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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Qt Toolkit - qtimage/qtimage.cpp example file</title><style type="text/css"><!--h3.fn,span.fn { margin-left: 1cm; text-indent: -1cm; }a:link { color: #004faf; text-decoration: none }a:visited { color: #672967; text-decoration: none }body { background: white; color: black; }--></style></head><body bgcolor="#ffffff"><table width="100%"><tr><td><a href="index.html"><img width="100" height="100" src="qtlogo.png"alt="Home" border="0"><img width="100"height="100" src="face.png" alt="Home" border="0"></a><td valign="top"><div align="right"><img src="dochead.png" width="472" height="27"><br><a href="classes.html"><b>Classes</b></a>- <a href="annotated.html">Annotated</a>- <a href="hierarchy.html">Tree</a>- <a href="functions.html">Functions</a>- <a href="index.html">Home</a>- <a href="topicals.html"><b>Structure</b> <font face="Arial,Helvetica,Geneva,Swiss,SunSans-Regular" align="center" size=32>Qte</font></a></div></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 QNPInstance::streamAsFile() 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 WWW browser. <p><table><tr><td valign=top><EMBED src=pnglogo.png WIDTH=256 HEIGHT=192><td valign=top> This plugin displays a <a href=http://www.cdrom.com/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.</table> <p>This plugin supports transparency and scaling of the image, just likeGIFs in most WWW browsers.<br><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><pre>// Qt stuff#include "<a name="qnp.h"></a><a href="qnp-h.html">qnp.h</a>"#include <<a name="qpainter.h"></a><a href="qpainter-h.html">qpainter.h</a>>#include <<a name="qimage.h"></a><a href="qimage-h.html">qimage.h</a>>#include <<a name="qpixmap.h"></a><a href="qpixmap-h.html">qpixmap.h</a>>#include <<a name="qmessagebox.h"></a><a href="qmessagebox-h.html">qmessagebox.h</a>>#include <<a name="qpopupmenu.h"></a><a href="qpopupmenu-h.html">qpopupmenu.h</a>>#include "<a name="qpngio.h"></a><a href="qpngio-h.html">qpngio.h</a>"#include <math.h>#include <stdlib.h>#include <stdio.h>class ImageView : public QNPWidget {public: ImageView() { popup = new <a name="QPopupMenu"></a><a href="qpopupmenu.html">QPopupMenu</a>; popup-><a name="insertItem"></a><a href="qmenudata.html#deddb9">insertItem</a>("Left as"); popup-><a href="qmenudata.html#deddb9">insertItem</a>("An exercise"); popup-><a href="qmenudata.html#deddb9">insertItem</a>("For the"); popup-><a href="qmenudata.html#deddb9">insertItem</a>("Reader!"); } void paintEvent(<a name="QPaintEvent"></a><a href="qpaintevent.html">QPaintEvent</a>* event) { <a name="QPainter"></a><a href="qpainter.html">QPainter</a> p(this); p.<a name="setClipRect"></a><a href="qpainter.html#898839">setClipRect</a>(event-><a name="rect"></a><a href="qpaintevent.html#2d6e18">rect</a>()); if ( pm.<a name="size"></a><a href="qpixmap.html#60b65f">size</a>() == size() ) { p.<a name="drawPixmap"></a><a href="qpainter.html#c64b89">drawPixmap</a>(0,0,pm); } else { if ( pmScaled.<a href="qpixmap.html#60b65f">size</a>() != size() ) { <a name="QWMatrix"></a><a href="qwmatrix.html">QWMatrix</a> m; m.<a name="scale"></a><a href="qwmatrix.html#41a356">scale</a>((double)width()/pm.<a name="width"></a><a href="qpixmap.html#86dbc5">width</a>(), (double)height()/pm.<a name="height"></a><a href="qpixmap.html#d5bb33">height</a>()); pmScaled = pm.<a name="xForm"></a><a href="qpixmap.html#ff5fcf">xForm</a>(m); } p.<a href="qpainter.html#c64b89">drawPixmap</a>(0,0,pmScaled); } } void mousePressEvent(<a name="QMouseEvent"></a><a href="qmouseevent.html">QMouseEvent</a>* e) { popup-><a name="popup"></a><a href="qpopupmenu.html#0d7b5f">popup</a>(mapToGlobal(e-><a name="pos"></a><a href="qmouseevent.html#ac6f25">pos</a>())); } void showImage(const QImage& image) { pm.<a name="convertFromImage"></a><a href="qpixmap.html#00951a">convertFromImage</a>(image, QPixmap::Color); repaint( FALSE ); }private: <a name="QPixmap"></a><a href="qpixmap.html">QPixmap</a> pm; <a href="qpixmap.html">QPixmap</a> pmScaled; <a href="qpopupmenu.html">QPopupMenu</a>* popup;};class ImageLoader : public QNPInstance { ImageView* iv; <a name="QImage"></a><a href="qimage.html">QImage</a> image;public: ImageLoader() : iv(0) { } <a name="QNPWidget"></a><a href="qnpwidget.html">QNPWidget</a>* newWindow() { iv = new ImageView; imageToIV(); return iv; } void imageToIV() { if (!iv || image.<a name="isNull"></a><a href="qimage.html#2f0bdd">isNull</a>()) return; iv->showImage(image); image.<a name="reset"></a><a href="qimage.html#4533e3">reset</a>(); } bool newStreamCreated(<a name="QNPStream"></a><a href="qnpstream.html">QNPStream</a>*, StreamMode& smode) { smode = AsFileOnly; return TRUE; } void streamAsFile(<a href="qnpstream.html">QNPStream</a>*, const char* fname) { qInitPngIO(); image = QImage(fname); if ( image.<a href="qimage.html#2f0bdd">isNull</a>() ) fprintf(stderr, "Could not convert file: %s\n", fname); imageToIV(); }};class ImagePlugin : public QNPlugin {public: ImagePlugin() { } <a name="QNPInstance"></a><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"; }};<a name="QNPlugin"></a><a href="qnplugin.html">QNPlugin</a>* QNPlugin::create(){ return new ImagePlugin;}</pre><p><address><hr><div align="center"><table width="100%" cellspacing="0" border="0"><tr><td>Copyright ⌨️ 快捷键说明
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