QPpmHandler Class Reference

#include <qppmhandler_p.h>

Inheritance diagram for QPpmHandler:

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...
	QPpmHandler ()
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, QByteArray *subType=0)

Private Types
enum	State { Ready, ReadHeader, Error }

Private Functions
bool	readHeader ()

Properties
int	height
int	mcc
State	state
QByteArray	subType
char	type
int	width

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 63 of file qppmhandler_p.h.

Enumerations

State

enum QPpmHandler::State

private

Enumerator
Ready
ReadHeader
Error

Definition at line 81 of file qppmhandler_p.h.

               {
        Ready,
        ReadHeader,
        Error
    };

Constructors and Destructors

QPpmHandler()

QPpmHandler::QPpmHandler

(

)

Definition at line 396 of file qppmhandler.cpp.

    : state(Ready)
{
}

Functions

canRead() [1/2]

bool QPpmHandler::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 410 of file qppmhandler.cpp.

Referenced by createReadHandlerHelper().

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

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

    return false;
}

canRead() [2/2]

bool QPpmHandler::canRead ( QIODevice *  device, QByteArray *  subType = 0  )

static

Definition at line 423 of file qppmhandler.cpp.

{
    if (!device) {
        qWarning("QPpmHandler::canRead() called with no device");
        return false;
    }

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

    if (head[0] != 'P')
        return false;

    if (head[1] == '1' || head[1] == '4') {
        if (subType)
            *subType = "pbm";
    } else if (head[1] == '2' || head[1] == '5') {
        if (subType)
            *subType = "pgm";
    } else if (head[1] == '3' || head[1] == '6') {
        if (subType)
            *subType = "ppm";
    } else {
        return false;
    }
    return true;
}

name()

QByteArray QPpmHandler::name ( ) const

virtual

Use format() instead.

Reimplemented from QImageIOHandler.

Definition at line 526 of file qppmhandler.cpp.

{
    return subType.isEmpty() ? QByteArray("ppm") : subType;
}

option()

QVariant QPpmHandler::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 483 of file qppmhandler.cpp.

{
    if (option == SubType) {
        return subType;
    } else if (option == Size) {
        if (state == Error)
            return QVariant();
        if (state == Ready && !const_cast<QPpmHandler*>(this)->readHeader())
            return QVariant();
        return QSize(width, height);
    } else if (option == ImageFormat) {
        if (state == Error)
            return QVariant();
        if (state == Ready && !const_cast<QPpmHandler*>(this)->readHeader())
            return QVariant();
        QImage::Format format = QImage::Format_Invalid;
        switch (type) {
            case '1':                                // ascii PBM
            case '4':                                // raw PBM
            format = QImage::Format_Mono;
            break;
            case '2':                                // ascii PGM
            case '5':                                // raw PGM
                format = QImage::Format_Indexed8;
                break;
            case '3':                                // ascii PPM
            case '6':                                // raw PPM
                format = QImage::Format_RGB32;
                break;
            default:
                break;
        }
        return format;
    }
    return QVariant();
}

read()

bool QPpmHandler::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 452 of file qppmhandler.cpp.

{
    if (state == Error)
        return false;

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

    if (!read_pbm_body(device(), type, width, height, mcc, image)) {
        state = Error;
        return false;
    }

    state = Ready;
    return true;
}

readHeader()

bool QPpmHandler::readHeader ( )

private

Definition at line 401 of file qppmhandler.cpp.

Referenced by option(), and read().

{
    state = Error;
    if (!read_pbm_header(device(), type, width, height, mcc))
        return false;
    state = ReadHeader;
    return true;
}

setOption()

void QPpmHandler::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 520 of file qppmhandler.cpp.

{
    if (option == SubType)
        subType = value.toByteArray().toLower();
}

supportsOption()

bool QPpmHandler::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 476 of file qppmhandler.cpp.

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

write()

bool QPpmHandler::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 471 of file qppmhandler.cpp.

{
    return write_pbm_image(device(), image, subType);
}

Properties

height

int QPpmHandler::height

private

Definition at line 89 of file qppmhandler_p.h.

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

mcc

int QPpmHandler::mcc

private

Definition at line 90 of file qppmhandler_p.h.

Referenced by read(), and readHeader().

state

State QPpmHandler::state

private

Definition at line 86 of file qppmhandler_p.h.

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

subType

QByteArray QPpmHandler::subType

mutableprivate

Definition at line 91 of file qppmhandler_p.h.

Referenced by canRead(), name(), option(), setOption(), and write().

type

char QPpmHandler::type

private

Definition at line 87 of file qppmhandler_p.h.

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

width

int QPpmHandler::width

private

Definition at line 88 of file qppmhandler_p.h.

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

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

• /src/gui/image/qppmhandler_p.h
• /src/gui/image/qppmhandler.cpp