
<a name="l00267"></a>00267 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (iChunkId == KPngIENDChunkId)
<a name="l00268"></a>00268 {
<a name="l00269"></a>00269 iDecompressor->InflateL();
<a name="l00270"></a>00270 imageProc->FlushPixels();
<a name="l00271"></a>00271 <span class="keywordflow">if</span> (maskProc)
<a name="l00272"></a>00272 maskProc->FlushPixels();
<a name="l00273"></a>00273 <span class="keywordflow">return</span> EFrameComplete;
<a name="l00274"></a>00274 }
<a name="l00275"></a>00275 <span class="keywordflow">else</span>
<a name="l00276"></a>00276 <span class="comment">// Skip other chunks</span>
<a name="l00277"></a>00277 {
<a name="l00278"></a>00278 TInt bytesLeft = dataPtrLimit - dataPtr;
<a name="l00279"></a>00279 <span class="keywordflow">if</span> (bytesLeft >= iChunkBytesRemaining + KPngChunkCRCSize)
<a name="l00280"></a>00280 {
<a name="l00281"></a>00281 dataPtr += iChunkBytesRemaining + KPngChunkCRCSize;
<a name="l00282"></a>00282 iChunkBytesRemaining = 0;
<a name="l00283"></a>00283 }
<a name="l00284"></a>00284 <span class="keywordflow">else</span>
<a name="l00285"></a>00285 {
<a name="l00286"></a>00286 dataPtr += bytesLeft;
<a name="l00287"></a>00287 iChunkBytesRemaining -= bytesLeft;
<a name="l00288"></a>00288 }
<a name="l00289"></a>00289 }
<a name="l00290"></a>00290 }
<a name="l00291"></a>00291
<a name="l00292"></a>00292 aSrc.Shift(dataPtr - startDataPtr);
<a name="l00293"></a>00293 <span class="keywordflow">return</span> EFrameIncomplete;
<a name="l00294"></a>00294 }
<a name="l00295"></a>00295
<a name="l00296"></a>00296 <span class="comment">// Process any optional PNG header chunks</span>
<a name="l00297"></a>00297 <span class="keywordtype">void</span> CPngReadCodec::DoProcessInfoL(<span class="keyword">const</span> TUint8*& aDataPtr,<span class="keyword">const</span> TUint8* aDataPtrLimit)
<a name="l00298"></a>00298 {
<a name="l00299"></a>00299 FOREVER
<a name="l00300"></a>00300 {
<a name="l00301"></a>00301 <span class="keywordflow">if</span> (aDataPtr + KPngChunkLengthSize + KPngChunkIdSize > aDataPtrLimit) <span class="comment">// Check there is enough data to read the chunk length</span>
<a name="l00302"></a>00302 User::Leave(KErrUnderflow);
<a name="l00303"></a>00303
<a name="l00304"></a>00304 TInt chunkLength = PtrReadUtil::ReadBigEndianUint32Inc(aDataPtr);
<a name="l00305"></a>00305 TPtrC8 chunkId (&aDataPtr[0],KPngChunkIdSize);
<a name="l00306"></a>00306
<a name="l00307"></a>00307 <span class="keywordflow">if</span> (chunkId == KPngIDATChunkId)
<a name="l00308"></a>00308 {
<a name="l00309"></a>00309 aDataPtr -= KPngChunkLengthSize; <span class="comment">// Rewind to start of chunkLength</span>
<a name="l00310"></a>00310 <span class="keywordflow">break</span>;
<a name="l00311"></a>00311 }
<a name="l00312"></a>00312
<a name="l00313"></a>00313 <span class="keywordflow">if</span> (aDataPtr + KPngChunkIdSize + chunkLength + KPngChunkCRCSize > aDataPtrLimit) <span class="comment">// Check there is enough data to read the whole chunk</span>
<a name="l00314"></a>00314 {
<a name="l00315"></a>00315 aDataPtr -= KPngChunkLengthSize; <span class="comment">// Rewind to start of chunkLength</span>
<a name="l00316"></a>00316 User::Leave(KErrUnderflow);
<a name="l00317"></a>00317 }
<a name="l00318"></a>00318
<a name="l00319"></a>00319 aDataPtr += KPngChunkIdSize;
<a name="l00320"></a>00320
<a name="l00321"></a>00321 <span class="keywordflow">if</span> (chunkId == KPngPLTEChunkId)
<a name="l00322"></a>00322 DoProcessPLTEL(aDataPtr,chunkLength);
<a name="l00323"></a>00323 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (chunkId == KPngbKGDChunkId)
<a name="l00324"></a>00324 DoProcessbKGDL(aDataPtr,chunkLength);
<a name="l00325"></a>00325 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (chunkId == KPngpHYsChunkId)
<a name="l00326"></a>00326 DoProcesspHYsL(aDataPtr,chunkLength);
<a name="l00327"></a>00327 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (chunkId == KPngtRNSChunkId)
<a name="l00328"></a>00328 DoProcesstRNSL(aDataPtr,chunkLength);
<a name="l00329"></a>00329 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (chunkId == KPngIHDRChunkId || chunkId == KPngIENDChunkId)
<a name="l00330"></a>00330 User::Leave(KErrCorrupt);
<a name="l00331"></a>00331
<a name="l00332"></a>00332 aDataPtr += chunkLength;
<a name="l00333"></a>00333 PtrReadUtil::ReadBigEndianUint32Inc(aDataPtr); <span class="comment">// Skip crc value</span>
<a name="l00334"></a>00334 }
<a name="l00335"></a>00335 }
<a name="l00336"></a>00336
<a name="l00337"></a>00337 <span class="comment">// Process the mandatory PNG header chunk</span>
<a name="l00338"></a>00338 <span class="keywordtype">void</span> CPngReadCodec::DoProcessIHDRL(<span class="keyword">const</span> TUint8* aDataPtr,TInt aChunkLength)
<a name="l00339"></a>00339 {
<a name="l00340"></a>00340 <span class="keywordflow">if</span> (aChunkLength != KPngIHDRChunkSize)
<a name="l00341"></a>00341 User::Leave(KErrCorrupt);
<a name="l00342"></a>00342
