[FEATURE] QgsTooltip support full HTML

mbernasocchi · m-kuhn · commit 45227e51d88a · 2016-06-03T09:24:04.000+02:00
This is useful for example to add URL links that
allow being clicked on.
diff --git a/src/gui/qgsmaptip.cpp b/src/gui/qgsmaptip.cpp
@@ -18,15 +18,22 @@
 #include "qgsvectorlayer.h"
 #include "qgsexpression.h"
 #include "qgslogger.h"
+#include "qgswebview.h"
+#include "qgswebframe.h"
 
 // Qt includes
 #include <QPoint>
 #include <QToolTip>
 #include <QSettings>
+#include <QLabel>
+#include <QWebElement>
+#include <QHBoxLayout>
+
 
 #include "qgsmaptip.h"
 
 QgsMapTip::QgsMapTip()
+    : mWidget( nullptr ), mWebView( nullptr )
 {
   // init the visible flag
   mMapTipVisible = false;
@@ -37,38 +44,115 @@ QgsMapTip::~QgsMapTip()
 
 }
 
-void QgsMapTip::showMapTip( QgsMapLayer *thepLayer,
-                            QgsPoint & theMapPosition,
+void QgsMapTip::showMapTip( QgsMapLayer *pLayer,
+                            QgsPoint & mapPosition,
                             QPoint & thePixelPosition,
-                            QgsMapCanvas *thepMapCanvas )
+                            QgsMapCanvas *pMapCanvas )
 {
-  // Do the search using the active layer and the preferred label
-  // field for the layer. The label field must be defined in the layer configuration
+  // Do the search using the active layer and the preferred label field for the
+  // layer. The label field must be defined in the layer configuration
   // file/database. The code required to do this is similar to identify, except
   // we only want the first qualifying feature and we will only display the
-  // field defined as the label field in the layer configuration file/database.
-  //
-  // TODO: Define the label (display) field for each map layer in the map configuration file/database
+  // field defined as the label field in the layer configuration file/database
 
   // Show the maptip on the canvas
-  QString myTipText = fetchFeature( thepLayer, theMapPosition, thepMapCanvas );
-  mMapTipVisible = !myTipText.isEmpty();
+  QString tipText, lastTipText, tipHtml, bodyStyle, containerStyle,
+  backgroundColor, borderColor;
+
+  delete mWidget;
+  mWidget = new QWidget( pMapCanvas );
+  mWebView = new QgsWebView( mWidget );
+
+  mWebView->page()->settings()->setAttribute(
+    QWebSettings::DeveloperExtrasEnabled, true );
+  mWebView->page()->settings()->setAttribute(
+    QWebSettings::JavascriptEnabled, true );
+
+  QHBoxLayout* layout = new QHBoxLayout;
+  layout->addWidget( mWebView );
+
+  mWidget->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
+  mWidget->setLayout( layout );
+
+  //assure the map tip is never larger than half the map canvas
+  const int MAX_WIDTH = pMapCanvas->geometry().width() / 2;
+  const int MAX_HEIGHT = pMapCanvas->geometry().height() / 2;
+  mWidget->setMaximumSize( MAX_WIDTH, MAX_HEIGHT );
+
+  // start with 0 size,
+  // the content will automatically make it grow up to MaximumSize
+  mWidget->resize( 0, 0 );
+
+  backgroundColor = mWidget->palette().base().color().name();
+  borderColor = mWidget->palette().shadow().color().name();
+  mWidget->setStyleSheet( QString(
+                            ".QWidget{"
+                            "border: 1px solid %1;"
+                            "background-color: %2;}" ).arg(
+                            borderColor, backgroundColor ) );
 
-  if ( mMapTipVisible )
+  tipText = fetchFeature( pLayer, mapPosition, pMapCanvas );
+
+  mMapTipVisible = !tipText.isEmpty();
+  if ( !mMapTipVisible )
   {
-    QToolTip::showText( thepMapCanvas->mapToGlobal( thePixelPosition ), myTipText, thepMapCanvas );
-    // store the point so we can use it to clear the maptip later
-    mLastPosition = thePixelPosition;
+    clear();
+    return;
+  }
+
+  if ( tipText == lastTipText )
+  {
+    return;
+  }
+
+  bodyStyle = QString(
+                "background-color: %1;"
+                "margin: 0;" ).arg( backgroundColor );
+
+  containerStyle = QString(
+                     "display: inline-block;"
+                     "margin: 0px" );
+
+  tipHtml = QString(
+              "<html>"
+              "<body style='%1'>"
+              "<div id='QgsWebViewContainer' style='%2'>%3</div>"
+              "</body>"
+              "</html>" ).arg( bodyStyle, containerStyle, tipText );
+
+  mWidget->move( thePixelPosition.x(),
+                 thePixelPosition.y() );
+
+  mWebView->setHtml( tipHtml );
+  lastTipText = tipText;
+
+  mWidget->show();
+
+  int scrollbarWidth = mWebView->page()->mainFrame()->scrollBarGeometry(
+                         Qt::Vertical ).width();
+  int scrollbarHeight = mWebView->page()->mainFrame()->scrollBarGeometry(
+                          Qt::Horizontal ).height();
+
+  if ( scrollbarWidth > 0 || scrollbarHeight > 0 )
+  {
+    // Get the content size
+    QWebElement container = mWebView->page()->mainFrame()->findFirstElement(
+                              "#QgsWebViewContainer" );
+    int width = container.geometry().width() + 5 + scrollbarWidth;
+    int height = container.geometry().height() + 5 + scrollbarHeight;
+
+    mWidget->resize( width, height );
   }
 }
 
