qtimage-nsplugin-example.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><!-- /home/reggie/tmp/qt-3.0-reggie-5401/qt-x11-commercial-3.0.5/extensions/nsplugin/examples/qtimage/qtimage.doc:1 --><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Display Images in Qt-supported Formats</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: #ffffff; color: black; }--></style></head><body><table border="0" cellpadding="0" cellspacing="0" width="100%"><tr bgcolor="#E5E5E5"><td valign=center> <a href="index.html"><font color="#004faf">Home</font></a> | <a href="classes.html"><font color="#004faf">All Classes</font></a> | <a href="mainclasses.html"><font color="#004faf">Main Classes</font></a> | <a href="annotated.html"><font color="#004faf">Annotated</font></a> | <a href="groups.html"><font color="#004faf">Grouped Classes</font></a> | <a href="functions.html"><font color="#004faf">Functions</font></a></td><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 formatsupported by Qt. Combining this with the Qt ImageIOExtension 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 webbrowser.<p> <embed src=\"pnglogo.png\" width=256 height=192><p> This plugin displays a <a href="http://www.libpng.org/pub/png/">PNG format</a> image.<p> New image formats can be supported by adding new image I/O handlersto the Qt library (see QImage::defineIOHandler), thus providing thefunctionality in both applications and WWW plugins from the samecode.<p> This plugin supports transparency and scaling of the image, justlike 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 <<a href="qpainter-h.html">qpainter.h</a>>#include <<a href="qimage-h.html">qimage.h</a>>#include <<a href="qpixmap-h.html">qpixmap.h</a>>#include <<a href="qmessagebox-h.html">qmessagebox.h</a>>#include <<a href="qpopupmenu-h.html">qpopupmenu.h</a>>#include "qpngio.h"#include <math.h>#include <stdlib.h>#include <stdio.h>class ImageView : public <a href="qnpwidget.html">QNPWidget</a> {public: ImageView() { popup = new <a href="qpopupmenu.html">QPopupMenu</a>; popup-><a href="qmenudata.html#insertItem">insertItem</a>("Left as"); popup-><a href="qmenudata.html#insertItem">insertItem</a>("An exercise"); popup-><a href="qmenudata.html#insertItem">insertItem</a>("For the"); popup-><a href="qmenudata.html#insertItem">insertItem</a>("Reader!"); } void paintEvent(QPaintEvent* event) { <a href="qpainter.html">QPainter</a> p(this);<a name="x2578"></a> p.<a href="qpainter.html#setClipRect">setClipRect</a>(event->rect());<a name="x2581"></a> if ( pm.<a href="qpixmap.html#size">size</a>() == size() ) {<a name="x2577"></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="x2585"></a><a name="x2582"></a> m.<a href="qwmatrix.html#scale">scale</a>((double)width()/pm.<a href="qpixmap.html#width">width</a>(),<a name="x2580"></a> (double)height()/pm.<a href="qpixmap.html#height">height</a>());<a name="x2583"></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="x2584"></a> popup-><a href="qpopupmenu.html#popup">popup</a>(mapToGlobal(e->pos())); } void showImage(const <a href="qimage.html">QImage</a>& image) {<a name="x2579"></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="x2574"></a> if (!iv || image.<a href="qimage.html#isNull">isNull</a>()) return; iv->showImage(image);<a name="x2575"></a> image.<a href="qimage.html#reset">reset</a>(); } bool newStreamCreated(QNPStream*, StreamMode& 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>.<!-- eof --><p><address><hr><div align=center><table width=100% cellspacing=0 border=0><tr><td>Copyright © 2002 <a href="http://www.trolltech.com">Trolltech</a><td><a href="http://www.trolltech.com/trademarks.html">Trademarks</a><td align=right><div align=right>Qt version 3.0.5</div></table></div></address></body></html>⌨️ 快捷键说明
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