📄 canvas-example.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><!-- /home/reggie/tmp/qt-3.0-reggie-5401/qt-x11-commercial-3.0.5/examples/canvas/canvas.doc:1 --><html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Canvas Example</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>Canvas Example</h1> <p> This example shows a <a href="qcanvas.html">QCanvas</a> and some <a href="qcanvasitem.html">QCanvasItem</a>s in action.You can do a lot more with QCanvas than we show here, but theexample provides a taste of what can be done.<p> <hr><p> Header file:<p> <pre>#ifndef EXAMPLE_H#define EXAMPLE_H#include <<a href="qpopupmenu-h.html">qpopupmenu.h</a>>#include <<a href="qmainwindow-h.html">qmainwindow.h</a>>#include <<a href="qintdict-h.html">qintdict.h</a>>#include <<a href="qcanvas-h.html">qcanvas.h</a>>class BouncyLogo : public <a href="qcanvassprite.html">QCanvasSprite</a> { void initPos(); void initSpeed();public: BouncyLogo(QCanvas*); void advance(int); int rtti() const;};class FigureEditor : public <a href="qcanvasview.html">QCanvasView</a> { <a href="metaobjects.html#Q_OBJECT">Q_OBJECT</a>public: FigureEditor(QCanvas&, QWidget* parent=0, const char* name=0, WFlags f=0); void clear();protected: void contentsMousePressEvent(QMouseEvent*); void contentsMouseMoveEvent(QMouseEvent*);signals: void status(const <a href="qstring.html">QString</a>&);private: <a href="qcanvasitem.html">QCanvasItem</a>* moving; <a href="qpoint.html">QPoint</a> moving_start;};class Main : public <a href="qmainwindow.html">QMainWindow</a> { Q_OBJECTpublic: Main(QCanvas&, QWidget* parent=0, const char* name=0, WFlags f=0); ~Main();public slots: void help();private slots: void aboutQt(); void newView(); void clear(); void init(); void addSprite(); void addCircle(); void addHexagon(); void addPolygon(); void addSpline(); void addText(); void addLine(); void addRectangle(); void addMesh(); void addLogo(); void addButterfly(); void enlarge(); void shrink(); void rotateClockwise(); void rotateCounterClockwise(); void zoomIn(); void zoomOut(); void mirror(); void moveL(); void moveR(); void moveU(); void moveD(); void print(); void toggleDoubleBuffer();private: <a href="qcanvas.html">QCanvas</a>& canvas; FigureEditor *editor; <a href="qpopupmenu.html">QPopupMenu</a>* options; <a href="qprinter.html">QPrinter</a>* printer; int dbf_id;};#endif</pre><p> <hr><p> Implementation:<p> <pre>#include <<a href="qdatetime-h.html">qdatetime.h</a>>#include <<a href="qmainwindow-h.html">qmainwindow.h</a>>#include <<a href="qstatusbar-h.html">qstatusbar.h</a>>#include <<a href="qmessagebox-h.html">qmessagebox.h</a>>#include <<a href="qmenubar-h.html">qmenubar.h</a>>#include <<a href="qapplication-h.html">qapplication.h</a>>#include <<a href="qpainter-h.html">qpainter.h</a>>#include <<a href="qprinter-h.html">qprinter.h</a>>#include <<a href="qlabel-h.html">qlabel.h</a>>#include <<a href="qimage-h.html">qimage.h</a>>#include <<a href="qprogressdialog-h.html">qprogressdialog.h</a>>#include "canvas.h"#include <stdlib.h>// We use a global variable to save memory - all the brushes and pens in// the mesh are shared.static QBrush *tb = 0;static QPen *tp = 0;class EdgeItem;class NodeItem;class EdgeItem: public <a href="qcanvasline.html">QCanvasLine</a>{public: EdgeItem( NodeItem*, NodeItem*, QCanvas *canvas ); void setFromPoint( int x, int y ) ; void setToPoint( int x, int y ); static int count() { return c; } void moveBy(double dx, double dy);private: static int c;};static const int imageRTTI = 984376;class ImageItem: public <a href="qcanvasrectangle.html">QCanvasRectangle</a>{public: ImageItem( <a href="qimage.html">QImage</a> img, QCanvas *canvas ); int rtti () const { return imageRTTI; } bool hit( const <a href="qpoint.html">QPoint</a>&) const;protected: void drawShape( <a href="qpainter.html">QPainter</a> & );private: <a href="qimage.html">QImage</a> image; <a href="qpixmap.html">QPixmap</a> pixmap;};<a name="f595"></a>ImageItem::ImageItem( <a href="qimage.html">QImage</a> img, QCanvas *canvas ) : <a href="qcanvasrectangle.html">QCanvasRectangle</a>( canvas ), image(img){<a name="x2711"></a><a name="x2708"></a> <a href="qcanvasrectangle.html#setSize">setSize</a>( image.<a href="qimage.html#width">width</a>(), image.<a href="qimage.html#height">height</a>() );#if !defined(Q_WS_QWS)<a name="x2719"></a> pixmap.