<a name="l00343"></a>00343 iImageInfo.iSize.iWidth = PtrReadUtil::ReadBigEndianUint32Inc(aDataPtr);
<a name="l00344"></a>00344 iImageInfo.iSize.iHeight = PtrReadUtil::ReadBigEndianUint32Inc(aDataPtr);
<a name="l00345"></a>00345 iImageInfo.iBitDepth = aDataPtr[0];
<a name="l00346"></a>00346 iImageInfo.iColorType = TPngImageInformation::TColorType(aDataPtr[1]);
<a name="l00347"></a>00347 iImageInfo.iCompressionMethod = TPngImageInformation::TCompressionMethod(aDataPtr[2]);
<a name="l00348"></a>00348 iImageInfo.iFilterMethod = TPngImageInformation::TFilterMethod(aDataPtr[3]);
<a name="l00349"></a>00349 iImageInfo.iInterlaceMethod = TPngImageInformation::TInterlaceMethod(aDataPtr[4]);
<a name="l00350"></a>00350
<a name="l00351"></a>00351 <span class="comment">// Check is one of the PNG formats we support</span>
<a name="l00352"></a>00352 <span class="keywordflow">if</span> (iImageInfo.iSize.iWidth < 1 || iImageInfo.iSize.iHeight < 1
<a name="l00353"></a>00353 || iImageInfo.iCompressionMethod != TPngImageInformation::EDeflateInflate32K
<a name="l00354"></a>00354 || iImageInfo.iFilterMethod != TPngImageInformation::EAdaptiveFiltering
<a name="l00355"></a>00355 || (iImageInfo.iInterlaceMethod != TPngImageInformation::ENoInterlace &&
<a name="l00356"></a>00356 iImageInfo.iInterlaceMethod != TPngImageInformation::EAdam7Interlace))
<a name="l00357"></a>00357 User::Leave(KErrCorrupt);
<a name="l00358"></a>00358 }
<a name="l00359"></a>00359
<a name="l00360"></a>00360 <span class="comment">// Process a PNG PLTE (palette) chunk</span>
<a name="l00361"></a>00361 <span class="keywordtype">void</span> CPngReadCodec::DoProcessPLTEL(<span class="keyword">const</span> TUint8* aDataPtr,TInt aChunkLength)
<a name="l00362"></a>00362 {
<a name="l00363"></a>00363 <span class="keywordflow">if</span> (aChunkLength % 3 != 0)
<a name="l00364"></a>00364 User::Leave(KErrCorrupt);
<a name="l00365"></a>00365
<a name="l00366"></a>00366 iImageInfo.iPalettePresent = ETrue;
<a name="l00367"></a>00367
<a name="l00368"></a>00368 <span class="keyword">const</span> TUint8* dataPtrLimit = aDataPtr + aChunkLength;
<a name="l00369"></a>00369 TRgb* palettePtr = iImageInfo.iPalette;
<a name="l00370"></a>00370
<a name="l00371"></a>00371 <span class="keywordflow">while</span> (aDataPtr < dataPtrLimit)
<a name="l00372"></a>00372 {
<a name="l00373"></a>00373 *palettePtr++ = TRgb(aDataPtr[0],aDataPtr[1],aDataPtr[2]);
<a name="l00374"></a>00374 aDataPtr += 3;
<a name="l00375"></a>00375 }
<a name="l00376"></a>00376 }
<a name="l00377"></a>00377
<a name="l00378"></a>00378 <span class="comment">// Process a PNG bKGD (background color) chunk</span>
<a name="l00379"></a>00379 <span class="keywordtype">void</span> CPngReadCodec::DoProcessbKGDL(<span class="keyword">const</span> TUint8* aDataPtr,TInt aChunkLength)
<a name="l00380"></a>00380 {
<a name="l00381"></a>00381 iImageInfo.iBackgroundPresent = ETrue;
<a name="l00382"></a>00382
<a name="l00383"></a>00383 <span class="keywordflow">if</span> (iImageInfo.iColorType == TPngImageInformation::EIndexedColor) <span class="comment">// 3</span>
<a name="l00384"></a>00384 {
<a name="l00385"></a>00385 <span class="keywordflow">if</span> (aChunkLength < 1)
<a name="l00386"></a>00386 User::Leave(KErrCorrupt);
<a name="l00387"></a>00387
<a name="l00388"></a>00388 iImageInfo.iBackgroundColor = iImageInfo.iPalette[aDataPtr[0]];
<a name="l00389"></a>00389 }
<a name="l00390"></a>00390 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (iImageInfo.iColorType & TPngImageInformation::EMonochrome) <span class="comment">// 0 & 4</span>
<a name="l00391"></a>00391 {
<a name="l00392"></a>00392 <span class="keywordflow">if</span> (aChunkLength < 2)
<a name="l00393"></a>00393 User::Leave(KErrCorrupt);
<a name="l00394"></a>00394
<a name="l00395"></a>00395 TInt grayLevel = PtrReadUtil::ReadBigEndianInt16(aDataPtr);
<a name="l00396"></a>00396 ASSERT(iImageInfo.iBitDepth<8);
<a name="l00397"></a>00397 grayLevel <<= (7-iImageInfo.iBitDepth);
<a name="l00398"></a>00398 iImageInfo.iBackgroundColor = TRgb::Gray256(grayLevel);
<a name="l00399"></a>00399 }
<a name="l00400"></a>00400 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (iImageInfo.iColorType & TPngImageInformation::EColorUsed) <span class="comment">// 2 & 6</span>
<a name="l00401"></a>00401 {
<a name="l00402"></a>00402 <span class="keywordflow">if</span> (aChunkLength < 6)
<a name="l00403"></a>00403 User::Leave(KErrCorrupt);
<a name="l00404"></a>00404
<a name="l00405"></a>00405 TInt red = PtrReadUtil::ReadBigEndianInt16(&aDataPtr[0]);
<a name="l00406"></a>00406 TInt green = PtrReadUtil::ReadBigEndianInt16(&aDataPtr[2]);
<a name="l00407"></a>00407 TInt blue = PtrReadUtil::ReadBigEndianInt16(&aDataPtr[4]);
<a name="l00408"></a>00408 ASSERT (iImageInfo.iBitDepth<8);
<a name="l00409"></a>00409 <span class="keyword">const</span> TInt offset = 7-iImageInfo.iBitDepth;
<a name="l00410"></a>00410 red <<= offset;
<a name="l00411"></a>00411 green <<= offset;
<a name="l00412"></a>00412 blue <<= offset;
<a name="l00413"></a>00413 iImageInfo.iBackgroundColor = TRgb(red,green,blue);
