/////////////////////////////////////////////////////////////////////////////
-// Name: imaggif.cpp
+// Name: src/common/imaggif.cpp
// Purpose: wxGIFHandler
-// Author: Vaclav Slavik & Guillermo Rodriguez Garcia
+// Author: Vaclav Slavik, Guillermo Rodriguez Garcia, Gershon Elber, Troels K
// RCS-ID: $Id$
-// Copyright: (c) 1999 Vaclav Slavik & Guillermo Rodriguez Garcia
+// Copyright: (c) 1999-2011 Vaclav Slavik, Guillermo Rodriguez Garcia, Gershon Elber, Troels K
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
-#if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
-#pragma implementation "imaggif.h"
-#endif
-
// For compilers that support precompilation, includes "wx.h".
#include "wx/wxprec.h"
#ifdef __BORLANDC__
-# pragma hdrstop
+ #pragma hdrstop
#endif
+#if wxUSE_IMAGE && wxUSE_GIF
+
#ifndef WX_PRECOMP
-# include "wx/defs.h"
+ #include "wx/intl.h"
+ #include "wx/log.h"
+ #include "wx/palette.h"
+ #include "wx/utils.h"
#endif
-#if wxUSE_IMAGE && wxUSE_GIF
-
#include "wx/imaggif.h"
#include "wx/gifdecod.h"
-#include "wx/wfstream.h"
-#include "wx/log.h"
-#include "wx/intl.h"
+#include "wx/stream.h"
+#include "wx/anidecod.h" // wxImageArray
+
+#define GIF89_HDR "GIF89a"
+#define NETSCAPE_LOOP "NETSCAPE2.0"
+
+// see members.aol.com/royalef/gifabout.htm
+// members.aol.com/royalef/gif89a.txt
+
+enum
+{
+ GIF_MARKER_EXT = '!', // 0x21
+ GIF_MARKER_SEP = ',', // 0x2C
+ GIF_MARKER_ENDOFDATA = ';', // 0x3B
+
+ GIF_MARKER_EXT_GRAPHICS_CONTROL = 0xF9,
+ GIF_MARKER_EXT_COMMENT = 0xFE,
+ GIF_MARKER_EXT_APP = 0xFF
+};
+
+#define LZ_MAX_CODE 4095 // Biggest code possible in 12 bits.
+#define FLUSH_OUTPUT 4096 // Impossible code, to signal flush.
+#define FIRST_CODE 4097 // Impossible code, to signal first.
+
+#define HT_SIZE 8192 // 12bits = 4096 or twice as big!
+#define HT_KEY_MASK 0x1FFF // 13bits keys
+
+#define HT_GET_KEY(l) (l >> 12)
+#define HT_GET_CODE(l) (l & 0x0FFF)
+#define HT_PUT_KEY(l) (l << 12)
+#define HT_PUT_CODE(l) (l & 0x0FFF)
+
+struct wxRGB
+{
+ wxUint8 red;
+ wxUint8 green;
+ wxUint8 blue;
+};
+
+struct GifHashTableType
+{
+ wxUint32 HTable[HT_SIZE];
+};
IMPLEMENT_DYNAMIC_CLASS(wxGIFHandler,wxImageHandler)
+//----------------------------------------------------------------------------
+// Forward declarations
+//----------------------------------------------------------------------------
+
+static int wxGIFHandler_KeyItem(unsigned long item);
+
+#if wxUSE_STREAMS
+
+static int wxGIFHandler_BitSize(int n);
+
+#if wxUSE_PALETTE
+static bool wxGIFHandler_GetPalette(const wxImage& image,
+ wxRGB *pal, int *palCount, int *mask_index);
+#endif
+static
+int wxGIFHandler_PaletteFind(const wxRGB& clr, const wxRGB *array, int count);
+
+static bool wxGIFHandler_Write(wxOutputStream *, const void *buf, size_t len);
+static bool wxGIFHandler_WriteByte(wxOutputStream *, wxUint8);
+static bool wxGIFHandler_WriteWord(wxOutputStream *, wxUint16);
+static bool wxGIFHandler_WriteHeader(wxOutputStream *, int width, int height,
+ bool loop, const wxRGB *pal, int palCount);
+static bool wxGIFHandler_WriteRect(wxOutputStream *, int width, int height);
+#if wxUSE_PALETTE
+static bool wxGIFHandler_WriteTerm(wxOutputStream *);