<a href="qpixmap.html#convertFromImage">convertFromImage</a>(image, OrderedAlphaDither);#endif}<a name="x2701"></a>void ImageItem::<a href="qcanvasrectangle.html#drawShape">drawShape</a>( <a href="qpainter.html">QPainter</a> &p ){// On Qt/Embedded, we can paint a QImage as fast as a QPixmap,// but on other platforms, we need to use a QPixmap.#if defined(Q_WS_QWS)<a name="x2717"></a> p.<a href="qpainter.html#drawImage">drawImage</a>( int(<a href="qcanvasitem.html#x">x</a>()), int(<a href="qcanvasitem.html#y">y</a>()), image, 0, 0, -1, -1, OrderedAlphaDither );#else p.<a href="qpainter.html#drawPixmap">drawPixmap</a>( int(<a href="qcanvasitem.html#x">x</a>()), int(<a href="qcanvasitem.html#y">y</a>()), pixmap );#endif}bool <a name="f596"></a>ImageItem::hit( const <a href="qpoint.html">QPoint</a> &p ) const{<a name="x2720"></a> int ix = p.<a href="qpoint.html#x">x</a>()-int(<a href="qcanvasitem.html#x">x</a>());<a name="x2721"></a> int iy = p.<a href="qpoint.html#y">y</a>()-int(<a href="qcanvasitem.html#y">y</a>());<a name="x2710"></a> if ( !image.<a href="qimage.html#valid">valid</a>( ix , iy ) ) return FALSE;<a name="x2709"></a> QRgb pixel = image.<a href="qimage.html#pixel">pixel</a>( ix, iy ); return qAlpha( pixel ) != 0;}class NodeItem: public <a href="qcanvasellipse.html">QCanvasEllipse</a>{public: NodeItem( <a href="qcanvas.html">QCanvas</a> *canvas ); ~NodeItem() {} void addInEdge( EdgeItem *edge ) { inList.<a href="qptrlist.html#append">append</a>( edge ); } void addOutEdge( EdgeItem *edge ) { outList.<a href="qptrlist.html#append">append</a>( edge ); } void moveBy(double dx, double dy); // QPoint center() { return boundingRect().center(); }private: <a href="qptrlist.html">QPtrList</a><EdgeItem> inList; <a href="qptrlist.html">QPtrList</a><EdgeItem> outList;};int EdgeItem::c = 0;<a name="x2692"></a>void EdgeItem::<a href="qcanvasitem.html#moveBy">moveBy</a>(double, double){ //nothing}<a name="f590"></a>EdgeItem::EdgeItem( NodeItem *from, NodeItem *to, QCanvas *canvas ) : <a href="qcanvasline.html">QCanvasLine</a>( canvas ){ c++; setPen( *tp ); setBrush( *tb ); from->addOutEdge( this ); to->addInEdge( this );<a name="x2697"></a><a name="x2696"></a> setPoints( int(from-><a href="qcanvasitem.html#x">x</a>()), int(from-><a href="qcanvasitem.html#y">y</a>()), int(to->x()), int(to->y()) ); setZ( 127 );}void <a name="f591"></a>EdgeItem::setFromPoint( int x, int y ){ setPoints( x,y, endPoint().x(), endPoint().y() );}void <a name="f592"></a>EdgeItem::setToPoint( int x, int y ){ setPoints( startPoint().x(), startPoint().y(), x, y );}void NodeItem::<a href="qcanvasitem.html#moveBy">moveBy</a>(double dx, double dy){ QCanvasEllipse::<a href="qcanvasitem.html#moveBy">moveBy</a>( dx, dy ); <a href="qptrlistiterator.html">QPtrListIterator</a><EdgeItem> it1( inList ); EdgeItem *edge;<a name="x2725"></a> while (( edge = it1.<a href="qptrlistiterator.html#current">current</a>() )) { ++it1; edge->setToPoint( int(<a href="qwidget.html#x">x</a>()), int(<a href="qcanvasitem.html#y">y</a>()) ); } <a href="qptrlistiterator.html">QPtrListIterator</a><EdgeItem> it2( outList ); while (( edge = it2.<a href="qptrlistiterator.html#current">current</a>() )) { ++it2; edge->setFromPoint( int(<a href="qcanvasitem.html#x">x</a>()), int(<a href="qcanvasitem.html#y">y</a>()) ); }}<a name="f627"></a>NodeItem::NodeItem( <a href="qcanvas.html">QCanvas</a> *canvas ) : <a href="qcanvasellipse.html">QCanvasEllipse</a>( 6, 6, canvas ){ setPen( *tp ); setBrush( *tb ); <a href="qcanvasitem.html#setZ">setZ</a>( 128 );}<a name="f593"></a>FigureEditor::FigureEditor( <a href="qcanvas.html">QCanvas</a>& c, QWidget* parent, const char* name, WFlags f) : <a href="qcanvasview.html">QCanvasView</a>(&c,parent,name,f){}<a name="x2727"></a>void FigureEditor::<a href="qscrollview.html#contentsMousePressEvent">contentsMousePressEvent</a>(QMouseEvent* e){ <a href="qpoint.html">QPoint</a> p = inverseWorldMatrix().map(e->pos()); <a href="qcanvasitemlist.html">QCanvasItemList</a> l=<a href="qcanvasitem.html#canvas">canvas</a>()->collisions(p); for (QCanvasItemList::Iterator it=l.<a href="qvaluelist.html#begin">begin</a>(); it!=l.<a href="qvaluelist.html#end">end</a>(); ++it) { if ( (*it)->rtti() == imageRTTI ) { ImageItem *item= (ImageItem*)(*it); if ( !item->hit( p ) ) continue; } moving = *it; moving_start = p; return; } moving = 0;}void <a name="f594"></a>FigureEditor::clear(){⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -