自学教程：C++ the_canvas函数代码示例

void UcClassCanvas::post_loaded() {  force_self_rel_visible();  if (the_canvas()->must_draw_all_relations()) {    draw_all_depend_gene();        draw_all_simple_relations();  }}

void ImageCanvas::open(){    QString s = path;    ImageDialog d(s);    if ((d.exec() == QDialog::Accepted) &&            !s.isEmpty() &&            (s != path)) {        QPixmap * p = get_pixmap(s.toLatin1().constData());        if (p != 0) {            path = s;            width_scale100 = p->width();            height_scale100 = p->height();            px = get_pixmap(path.toLatin1().constData(), the_canvas()->zoom());            hide();            hide_lines();            setRect(rect().x(), rect().y(), px->width(), px->height());            recenter();            show();            update_show_lines();            canvas()->update();            package_modified();        }    }}

void ArrowPointCanvas::delete_it(){    if (lines.isEmpty())        the_canvas()->del(this);    else        lines.first()->delete_it();	// will apply del on this}

aCorner PackageCanvas::on_resize_point(const QPoint & p) {  return (ProfiledStereotypes::diagramPixmap(browser_node->get_data()->get_stereotype(),					     the_canvas()->zoom())	  != 0)    ? NoCorner    : ::on_resize_point(p, rect());}

void PackageCanvas::prepare_for_move(bool on_resize) {  if (! on_resize) {    DiagramCanvas::prepare_for_move(on_resize);        Q3CanvasItemList l = collisions(TRUE);    Q3CanvasItemList::ConstIterator it;    Q3CanvasItemList::ConstIterator end = l.end();    DiagramItem * di;    BrowserNode * p = get_bn();      for (it = l.begin(); it != end; ++it) {      if ((*it)->visible() && // at least not deleted	  !(*it)->selected() &&	  ((di = QCanvasItemToDiagramItem(*it)) != 0) &&	  di->move_with_its_package()) {	BrowserNode * bn = di->get_bn();		do	  bn = (BrowserNode *) bn->parent();	while (bn->get_type() != UmlPackage);		if (bn == p) {	  the_canvas()->select(*it);	  di->prepare_for_move(FALSE);	}      }    }  }}

void UcUseCaseCanvas::post_loaded(){    force_self_rel_visible();    if (the_canvas()->must_draw_all_relations())        draw_all_simple_relations();}

void TextCanvas::open(){    static QSize sz;    // warning : 'note' is already unicode    QString s = fromUnicode(text);    bool created = s.isEmpty();    MLEDialog::get(s, QCursor::pos(), sz);    if (s.isEmpty())        delete_it();    else {        text = s;        if (created) {            QFontMetrics fm(the_canvas()->get_font(UmlNormalFont));            QSize sz = fm.size(0, text);            DiagramCanvas::resize(sz.width(), sz.height());        }        // force son reaffichage        hide();        show();    }    canvas()->update();    package_modified();}

void ObjectDiagramView::read(char * st, char * k) {  UmlCanvas * canvas = the_canvas();    // reads first the instances, package, fragment notes, icons text and image  while (OdClassInstCanvas::read(st, canvas, k) ||	 NoteCanvas::read(st, canvas, k) ||	 TextCanvas::read(st, canvas, k) ||	 IconCanvas::read(st, canvas, k) ||	 PackageCanvas::read(st, canvas, k) ||	 FragmentCanvas::read(st, canvas, k) ||	 ImageCanvas::read(st, canvas, k))    k = read_keyword(st);    // then reads links   while (ObjectLinkCanvas::read(st, canvas, k))    k = read_keyword(st);    // then reads anchors  while (ArrowCanvas::read(st, canvas, k))    k = read_keyword(st);    if (!strcmp(k, "preferred_whz") || !strcmp(k, "prefered_whz")) {    preferred_size.setWidth(read_unsigned(st));    preferred_size.setHeight(read_unsigned(st));    preferred_zoom = read_double(st);    k = read_keyword(st);  }    if (strcmp(k, "end"))    wrong_keyword(k, "end");}