+#endif
+static bool wxGIFHandler_WriteZero(wxOutputStream *);
+static bool wxGIFHandler_WritePalette(wxOutputStream *,
+ const wxRGB *pal, size_t palCount, int bpp);
+static bool wxGIFHandler_WriteControl(wxOutputStream *,
+ int maskIndex, int delayMilliSecs);
+static bool wxGIFHandler_WriteComment(wxOutputStream *, const wxString&);
+static bool wxGIFHandler_WriteLoop(wxOutputStream *);
+
+static bool wxGIFHandler_BufferedOutput(wxOutputStream *, wxUint8 *buf, int c);
+#endif // wxUSE_STREAMS
+
//-----------------------------------------------------------------------------
// wxGIFHandler
//-----------------------------------------------------------------------------
#if wxUSE_STREAMS
bool wxGIFHandler::LoadFile(wxImage *image, wxInputStream& stream,
- bool verbose, int index)
+ bool verbose, int index)
{
wxGIFDecoder *decod;
- int error;
+ wxGIFErrorCode error;
bool ok = true;
// image->Destroy();
- decod = new wxGIFDecoder(&stream, true);
- error = decod->ReadGIF();
+ decod = new wxGIFDecoder();
+ error = decod->LoadGIF(stream);
if ((error != wxGIF_OK) && (error != wxGIF_TRUNCATED))
{
if ((error == wxGIF_TRUNCATED) && verbose)
{
wxLogError(_("GIF: data stream seems to be truncated."));
- /* go on; image data is OK */
- }
-
- if (index != -1)
- {
- // We're already on index = 0 by default. So no need
- // to call GoFrame(0) then. On top of that GoFrame doesn't
- // accept an index of 0. (Instead GoFirstFrame() should be used)
- // Also if the gif image has only one frame, calling GoFrame(0)
- // fails because GoFrame() only works with gif animations.
- // (It fails if IsAnimation() returns false)
- // All valid reasons to NOT call GoFrame when index equals 0.
- if (index != 0)
- {
- ok = decod->GoFrame(index);
- }
+ // go on; image data is OK
}
if (ok)
{
- ok = decod->ConvertToImage(image);
+ ok = decod->ConvertToImage(index != -1 ? (size_t)index : 0, image);
}
else
{
return ok;
}
-bool wxGIFHandler::SaveFile( wxImage * WXUNUSED(image),
- wxOutputStream& WXUNUSED(stream), bool verbose )
+bool wxGIFHandler::SaveFile(wxImage *image,
+ wxOutputStream& stream, bool verbose)
{
- if (verbose)
- wxLogDebug(wxT("GIF: the handler is read-only!!"));
+#if wxUSE_PALETTE
+ wxRGB pal[256];
+ int palCount;
+ int maskIndex;
+ return wxGIFHandler_GetPalette(*image, pal, &palCount, &maskIndex)
+ && DoSaveFile(*image, &stream, verbose, true /*first?*/, 0,
+ false /*loop?*/, pal, palCount, maskIndex)
+ && wxGIFHandler_WriteTerm(&stream);
+#else
+ wxUnusedVar(image);
+ wxUnusedVar(stream);
+ wxUnusedVar(verbose);
return false;
+#endif
}
bool wxGIFHandler::DoCanRead( wxInputStream& stream )
{
- wxGIFDecoder decod(&stream);
- return decod.CanRead();
+ wxGIFDecoder decod;
+ return decod.CanRead(stream);
+ // it's ok to modify the stream position here
+}
+
+int wxGIFHandler::DoGetImageCount( wxInputStream& stream )
+{
+ wxGIFDecoder decod;
+ wxGIFErrorCode error = decod.LoadGIF(stream);
+ if ( (error != wxGIF_OK) && (error != wxGIF_TRUNCATED) )
+ return -1;
+
+ // NOTE: this function modifies the current stream position but it's ok
+ // (see wxImageHandler::GetImageCount)
+
+ return decod.GetFrameCount();
+}
+