<a name="l00414"></a>00414 }
<a name="l00415"></a>00415 }
<a name="l00416"></a>00416
<a name="l00417"></a>00417 <span class="comment">// Process a PNG pHYs (Physical pixel dimensions) chunk</span>
<a name="l00418"></a>00418 <span class="keywordtype">void</span> CPngReadCodec::DoProcesspHYsL(<span class="keyword">const</span> TUint8* aDataPtr,TInt aChunkLength)
<a name="l00419"></a>00419 {
<a name="l00420"></a>00420 <span class="keywordflow">if</span> (aChunkLength != KPngpHYsChunkSize)
<a name="l00421"></a>00421 User::Leave(KErrCorrupt);
<a name="l00422"></a>00422
<a name="l00423"></a>00423 iImageInfo.iPhysicalUnits = TPngImageInformation::TPhysicalUnits(aDataPtr[8]);
<a name="l00424"></a>00424
<a name="l00425"></a>00425 <span class="keywordflow">if</span> (iImageInfo.iPhysicalUnits == TPngImageInformation::EMeters)
<a name="l00426"></a>00426 {
<a name="l00427"></a>00427 iImageInfo.iPhysicalPresent = ETrue;
<a name="l00428"></a>00428
<a name="l00429"></a>00429 TInt horzPixelsPerMeter = PtrReadUtil::ReadBigEndianUint32Inc(aDataPtr);
<a name="l00430"></a>00430 TInt vertPixelsPerMeter = PtrReadUtil::ReadBigEndianUint32Inc(aDataPtr);
<a name="l00431"></a>00431
<a name="l00432"></a>00432 <span class="keywordflow">if</span> (horzPixelsPerMeter > 0)
<a name="l00433"></a>00433 iImageInfo.iPhysicalSize.iWidth = iImageInfo.iSize.iWidth * KTwipsPerMeter / horzPixelsPerMeter;
<a name="l00434"></a>00434 <span class="keywordflow">if</span> (vertPixelsPerMeter > 0)
<a name="l00435"></a>00435 iImageInfo.iPhysicalSize.iHeight = iImageInfo.iSize.iHeight * KTwipsPerMeter / vertPixelsPerMeter;
<a name="l00436"></a>00436 }
<a name="l00437"></a>00437 }
<a name="l00438"></a>00438
<a name="l00439"></a>00439 <span class="comment">// Process a PNG tRNS (Transparency) chunk</span>
<a name="l00440"></a>00440 <span class="keywordtype">void</span> CPngReadCodec::DoProcesstRNSL(<span class="keyword">const</span> TUint8* aDataPtr,TInt aChunkLength)
<a name="l00441"></a>00441 {
<a name="l00442"></a>00442 iImageInfo.iTransparencyPresent = ETrue;
<a name="l00443"></a>00443
<a name="l00444"></a>00444 <span class="keywordflow">if</span> (iImageInfo.iColorType == TPngImageInformation::EIndexedColor) <span class="comment">// 3</span>
<a name="l00445"></a>00445 {
<a name="l00446"></a>00446 <span class="keywordflow">if</span> (aChunkLength < 1)
<a name="l00447"></a>00447 User::Leave(KErrCorrupt);
<a name="l00448"></a>00448
<a name="l00449"></a>00449 Mem::Copy(iImageInfo.iTransparencyValue,aDataPtr,aChunkLength);
<a name="l00450"></a>00450 }
<a name="l00451"></a>00451 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (iImageInfo.iColorType == TPngImageInformation::EGrayscale) <span class="comment">// 0</span>
<a name="l00452"></a>00452 {
<a name="l00453"></a>00453 <span class="keywordflow">if</span> (aChunkLength < 2)
<a name="l00454"></a>00454 User::Leave(KErrCorrupt);
<a name="l00455"></a>00455
<a name="l00456"></a>00456 iImageInfo.iTransparentGray = TUint16((aDataPtr[0] << 8) | aDataPtr[1]);
<a name="l00457"></a>00457 }
<a name="l00458"></a>00458 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (iImageInfo.iColorType == TPngImageInformation::EDirectColor) <span class="comment">// 2</span>
<a name="l00459"></a>00459 {
<a name="l00460"></a>00460 <span class="keywordflow">if</span> (aChunkLength < 6)
<a name="l00461"></a>00461 User::Leave(KErrCorrupt);
<a name="l00462"></a>00462
<a name="l00463"></a>00463 iImageInfo.iTransparentRed = TUint16((aDataPtr[0] << 8) | aDataPtr[1]);
<a name="l00464"></a>00464 iImageInfo.iTransparentGreen = TUint16((aDataPtr[2] << 8) | aDataPtr[3]);
<a name="l00465"></a>00465 iImageInfo.iTransparentBlue = TUint16((aDataPtr[4] << 8) | aDataPtr[5]);
<a name="l00466"></a>00466 }
<a name="l00467"></a>00467 }
<a name="l00468"></a>00468
<a name="l00469"></a>00469 <span class="comment">// Process a PNG image data</span>
<a name="l00470"></a>00470 <span class="keywordtype">void</span> CPngReadCodec::DoProcessDataL(<span class="keyword">const</span> TUint8*& aDataPtr,<span class="keyword">const</span> TUint8* aDataPtrLimit)
<a name="l00471"></a>00471 {
<a name="l00472"></a>00472 <span class="comment">// Data is passed to the decompressor</span>
<a name="l00473"></a>00473 TInt bytesToProcess = Min(aDataPtrLimit - aDataPtr,iChunkBytesRemaining);
<a name="l00474"></a>00474 iDataDes.Set(aDataPtr,bytesToProcess);
<a name="l00475"></a>00475 iDecompressor->SetInput(iDataDes);
<a name="l00476"></a>00476
<a name="l00477"></a>00477 <span class="keywordflow">while</span> (iDecompressor->AvailIn() > 0)
<a name="l00478"></a>00478 iDecompressor->InflateL();
<a name="l00479"></a>00479
<a name="l00480"></a>00480 aDataPtr += bytesToProcess;
<a name="l00481"></a>00481 iChunkBytesRemaining -= bytesToProcess;
<a name="l00482"></a>00482 }
<a name="l00483"></a>00483
<a name="l00484"></a>00484 <span class="comment">// From MEZBufferManager: manage decompressor stream</span>
<a name="l00485"></a>00485 <span class="keywordtype">void</span> CPngReadCodec::InitializeL(CEZZStream& aZStream)
