QGis添加圖層後可以用鼠標滾動縮放,如果想添加圖標到工具欄實現相同的效果,如圖:
(1)在QMainWindow中添加如下變量:
QToolBar *mpMapToolBar; ///<地圖操作相關的工具欄
QgsMapTool *mpPanTool; ///<漫遊
QgsMapTool *mpZoomInTool;///<放大
QgsMapTool *mpZoomOutTool;///<縮小
QgsMapTool *mpZoomFull; ///<全圖顯示
在Qt設計師裏面添加Action:
(2)然後在初始化函數裏添加:
//添加工具欄上按鈕
mpMapToolBar = addToolBar(tr("Tools"));
mpMapToolBar->addSeparator();
mpMapToolBar->addAction(ui.mpActionPan);
mpMapToolBar->addAction(ui.mpActionZoomIn);
mpMapToolBar->addAction(ui.mpActionZoomOut);
mpMapToolBar->addAction(ui.mpActionZoomFull);
mpPanTool= new QgsMapToolPan(mainMapCanvas);
mpPanTool->setAction(ui.mpActionPan);
mpZoomInTool = new QgsMapToolZoom(mainMapCanvas,false);
mpZoomInTool->setAction(ui.mpActionZoomIn);
mpZoomOutTool = new QgsMapToolZoom(mainMapCanvas,true);
mpZoomOutTool->setAction(ui.mpActionZoomOut);
(3)添加信號槽函數連接:
connect(ui.mpActionPan,SIGNAL(triggered()),this,SLOT(panMode()));
connect(ui.mpActionZoomIn,SIGNAL(triggered()),this,SLOT(zoomInMode()));
connect(ui.mpActionZoomOut,SIGNAL(triggered()),this,SLOT(zoomOutMode()));
connect(ui.mpActionZoomFull, SIGNAL(triggered()), this, SLOT(zoomFull()));
(4)槽函數實現:
void MainWindow::zoomInMode()
{
mainMapCanvas->setMapTool(mpZoomInTool);
if ( mainMapCanvas->layer(0)->type() == QgsMapLayer::RasterLayer)
{
return;
}
QgsVectorLayer *pLayer=(QgsVectorLayer *)mainMapCanvas->layer(0);
pLayer->removeSelection(true);
}
void MainWindow::zoomOutMode()
{
mainMapCanvas->setMapTool(mpZoomOutTool);
if ( mainMapCanvas->layer(0)->type() == QgsMapLayer::RasterLayer)
{
return;
}
QgsVectorLayer *pLayer=(QgsVectorLayer *)mainMapCanvas->layer(0);
pLayer->removeSelection(true);
}
void MainWindow::panMode()
{
mainMapCanvas->setMapTool(mpPanTool);
ui.mpActionPan->setCheckable(true);
ui.mpActionPan->setChecked(true);
if ( mainMapCanvas->layer(0)->type() == QgsMapLayer::RasterLayer)
{
return;
}
QgsVectorLayer *pLayer=(QgsVectorLayer *)mainMapCanvas->layer(0);
pLayer->removeSelection(true);
}
void MainWindow::zoomFull()
{
mainMapCanvas->zoomToFullExtent();
if ( mainMapCanvas->layer(0)->type() == QgsMapLayer::RasterLayer)
{
return;
}
QgsVectorLayer *pLayer=(QgsVectorLayer *)mainMapCanvas->layer(0);
pLayer->removeSelection(true);
}
上面的mainMapCanvas就是已經加載了矢量圖層的。