+bool wxGIFHandler::DoSaveFile(const wxImage& image, wxOutputStream *stream,
+ bool WXUNUSED(verbose), bool first, int delayMilliSecs, bool loop,
+ const wxRGB *pal, int palCount, int maskIndex)
+{
+ const unsigned long colorcount = image.CountColours(256+1);
+ bool ok = colorcount && (colorcount <= 256);
+ if (!ok)
+ {
+ return false;
+ }
+
+ int width = image.GetWidth();
+ int height = image.GetHeight();
+ int width_even = width + ((width % 2) ? 1 : 0);
+
+ if (first)
+ {
+ ok = wxGIFHandler_WriteHeader(stream, width, height, loop,
+ pal, palCount);
+ }
+
+ ok = ok
+ && wxGIFHandler_WriteComment(stream,
+ image.GetOption(wxIMAGE_OPTION_GIF_COMMENT))
+ && wxGIFHandler_WriteControl(stream, maskIndex, delayMilliSecs)
+ && wxGIFHandler_WriteByte(stream, GIF_MARKER_SEP)
+ && wxGIFHandler_WriteRect(stream, width, height);
+
+ // local palette
+ if (first)
+ {
+ // we already saved the (global) palette
+ ok = ok && wxGIFHandler_WriteZero(stream);
+ }
+ else
+ {
+ const int bpp = wxGIFHandler_BitSize(palCount);
+ wxUint8 b;
+
+ b = 0x80;
+ b |=(bpp - 1) << 5;
+ b |=(bpp - 1);
+ b &=~0x40; // clear interlaced
+
+ ok = ok && wxGIFHandler_WriteByte(stream, b)
+ && wxGIFHandler_WritePalette(stream, pal, palCount, bpp);
+ }
+
+ if (!ok)
+ {
+ return false;
+ }
+
+ if (!InitHashTable())
+ {
+ wxLogError(_("Couldn't initialize GIF hash table."));
+ return false;
+ }
+
+ const wxUint8 *src = image.GetData();
+ wxUint8 *eightBitData = new wxUint8[width];
+
+ SetupCompress(stream, 8);
+
+ m_pixelCount = height * width_even;
+ for (int y = 0; y < height; y++)
+ {
+ m_pixelCount -= width_even;
+ for (int x = 0; x < width; x++)
+ {
+ wxRGB rgb;
+ rgb.red = src[0];
+ rgb.green = src[1];
+ rgb.blue = src[2];
+ int index = wxGIFHandler_PaletteFind(rgb, pal, palCount);
+ wxASSERT(index != wxNOT_FOUND);
+ eightBitData[x] = (wxUint8)index;
+ src+=3;
+ }
+
+ ok = CompressLine(stream, eightBitData, width);
+ if (!ok)
+ {
+ break;
+ }
+ }
+
+ delete [] eightBitData;
+
+ wxDELETE(m_hashTable);
+
+ return ok;
+}
+
+bool wxGIFHandler::SaveAnimation(const wxImageArray& images,
+ wxOutputStream *stream, bool verbose, int delayMilliSecs)
+{
+#if wxUSE_PALETTE
+ bool ok = true;
+ size_t i;
+
+ wxSize size(0,0);
+ for (i = 0; (i < images.GetCount()) && ok; i++)
+ {
+ const wxImage& image = images.Item(i);
+ wxSize temp(image.GetWidth(), image.GetHeight());
+ ok = ok && image.HasPalette();
+ if (i)
+ {
+ ok = ok && (size == temp);
+ }
+ else
+ {
+ size = temp;
+ }
+ }
+
+ for (i = 0; (i < images.GetCount()) && ok; i++)
+ {
+ const wxImage& image = images.Item(i);
+
+ wxRGB pal[256];
+ int palCount;
+ int maskIndex;
+
+ ok = wxGIFHandler_GetPalette(image, pal, &palCount, &maskIndex)
+ && DoSaveFile(image, stream, verbose, i == 0 /*first?*/, delayMilliSecs,
+ true /*loop?*/, pal, palCount, maskIndex);
+ }
+
+ return ok && wxGIFHandler_WriteTerm(stream);
+#else
+ wxUnusedVar(images);
+ wxUnusedVar(stream);
+ wxUnusedVar(verbose);
+ wxUnusedVar(delayMilliSecs);
+
+ return false;
+#endif
+}
+
+bool wxGIFHandler::CompressOutput(wxOutputStream *stream, int code)
+{
+ if (code == FLUSH_OUTPUT)
+ {
+ while (m_crntShiftState > 0)
+ {
+ // Get rid of what is left in DWord, and flush it.