void ArtifactCanvas::update_relations(ArtifactCanvas * other) {  // 'this' is a non source, check association with 'other'  const Q3PtrDict<BrowserArtifact> * associated =     ((ArtifactData *) browser_node->get_data())->get_associated();  bool association_must_exist =     ((associated != 0) &&     (associated->find((BrowserArtifact *) other->browser_node) != 0));  Q3PtrListIterator<ArrowCanvas> it(lines);      while (it.current()) {    if ((it.current()->type() == UmlContain) &&	(((AssocContainCanvas *) it.current())->get_end() == other)) {      if (! association_must_exist)	it.current()->delete_it();      return;    }    ++it;  }  // association not yet exist    if (association_must_exist)    (new AssocContainCanvas(the_canvas(), this, other, 0, -1.0, -1.0))      ->show();}

void LabelCanvas::moveBy(double dx, double dy){    QGraphicsSimpleTextItem::moveBy(dx, dy);    if (! the_canvas()->do_zoom())        set_center100();}

void SubjectCanvas::menu(const QPoint&) {  Q3PopupMenu m(0);    MenuFactory::createTitle(m, TR("Subject"));  m.insertSeparator();  m.insertItem(TR("Upper"), 0);  m.insertItem(TR("Lower"), 1);  m.insertItem(TR("Go up"), 6);  m.insertItem(TR("Go down"), 7);  m.insertSeparator();  m.insertItem(TR("Edit"), 2);  m.insertSeparator();  m.insertItem(TR("Edit drawing settings"), 3);  if (linked()) {    m.insertSeparator();    m.insertItem(TR("Select linked items"), 4);  }  m.insertSeparator();  m.insertItem(TR("Remove from diagram"),5);  int index = m.exec(QCursor::pos());    switch (index) {  case 0:    upper();    modified();	// call package_modified()    return;  case 1:    lower();    modified();	// call package_modified()    return;  case 6:    z_up();    modified();	// call package_modified()    return;  case 7:    z_down();    modified();	// call package_modified()    return;  case 2:    open();    // modified then package_modified already called    return;  case 3:    edit_drawing_settings();    return;  case 4:    the_canvas()->unselect_all();    select_associated();    return;  case 5:    delete_it();    break;  default:    return;  }    package_modified();}

void CodLinkCanvas::moveBy(double dx, double dy) {  if (selected())    the_canvas()->unselect(this);    ArrowCanvas::moveBy(dx, dy);  if (dirs)    dirs->update_pos(beginp, endp);}

void DiagramCanvas::set_center100(){    QPoint c = center();    double scale = the_canvas()->zoom();    center_x_scale100  = (int)(c.x() / scale + 0.5);    center_y_scale100  = (int)(c.y() / scale + 0.5);}

void DiagramCanvas::recenter(){    double scale = the_canvas()->zoom();    QPoint c = center();    QGraphicsRectItem::moveBy(center_x_scale100 * scale - c.x(),                              center_y_scale100 * scale - c.y());}

void DeploymentNodeCanvas::check_size() {  DeploymentDiagramSettings dflt;    dflt.write_horizontally = write_horizontally;  the_canvas()->browser_diagram()->get_deploymentdiagramsettings(dflt);  horiz = (dflt.write_horizontally == UmlYes);  show_properties = (dflt.componentdrawingsettings.show_stereotype_properties == UmlYes);      const QPixmap * px =     ProfiledStereotypes::diagramPixmap(browser_node->get_data()->get_stereotype(),				       the_canvas()->zoom());    if (px != 0) {    QFontMetrics fm(the_canvas()->get_font(UmlNormalBoldFont));    int w;    int h = px->height() + fm.height();        if (horiz)      w = fm.width(iname + ":" + browser_node->get_name());    else {      w = fm.width(browser_node->get_name());            int iw = fm.width(iname + ":");            if (iw > w)	w = iw;            h += fm.height() + (int) (3 * the_canvas()->zoom());    }        if (w < px->width())      w = px->width();        // force odd width and height for line alignment    DiagramCanvas::resize(w | 1, h | 1);  }  else {    int wi = min_width();    int he = min_height();        // warning : do NOT check if ((width() < wi) || (height() < he))    // because te resize must be done to set data on scale change    DiagramCanvas::resize((width() < wi) ? wi : width(),			  (height() < he) ? he : height());  }}

void SdLifeLineCanvas::change_scale(){    double scale = the_canvas()->zoom();    int w = (int)(width_scale100 * scale);    // force odd width    setSize(((w & 1) == 0) ? w + 1 : w, LIFE_LINE_HEIGHT);    // don't move, the position is updated with its obj}