--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/plugins/imageformats/gif/qgifhandler.cpp Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,892 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+** WARNING:
+** A separate license from Unisys may be required to use the gif
+** reader. See http://www.unisys.com/about__unisys/lzw/
+** for information from Unisys
+**
+****************************************************************************/
+
+#include "qgifhandler.h"
+
+#include <qimage.h>
+#include <qiodevice.h>
+#include <qvariant.h>
+
+QT_BEGIN_NAMESPACE
+
+#define Q_TRANSPARENT 0x00ffffff
+
+/*
+ Incremental image decoder for GIF image format.
+
+ This subclass of QImageFormat decodes GIF format images,
+ including animated GIFs. Internally in
+*/
+
+class QGIFFormat {
+public:
+ QGIFFormat();
+ ~QGIFFormat();
+
+ int decode(QImage *image, const uchar* buffer, int length,
+ int *nextFrameDelay, int *loopCount, QSize *nextSize);
+
+ bool newFrame;
+ bool partialNewFrame;
+
+private:
+ void fillRect(QImage *image, int x, int y, int w, int h, QRgb col);
+ inline QRgb color(uchar index) const;
+
+ // GIF specific stuff
+ QRgb* globalcmap;
+ QRgb* localcmap;
+ QImage backingstore;
+ unsigned char hold[16];
+ bool gif89;
+ int count;
+ int ccount;
+ int expectcount;
+ enum State {
+ Header,
+ LogicalScreenDescriptor,
+ GlobalColorMap,
+ LocalColorMap,
+ Introducer,
+ ImageDescriptor,
+ TableImageLZWSize,
+ ImageDataBlockSize,
+ ImageDataBlock,
+ ExtensionLabel,
+ GraphicControlExtension,
+ ApplicationExtension,
+ NetscapeExtensionBlockSize,
+ NetscapeExtensionBlock,
+ SkipBlockSize,
+ SkipBlock,
+ Done,
+ Error
+ } state;
+ int gncols;
+ int lncols;
+ int ncols;
+ int lzwsize;
+ bool lcmap;
+ int swidth, sheight;
+ int width, height;
+ int left, top, right, bottom;
+ enum Disposal { NoDisposal, DoNotChange, RestoreBackground, RestoreImage };
+ Disposal disposal;
+ bool disposed;
+ int trans_index;
+ bool gcmap;
+ int bgcol;
+ int interlace;
+ int accum;
+ int bitcount;
+
+ enum { max_lzw_bits=12 }; // (poor-compiler's static const int)
+
+ int code_size, clear_code, end_code, max_code_size, max_code;
+ int firstcode, oldcode, incode;
+ short table[2][1<< max_lzw_bits];
+ short stack[(1<<(max_lzw_bits))*2];
+ short *sp;
+ bool needfirst;
+ int x, y;
+ int frame;
+ bool out_of_bounds;
+ bool digress;
+ void nextY(QImage *image);
+ void disposePrevious(QImage *image);
+};
+
+/*!
+ Constructs a QGIFFormat.
+*/
+QGIFFormat::QGIFFormat()
+{
+ globalcmap = 0;
+ localcmap = 0;
+ lncols = 0;
+ gncols = 0;
+ disposal = NoDisposal;
+ out_of_bounds = false;
+ disposed = true;
+ frame = -1;
+ state = Header;
+ count = 0;
+ lcmap = false;
+ newFrame = false;
+ partialNewFrame = false;
+}
+
+/*!
+ Destroys a QGIFFormat.
