Avoid overlapping vertical bands #553

In case one vertical band comes after another it does not consider actual rendered range of previous band and starts rendering from defined template range.
This fix takes into account already rendered band in the same row and adds appropriate offset for current vertical band

core/modules/core/src/com/haulmont/yarg/formatters/impl/XlsxFormatter.java

@@ -682,7 +682,7 @@ private void setPreviousRangeVerticalOffset(int previousRangesRightOffset, BandD
     protected Row findNextRowForVBand(BandData band, Range templateRange, List<Row> resultSheetRows) {
         Row firstRow = null;
         boolean isFirstLevelBand = BandData.ROOT_BAND_NAME.equals(band.getParentBand().getName());
-        setPreviousRangeVerticalOffset(0, null);
+        this.previousRangesRightOffset = 0;
 
         Range lastRenderedRange = getLastRenderedBandForThisLevel(band);
         if (lastRenderedRange != null) {//this band has been already rendered at least once
@@ -696,6 +696,18 @@ protected Row findNextRowForVBand(BandData band, Range templateRange, List<Row>
             firstRow = findNextRowForChildBand(band, templateRange, resultSheetRows);
         } else {//this is the first render
             firstRow = findNextRowForFirstRender(templateRange, resultSheetRows);
+            if (previousRangeBandData != null && firstRow != null) {//row for rendering and previously rendered data already there
+                Range lastRenderedBandRange = getLastRenderedBandForThisLevel(previousRangeBandData);
+                if (firstRow.getR() != null && firstRow.getR().intValue() <= lastRenderedBandRange.getLastRow()) {
+                    //we have intersection between previously rendered data and what we want to add
+                    int lastRenderedColumn = lastRenderedBandRange.getLastColumn();
+                    int firstTemplateColumn = templateRange.getFirstColumn();
+                    if (lastRenderedColumn != firstTemplateColumn) {
+                        previousRangesRightOffset = lastRenderedColumn - firstTemplateColumn + 1;
+                    }
+                    previousRangeBandData = band;
+                }
+            }
         }
         return firstRow;
     }