source: trunk/src/kernel/qbitmap.cpp@ 184

/****************************************************************************
** $Id: qbitmap.cpp 2 2005-11-16 15:49:26Z dmik $
**
** Implementation of QBitmap class
**
** Created : 941020
**
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#include "qbitmap.h"
#include "qimage.h"


/*!
    \class QBitmap qbitmap.h
    \brief The QBitmap class provides monochrome (1-bit depth) pixmaps.

    \ingroup graphics
    \ingroup images
    \ingroup shared

    The QBitmap class is a monochrome off-screen paint device used
    mainly for creating custom QCursor and QBrush objects, in
    QPixmap::setMask() and for QRegion.

    A QBitmap is a QPixmap with a \link QPixmap::depth() depth\endlink
    of 1. If a pixmap with a depth greater than 1 is assigned to a
    bitmap, the bitmap will be dithered automatically. A QBitmap is
    guaranteed to always have the depth 1, unless it is
    QPixmap::isNull() which has depth 0.

    When drawing in a QBitmap (or QPixmap with depth 1), we recommend
    using the  QColor objects \c Qt::color0 and \c Qt::color1.
    Painting with \c color0 sets the bitmap bits to 0, and painting
    with \c color1 sets the bits to 1. For a bitmap, 0-bits indicate
    background (or transparent) and 1-bits indicate foreground (or
    opaque). Using the \c black and \c white QColor objects make no
    sense because the QColor::pixel() value is not necessarily 0 for
    black and 1 for white.

    The QBitmap can be transformed (translated, scaled, sheared or
    rotated) using xForm().

    Just like the QPixmap class, QBitmap is optimized by the use of
    \link shclass.html implicit sharing\endlink, so it is very
    efficient to pass QBitmap objects as arguments.

    \sa QPixmap, QPainter::drawPixmap(), bitBlt(), \link shclass.html Shared Classes\endlink
*/


/*!
    Constructs a null bitmap.

    \sa QPixmap::isNull()
*/

QBitmap::QBitmap()
{
    data->bitmap = TRUE;
}


/*!
    Constructs a bitmap with width \a w and height \a h.

    The contents of the bitmap is uninitialized if \a clear is FALSE;
    otherwise it is filled with pixel value 0 (the QColor \c
    Qt::color0).

    The optional \a optimization argument specifies the optimization
    setting for the bitmap. The default optimization should be used in
    most cases. Games and other pixmap-intensive applications may
    benefit from setting this argument; see \l{QPixmap::Optimization}.

    \sa QPixmap::setOptimization(), QPixmap::setDefaultOptimization()
*/

QBitmap::QBitmap( int w, int h, bool clear,
                  QPixmap::Optimization optimization )
    : QPixmap( w, h, 1, optimization )
{
    data->bitmap = TRUE;
    if ( clear )
        fill( Qt::color0 );
}


/*!
    \overload

    Constructs a bitmap with the size \a size.

    The contents of the bitmap is uninitialized if \a clear is FALSE;
    otherwise it is filled with pixel value 0 (the QColor \c
    Qt::color0).

    The optional \a optimization argument specifies the optimization
    setting for the bitmap. The default optimization should be used in
    most cases. Games and other pixmap-intensive applications may
    benefit from setting this argument; see \l{QPixmap::Optimization}.
*/

QBitmap::QBitmap( const QSize &size, bool clear,
                  QPixmap::Optimization optimization )
    : QPixmap( size, 1, optimization )
{
    data->bitmap = TRUE;
    if ( clear )
        fill( Qt::color0 );
}


/*!
    Constructs a bitmap with width \a w and height \a h and sets the
    contents to \a bits.

    The \a isXbitmap flag should be TRUE if \a bits was generated by
    the X11 bitmap program. The X bitmap bit order is little endian.
    The QImage documentation discusses bit order of monochrome images.

    Example (creates an arrow bitmap):
    \code
        uchar arrow_bits[] = { 0x3f, 0x1f, 0x0f, 0x1f, 0x3b, 0x71, 0xe0, 0xc0 };
        QBitmap bm( 8, 8, arrow_bits, TRUE );
    \endcode
*/

QBitmap::QBitmap( int w, int h, const uchar *bits, bool isXbitmap )
    : QPixmap( w, h, bits, isXbitmap )
{
    data->bitmap = TRUE;
}


/*!
    \overload

    Constructs a bitmap with the size \a size and sets the contents to
    \a bits.

