qasyncimageio.h

/****************************************************************************
** $Id: qasyncimageio.h,v 1.18.2.1 1998/08/19 16:02:28 agulbra Exp $
**
**                    ***   INTERNAL HEADER FILE   ***
**
**              This file is NOT a part of the Qt interface!
**
** Definition of asynchronous image/movie loading classes
**
** Created : 970617
**
** Copyright (C) 1992-1998 Troll Tech AS.  All rights reserved.
**
** This file is part of Qt Free Edition, version 1.42.
**
** See the file LICENSE included in the distribution for the usage
** and distribution terms, or http://www.troll.no/free-license.html.
**
** IMPORTANT NOTE: You may NOT copy this file or any part of it into
** your own programs or libraries.
**
** Please see http://www.troll.no/pricing.html for information about 
** Qt Professional Edition, which is this same library but with a
** license which allows creation of commercial/proprietary software.
**
*****************************************************************************/

#ifndef QASYNCIMAGEIO_H
#define QASYNCIMAGEIO_H

#ifndef QT_H
#include "qimage.h"
#endif // QT_H



class Q_EXPORT QImageConsumer {
public:
    virtual void changed(const QRect&)=0;
    virtual void end()=0;
    virtual void frameDone()=0;
    virtual void setLooping(int)=0;
    virtual void setFramePeriod(int)=0;
    virtual void setSize(int, int)=0;
};

class Q_EXPORT QImageFormat {
public:
    virtual ~QImageFormat();
    virtual int decode(QImage& img, QImageConsumer* consumer,
            const uchar* buffer, int length)=0;
};

class Q_EXPORT QImageFormatType {
public:
    virtual ~QImageFormatType();
    virtual QImageFormat* decoderFor(const uchar* buffer, int length)=0;
    virtual const char* formatName() const=0;
protected:
    QImageFormatType();
};

struct QImageDecoderPrivate;

class Q_EXPORT QImageDecoder {
public:
    QImageDecoder(QImageConsumer* c);
    ~QImageDecoder();

    const QImage& image() { return img; }
    int decode(const uchar* buffer, int length);

    static const char* formatName(const uchar* buffer, int length);

    static QStrList inputFormats();
    static void registerDecoderFactory(QImageFormatType*);
    static void unregisterDecoderFactory(QImageFormatType*);

private:
    QImageFormat* actual_decoder;
    QImageConsumer* consumer;
    QImage img;
    QImageDecoderPrivate *d;
};


class Q_EXPORT QGIFFormat : public QImageFormat {
public:
    QGIFFormat();
    virtual ~QGIFFormat();

    int decode(QImage& img, QImageConsumer* consumer,
            const uchar* buffer, int length);

private:
    void fillRect(QImage&, int x, int y, int w, int h, uchar col);

    // GIF specific stuff
    QRgb* globalcmap;
    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 ncols;
    int lzwsize;
    bool lcmap;
    int swidth, sheight;
    int left, top, right, bottom;
    enum Disposal { NoDisposal, DoNotChange, RestoreBackground, RestoreImage };
    Disposal disposal;
    bool disposed;
    int trans;
    bool preserve_trans;
    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& img, QImageConsumer* consumer);
    void disposePrevious( QImage& img, QImageConsumer* consumer );
};

class Q_EXPORT QGIFFormatType : public QImageFormatType
{
    QImageFormat* decoderFor(const uchar* buffer, int length);
    const char* formatName() const;
};


#endif // QASYNCIMAGEIO_H