<a name="l00486"></a>00486 {
<a name="l00487"></a>00487 aZStream.SetOutput(iDecoder->FirstBuffer());
<a name="l00488"></a>00488 }
<a name="l00489"></a>00489
<a name="l00490"></a>00490 <span class="keywordtype">void</span> CPngReadCodec::NeedInputL(CEZZStream& <span class="comment">/*aZStream*/</span>)
<a name="l00491"></a>00491 {
<a name="l00492"></a>00492 }
<a name="l00493"></a>00493
<a name="l00494"></a>00494 <span class="keywordtype">void</span> CPngReadCodec::NeedOutputL(CEZZStream& aZStream)
<a name="l00495"></a>00495 {
<a name="l00496"></a>00496 aZStream.SetOutput(iDecoder->DecodeL());
<a name="l00497"></a>00497 }
<a name="l00498"></a>00498
<a name="l00499"></a>00499 <span class="keywordtype">void</span> CPngReadCodec::FinalizeL(CEZZStream& <span class="comment">/*aZStream*/</span>)
<a name="l00500"></a>00500 {
<a name="l00501"></a>00501 iDecoder->DecodeL();
<a name="l00502"></a>00502 }
<a name="l00503"></a>00503
<a name="l00504"></a>00504
<a name="l00505"></a>00505
<a name="l00506"></a>00506 <span class="comment">//</span>
<a name="l00507"></a>00507 <span class="comment">// CPngWriteCodec: writes a PNG image</span>
<a name="l00508"></a>00508 <span class="comment">//</span>
<a name="l00509"></a>00509
<a name="l00510"></a>00510
<a name="l00511"></a>00511 CPngWriteCodec::CPngWriteCodec(TInt aBpp, TBool aColor, TBool aPaletted, TInt aCompressionLevel)
<a name="l00512"></a>00512 : iCompressionLevel(aCompressionLevel), iCompressorPtr(NULL, 0)
<a name="l00513"></a>00513 {
<a name="l00514"></a>00514 <span class="comment">// Set bpp</span>
<a name="l00515"></a>00515 iImageInfo.iBitsPerPixel = aBpp;
<a name="l00516"></a>00516 <span class="keywordflow">switch</span> (aBpp)
<a name="l00517"></a>00517 {
<a name="l00518"></a>00518 <span class="keywordflow">case</span> 1:
<a name="l00519"></a>00519 iImageInfo.iBitDepth = 1;
<a name="l00520"></a>00520 <span class="keywordflow">break</span>;
<a name="l00521"></a>00521 <span class="keywordflow">case</span> 2:
<a name="l00522"></a>00522 iImageInfo.iBitDepth = 2;
<a name="l00523"></a>00523 <span class="keywordflow">break</span>;
<a name="l00524"></a>00524 <span class="keywordflow">case</span> 4:
<a name="l00525"></a>00525 iImageInfo.iBitDepth = 4;
<a name="l00526"></a>00526 <span class="keywordflow">break</span>;
<a name="l00527"></a>00527 <span class="keywordflow">case</span> 8:
<a name="l00528"></a>00528 <span class="keywordflow">case</span> 24:
<a name="l00529"></a>00529 iImageInfo.iBitDepth = 8;
<a name="l00530"></a>00530 <span class="keywordflow">break</span>;
<a name="l00531"></a>00531 <span class="keywordflow">default</span>:
<a name="l00532"></a>00532 <span class="keywordflow">break</span>;
<a name="l00533"></a>00533 }
<a name="l00534"></a>00534
<a name="l00535"></a>00535 <span class="comment">// Set color type</span>
<a name="l00536"></a>00536 <span class="keywordflow">if</span> (aColor && aPaletted)
<a name="l00537"></a>00537 iImageInfo.iColorType = TPngImageInformation::EIndexedColor;
<a name="l00538"></a>00538 <span class="keywordflow">else</span> <span class="keywordflow">if</span> (aColor)
<a name="l00539"></a>00539 iImageInfo.iColorType = TPngImageInformation::EDirectColor;
<a name="l00540"></a>00540 <span class="keywordflow">else</span>
<a name="l00541"></a>00541 iImageInfo.iColorType = TPngImageInformation::EGrayscale;
<a name="l00542"></a>00542 }
<a name="l00543"></a>00543
<a name="l00544"></a>00544 CPngWriteCodec::~CPngWriteCodec()
<a name="l00545"></a>00545 {
<a name="l00546"></a>00546 <span class="keyword">delete</span> iCompressor;
<a name="l00547"></a>00547 <span class="keyword">delete</span> iEncoder;
<a name="l00548"></a>00548 }
<a name="l00549"></a>00549
<a name="l00550"></a>00550 <span class="comment">// Called by framework at start of conversion operation</span>
<a name="l00551"></a>00551 <span class="keywordtype">void</span> CPngWriteCodec::InitFrameL(TBufPtr8& aDst, <span class="keyword">const</span> CFbsBitmap& aSource)
<a name="l00552"></a>00552 {
<a name="l00553"></a>00553 <span class="keywordflow">if</span> (aDst.Length() == 0)
<a name="l00554"></a>00554 User::Leave(KErrArgument); <span class="comment">// Not enough length for anything</span>
<a name="l00555"></a>00555
<a name="l00556"></a>00556 SetSource(&aSource);
<a name="l00557"></a>00557 iDestStartPtr = <span class="keyword">const_cast<</span>TUint8*<span class="keyword">></span>(aDst.Ptr());
<a name="l00558"></a>00558 iDestPtr = iDestStartPtr;
<a name="l00559"></a>00559 iDestPtrLimit = iDestPtr + aDst.MaxLength();
<a name="l00560"></a>00560
<a name="l00561"></a>00561 <span class="comment">// Set image information</span>
<a name="l00562"></a>00562 <span class="keyword">const</span> SEpocBitmapHeader& header = aSource.Header();
<a name="l00563"></a>00563 iImageInfo.iSize = header.iSizeInPixels;
<a name="l00564"></a>00564
<a name="l00565"></a>00565 <span class="keywordflow">switch</span> (iImageInfo.iBitDepth)
<a name="l00566"></a>00566 {
<a name="l00567"></a>00567 <span class="keywordflow">case</span> 1:
<a name="l00568"></a>00568 <span class="keywordflow">case</span> 2:
<a name="l00569"></a>00569 <span class="keywordflow">case</span> 4:
<a name="l00570"></a>00570 <span class="keywordflow">if</span> (iImageInfo.iColorType == TPngImageInformation::EDirectColor)
<a name="l00571"></a>00571 {
<a name="l00572"></a>00572 <span class="comment">// Bit depths 1, 2 and 4 don't support RGB colour (color mode 2)</span>
<a name="l00573"></a>00573 <span class="comment">// Must use paletted colour or greyscale</span>
<a name="l00574"></a>00574 User::Leave(KErrNotSupported);
<a name="l00575"></a>00575 <span class="keywordflow">break</span>;
<a name="l00576"></a>00576 }
<a name="l00577"></a>00577 <span class="comment">// fall through to case 8</span>
<a name="l00578"></a>00578 <span class="keywordflow">case</span> 8:
<a name="l00579"></a>00579 <span class="keywordflow">break</span>;
<a name="l00580"></a>00580 <span class="keywordflow">default</span>:
<a name="l00581"></a>00581 User::Leave(KErrNotSupported); <span class="comment">// unsupported bit depth</span>
<a name="l00582"></a>00582 <span class="keywordflow">break</span>;
<a name="l00583"></a>00583 }
<a name="l00584"></a>00584
<a name="l00585"></a>00585 iImageInfo.iCompressionMethod = TPngImageInformation::EDeflateInflate32K;
<a name="l00586"></a>00586 iImageInfo.iFilterMethod = TPngImageInformation::EAdaptiveFiltering;
<a name="l00587"></a>00587 iImageInfo.iInterlaceMethod = TPngImageInformation::ENoInterlace;
<a name="l00588"></a>00588
<a name="l00589"></a>00589 <span class="comment">// Create encoder</span>
<a name="l00590"></a>00590 <span class="keywordflow">if</span> (iEncoder)
<a name="l00591"></a>00591 {
<a name="l00592"></a>00592 <span class="keyword">delete</span> iEncoder;
<a name="l00593"></a>00593 iEncoder = NULL;
<a name="l00594"></a>00594 }
<a name="l00595"></a>00595 iEncoder = CPngWriteSubCodec::NewL(iImageInfo, &aSource);
<a name="l00596"></a>00596
<a name="l00597"></a>00597 <span class="comment">// Create compressor</span>
<a name="l00598"></a>00598 <span class="keywordflow">if</span> (iCompressor)
<a name="l00599"></a>00599 {
<a name="l00600"></a>00600 <span class="keyword">delete</span> iCompressor;
<a name="l00601"></a>00601 iCompressor = NULL;
<a name="l00602"></a>00602 }
<a name="l00603"></a>00603 iCompressor = CEZCompressor::NewL(*<span class="keyword">this</span>, iCompressionLevel);
<a name="l00604"></a>00604
<a name="l00605"></a>00605 <span class="comment">// Initial encoder state</span>
<a name="l00606"></a>00606 <span class="keywordflow">if</span> (iImageInfo.iColorType == TPngImageInformation::EIndexedColor)
<a name="l00607"></a>00607 iEncoderState = EPngWritePLTE;
<a name="l00608"></a>00608 <span class="keywordflow">else</span>
<a name="l00609"></a>00609 iEncoderState = EPngDeflate;
<a name="l00610"></a>00610 iCallAgain = ETrue; <span class="comment">// to make sure we call DeflateL</span>
<a name="l00611"></a>00611
<a name="l00612"></a>00612 <span class="comment">// Write header</span>
<a name="l00613"></a>00613 User::LeaveIfError(WriteHeaderChunk(aDst));
<a name="l00614"></a>00614 }
<a name="l00615"></a>00615
<a name="l00616"></a>00616 <span class="comment">// Called by the framework to process frame data</span>
<a name="l00617"></a>00617 TFrameState CPngWriteCodec::ProcessFrameL(TBufPtr8& aDst)
<a name="l00618"></a>00618 {
<a name="l00619"></a>00619 <span class="keywordflow">if</span> (aDst.Length() == 0)
<a name="l00620"></a>00620 User::Leave(KErrArgument); <span class="comment">// Not enough length for anything</span>
<a name="l00621"></a>00621
<a name="l00622"></a>00622 TFrameState state = EFrameIncomplete;
<a name="l00623"></a>00623 iDestStartPtr = <span class="keyword">const_cast<</span>TUint8*<span class="keyword">></span>(aDst.Ptr());
<a name="l00624"></a>00624 iDestPtr = iDestStartPtr;
<a name="l00625"></a>00625 iDestPtrLimit = iDestPtr + aDst.MaxLength();
<a name="l00626"></a>00626
<a name="l00627"></a>00627 <span class="comment">// Set return buffer length to 0 initially</span>
<a name="l00628"></a>00628 aDst.SetLength(0);
<a name="l00629"></a>00629
<a name="l00630"></a>00630 <span class="keywordflow">while</span> (aDst.Length() == 0 && state != EFrameComplete)
<a name="l00631"></a>00631 {
<a name="l00632"></a>00632 <span class="comment">// Loop round until we have some data to return or</span>
<a name="l00633"></a>00633 <span class="comment">// the image is encoded</span>
<a name="l00634"></a>00634 <span class="keywordflow">switch</span> (iEncoderState)
<a name="l00635"></a>00635 {
<a name="l00636"></a>00636 <span class="keywordflow">case</span> EPngWritePLTE:
<a name="l00637"></a>00637 WritePLTEChunk(aDst);
<a name="l00638"></a>00638 <span class="keywordflow">break</span>;
<a name="l00639"></a>00639 <span class="keywordflow">case</span> EPngDeflate:
<a name="l00640"></a>00640 DeflateEncodedDataL(aDst, state);
<a name="l00641"></a>00641 <span class="keywordflow">break</span>;
<a name="l00642"></a>00642 <span class="keywordflow">case</span> EPngWriteIDAT:
<a name="l00643"></a>00643 WriteIDATChunk(aDst);