+ if (!wxGIFHandler_BufferedOutput(stream, m_LZBuf,
+ m_crntShiftDWord & 0xff))
+ {
+ return false;
+ }
+ m_crntShiftDWord >>= 8;
+ m_crntShiftState -= 8;
+ }
+ m_crntShiftState = 0; // For next time.
+ if (!wxGIFHandler_BufferedOutput(stream, m_LZBuf, FLUSH_OUTPUT))
+ {
+ return false;
+ }
+ }
+ else
+ {
+ m_crntShiftDWord |= ((long) code) << m_crntShiftState;
+ m_crntShiftState += m_runningBits;
+ while (m_crntShiftState >= 8)
+ {
+ // Dump out full bytes:
+ if (!wxGIFHandler_BufferedOutput(stream, m_LZBuf,
+ m_crntShiftDWord & 0xff))
+ {
+ return false;
+ }
+ m_crntShiftDWord >>= 8;
+ m_crntShiftState -= 8;
+ }
+ }
+
+ // If code can't fit into RunningBits bits, must raise its size. Note
+ // however that codes above LZ_MAX_CODE are used for special signaling.
+ if ( (m_runningCode >= m_maxCode1) && (code <= LZ_MAX_CODE))
+ {
+ m_maxCode1 = 1 << ++m_runningBits;
+ }
+ return true;
+}
+
+bool wxGIFHandler::SetupCompress(wxOutputStream *stream, int bpp)
+{
+ m_LZBuf[0] = 0; // Nothing was output yet.
+ m_clearCode = (1 << bpp);
+ m_EOFCode = m_clearCode + 1;
+ m_runningCode = m_EOFCode + 1;
+ m_runningBits = bpp + 1; // Number of bits per code.
+ m_maxCode1 = 1 << m_runningBits; // Max. code + 1.
+ m_crntCode = FIRST_CODE; // Signal that this is first one!
+ m_crntShiftState = 0; // No information in CrntShiftDWord.
+ m_crntShiftDWord = 0;
+
+ // Clear hash table and send Clear to make sure the decoder does the same.
+ ClearHashTable();
+
+ return wxGIFHandler_WriteByte(stream, (wxUint8)bpp)
+ && CompressOutput(stream, m_clearCode);
+}
+
+bool wxGIFHandler::CompressLine(wxOutputStream *stream,
+ const wxUint8 *line, int lineLen)
+{
+ int i = 0, crntCode, newCode;
+ unsigned long newKey;
+ wxUint8 pixel;
+ if (m_crntCode == FIRST_CODE) // It's first time!
+ crntCode = line[i++];
+ else
+ crntCode = m_crntCode; // Get last code in compression.
+
+ while (i < lineLen)
+ {
+ // Decode lineLen items.
+ pixel = line[i++]; // Get next pixel from stream.
+ // Form a new unique key to search hash table for the code combines
+ // crntCode as Prefix string with Pixel as postfix char.
+ newKey = (((unsigned long) crntCode) << 8) + pixel;
+ if ((newCode = ExistsHashTable(newKey)) >= 0)
+ {
+ // This Key is already there, or the string is old one, so
+ // simply take new code as our crntCode:
+ crntCode = newCode;
+ }
+ else
+ {
+ // Put it in hash table, output the prefix code, and make our
+ // crntCode equal to Pixel.