-void QgsMapTip::clear( QgsMapCanvas *mpMapCanvas )
+void QgsMapTip::clear( QgsMapCanvas * )
 {
   if ( !mMapTipVisible )
     return;
 
-  // set the maptip to blank
-  QToolTip::showText( mpMapCanvas->mapToGlobal( mLastPosition ), "", mpMapCanvas );
+  mWebView->setHtml( QString() );
+  mWidget->hide();
+
   // reset the visible flag
   mMapTipVisible = false;
 }
@@ -77,7 +161,7 @@ QString QgsMapTip::fetchFeature( QgsMapLayer *layer, QgsPoint &mapPosition, QgsM
 {
   QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( layer );
   if ( !vlayer )
-    return "";
+    return QString();
 
   double searchRadius = QgsMapTool::searchRadiusMU( mpMapCanvas );
 
@@ -92,7 +176,7 @@ QString QgsMapTip::fetchFeature( QgsMapLayer *layer, QgsPoint &mapPosition, QgsM
   QgsFeature feature;
 
   if ( !vlayer->getFeatures( QgsFeatureRequest().setFilterRect( r ).setFlags( QgsFeatureRequest::ExactIntersect ) ).nextFeature( feature ) )
-    return "";
+    return QString();
 
   int idx = vlayer->fieldNameIndex( vlayer->displayField() );
   if ( idx < 0 )
@@ -108,5 +192,7 @@ QString QgsMapTip::fetchFeature( QgsMapLayer *layer, QgsPoint &mapPosition, QgsM
     return QgsExpression::replaceExpressionText( vlayer->displayField(), &context );
   }
   else
+  {
     return feature.attribute( idx ).toString();
+  }
 }
diff --git a/src/gui/qgsmaptip.h b/src/gui/qgsmaptip.h
@@ -19,12 +19,28 @@ class QgsMapLayer;
 class QgsMapCanvas;
 class QPoint;
 class QString;
+class QgsWebView;
 
 #include "qgsfeature.h"
 
 /** \ingroup gui
  * A maptip is a class to display a tip on a map canvas
  * when a mouse is hovered over a feature.
+ *
+ * Since QGIS 2.16 a maptip can show full html.
+ * QgsMapTip is a QgsWebview, so you can load full HTML/JS/CSS in it.
+ *
+ * The code found in the map tips tab is inserted in a inline-block div
+ * so the frame can be resized based on the content size.
+ *
+ * If no element in the html has a width attribute, the frame will squeeze down
+ * to the widest word. To avoid this you can wrap your HTML in a
+ * div style="width:300px" or similar.
+ *
+ * JS can be included using the script tag as usual, while CSS files must be
+ * linked using link rel="stylesheet" href="URL.css" the html specs
+ * discourages link rel="stylesheet" in the body, but all browsers allow it.
+ * see https://jakearchibald.com/2016/link-in-body/
  */
 class GUI_EXPORT QgsMapTip
 {
@@ -51,21 +67,22 @@ class GUI_EXPORT QgsMapTip
     /** Clear the current maptip if it exists
      * @param mpMapCanvas the canvas from which the tip should be cleared.
      */
-    void clear( QgsMapCanvas *mpMapCanvas );
+    void clear( QgsMapCanvas *mpMapCanvas = nullptr );
   private:
-    // Fetch the feature to use for the maptip text. Only the first feature in the
-    // search radius is used
+    // Fetch the feature to use for the maptip text.
+    // Only the first feature in the search radius is used
     QString fetchFeature( QgsMapLayer * thepLayer,
                           QgsPoint & theMapPosition,
                           QgsMapCanvas *thepMapCanvas );
 
-    QString replaceText( QString displayText, QgsVectorLayer *layer, QgsFeature &feat );
+    QString replaceText(
+      QString displayText, QgsVectorLayer *layer, QgsFeature &feat );
 
     // Flag to indicate if a maptip is currently being displayed
     bool mMapTipVisible;
-    // Last point on the map canvas when the maptip timer fired. This point is in widget pixel
-    // coordinates
-    QPoint mLastPosition;
+
+    QWidget* mWidget;
+    QgsWebView* mWebView;
 
 };
 #endif // QGSMAPTIP_H