<a name="l00644"></a>00644 <span class="keywordflow">break</span>;
<a name="l00645"></a>00645 <span class="keywordflow">case</span> EPngFlush:
<a name="l00646"></a>00646 FlushCompressedDataL(aDst, state);
<a name="l00647"></a>00647 <span class="keywordflow">break</span>;
<a name="l00648"></a>00648 <span class="keywordflow">case</span> EPngEndChunk:
<a name="l00649"></a>00649 WriteEndChunk(aDst);
<a name="l00650"></a>00650 state = EFrameComplete;
<a name="l00651"></a>00651 <span class="keywordflow">break</span>;
<a name="l00652"></a>00652 <span class="keywordflow">default</span>:
<a name="l00653"></a>00653 <span class="keywordflow">break</span>;
<a name="l00654"></a>00654 }
<a name="l00655"></a>00655 }
<a name="l00656"></a>00656
<a name="l00657"></a>00657 <span class="keywordflow">return</span> state;
<a name="l00658"></a>00658 }
<a name="l00659"></a>00659
<a name="l00660"></a>00660 <span class="comment">// Write a compressed image data chunk</span>
<a name="l00661"></a>00661 <span class="keywordtype">void</span> CPngWriteCodec::DeflateEncodedDataL(TBufPtr8& aDst, TFrameState& <span class="comment">/*aState*/</span>)
<a name="l00662"></a>00662 {
<a name="l00663"></a>00663 <span class="comment">// Set ptr for compressed data</span>
<a name="l00664"></a>00664 <span class="keyword">const</span> TInt dataLength = aDst.MaxLength() - KPngChunkLengthSize - KPngChunkIdSize - KPngChunkCRCSize;
<a name="l00665"></a>00665 ASSERT(dataLength > 0);
<a name="l00666"></a>00666 iCompressorPtr.Set(iDestPtr + KPngChunkIdSize + KPngChunkLengthSize, dataLength, dataLength);
<a name="l00667"></a>00667
<a name="l00668"></a>00668 <span class="comment">// Initialise input/output for compressor</span>
<a name="l00669"></a>00669 iCompressor->SetInput(iEncoder->EncodeL(iScanline));
<a name="l00670"></a>00670 iScanline++;
<a name="l00671"></a>00671 iCompressor->SetOutput(iCompressorPtr);
<a name="l00672"></a>00672
<a name="l00673"></a>00673 <span class="keywordflow">while</span> ((iEncoderState == EPngDeflate) && iCallAgain)
<a name="l00674"></a>00674 iCallAgain = iCompressor->DeflateL();
<a name="l00675"></a>00675
<a name="l00676"></a>00676 <span class="comment">// Write the IDAT chunk</span>
<a name="l00677"></a>00677 WriteIDATChunk(aDst);
<a name="l00678"></a>00678 iEncoderState = EPngFlush;
<a name="l00679"></a>00679 }
<a name="l00680"></a>00680
<a name="l00681"></a>00681 <span class="keywordtype">void</span> CPngWriteCodec::FlushCompressedDataL(TBufPtr8& aDst, TFrameState& <span class="comment">/*aState*/</span>)
<a name="l00682"></a>00682 {
<a name="l00683"></a>00683 <span class="keywordflow">if</span> (iCallAgain)
<a name="l00684"></a>00684 {
<a name="l00685"></a>00685 iCallAgain = iCompressor->DeflateL();
<a name="l00686"></a>00686 WriteIDATChunk(aDst);
<a name="l00687"></a>00687 }
<a name="l00688"></a>00688 <span class="keywordflow">else</span>
<a name="l00689"></a>00689 {
<a name="l00690"></a>00690 iEncoderState = EPngEndChunk;
<a name="l00691"></a>00691 }
<a name="l00692"></a>00692 }
<a name="l00693"></a>00693
<a name="l00694"></a>00694 <span class="comment">// Write a PLTE chunk</span>
<a name="l00695"></a>00695 <span class="keywordtype">void</span> CPngWriteCodec::WritePLTEChunk(TBufPtr8& aDst)
<a name="l00696"></a>00696 {
<a name="l00697"></a>00697 ASSERT(iEncoder->Palette() &&
<a name="l00698"></a>00698 (iImageInfo.iColorType == TPngImageInformation::EIndexedColor ||
<a name="l00699"></a>00699 iImageInfo.iColorType == TPngImageInformation::EDirectColor ||
<a name="l00700"></a>00700 iImageInfo.iColorType == TPngImageInformation::EAlphaDirectColor)); <span class="comment">// allowed color types for PLTE chunk</span>
<a name="l00701"></a>00701
<a name="l00702"></a>00702 <span class="comment">// Get palette entries</span>
<a name="l00703"></a>00703 CPalette* palette = iEncoder->Palette();
<a name="l00704"></a>00704 ASSERT(palette);
<a name="l00705"></a>00705 <span class="keyword">const</span> TInt count = palette->Entries();
<a name="l00706"></a>00706 TUint8* ptr = iDestPtr + KPngChunkIdSize + KPngChunkLengthSize;
<a name="l00707"></a>00707 TInt length = count * 3;
<a name="l00708"></a>00708 TPtr8 data(ptr, length, length);
<a name="l00709"></a>00709 <span class="keywordflow">for</span> (TInt i=0; i < count; i++)
<a name="l00710"></a>00710 {
<a name="l00711"></a>00711 TRgb rgb = palette->GetEntry(i);
<a name="l00712"></a>00712 *ptr = TUint8(rgb.Red());
<a name="l00713"></a>00713 ptr++;
<a name="l00714"></a>00714 *ptr = TUint8(rgb.Green());
<a name="l00715"></a>00715 ptr++;
<a name="l00716"></a>00716 *ptr = TUint8(rgb.Blue());
<a name="l00717"></a>00717 ptr++;
<a name="l00718"></a>00718 }
<a name="l00719"></a>00719 <span class="comment">// Write PLTE chunk</span>
<a name="l00720"></a>00720 WritePngChunk(iDestPtr, KPngPLTEChunkId, data, length);
<a name="l00721"></a>00721 ASSERT(length % 3 == 0); <span class="comment">// length must be divisible by 3</span>
<a name="l00722"></a>00722 aDst.SetLength(length);
<a name="l00723"></a>00723 iEncoderState = EPngDeflate;
