This closes #1536, support fallback to default column width in sheet format property

Author: xuri

col.go

@@ -657,6 +657,9 @@ func (f *File) getColWidth(sheet string, col int) int {
 			return int(convertColWidthToPixels(width))
 		}
 	}
+	if ws.SheetFormatPr != nil && ws.SheetFormatPr.DefaultColWidth > 0 {
+		return int(convertColWidthToPixels(ws.SheetFormatPr.DefaultColWidth))
+	}
 	// Optimization for when the column widths haven't changed.
 	return int(defaultColWidthPixels)
 }
@@ -715,6 +718,9 @@ func (f *File) GetColWidth(sheet, col string) (float64, error) {
 			return width, err
 		}
 	}
+	if ws.SheetFormatPr != nil && ws.SheetFormatPr.DefaultColWidth > 0 {
+		return ws.SheetFormatPr.DefaultColWidth, err
+	}
 	// Optimization for when the column widths haven't changed.
 	return defaultColWidth, err
 }

col_test.go

@@ -366,6 +366,15 @@ func TestColWidth(t *testing.T) {
 	assert.Equal(t, defaultColWidth, width)
 	assert.NoError(t, err)
 
+	ws, ok := f.Sheet.Load("xl/worksheets/sheet1.xml")
+	assert.True(t, ok)
+	ws.(*xlsxWorksheet).SheetFormatPr = &xlsxSheetFormatPr{DefaultColWidth: 10}
+	ws.(*xlsxWorksheet).Cols = nil
+	width, err = f.GetColWidth("Sheet1", "A")
+	assert.NoError(t, err)
+	assert.Equal(t, 10.0, width)
+	assert.Equal(t, 76, f.getColWidth("Sheet1", 1))
+
 	// Test set and get column width with illegal cell reference
 	width, err = f.GetColWidth("Sheet1", "*")
 	assert.Equal(t, defaultColWidth, width)