QBmpHandler Class Reference

#include <qbmphandler_p.h>

Inheritance diagram for QBmpHandler:

Public Functions
bool	canRead () const
	Returns true if an image can be read from the device (i. More...
QByteArray	name () const
	Use format() instead. More...
QVariant	option (ImageOption option) const
	Returns the value assigned to option as a QVariant. More...
	QBmpHandler ()
bool	read (QImage *image)
	Read an image from the device, and stores it in image. More...
void	setOption (ImageOption option, const QVariant &value)
	Sets the option option with the value value. More...
bool	supportsOption (ImageOption option) const
	Returns true if the QImageIOHandler supports the option option; otherwise returns false. More...
bool	write (const QImage &image)
	Writes the image image to the assigned device. More...
Public Functions inherited from QImageIOHandler
virtual int	currentImageNumber () const
	For image formats that support animation, this function returns the sequence number of the current image in the animation. More...
virtual QRect	currentImageRect () const
	Returns the rect of the current image. More...
QIODevice *	device () const
	Returns the device currently assigned to the QImageIOHandler. More...
QByteArray	format () const
	Returns the format that is currently assigned to QImageIOHandler. More...
virtual int	imageCount () const
	For image formats that support animation, this function returns the number of images in the animation. More...
virtual bool	jumpToImage (int imageNumber)
	For image formats that support animation, this function jumps to the image whose sequence number is imageNumber. More...
virtual bool	jumpToNextImage ()
	For image formats that support animation, this function jumps to the next image. More...
virtual int	loopCount () const
	For image formats that support animation, this function returns the number of times the animation should loop. More...
virtual int	nextImageDelay () const
	For image formats that support animation, this function returns the number of milliseconds to wait until reading the next image. More...
	QImageIOHandler ()
	Constructs a QImageIOHandler object. More...
void	setDevice (QIODevice *device)
	Sets the device of the QImageIOHandler to device. More...
void	setFormat (const QByteArray &format)
	Sets the format of the QImageIOHandler to format. More...
void	setFormat (const QByteArray &format) const
	Sets the format of the QImageIOHandler to format. More...
virtual	~QImageIOHandler ()
	Destructs the QImageIOHandler object. More...

Static Public Functions
static bool	canRead (QIODevice *device)

Private Types
enum	State { Ready, ReadHeader, Error }

Private Functions
bool	readHeader ()

Properties
BMP_FILEHDR	fileHeader
BMP_INFOHDR	infoHeader
int	startpos
State	state

Additional Inherited Members
Public Types inherited from QImageIOHandler
enum	ImageOption {   Size, ClipRect, Description, ScaledClipRect,   ScaledSize, CompressionRatio, Gamma, Quality,   Name, SubType, IncrementalReading, Endianness,   Animation, BackgroundColor, ImageFormat }
	This enum describes the different options supported by QImageIOHandler. More...
Protected Functions inherited from QImageIOHandler
	QImageIOHandler (QImageIOHandlerPrivate &dd)
	Constructs a QImageIOHandler object, using the private member dd. More...
Protected Variables inherited from QImageIOHandler
QScopedPointer< QImageIOHandlerPrivate >	d_ptr

Detailed Description

Definition at line 84 of file qbmphandler_p.h.

Enumerations

State

enum QBmpHandler::State

private

Enumerator
Ready
ReadHeader
Error

Definition at line 102 of file qbmphandler_p.h.

               {
        Ready,
        ReadHeader,
        Error
    };

Constructors and Destructors

QBmpHandler()

QBmpHandler::QBmpHandler

(

)

Definition at line 693 of file qbmphandler.cpp.

    : state(Ready)
{
}

Functions

canRead() [1/2]

bool QBmpHandler::canRead ( ) const

virtual

Returns true if an image can be read from the device (i.

e., the image format is supported, the device can be read from and the initial header information suggests that the image can be read); otherwise returns false.

When reimplementing canRead(), make sure that the I/O device (device()) is left in its original state (e.g., by using peek() rather than read()).

See also

read(), QIODevice::peek()

Implements QImageIOHandler.

Definition at line 721 of file qbmphandler.cpp.

Referenced by createReadHandlerHelper().

{
    if (state == Ready && !canRead(device()))
        return false;

    if (state != Error) {
        setFormat("bmp");
        return true;
    }

    return false;
}

canRead() [2/2]

bool QBmpHandler::canRead ( QIODevice *  device )

static

Definition at line 734 of file qbmphandler.cpp.

{
    if (!device) {
        qWarning("QBmpHandler::canRead() called with 0 pointer");
        return false;
    }

    char head[2];
    if (device->peek(head, sizeof(head)) != sizeof(head))
        return false;

    return (qstrncmp(head, "BM", 2) == 0);
}

name()

QByteArray QBmpHandler::name ( ) const

virtual

Use format() instead.

Reimplemented from QImageIOHandler.

Definition at line 874 of file qbmphandler.cpp.

{
    return "bmp";
}

option()

QVariant QBmpHandler::option ( ImageOption  option ) const

virtual

Returns the value assigned to option as a QVariant.

The type of the value depends on the option. For example, option(Size) returns a QSize variant.

See also

setOption(), supportsOption()

Reimplemented from QImageIOHandler.

Definition at line 836 of file qbmphandler.cpp.