+*/
+QGIFFormat::~QGIFFormat()
+{
+ if (globalcmap) delete[] globalcmap;
+ if (localcmap) delete[] localcmap;
+}
+
+void QGIFFormat::disposePrevious(QImage *image)
+{
+ if (out_of_bounds) {
+ // flush anything that survived
+ // ### Changed: QRect(0, 0, swidth, sheight)
+ }
+
+ // Handle disposal of previous image before processing next one
+
+ if (disposed) return;
+
+ int l = qMin(swidth-1,left);
+ int r = qMin(swidth-1,right);
+ int t = qMin(sheight-1,top);
+ int b = qMin(sheight-1,bottom);
+
+ switch (disposal) {
+ case NoDisposal:
+ break;
+ case DoNotChange:
+ break;
+ case RestoreBackground:
+ if (trans_index>=0) {
+ // Easy: we use the transparent color
+ fillRect(image, l, t, r-l+1, b-t+1, Q_TRANSPARENT);
+ } else if (bgcol>=0) {
+ // Easy: we use the bgcol given
+ fillRect(image, l, t, r-l+1, b-t+1, color(bgcol));
+ } else {
+ // Impossible: We don't know of a bgcol - use pixel 0
+ QRgb *bits = (QRgb*)image->bits();
+ fillRect(image, l, t, r-l+1, b-t+1, bits[0]);
+ }
+ // ### Changed: QRect(l, t, r-l+1, b-t+1)
+ break;
+ case RestoreImage: {
+ if (frame >= 0) {
+ for (int ln=t; ln<=b; ln++) {
+ memcpy(image->scanLine(ln)+l,
+ backingstore.scanLine(ln-t),
+ (r-l+1)*sizeof(QRgb));
+ }
+ // ### Changed: QRect(l, t, r-l+1, b-t+1)
+ }
+ }
+ }
+ disposal = NoDisposal; // Until an extension says otherwise.
+
+ disposed = true;
+}
+
+/*!
+ This function decodes some data into image changes.
+
+ Returns the number of bytes consumed.
+*/
+int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
+ int *nextFrameDelay, int *loopCount, QSize *nextSize)
+{
+ // We are required to state that
+ // "The Graphics Interchange Format(c) is the Copyright property of
+ // CompuServe Incorporated. GIF(sm) is a Service Mark property of
+ // CompuServe Incorporated."
+
+#define LM(l, m) (((m)<<8)|l)
+ digress = false;
+ const int initial = length;
+ while (!digress && length) {
+ length--;
+ unsigned char ch=*buffer++;
+ switch (state) {
+ case Header:
+ hold[count++]=ch;
+ if (count==6) {
+ // Header
+ gif89=(hold[3]!='8' || hold[4]!='7');
+ state=LogicalScreenDescriptor;
+ count=0;
+ }
+ break;
+ case LogicalScreenDescriptor:
+ hold[count++]=ch;
+ if (count==7) {
+ // Logical Screen Descriptor
+ swidth=LM(hold[0], hold[1]);
+ sheight=LM(hold[2], hold[3]);
+ gcmap=!!(hold[4]&0x80);
+ //UNUSED: bpchan=(((hold[4]&0x70)>>3)+1);
+ //UNUSED: gcmsortflag=!!(hold[4]&0x08);
+ gncols=2<<(hold[4]&0x7);
+ bgcol=(gcmap) ? hold[5] : -1;
+ //aspect=hold[6] ? double(hold[6]+15)/64.0 : 1.0;
+
+ trans_index = -1;
+ count=0;
+ ncols=gncols;
+ if (gcmap) {
+ ccount=0;
+ state=GlobalColorMap;
+ globalcmap = new QRgb[gncols+1]; // +1 for trans_index
+ globalcmap[gncols] = Q_TRANSPARENT;
+ } else {
+ state=Introducer;
+ }
+ }
+ break;
+ case GlobalColorMap: case LocalColorMap:
+ hold[count++]=ch;
+ if (count==3) {
+ QRgb rgb = qRgb(hold[0], hold[1], hold[2]);
+ if (state == LocalColorMap) {
+ if (ccount < lncols)
+ localcmap[ccount] = rgb;
+ } else {
+ globalcmap[ccount] = rgb;
+ }
+ if (++ccount >= ncols) {
+ if (state == LocalColorMap)
+ state=TableImageLZWSize;
+ else
+ state=Introducer;
+ }
+ count=0;
+ }
+ break;
+ case Introducer:
+ hold[count++]=ch;
+ switch (ch) {
+ case ',':
+ state=ImageDescriptor;
+ break;
+ case '!':
+ state=ExtensionLabel;
+ break;
+ case ';':
+ // ### Changed: QRect(0, 0, swidth, sheight)
+ state=Done;
+ break;
+ default:
+ digress=true;
+ // Unexpected Introducer - ignore block
+ state=Error;
+ }
+ break;
+ case ImageDescriptor:
+ hold[count++]=ch;
+ if (count==10) {
+ int newleft=LM(hold[1], hold[2]);
+ int newtop=LM(hold[3], hold[4]);
+ int newwidth=LM(hold[5], hold[6]);
+ int newheight=LM(hold[7], hold[8]);
+
+ // disbelieve ridiculous logical screen sizes,
+ // unless the image frames are also large.
