More roboust zoom tool - prevent zooming to empty extent

wonder · wonder · commit 22f57697eedb · 2007-05-31T00:32:41.000Z
git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@6970 c8812cc2-4d05-0410-92ff-de0c093fc19c
diff --git a/src/gui/qgsmaptoolzoom.cpp b/src/gui/qgsmaptoolzoom.cpp
@@ -37,7 +37,7 @@ QgsMapToolZoom::QgsMapToolZoom(QgsMapCanvas* canvas, bool zoomOut)
 
 void QgsMapToolZoom::canvasMoveEvent(QMouseEvent * e)
 {
-  if (e->state() != Qt::LeftButton)
+  if ( ! (e->buttons() & Qt::LeftButton) )
     return;
 
   if (!mDragging)
@@ -54,12 +54,18 @@ void QgsMapToolZoom::canvasMoveEvent(QMouseEvent * e)
 
 void QgsMapToolZoom::canvasPressEvent(QMouseEvent * e)
 {
+  if (e->button() != Qt::LeftButton)
+    return;
+  
   mZoomRect.setRect(0, 0, 0, 0);
 }
 
 
 void QgsMapToolZoom::canvasReleaseEvent(QMouseEvent * e)
 {
+  if (e->button() != Qt::LeftButton)
+    return;
+  
   if (mDragging)
   {
     mDragging = false;
@@ -83,6 +89,12 @@ void QgsMapToolZoom::canvasReleaseEvent(QMouseEvent * e)
     r.setYmax(ur.y());
     r.normalize();
     
+    // prevent zooming to an empty extent
+    if (r.width() == 0 || r.height() == 0)
+    {
+      return;
+    }
+    
     if (mZoomOut)
     {
       QgsPoint cer = r.center();
@@ -91,18 +103,10 @@ void QgsMapToolZoom::canvasReleaseEvent(QMouseEvent * e)
       double sf;
       if (mZoomRect.width() > mZoomRect.height())
       {
-	if(r.width() == 0)//prevent nan map extent
-	  {
-	    return;
-	  }
         sf = extent.width() / r.width();
       }
       else
       {
-	if(r.height() == 0)//prevent nan map extent
-	  {
-	    return;
-	  }
         sf = extent.height() / r.height();
       }
       r.expand(sf);

Original file line number	Diff line number	Diff line change
`@@ -37,7 +37,7 @@ QgsMapToolZoom::QgsMapToolZoom(QgsMapCanvas* canvas, bool zoomOut)`
`37`	`37`
`38`	`38`	`void QgsMapToolZoom::canvasMoveEvent(QMouseEvent * e)`
`39`	`39`	`{`
`40`		`- if (e->state() != Qt::LeftButton)`
	`40`	`+ if ( ! (e->buttons() & Qt::LeftButton) )`
`41`	`41`	`return;`
`42`	`42`
`43`	`43`	`if (!mDragging)`
`@@ -54,12 +54,18 @@ void QgsMapToolZoom::canvasMoveEvent(QMouseEvent * e)`
`54`	`54`
`55`	`55`	`void QgsMapToolZoom::canvasPressEvent(QMouseEvent * e)`
`56`	`56`	`{`
	`57`	`+ if (e->button() != Qt::LeftButton)`
	`58`	`+ return;`
	`59`	`+`
`57`	`60`	`mZoomRect.setRect(0, 0, 0, 0);`
`58`	`61`	`}`
`59`	`62`
`60`	`63`
`61`	`64`	`void QgsMapToolZoom::canvasReleaseEvent(QMouseEvent * e)`
`62`	`65`	`{`
	`66`	`+ if (e->button() != Qt::LeftButton)`
	`67`	`+ return;`
	`68`	`+`
`63`	`69`	`if (mDragging)`
`64`	`70`	`{`
`65`	`71`	`mDragging = false;`
`@@ -83,6 +89,12 @@ void QgsMapToolZoom::canvasReleaseEvent(QMouseEvent * e)`
`83`	`89`	`r.setYmax(ur.y());`
`84`	`90`	`r.normalize();`
`85`	`91`
	`92`	`+ // prevent zooming to an empty extent`
	`93`	`+ if (r.width() == 0 \|\| r.height() == 0)`
	`94`	`+ {`
	`95`	`+ return;`
	`96`	`+ }`
	`97`	`+`
`86`	`98`	`if (mZoomOut)`
`87`	`99`	`{`
`88`	`100`	`QgsPoint cer = r.center();`
`@@ -91,18 +103,10 @@ void QgsMapToolZoom::canvasReleaseEvent(QMouseEvent * e)`
`91`	`103`	`double sf;`
`92`	`104`	`if (mZoomRect.width() > mZoomRect.height())`
`93`	`105`	`{`
`94`		`- if(r.width() == 0)//prevent nan map extent`
`95`		`- {`
`96`		`- return;`
`97`		`- }`
`98`	`106`	`sf = extent.width() / r.width();`
`99`	`107`	`}`
`100`	`108`	`else`
`101`	`109`	`{`
`102`		`- if(r.height() == 0)//prevent nan map extent`
`103`		`- {`
`104`		`- return;`
`105`		`- }`
`106`	`110`	`sf = extent.height() / r.height();`
`107`	`111`	`}`
`108`	`112`	`r.expand(sf);`