{
    if (option == Size) {
        if (state == Error)
            return QVariant();
        if (state == Ready && !const_cast<QBmpHandler*>(this)->readHeader())
            return QVariant();
        return QSize(infoHeader.biWidth, infoHeader.biHeight);
    } else if (option == ImageFormat) {
        if (state == Error)
            return QVariant();
        if (state == Ready && !const_cast<QBmpHandler*>(this)->readHeader())
            return QVariant();
        QImage::Format format;
        switch (infoHeader.biBitCount) {
            case 32:
            case 24:
            case 16:
                format = QImage::Format_RGB32;
                break;
            case 8:
            case 4:
                format = QImage::Format_Indexed8;
                break;
            default:
                format = QImage::Format_Mono;
            }
        return format;
    }
    return QVariant();
}

read()

bool QBmpHandler::read ( QImage *  image )

virtual

Read an image from the device, and stores it in image.

Returns true if the image is successfully read; otherwise returns false.

For image formats that support incremental loading, and for animation formats, the image handler can assume that image points to the previous frame.

See also

canRead()

Implements QImageIOHandler.

Definition at line 748 of file qbmphandler.cpp.

{
    if (state == Error)
        return false;

    if (!image) {
        qWarning("QBmpHandler::read: cannot read into null pointer");
        return false;
    }

    if (state == Ready && !readHeader()) {
        state = Error;
        return false;
    }

    QIODevice *d = device();
    QDataStream s(d);

    // Intel byte order
    s.setByteOrder(QDataStream::LittleEndian);

    // read image
    if (!read_dib_body(s, infoHeader, fileHeader.bfOffBits, startpos, *image))
        return false;

    state = Ready;
    return true;
}

readHeader()

bool QBmpHandler::readHeader ( )

private

Definition at line 698 of file qbmphandler.cpp.

Referenced by option(), and read().

{
    state = Error;

    QIODevice *d = device();
    QDataStream s(d);
    startpos = d->pos();

    // Intel byte order
    s.setByteOrder(QDataStream::LittleEndian);

    // read BMP file header
    if (!read_dib_fileheader(s, fileHeader))
        return false;

    // read BMP info header
    if (!read_dib_infoheader(s, infoHeader))
        return false;

    state = ReadHeader;
    return true;
}

setOption()

void QBmpHandler::setOption ( ImageOption  option, const QVariant &  value  )

virtual

Sets the option option with the value value.

See also

option(), ImageOption

Reimplemented from QImageIOHandler.

Definition at line 868 of file qbmphandler.cpp.

{
    Q_UNUSED(option);
    Q_UNUSED(value);
}

supportsOption()

bool QBmpHandler::supportsOption ( ImageOption  option ) const

virtual

Returns true if the QImageIOHandler supports the option option; otherwise returns false.

For example, if the QImageIOHandler supports the Size option, supportsOption(Size) must return true.

See also

setOption(), option()

Reimplemented from QImageIOHandler.

Definition at line 830 of file qbmphandler.cpp.

{
    return option == Size
            || option == ImageFormat;
}

write()

bool QBmpHandler::write ( const QImage &  image )

virtual

Writes the image image to the assigned device.

Returns true on success; otherwise returns false.

The default implementation does nothing, and simply returns false.

Reimplemented from QImageIOHandler.

Definition at line 777 of file qbmphandler.cpp.

{
    QImage image;
    switch (img.format()) {
    case QImage::Format_ARGB8565_Premultiplied:
    case QImage::Format_ARGB8555_Premultiplied:
    case QImage::Format_ARGB6666_Premultiplied:
    case QImage::Format_ARGB4444_Premultiplied:
        image = img.convertToFormat(QImage::Format_ARGB32);
        break;
    case QImage::Format_RGB16:
    case QImage::Format_RGB888:
    case QImage::Format_RGB666:
    case QImage::Format_RGB555:
    case QImage::Format_RGB444:
        image = img.convertToFormat(QImage::Format_RGB32);
        break;
    default:
        image = img;
    }

    QIODevice *d = device();
    QDataStream s(d);
    BMP_FILEHDR bf;
    int bpl_bmp;
    int bpl = image.bytesPerLine();

    // Code partially repeated in qt_write_dib
    if (image.depth() == 8 && image.colorCount() <= 16) {
        bpl_bmp = (((bpl+1)/2+3)/4)*4;
    } else if (image.depth() == 32) {
        bpl_bmp = ((image.width()*24+31)/32)*4;
    } else {
        bpl_bmp = bpl;
    }

    // Intel byte order
    s.setByteOrder(QDataStream::LittleEndian);

    // build file header
    memcpy(bf.bfType, "BM", 2);

    // write file header
    bf.bfReserved1 = 0;
    bf.bfReserved2 = 0;
    bf.bfOffBits = BMP_FILEHDR_SIZE + BMP_WIN + image.colorCount() * 4;
    bf.bfSize = bf.bfOffBits + bpl_bmp*image.height();
    s << bf;

    // write image
    return qt_write_dib(s, image);
}

Properties

fileHeader

BMP_FILEHDR QBmpHandler::fileHeader

private

Definition at line 108 of file qbmphandler_p.h.

Referenced by read(), and readHeader().

infoHeader

BMP_INFOHDR QBmpHandler::infoHeader

private

Definition at line 109 of file qbmphandler_p.h.

Referenced by option(), read(), and readHeader().

startpos

int QBmpHandler::startpos

private

Definition at line 110 of file qbmphandler_p.h.

Referenced by read(), and readHeader().

state

State QBmpHandler::state

private

Definition at line 107 of file qbmphandler_p.h.

Referenced by canRead(), option(), read(), and readHeader().

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The documentation for this class was generated from the following files:

• /src/gui/image/qbmphandler_p.h
• /src/gui/image/qbmphandler.cpp