+ if (!CompressOutput(stream, crntCode))
+ {
+ return false;
+ }
+
+ crntCode = pixel;
+
+ // If however the HashTable is full, we send a clear first and
+ // Clear the hash table.
+ if (m_runningCode >= LZ_MAX_CODE)
+ {
+ // Time to do some clearance:
+ if (!CompressOutput(stream, m_clearCode))
+ {
+ return false;
+ }
+
+ m_runningCode = m_EOFCode + 1;
+ m_runningBits = 8 + 1;
+ m_maxCode1 = 1 << m_runningBits;
+ ClearHashTable();
+ }
+ else
+ {
+ // Put this unique key with its relative Code in hash table:
+ InsertHashTable(newKey, m_runningCode++);
+ }
+ }
+ }
+ // Preserve the current state of the compression algorithm:
+ m_crntCode = crntCode;
+ if (m_pixelCount == 0)
+ {
+ // We are done - output last Code and flush output buffers:
+ if (!CompressOutput(stream, crntCode)
+ || !CompressOutput(stream, m_EOFCode)
+ || !CompressOutput(stream, FLUSH_OUTPUT))
+ {
+ return false;
+ }
+ }
+
+ return true;
}
#endif // wxUSE_STREAMS
-#endif // wxUSE_GIF
+bool wxGIFHandler::InitHashTable()
+{
+ if (!m_hashTable)
+ {
+ m_hashTable = new GifHashTableType();
+ }
+
+ if (!m_hashTable)
+ {
+ return false;
+ }
+
+ ClearHashTable();
+
+ return true;
+}
+
+void wxGIFHandler::ClearHashTable()
+{
+ int index = HT_SIZE;
+ wxUint32 *HTable = m_hashTable->HTable;
+
+ while (--index>=0)
+ {
+ HTable[index] = 0xfffffffful;
+ }
+}
+
+void wxGIFHandler::InsertHashTable(unsigned long key, int code)
+{
+ int hKey = wxGIFHandler_KeyItem(key);
+ wxUint32 *HTable = m_hashTable->HTable;
+
+ while (HT_GET_KEY(HTable[hKey]) != 0xFFFFFL)
+ {
+ hKey = (hKey + 1) & HT_KEY_MASK;
+ }
+ HTable[hKey] = HT_PUT_KEY(key) | HT_PUT_CODE(code);
+}
+
+
+int wxGIFHandler::ExistsHashTable(unsigned long key)
+{
+ int hKey = wxGIFHandler_KeyItem(key);
+ wxUint32 *HTable = m_hashTable->HTable, HTKey;
+
+ while ((HTKey = HT_GET_KEY(HTable[hKey])) != 0xFFFFFL)
+ {
+ if (key == HTKey)
+ {
+ return HT_GET_CODE(HTable[hKey]);
+ }
+ hKey = (hKey + 1) & HT_KEY_MASK;
+ }
+ return -1;
+}
+
+// ---------------------------------------------------------------------------
+// implementation of global private functions
+// ---------------------------------------------------------------------------
+
+int wxGIFHandler_KeyItem(unsigned long item)
+{
+ return ((item >> 12) ^ item) & HT_KEY_MASK;
+}
+
+#if wxUSE_STREAMS
+
+int wxGIFHandler_BitSize(int n)
+{
+ int i;
+ for (i = 1; i <= 8; i++)
+ {
+ if ((1 << i) >= n)
+ {
+ break;
+ }
+ }
+ return i;
+}
+
+#if wxUSE_PALETTE
+bool wxGIFHandler_GetPalette(const wxImage& image,
+ wxRGB *pal, int *pPalCount, int *pMaskIndex)
+{
+ if (!image.HasPalette())
+ {
+ return false;
+ }
+
+ const wxPalette& palette = image.GetPalette();
+ int palCount = palette.GetColoursCount();
+
+ for (int i = 0; i < palCount; ++i)
+ {
