Sophie: libqt3-devel-3.0.2-2mdk i586

libqt3-devel-3.0.2-2mdk.i586.rpm

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<title>Display Images in Qt-supported Formats</title>
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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Display Images in Qt-supported Formats</h1>

 

<p> This example displays images which are in any format
supported by Qt.  Combining this with the Qt ImageIO
Extension adds PNG image support to your browser.
It demonstrates the use of the <a href="qnpinstance.html#streamAsFile">QNPInstance::streamAsFile</a>()
function.
<p> To build the example, you must first build the <a href="nsplugin.html">Qt Netscape Plugin Extension</a> library. Then type <tt>make</tt> in
<tt>extensions/nsplugin/examples/qtimage/</tt> and copy the resulting <tt>qtimage.so</tt> or <tt>npqtimage.dll</tt> to the Plugins directory of your web
browser.
<p> <embed src=&#92;"pnglogo.png&#92;" width=256 height=192>
<p> This plugin displays a <a href="http://www.libpng.org/pub/png/">PNG format</a> image.
<p> New image format can be supported by adding new image I/O handlers
to the Qt library (see QImage::defineIOHandler), thus providing the
functionality in both applications and WWW plugins from the same
code.
<p> This plugin supports transparency and scaling of the image, just
like GIFs in most web browsers.
<p> <embed align=middle src="test.png" width=182 height=138>
<embed align=middle src="test.png" width=137 height=104>
<embed align=middle src="test.png" width=91 height=69>
<embed align=middle src="test.png" width=46 height=35>
<p> Implementation:
<p> <pre>// Qt stuff
#include "qnp.h"
#include &lt;<a href="qpainter-h.html">qpainter.h</a>&gt;
#include &lt;<a href="qimage-h.html">qimage.h</a>&gt;
#include &lt;<a href="qpixmap-h.html">qpixmap.h</a>&gt;
#include &lt;<a href="qmessagebox-h.html">qmessagebox.h</a>&gt;
#include &lt;<a href="qpopupmenu-h.html">qpopupmenu.h</a>&gt;
#include "qpngio.h"

#include &lt;math.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;stdio.h&gt;

class ImageView : public <a href="qnpwidget.html">QNPWidget</a> {
public:
    ImageView()
    {
        popup = new <a href="qpopupmenu.html">QPopupMenu</a>;
        popup-&gt;<a href="qmenudata.html#insertItem">insertItem</a>("Left as");
        popup-&gt;<a href="qmenudata.html#insertItem">insertItem</a>("An exercise");
        popup-&gt;<a href="qmenudata.html#insertItem">insertItem</a>("For the");
        popup-&gt;<a href="qmenudata.html#insertItem">insertItem</a>("Reader!");
    }

    void paintEvent(QPaintEvent* event)
    {
        <a href="qpainter.html">QPainter</a> p(this);
<a name="x2442"></a>        p.<a href="qpainter.html#setClipRect">setClipRect</a>(event-&gt;rect());

<a name="x2445"></a>        if ( pm.<a href="qpixmap.html#size">size</a>() == size() ) {
<a name="x2441"></a>            p.<a href="qpainter.html#drawPixmap">drawPixmap</a>(0,0,pm);
        } else {
            if ( pmScaled.<a href="qpixmap.html#size">size</a>() != size() ) {
                <a href="qwmatrix.html">QWMatrix</a> m;
<a name="x2449"></a><a name="x2446"></a>                m.<a href="qwmatrix.html#scale">scale</a>((double)width()/pm.<a href="qpixmap.html#width">width</a>(),
<a name="x2444"></a>                        (double)height()/pm.<a href="qpixmap.html#height">height</a>());
<a name="x2447"></a>                pmScaled = pm.<a href="qpixmap.html#xForm">xForm</a>(m);
            }
            p.<a href="qpainter.html#drawPixmap">drawPixmap</a>(0,0,pmScaled);
        }
    }

    void mousePressEvent(QMouseEvent* e)
    {
<a name="x2448"></a>        popup-&gt;<a href="qpopupmenu.html#popup">popup</a>(mapToGlobal(e-&gt;pos()));
    }

    void showImage(const <a href="qimage.html">QImage</a>&amp; image)
    {
<a name="x2443"></a>        pm.<a href="qpixmap.html#convertFromImage">convertFromImage</a>(image, QPixmap::Color);
        repaint( FALSE );
    }

private:
    <a href="qpixmap.html">QPixmap</a> pm;
    <a href="qpixmap.html">QPixmap</a> pmScaled;
    <a href="qpopupmenu.html">QPopupMenu</a>* popup;
};

class ImageLoader : public <a href="qnpinstance.html">QNPInstance</a> {
    ImageView* iv;
    <a href="qimage.html">QImage</a> image;

public:
    ImageLoader() : iv(0)
    {
    }

    <a href="qnpwidget.html">QNPWidget</a>* newWindow()
    {
        iv = new ImageView;
        imageToIV();
        return iv;
    }

    void imageToIV()
    {
<a name="x2438"></a>        if (!iv || image.<a href="qimage.html#isNull">isNull</a>()) return;

        iv-&gt;showImage(image);
<a name="x2439"></a>        image.<a href="qimage.html#reset">reset</a>();
    }

    bool newStreamCreated(QNPStream*, StreamMode&amp; smode)
    {
        smode = AsFileOnly;
        return TRUE;
    }

    void streamAsFile(QNPStream*, const char* fname)
    {
        //qInitPngIO();

        image = QImage(fname);
        if ( image.<a href="qimage.html#isNull">isNull</a>() )
            fprintf(stderr, "Could not convert file: %s\n", fname);
        imageToIV();
    }
};

class ImagePlugin : public <a href="qnplugin.html">QNPlugin</a> {

public:
    ImagePlugin()
    {
    }

    <a href="qnpinstance.html">QNPInstance</a>* newInstance()
    {
        return new ImageLoader;
    }

    const char* getMIMEDescription() const
    {
        return "image/x-png:png:PNG Image;"
               "image/png:png:PNG Image;"
               "image/x-portable-bitmap:pbm:PBM Image;"
               "image/x-portable-graymap:pgm:PGM Image;"
               "image/x-portable-pixmap:ppm:PPM Image;"
               "image/bmp:bmp:BMP Image;"
               "image/x-ms-bmp:bmp:BMP Image;"
               "image/x-xpixmap:xpm:XPM Image;"
               "image/xpm:xpm:XPM Image";
    }

    const char * getPluginNameString() const
    {
        return "Qt-based Image Plugin";
    }

    const char * getPluginDescriptionString() const
    {
        return "Supports all image formats supported by Qt";
    }
};

QNPlugin* QNPlugin::create()
{
    return new ImagePlugin;
}
</pre>

<p>See also <a href="nsplugin-examples.html">LiveConnect Examples</a>.

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