+ if (swidth/10 > qMax(newwidth,200))
+ swidth = -1;
+ if (sheight/10 > qMax(newheight,200))
+ sheight = -1;
+
+ if (swidth <= 0)
+ swidth = newleft + newwidth;
+ if (sheight <= 0)
+ sheight = newtop + newheight;
+
+ QImage::Format format = trans_index >= 0 ? QImage::Format_ARGB32 : QImage::Format_RGB32;
+ if (image->isNull()) {
+ (*image) = QImage(swidth, sheight, format);
+ memset(image->bits(), 0, image->numBytes());
+
+ // ### size of the upcoming frame, should rather
+ // be known before decoding it.
+ *nextSize = QSize(swidth, sheight);
+ }
+
+ disposePrevious(image);
+ disposed = false;
+
+ left = newleft;
+ top = newtop;
+ width = newwidth;
+ height = newheight;
+
+ right=qMax(0, qMin(left+width, swidth)-1);
+ bottom=qMax(0, qMin(top+height, sheight)-1);
+ lcmap=!!(hold[9]&0x80);
+ interlace=!!(hold[9]&0x40);
+ //bool lcmsortflag=!!(hold[9]&0x20);
+ lncols=lcmap ? (2<<(hold[9]&0x7)) : 0;
+ if (lncols) {
+ if (localcmap)
+ delete [] localcmap;
+ localcmap = new QRgb[lncols+1];
+ localcmap[lncols] = Q_TRANSPARENT;
+ ncols = lncols;
+ } else {
+ ncols = gncols;
+ }
+ frame++;
+ if (frame == 0) {
+ if (left || top || width<swidth || height<sheight) {
+ // Not full-size image - erase with bg or transparent
+ if (trans_index >= 0) {
+ fillRect(image, 0, 0, swidth, sheight, color(trans_index));
+ // ### Changed: QRect(0, 0, swidth, sheight)
+ } else if (bgcol>=0) {
+ fillRect(image, 0, 0, swidth, sheight, color(bgcol));
+ // ### Changed: QRect(0, 0, swidth, sheight)
+ }
+ }
+ }
+
+ if (disposal == RestoreImage) {
+ int l = qMin(swidth-1,left);
+ int r = qMin(swidth-1,right);
+ int t = qMin(sheight-1,top);
+ int b = qMin(sheight-1,bottom);
+ int w = r-l+1;
+ int h = b-t+1;
+
+ if (backingstore.width() < w
+ || backingstore.height() < h) {
+ // We just use the backing store as a byte array
+ backingstore = QImage(qMax(backingstore.width(), w),
+ qMax(backingstore.height(), h),
+ QImage::Format_RGB32);
+ memset(image->bits(), 0, image->numBytes());
+ }
+ for (int ln=0; ln<h; ln++) {
+ memcpy(backingstore.scanLine(ln),
+ image->scanLine(t+ln)+l, w*sizeof(QRgb));
+ }
+ }
+
+ count=0;
+ if (lcmap) {
+ ccount=0;
+ state=LocalColorMap;
+ } else {
+ state=TableImageLZWSize;
+ }
+ x = left;
+ y = top;
+ accum = 0;
+ bitcount = 0;
+ sp = stack;
+ firstcode = oldcode = 0;
+ needfirst = true;
+ out_of_bounds = left>=swidth || y>=sheight;
+ }
+ break;
+ case TableImageLZWSize: {
+ lzwsize=ch;
+ if (lzwsize > max_lzw_bits) {
+ state=Error;
+ } else {
+ code_size=lzwsize+1;
+ clear_code=1<<lzwsize;
+ end_code=clear_code+1;
+ max_code_size=2*clear_code;
+ max_code=clear_code+2;
+ int i;
+ for (i=0; i<clear_code; i++) {
+ table[0][i]=0;
+ table[1][i]=i;
+ }
+ state=ImageDataBlockSize;
+ }
+ count=0;
+ break;
+ } case ImageDataBlockSize:
+ expectcount=ch;
+ if (expectcount) {
+ state=ImageDataBlock;
+ } else {
+ state=Introducer;
+ digress = true;
+ newFrame = true;
+ }
+ break;
+ case ImageDataBlock:
+ count++;
+ accum|=(ch<<bitcount);
+ bitcount+=8;
+ while (bitcount>=code_size && state==ImageDataBlock) {
+ int code=accum&((1<<code_size)-1);
+ bitcount-=code_size;
+ accum>>=code_size;
+
+ if (code==clear_code) {