+ if (!palette.GetRGB(i, &pal[i].red, &pal[i].green, &pal[i].blue))
+ {
+ break;
+ }
+ }
+ if (image.HasMask())
+ {
+ wxRGB mask;
+
+ mask.red = image.GetMaskRed();
+ mask.green = image.GetMaskGreen();
+ mask.blue = image.GetMaskBlue();
+ *pMaskIndex = wxGIFHandler_PaletteFind(mask, pal, palCount);
+ if ( (*pMaskIndex == wxNOT_FOUND) && (palCount < 256))
+ {
+ *pMaskIndex = palCount;
+ pal[palCount++] = mask;
+ }
+ }
+ else
+ {
+ *pMaskIndex = wxNOT_FOUND;
+ }
+ *pPalCount = palCount;
+
+ return true;
+}
+#endif // wxUSE_PALETTE
+
+int wxGIFHandler_PaletteFind(const wxRGB& clr, const wxRGB *array, int count)
+{
+ for (int i = 0; i < count; i++)
+ {
+ if ( (clr.red == array[i].red)
+ && (clr.green == array[i].green)
+ && (clr.blue == array[i].blue))
+ {
+ return i;
+ }
+ }
+
+ return wxNOT_FOUND;
+}
+
+bool wxGIFHandler_Write(wxOutputStream *stream, const void *buf, size_t len)
+{
+ return (len == stream->Write(buf, len).LastWrite());
+}
+
+bool wxGIFHandler_WriteByte(wxOutputStream *stream, wxUint8 byte)
+{
+ return wxGIFHandler_Write(stream, &byte, sizeof(byte));
+}
+
+bool wxGIFHandler_WriteWord(wxOutputStream *stream, wxUint16 word)
+{
+ wxUint8 buf[2];
+
+ buf[0] = word & 0xff;
+ buf[1] = (word >> 8) & 0xff;
+ return wxGIFHandler_Write(stream, &buf, sizeof(buf));
+}
+
+bool wxGIFHandler_WriteHeader(wxOutputStream *stream, int width, int height,
+ bool loop, const wxRGB *pal, int palCount)
+{
+ const int bpp = wxGIFHandler_BitSize(palCount);
+ wxUint8 buf[3];
+
+ bool ok = wxGIFHandler_Write(stream, GIF89_HDR, sizeof(GIF89_HDR)-1)
+ && wxGIFHandler_WriteWord(stream, (wxUint16) width)
+ && wxGIFHandler_WriteWord(stream, (wxUint16) height);
+
+ buf[0] = 0x80;
+ buf[0] |=(bpp - 1) << 5;
+ buf[0] |=(bpp - 1);
+ buf[1] = 0; // background color == entry 0
+ buf[2] = 0; // aspect ratio 1:1
+ ok = ok && wxGIFHandler_Write(stream, buf, sizeof(buf))
+ && wxGIFHandler_WritePalette(stream, pal, palCount, bpp);
+
+ if (loop)
+ {
+ ok = ok && wxGIFHandler_WriteLoop(stream);
+ }
+
+ return ok;
+}
+
+bool wxGIFHandler_WriteRect(wxOutputStream *stream, int width, int height)
+{
+ return wxGIFHandler_WriteWord(stream, 0) // left
+ && wxGIFHandler_WriteWord(stream, 0) // top
+ && wxGIFHandler_WriteWord(stream, (wxUint16) width)
+ && wxGIFHandler_WriteWord(stream, (wxUint16) height);
+}
+
+#if wxUSE_PALETTE
+bool wxGIFHandler_WriteTerm(wxOutputStream *stream)
+{
+ return wxGIFHandler_WriteByte(stream, GIF_MARKER_ENDOFDATA);
+}
+#endif
+
+bool wxGIFHandler_WriteZero(wxOutputStream *stream)
+{
+ return wxGIFHandler_WriteByte(stream, 0);
+}
+
+bool wxGIFHandler_WritePalette(wxOutputStream *stream,
+ const wxRGB *array, size_t count, int bpp)
+{
+ wxUint8 buf[3];
+ for (int i = 0; (i < (1 << bpp)); i++)
+ {