<a name="l00724"></a>00724 }
<a name="l00725"></a>00725
<a name="l00726"></a>00726 <span class="comment">// Write a data chunk</span>
<a name="l00727"></a>00727 <span class="keywordtype">void</span> CPngWriteCodec::WriteIDATChunk(TBufPtr8& aDst)
<a name="l00728"></a>00728 {
<a name="l00729"></a>00729 TPtrC8 ptr(iCompressor->OutputDescriptor());
<a name="l00730"></a>00730 <span class="keywordflow">if</span> (ptr.Length())
<a name="l00731"></a>00731 {
<a name="l00732"></a>00732 TInt length = 0;
<a name="l00733"></a>00733 WritePngChunk(iDestPtr, KPngIDATChunkId, ptr, length);
<a name="l00734"></a>00734 aDst.SetLength(length);
<a name="l00735"></a>00735
<a name="l00736"></a>00736 <span class="comment">// New output can write to the same compressor ptr</span>
<a name="l00737"></a>00737 iCompressor->SetOutput(iCompressorPtr);
<a name="l00738"></a>00738 }
<a name="l00739"></a>00739
<a name="l00740"></a>00740 <span class="keywordflow">if</span> (iCallAgain)
<a name="l00741"></a>00741 iEncoderState = EPngFlush;
<a name="l00742"></a>00742 }
<a name="l00743"></a>00743
<a name="l00744"></a>00744 <span class="comment">// Write an END chunk</span>
<a name="l00745"></a>00745 <span class="keywordtype">void</span> CPngWriteCodec::WriteEndChunk(TBufPtr8& aDst)
<a name="l00746"></a>00746 {
<a name="l00747"></a>00747 <span class="comment">// Write IEND chunk</span>
<a name="l00748"></a>00748 TInt length = 0;
<a name="l00749"></a>00749 WritePngChunk(iDestPtr, KPngIENDChunkId, KNullDesC8, length);
<a name="l00750"></a>00750 aDst.SetLength(length);
<a name="l00751"></a>00751 }
<a name="l00752"></a>00752
<a name="l00753"></a>00753 <span class="comment">// Write a header chunk</span>
<a name="l00754"></a>00754 TInt CPngWriteCodec::WriteHeaderChunk(TBufPtr8& aDst)
<a name="l00755"></a>00755 {
<a name="l00756"></a>00756 <span class="comment">// Write signature</span>
<a name="l00757"></a>00757 Mem::Copy(iDestPtr, &KPngSignature[0], KPngFileSignatureLength);
<a name="l00758"></a>00758 iDestPtr += KPngFileSignatureLength;
<a name="l00759"></a>00759
<a name="l00760"></a>00760 <span class="comment">// Write IHDR chunk</span>
<a name="l00761"></a>00761 TBuf8<KPngIHDRChunkSize> buffer;
<a name="l00762"></a>00762 TUint8* ptr = <span class="keyword">const_cast<</span>TUint8*<span class="keyword">></span>(buffer.Ptr());
<a name="l00763"></a>00763 <span class="comment">// Set length of data</span>
<a name="l00764"></a>00764 buffer.SetLength(KPngIHDRChunkSize);
<a name="l00765"></a>00765 <span class="comment">// Chunk data</span>
<a name="l00766"></a>00766 <span class="comment">// width (4 bytes)</span>
<a name="l00767"></a>00767 <span class="keywordflow">if</span> ((iImageInfo.iSize.iWidth == 0) ||
<a name="l00768"></a>00768 (static_cast<TUint>(iImageInfo.iSize.iWidth) > KPngMaxImageSize))
<a name="l00769"></a>00769 {
<a name="l00770"></a>00770 <span class="keywordflow">return</span> KErrArgument; <span class="comment">// invalid width</span>
<a name="l00771"></a>00771 }
<a name="l00772"></a>00772 PtrWriteUtil::WriteBigEndianInt32(ptr, iImageInfo.iSize.iWidth);
<a name="l00773"></a>00773 ptr += 4;
<a name="l00774"></a>00774 <span class="comment">// height (4 bytes)</span>
<a name="l00775"></a>00775 <span class="keywordflow">if</span> ((iImageInfo.iSize.iHeight == 0) ||
<a name="l00776"></a>00776 (static_cast<TUint>(iImageInfo.iSize.iHeight) > KPngMaxImageSize))
<a name="l00777"></a>00777 {
<a name="l00778"></a>00778 <span class="keywordflow">return</span> KErrArgument; <span class="comment">// invalid height</span>
<a name="l00779"></a>00779 }
<a name="l00780"></a>00780 PtrWriteUtil::WriteBigEndianInt32(ptr, iImageInfo.iSize.iHeight);
<a name="l00781"></a>00781 ptr += 4;
<a name="l00782"></a>00782 <span class="comment">// bit depth (1 byte)</span>
<a name="l00783"></a>00783 PtrWriteUtil::WriteInt8(ptr, iImageInfo.iBitDepth);
<a name="l00784"></a>00784 ptr++;
<a name="l00785"></a>00785 <span class="comment">// colour type (1 byte)</span>
<a name="l00786"></a>00786 PtrWriteUtil::WriteInt8(ptr, iImageInfo.iColorType);
<a name="l00787"></a>00787 ptr++;
<a name="l00788"></a>00788 <span class="comment">// compression method (1 byte)</span>
<a name="l00789"></a>00789 PtrWriteUtil::WriteInt8(ptr, iImageInfo.iCompressionMethod);
<a name="l00790"></a>00790 ptr++;
<a name="l00791"></a>00791 <span class="comment">// filter method (1 byte)</span>
<a name="l00792"></a>00792 PtrWriteUtil::WriteInt8(ptr, iImageInfo.iFilterMethod);
<a name="l00793"></a>00793 ptr++;
<a name="l00794"></a>00794 <span class="comment">// interlace method (1 byte)</span>
<a name="l00795"></a>00795 PtrWriteUtil::WriteInt8(ptr, iImageInfo.iInterlaceMethod);
<a name="l00796"></a>00796 ptr++;
<a name="l00797"></a>00797
<a name="l00798"></a>00798 TInt length = 0;
<a name="l00799"></a>00799 WritePngChunk(iDestPtr, KPngIHDRChunkId, buffer, length);
<a name="l00800"></a>00800 aDst.SetLength(KPngFileSignatureLength + length);
<a name="l00801"></a>00801
<a name="l00802"></a>00802 <span class="keywordflow">return</span> KErrNone;
<a name="l00803"></a>00803 }