    The \a isXbitmap flag should be TRUE if \a bits was generated by
    the X11 bitmap program. The X bitmap bit order is little endian.
    The QImage documentation discusses bit order of monochrome images.
*/

QBitmap::QBitmap( const QSize &size, const uchar *bits, bool isXbitmap )
    : QPixmap( size.width(), size.height(), bits, isXbitmap )
{
    data->bitmap = TRUE;
}


/*!
    Constructs a bitmap that is a copy of \a bitmap.
*/

QBitmap::QBitmap( const QBitmap &bitmap )
    : QPixmap( bitmap )
{
}

#ifndef QT_NO_IMAGEIO
/*!
    Constructs a bitmap from the file \a fileName. If the file does
    not exist or is of an unknown format, the bitmap becomes a null
    bitmap.

    The parameters \a fileName and \a format are passed on to
    QPixmap::load(). Dithering will be performed if the file format
    uses more than 1 bit per pixel.

    \sa QPixmap::isNull(), QPixmap::load(), QPixmap::loadFromData(),
    QPixmap::save(), QPixmap::imageFormat()
*/

QBitmap::QBitmap( const QString& fileName, const char *format )
    : QPixmap() // Will set bitmap to null bitmap, explicit call for clarity
{
    data->bitmap = TRUE;
    load( fileName, format, Mono );
}
#endif

/*!
    Assigns the bitmap \a bitmap to this bitmap and returns a
    reference to this bitmap.
*/

QBitmap &QBitmap::operator=( const QBitmap &bitmap )
{
    QPixmap::operator=(bitmap);
#if defined(QT_CHECK_STATE)
    Q_ASSERT( data->bitmap );
#endif
    return *this;
}


/*!
    \overload

    Assigns the pixmap \a pixmap to this bitmap and returns a
    reference to this bitmap.

    Dithering will be performed if the pixmap has a QPixmap::depth()
    greater than 1.
*/

QBitmap &QBitmap::operator=( const QPixmap &pixmap )
{
    if ( pixmap.isNull() ) {                    // a null pixmap
        QBitmap bm( 0, 0, FALSE, pixmap.optimization() );
        QBitmap::operator=(bm);
    } else if ( pixmap.depth() == 1 ) {         // 1-bit pixmap
        if ( pixmap.isQBitmap() ) {             // another QBitmap
            QPixmap::operator=(pixmap);         // shallow assignment
        } else {                                // not a QBitmap, but 1-bit
            QBitmap bm( pixmap.size(), FALSE, pixmap.optimization() );
            bitBlt( &bm, 0,0, &pixmap, 0,0,pixmap.width(),pixmap.height() );
            QBitmap::operator=(bm);
        }
    } else {                                    // n-bit depth pixmap
        QImage image;
        image = pixmap;                         // convert pixmap to image
        *this = image;                          // will dither image
    }
    return *this;
}


/*!
    \overload

    Converts the image \a image to a bitmap and assigns the result to
    this bitmap. Returns a reference to the bitmap.

    Dithering will be performed if the image has a QImage::depth()
    greater than 1.
*/

QBitmap &QBitmap::operator=( const QImage &image )
{
    convertFromImage( image );
    return *this;
}


#ifndef QT_NO_PIXMAP_TRANSFORMATION
/*!
    Returns a transformed copy of this bitmap by using \a matrix.

    This function does exactly the same as QPixmap::xForm(), except
    that it returns a QBitmap instead of a QPixmap.

    \sa QPixmap::xForm()
*/

QBitmap QBitmap::xForm( const QWMatrix &matrix ) const
{
    QPixmap pm = QPixmap::xForm( matrix );
    QBitmap bm;
    // Here we fake the pixmap to think it's a QBitmap. With this trick,
    // the QBitmap::operator=(const QPixmap&) will just refer the
    // pm.data and we do not need to perform a bitBlt.
    pm.data->bitmap = TRUE;
    bm = pm;
    return bm;
}
#endif // QT_NO_TRANSFORMATIONS