+ if (!needfirst) {
+ code_size=lzwsize+1;
+ max_code_size=2*clear_code;
+ max_code=clear_code+2;
+ }
+ needfirst=true;
+ } else if (code==end_code) {
+ bitcount = -32768;
+ // Left the block end arrive
+ } else {
+ if (needfirst) {
+ firstcode=oldcode=code;
+ if (!out_of_bounds && image->height() > y && firstcode!=trans_index)
+ ((QRgb*)image->scanLine(y))[x] = color(firstcode);
+ x++;
+ if (x>=swidth) out_of_bounds = true;
+ needfirst=false;
+ if (x>=left+width) {
+ x=left;
+ out_of_bounds = left>=swidth || y>=sheight;
+ nextY(image);
+ }
+ } else {
+ incode=code;
+ if (code>=max_code) {
+ *sp++=firstcode;
+ code=oldcode;
+ }
+ while (code>=clear_code+2) {
+ *sp++=table[1][code];
+ if (code==table[0][code]) {
+ state=Error;
+ break;
+ }
+ if (sp-stack>=(1<<(max_lzw_bits))*2) {
+ state=Error;
+ break;
+ }
+ code=table[0][code];
+ }
+ *sp++=firstcode=table[1][code];
+ code=max_code;
+ if (code<(1<<max_lzw_bits)) {
+ table[0][code]=oldcode;
+ table[1][code]=firstcode;
+ max_code++;
+ if ((max_code>=max_code_size)
+ && (max_code_size<(1<<max_lzw_bits)))
+ {
+ max_code_size*=2;
+ code_size++;
+ }
+ }
+ oldcode=incode;
+ const int h = image->height();
+ const QRgb *map = lcmap ? localcmap : globalcmap;
+ QRgb *line = 0;
+ if (!out_of_bounds && h > y)
+ line = (QRgb*)image->scanLine(y);
+ while (sp>stack) {
+ const uchar index = *(--sp);
+ if (!out_of_bounds && h > y && index!=trans_index) {
+ if (index > ncols)
+ line[x] = Q_TRANSPARENT;
+ else
+ line[x] = map ? map[index] : 0;
+ }
+ x++;
+ if (x>=swidth) out_of_bounds = true;
+ if (x>=left+width) {
+ x=left;
+ out_of_bounds = left>=swidth || y>=sheight;
+ nextY(image);
+ if (!out_of_bounds && h > y)
+ line = (QRgb*)image->scanLine(y);
+ }
+ }
+ }
+ }
+ }
+ partialNewFrame = true;
+ if (count==expectcount) {
+ count=0;
+ state=ImageDataBlockSize;
+ }
+ break;
+ case ExtensionLabel:
+ switch (ch) {
+ case 0xf9:
+ state=GraphicControlExtension;
+ break;
+ case 0xff:
+ state=ApplicationExtension;
+ break;
+#if 0
+ case 0xfe:
+ state=CommentExtension;
+ break;
+ case 0x01:
+ break;
+#endif
+ default:
+ state=SkipBlockSize;
+ }
+ count=0;
+ break;
+ case ApplicationExtension:
+ if (count<11) hold[count]=ch;
+ count++;
+ if (count==hold[0]+1) {
+ if (qstrncmp((char*)(hold+1), "NETSCAPE", 8)==0) {
+ // Looping extension
+ state=NetscapeExtensionBlockSize;
+ } else {
+ state=SkipBlockSize;
+ }
+ count=0;
+ }
+ break;
+ case NetscapeExtensionBlockSize:
+ expectcount=ch;
+ count=0;
+ if (expectcount) state=NetscapeExtensionBlock;
+ else state=Introducer;
+ break;
+ case NetscapeExtensionBlock:
+ if (count<3) hold[count]=ch;
+ count++;
+ if (count==expectcount) {
+ *loopCount = hold[1]+hold[2]*256;
+ state=SkipBlockSize; // Ignore further blocks
+ }
+ break;
+ case GraphicControlExtension:
+ if (count<5) hold[count]=ch;
+ count++;
+ if (count==hold[0]+1) {
+ disposePrevious(image);
+ disposal=Disposal((hold[1]>>2)&0x7);
+ //UNUSED: waitforuser=!!((hold[1]>>1)&0x1);
+ int delay=count>3 ? LM(hold[2], hold[3]) : 1;
+ // IE and mozilla use a minimum delay of 10. With the minimum delay of 10
+ // we are compatible to them and avoid huge loads on the app and xserver.