<a name="l00804"></a>00804
<a name="l00805"></a>00805 <span class="comment">// Chunk writing helper function</span>
<a name="l00806"></a>00806 <span class="keywordtype">void</span> CPngWriteCodec::WritePngChunk(TUint8*& aDestPtr, <span class="keyword">const</span> TDesC8& aChunkId, <span class="keyword">const</span> TDesC8& aData, TInt& aLength)
<a name="l00807"></a>00807 {
<a name="l00808"></a>00808 <span class="comment">// Chunk length (4 bytes)</span>
<a name="l00809"></a>00809 PtrWriteUtil::WriteBigEndianInt32(aDestPtr, aData.Length());
<a name="l00810"></a>00810 aDestPtr += KPngChunkLengthSize;
<a name="l00811"></a>00811 TUint8* crcPtr = aDestPtr; <span class="comment">// start position for calculating CRC</span>
<a name="l00812"></a>00812 <span class="comment">// Chunk type (4 bytes)</span>
<a name="l00813"></a>00813 Mem::Copy(aDestPtr, aChunkId.Ptr(), KPngChunkIdSize);
<a name="l00814"></a>00814 aDestPtr += KPngChunkIdSize;
<a name="l00815"></a>00815 <span class="comment">// Chunk data (0...n bytes)</span>
<a name="l00816"></a>00816 Mem::Copy(aDestPtr, aData.Ptr(), aData.Length());
<a name="l00817"></a>00817 aDestPtr += aData.Length();
<a name="l00818"></a>00818 <span class="comment">// CRC (4 bytes)</span>
<a name="l00819"></a>00819 TUint32 crc = KPngCrcMask;
<a name="l00820"></a>00820 GetCrc(crc, crcPtr, KPngChunkIdSize + aData.Length());
<a name="l00821"></a>00821 crc ^= KPngCrcMask;
<a name="l00822"></a>00822 PtrWriteUtil::WriteBigEndianInt32(aDestPtr, crc);
<a name="l00823"></a>00823 aDestPtr += KPngChunkCRCSize;
<a name="l00824"></a>00824 <span class="comment">// Length of chunk</span>
<a name="l00825"></a>00825 aLength = KPngChunkLengthSize + KPngChunkIdSize + aData.Length() + KPngChunkCRCSize;
<a name="l00826"></a>00826 }
<a name="l00827"></a>00827
<a name="l00828"></a>00828 <span class="comment">// from MEZBufferManager, manage data compressor</span>
<a name="l00829"></a>00829 <span class="keywordtype">void</span> CPngWriteCodec::InitializeL(CEZZStream& <span class="comment">/*aZStream*/</span>)
<a name="l00830"></a>00830 {
<a name="l00831"></a>00831 }
<a name="l00832"></a>00832
<a name="l00833"></a>00833 <span class="keywordtype">void</span> CPngWriteCodec::NeedInputL(CEZZStream& aZStream)
<a name="l00834"></a>00834 {
<a name="l00835"></a>00835 <span class="comment">// Give compressor more data from encoder</span>
<a name="l00836"></a>00836 aZStream.SetInput(iEncoder->EncodeL(iScanline));
<a name="l00837"></a>00837 <span class="keywordflow">if</span> (iCompressor->AvailIn() != 0)
<a name="l00838"></a>00838 iScanline++;
<a name="l00839"></a>00839 }
<a name="l00840"></a>00840
<a name="l00841"></a>00841 <span class="keywordtype">void</span> CPngWriteCodec::NeedOutputL(CEZZStream& <span class="comment">/*aZStream*/</span>)
<a name="l00842"></a>00842 {
<a name="l00843"></a>00843 <span class="comment">// Signal to write an IDAT chunk</span>
<a name="l00844"></a>00844 iEncoderState = EPngWriteIDAT;
<a name="l00845"></a>00845 }
<a name="l00846"></a>00846
<a name="l00847"></a>00847 <span class="keywordtype">void</span> CPngWriteCodec::FinalizeL(CEZZStream& <span class="comment">/*aZStream*/</span>)
<a name="l00848"></a>00848 {
<a name="l00849"></a>00849 }
<a name="l00850"></a>00850
<a name="l00851"></a>00851 <span class="comment">// Calculate CRC for PNG chunks</span>
<a name="l00852"></a>00852 <span class="keywordtype">void</span> CPngWriteCodec::GetCrc(TUint32& aCrc, <span class="keyword">const</span> TUint8* aPtr, <span class="keyword">const</span> TInt aLength)
<a name="l00853"></a>00853 {
<a name="l00854"></a>00854 <span class="keywordflow">if</span> (!iCrcTableCalculated)
<a name="l00855"></a>00855 CalcCrcTable();
<a name="l00856"></a>00856 TUint32 code = aCrc;
<a name="l00857"></a>00857 <span class="keywordflow">for</span> (TInt i=0; i < aLength; i++)
<a name="l00858"></a>00858 code = iCrcTable[(code ^ aPtr[i]) & 0xff] ^ (code >> 8);
<a name="l00859"></a>00859 aCrc = code;
<a name="l00860"></a>00860 }
<a name="l00861"></a>00861
<a name="l00862"></a>00862 <span class="keywordtype">void</span> CPngWriteCodec::CalcCrcTable()
<a name="l00863"></a>00863 {
<a name="l00864"></a>00864 <span class="keywordflow">for</span> (TInt i=0; i < KPngCrcTableLength; i++)
<a name="l00865"></a>00865 {
<a name="l00866"></a>00866 TUint32 code = <span class="keyword">static_cast<</span>TUint32<span class="keyword">></span>(i);
<a name="l00867"></a>00867
<a name="l00868"></a>00868 <span class="keywordflow">for</span> (TInt j = 0; j < 8; j++)
<a name="l00869"></a>00869 {
<a name="l00870"></a>00870 <span class="keywordflow">if</span> (code & 1)
<a name="l00871"></a>00871 code = 0xedb88320 ^ (code >> 1);
<a name="l00872"></a>00872 <span class="keywordflow">else</span>
<a name="l00873"></a>00873 code = code >> 1;
<a name="l00874"></a>00874 }
<a name="l00875"></a>00875 iCrcTable[i] = code;
<a name="l00876"></a>00876 }
<a name="l00877"></a>00877 iCrcTableCalculated = ETrue;
<a name="l00878"></a>00878 }
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