Bands allways inside viewport

BollingerBands.js

@@ -522,6 +522,26 @@
                         continue;
                     }
 
+                    let diffA = bandPoint2.y - canvas.chartSpace.viewport.visibleArea.bottomLeft.y
+                    if (diffA > 0) {
+                        bandPoint1.y = bandPoint1.y - diffA
+                        bandPoint2.y = bandPoint2.y - diffA
+                        bandPoint3.y = bandPoint3.y - diffA
+                        bandPoint4.y = bandPoint4.y - diffA
+                        bandPoint5.y = bandPoint5.y - diffA
+                        bandPoint6.y = bandPoint6.y - diffA
+                    }
+
+                    let diffB = bandPoint1.y - canvas.chartSpace.viewport.visibleArea.topLeft.y
+                    if (diffB < 0) {
+                        bandPoint1.y = bandPoint1.y - diffB
+                        bandPoint2.y = bandPoint2.y - diffB
+                        bandPoint3.y = bandPoint3.y - diffB
+                        bandPoint4.y = bandPoint4.y - diffB
+                        bandPoint5.y = bandPoint5.y - diffB
+                        bandPoint6.y = bandPoint6.y - diffB
+                    }
+
                     bandPoint1 = canvas.chartSpace.viewport.fitIntoVisibleArea(bandPoint1);
                     bandPoint2 = canvas.chartSpace.viewport.fitIntoVisibleArea(bandPoint2);
                     bandPoint3 = canvas.chartSpace.viewport.fitIntoVisibleArea(bandPoint3);