+ *nextFrameDelay = (delay < 2 ? 10 : delay) * 10;
+
+ bool havetrans=hold[1]&0x1;
+ trans_index = havetrans ? hold[4] : -1;
+
+ count=0;
+ state=SkipBlockSize;
+ }
+ break;
+ case SkipBlockSize:
+ expectcount=ch;
+ count=0;
+ if (expectcount) state=SkipBlock;
+ else state=Introducer;
+ break;
+ case SkipBlock:
+ count++;
+ if (count==expectcount) state=SkipBlockSize;
+ break;
+ case Done:
+ digress=true;
+ /* Netscape ignores the junk, so we do too.
+ length++; // Unget
+ state=Error; // More calls to this is an error
+ */
+ break;
+ case Error:
+ return -1; // Called again after done.
+ }
+ }
+ return initial-length;
+}
+
+void QGIFFormat::fillRect(QImage *image, int col, int row, int w, int h, QRgb color)
+{
+ if (w>0) {
+ for (int j=0; j<h; j++) {
+ QRgb *line = (QRgb*)image->scanLine(j+row);
+ for (int i=0; i<w; i++)
+ *(line+col+i) = color;
+ }
+ }
+}
+
+void QGIFFormat::nextY(QImage *image)
+{
+ int my;
+ switch (interlace) {
+ case 0: // Non-interlaced
+ // if (!out_of_bounds) {
+ // ### Changed: QRect(left, y, right - left + 1, 1);
+ // }
+ y++;
+ break;
+ case 1: {
+ int i;
+ my = qMin(7, bottom-y);
+ // Don't dup with transparency
+ if (trans_index < 0) {
+ for (i=1; i<=my; i++) {
+ memcpy(image->scanLine(y+i)+left*sizeof(QRgb), image->scanLine(y)+left*sizeof(QRgb),
+ (right-left+1)*sizeof(QRgb));
+ }
+ }
+
+ // if (!out_of_bounds) {
+ // ### Changed: QRect(left, y, right - left + 1, my + 1);
+ // }
+// if (!out_of_bounds)
+// qDebug("consumer->changed(QRect(%d, %d, %d, %d))", left, y, right-left+1, my+1);
+ y+=8;
+ if (y>bottom) {
+ interlace++; y=top+4;
+ if (y > bottom) { // for really broken GIFs with bottom < 5
+ interlace=2;
+ y = top + 2;
+ if (y > bottom) { // for really broken GIF with bottom < 3
+ interlace = 0;
+ y = top + 1;
+ }
+ }
+ }
+ } break;
+ case 2: {
+ int i;
+ my = qMin(3, bottom-y);
+ // Don't dup with transparency
+ if (trans_index < 0) {
+ for (i=1; i<=my; i++) {
+ memcpy(image->scanLine(y+i)+left*sizeof(QRgb), image->scanLine(y)+left*sizeof(QRgb),
+ (right-left+1)*sizeof(QRgb));
+ }
+ }
+
+ // if (!out_of_bounds) {
+ // ### Changed: QRect(left, y, right - left + 1, my + 1);
+ // }
+ y+=8;
+ if (y>bottom) {
+ interlace++; y=top+2;
+ // handle broken GIF with bottom < 3
+ if (y > bottom) {
+ interlace = 3;
+ y = top + 1;
+ }
+ }
+ } break;
+ case 3: {
+ int i;
+ my = qMin(1, bottom-y);
+ // Don't dup with transparency
+ if (trans_index < 0) {
+ for (i=1; i<=my; i++) {
+ memcpy(image->scanLine(y+i)+left*sizeof(QRgb), image->scanLine(y)+left*sizeof(QRgb),
+ (right-left+1)*sizeof(QRgb));
+ }
+ }
+ // if (!out_of_bounds) {
+ // ### Changed: QRect(left, y, right - left + 1, my + 1);
+ // }
+ y+=4;
+ if (y>bottom) { interlace++; y=top+1; }
+ } break;
+ case 4:
+ // if (!out_of_bounds) {
+ // ### Changed: QRect(left, y, right - left + 1, 1);
+ // }
+ y+=2;
+ }
+
+ // Consume bogus extra lines
+ if (y >= sheight) out_of_bounds=true; //y=bottom;
+}
+
+inline QRgb QGIFFormat::color(uchar index) const
+{
+ if (index == trans_index || index > ncols)
+ return Q_TRANSPARENT;
+
+ QRgb *map = lcmap ? localcmap : globalcmap;