+ if (i < (int)count)
+ {
+ buf[0] = array[i].red;
+ buf[1] = array[i].green;
+ buf[2] = array[i].blue;
+ }
+ else
+ {
+ buf[0] = buf[1] = buf[2] = 0;
+ }
+
+ if ( !wxGIFHandler_Write(stream, buf, sizeof(buf)) )
+ {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+bool wxGIFHandler_WriteControl(wxOutputStream *stream,
+ int maskIndex, int delayMilliSecs)
+{
+ wxUint8 buf[8];
+
+ buf[0] = GIF_MARKER_EXT; // extension marker
+ buf[1] = GIF_MARKER_EXT_GRAPHICS_CONTROL;
+ buf[2] = 4; // length of block
+ buf[3] = (maskIndex != wxNOT_FOUND) ? 1 : 0; // has transparency
+ buf[4] = delayMilliSecs / 10; // delay time
+ buf[5] = 0;
+ buf[6] = (maskIndex != wxNOT_FOUND) ? (wxUint8) maskIndex : 0;
+ buf[7] = 0;
+ return wxGIFHandler_Write(stream, buf, sizeof(buf));
+}
+
+bool wxGIFHandler_WriteComment(wxOutputStream *stream, const wxString& comment)
+{
+ if ( comment.empty() )
+ {
+ return true;
+ }
+
+ // Write comment header.
+ wxUint8 buf[2];
+ buf[0] = GIF_MARKER_EXT;
+ buf[1] = GIF_MARKER_EXT_COMMENT;
+ if ( !wxGIFHandler_Write(stream, buf, sizeof(buf)) )
+ {
+ return false;
+ }
+
+ /*
+ If comment is longer than 255 bytes write it in blocks of maximum 255
+ bytes each.
+ */
+ wxCharBuffer text( comment.mb_str() );
+
+ size_t pos = 0, fullLength = text.length();
+
+ do
+ {
+ size_t blockLength = wxMin(fullLength - pos, 255);
+
+ if ( !wxGIFHandler_WriteByte(stream, (wxUint8) blockLength)
+ || !wxGIFHandler_Write(stream, &text.data()[pos], blockLength) )
+ {
+ return false;
+ }
+
+ pos += blockLength;
+ }while (pos < fullLength);
+
+
+ // Write comment footer.
+ return wxGIFHandler_WriteZero(stream);
+}
+
+bool wxGIFHandler_WriteLoop(wxOutputStream *stream)
+{
+ wxUint8 buf[4];
+ const int loopcount = 0; // infinite
+
+ buf[0] = GIF_MARKER_EXT;
+ buf[1] = GIF_MARKER_EXT_APP;
+ buf[2] = 0x0B;
+ bool ok = wxGIFHandler_Write(stream, buf, 3)
+ && wxGIFHandler_Write(stream, NETSCAPE_LOOP, sizeof(NETSCAPE_LOOP)-1);
+
+ buf[0] = 3;
+ buf[1] = 1;
+ buf[2] = loopcount & 0xFF;
+ buf[3] = loopcount >> 8;
+
+ return ok && wxGIFHandler_Write(stream, buf, 4)
+ && wxGIFHandler_WriteZero(stream);
+}
+
+bool wxGIFHandler_BufferedOutput(wxOutputStream *stream, wxUint8 *buf, int c)
+{
+ bool ok = true;
+
+ if (c == FLUSH_OUTPUT)
+ {
+ // Flush everything out.
+ if (buf[0])
+ {
+ ok = wxGIFHandler_Write(stream, buf, buf[0]+1);
+ }
+ // Mark end of compressed data, by an empty block (see GIF doc):
+ wxGIFHandler_WriteZero(stream);
+ }
+ else
+ {
+ if (buf[0] == 255)
+ {
+ // Dump out this buffer - it is full:
+ ok = wxGIFHandler_Write(stream, buf, buf[0] + 1);
+ buf[0] = 0;
+ }
+ buf[++buf[0]] = c;
+ }
+
+ return ok;
+}
+
+#endif // wxUSE_STREAMS
+
+#endif // wxUSE_IMAGE && wxUSE_GIF
projects / wxWidgets.git / blobdiff