+ return map ? map[index] : 0;
+}
+
+//-------------------------------------------------------------------------
+//-------------------------------------------------------------------------
+//-------------------------------------------------------------------------
+
+QGifHandler::QGifHandler()
+{
+ gifFormat = new QGIFFormat;
+ nextDelay = 0;
+ loopCnt = 0;
+ frameNumber = -1;
+ nextSize = QSize();
+}
+
+QGifHandler::~QGifHandler()
+{
+ delete gifFormat;
+}
+
+// Does partial decode if necessary, just to see if an image is coming
+
+bool QGifHandler::imageIsComing() const
+{
+ const int GifChunkSize = 4096;
+
+ while (!gifFormat->partialNewFrame) {
+ if (buffer.isEmpty()) {
+ buffer += device()->read(GifChunkSize);
+ if (buffer.isEmpty())
+ break;
+ }
+
+ int decoded = gifFormat->decode(&lastImage, (const uchar *)buffer.constData(), buffer.size(),
+ &nextDelay, &loopCnt, &nextSize);
+ if (decoded == -1)
+ break;
+ buffer.remove(0, decoded);
+ }
+ return gifFormat->partialNewFrame;
+}
+
+bool QGifHandler::canRead() const
+{
+ if (!nextDelay && canRead(device())) {
+ setFormat("gif");
+ return true;
+ }
+
+ return imageIsComing();
+}
+
+bool QGifHandler::canRead(QIODevice *device)
+{
+ if (!device) {
+ qWarning("QGifHandler::canRead() called with no device");
+ return false;
+ }
+
+ char head[6];
+ if (device->peek(head, sizeof(head)) == sizeof(head))
+ return qstrncmp(head, "GIF87a", 6) == 0
+ || qstrncmp(head, "GIF89a", 6) == 0;
+ return false;
+}
+
+bool QGifHandler::read(QImage *image)
+{
+ const int GifChunkSize = 4096;
+
+ while (!gifFormat->newFrame) {
+ if (buffer.isEmpty()) {
+ buffer += device()->read(GifChunkSize);
+ if (buffer.isEmpty())
+ break;
+ }
+
+ int decoded = gifFormat->decode(&lastImage, (const uchar *)buffer.constData(), buffer.size(),
+ &nextDelay, &loopCnt, &nextSize);
+ if (decoded == -1)
+ break;
+ buffer.remove(0, decoded);
+ }
+ if (gifFormat->newFrame || (gifFormat->partialNewFrame && device()->atEnd())) {
+ *image = lastImage;
+ ++frameNumber;
+ gifFormat->newFrame = false;
+ gifFormat->partialNewFrame = false;
+ return true;
+ }
+
+ return false;
+}
+
+bool QGifHandler::write(const QImage &image)
+{
+ Q_UNUSED(image);
+ return false;
+}
+
+bool QGifHandler::supportsOption(ImageOption option) const
+{
+ return option == Size
+ || option == Animation;
+}
+
+QVariant QGifHandler::option(ImageOption option) const
+{
+ if (option == Size) {
+ if (imageIsComing())
+ return nextSize;
+ } else if (option == Animation) {
+ return true;
+ }
+ return QVariant();
+}
+
+void QGifHandler::setOption(ImageOption option, const QVariant &value)
+{
+ Q_UNUSED(option);
+ Q_UNUSED(value);
+}
+
+int QGifHandler::nextImageDelay() const
+{
+ return nextDelay;
+}
+
+int QGifHandler::imageCount() const
+{
+ return 0; // Don't know
+}
+
+int QGifHandler::loopCount() const
+{
+ return loopCnt-1; // In GIF, loop count is iteration count, so subtract one
+}
+
+int QGifHandler::currentImageNumber() const
+{
+ return frameNumber;
+}
+
+QByteArray QGifHandler::name() const
+{
+ return "gif";
+}
+
+QT_END_NAMESPACE