Resolve #501, support set minor grid lines for the chart

chart.go

@@ -652,10 +652,16 @@ func parseFormatChartSet(formatSet string) (*formatChart, error) {
 //
 // Set the primary horizontal and vertical axis options by x_axis and y_axis. The properties that can be set are:
 //
+//    major_grid_lines
+//    minor_grid_lines
 //    reverse_order
 //    maximum
 //    minimum
 //
+// major_grid_lines: Specifies major gridlines.
+//
+// minor_grid_lines: Specifies minor gridlines.
+//
 // reverse_order: Specifies that the categories or values on reverse order (orientation of the chart). The reverse_order property is optional. The default value is false.
 //
 // maximum: Specifies that the fixed maximum, 0 is auto. The maximum property is optional. The default value is auto.
@@ -1601,6 +1607,9 @@ func (f *File) drawPlotAreaCatAx(formatSet *formatChart) []*cAxs {
 	if formatSet.XAxis.MajorGridlines {
 		axs[0].MajorGridlines = &cChartLines{SpPr: f.drawPlotAreaSpPr()}
 	}
+	if formatSet.XAxis.MinorGridlines {
+		axs[0].MinorGridlines = &cChartLines{SpPr: f.drawPlotAreaSpPr()}
+	}
 	return axs
 }
 
@@ -1641,6 +1650,9 @@ func (f *File) drawPlotAreaValAx(formatSet *formatChart) []*cAxs {
 	if formatSet.YAxis.MajorGridlines {
 		axs[0].MajorGridlines = &cChartLines{SpPr: f.drawPlotAreaSpPr()}
 	}
+	if formatSet.YAxis.MinorGridlines {
+		axs[0].MinorGridlines = &cChartLines{SpPr: f.drawPlotAreaSpPr()}
+	}
 	if pos, ok := valTickLblPos[formatSet.Type]; ok {
 		axs[0].TickLblPos.Val = pos
 	}

chart_test.go

@@ -144,7 +144,7 @@ func TestAddChart(t *testing.T) {
 	assert.NoError(t, f.AddChart("Sheet2", "P1", `{"type":"radar","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$30:$D$30"},{"name":"Sheet1!$A$31","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$31:$D$31"},{"name":"Sheet1!$A$32","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$32:$D$32"},{"name":"Sheet1!$A$33","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$33:$D$33"},{"name":"Sheet1!$A$34","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$34:$D$34"},{"name":"Sheet1!$A$35","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$35:$D$35"},{"name":"Sheet1!$A$36","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$36:$D$36"},{"name":"Sheet1!$A$37","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$37:$D$37"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"top_right","show_legend_key":false},"title":{"name":"Radar Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":true,"show_val":true},"show_blanks_as":"span"}`))
 	assert.NoError(t, f.AddChart("Sheet2", "X1", `{"type":"scatter","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$30:$D$30"},{"name":"Sheet1!$A$31","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$31:$D$31"},{"name":"Sheet1!$A$32","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$32:$D$32"},{"name":"Sheet1!$A$33","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$33:$D$33"},{"name":"Sheet1!$A$34","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$34:$D$34"},{"name":"Sheet1!$A$35","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$35:$D$35"},{"name":"Sheet1!$A$36","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$36:$D$36"},{"name":"Sheet1!$A$37","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$37:$D$37"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"bottom","show_legend_key":false},"title":{"name":"Scatter Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":true,"show_val":true},"show_blanks_as":"zero"}`))
 	assert.NoError(t, f.AddChart("Sheet2", "P16", `{"type":"doughnut","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$A$30:$D$37","values":"Sheet1!$B$30:$B$37"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"right","show_legend_key":false},"title":{"name":"Doughnut Chart"},"plotarea":{"show_bubble_size":false,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":false,"show_val":false},"show_blanks_as":"zero"}`))
-	assert.NoError(t, f.AddChart("Sheet2", "X16", `{"type":"line","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$30:$D$30"},{"name":"Sheet1!$A$31","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$31:$D$31"},{"name":"Sheet1!$A$32","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$32:$D$32"},{"name":"Sheet1!$A$33","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$33:$D$33"},{"name":"Sheet1!$A$34","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$34:$D$34"},{"name":"Sheet1!$A$35","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$35:$D$35"},{"name":"Sheet1!$A$36","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$36:$D$36"},{"name":"Sheet1!$A$37","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$37:$D$37","line":{"width":0.25}}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"top","show_legend_key":false},"title":{"name":"Line Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":true,"show_val":true},"show_blanks_as":"zero"}`))
+	assert.NoError(t, f.AddChart("Sheet2", "X16", `{"type":"line","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$30:$D$30"},{"name":"Sheet1!$A$31","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$31:$D$31"},{"name":"Sheet1!$A$32","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$32:$D$32"},{"name":"Sheet1!$A$33","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$33:$D$33"},{"name":"Sheet1!$A$34","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$34:$D$34"},{"name":"Sheet1!$A$35","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$35:$D$35"},{"name":"Sheet1!$A$36","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$36:$D$36"},{"name":"Sheet1!$A$37","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$37:$D$37","line":{"width":0.25}}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"top","show_legend_key":false},"title":{"name":"Line Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":true,"show_val":true},"show_blanks_as":"zero","x_axis":{"major_grid_lines":true,"minor_grid_lines":true},"y_axis":{"major_grid_lines":true,"minor_grid_lines":true}}`))
 	assert.NoError(t, f.AddChart("Sheet2", "P32", `{"type":"pie3D","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$A$30:$D$37","values":"Sheet1!$B$30:$B$37"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"bottom","show_legend_key":false},"title":{"name":"3D Pie Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":false,"show_val":false},"show_blanks_as":"zero"}`))
 	assert.NoError(t, f.AddChart("Sheet2", "X32", `{"type":"pie","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$A$30:$D$37","values":"Sheet1!$B$30:$B$37"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"bottom","show_legend_key":false},"title":{"name":"Pie Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":false,"show_val":false},"show_blanks_as":"gap"}`))
 	assert.NoError(t, f.AddChart("Sheet2", "P48", `{"type":"bar","series":[{"name":"Sheet1!$A$30","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$30:$D$30"},{"name":"Sheet1!$A$31","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$31:$D$31"},{"name":"Sheet1!$A$32","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$32:$D$32"},{"name":"Sheet1!$A$33","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$33:$D$33"},{"name":"Sheet1!$A$34","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$34:$D$34"},{"name":"Sheet1!$A$35","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$35:$D$35"},{"name":"Sheet1!$A$36","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$36:$D$36"},{"name":"Sheet1!$A$37","categories":"Sheet1!$B$29:$D$29","values":"Sheet1!$B$37:$D$37"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"left","show_legend_key":false},"title":{"name":"2D Clustered Bar Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":true,"show_val":true},"show_blanks_as":"zero"}`))

xmlChart.go

@@ -347,6 +347,7 @@ type cAxs struct {
 	Delete         *attrValBool   `xml:"delete"`
 	AxPos          *attrValString `xml:"axPos"`
 	MajorGridlines *cChartLines   `xml:"majorGridlines"`
+	MinorGridlines *cChartLines   `xml:"minorGridlines"`
 	NumFmt         *cNumFmt       `xml:"numFmt"`
 	MajorTickMark  *attrValString `xml:"majorTickMark"`
 	MinorTickMark  *attrValString `xml:"minorTickMark"`
@@ -514,6 +515,7 @@ type cPageMargins struct {
 type formatChartAxis struct {
 	Crossing            string  `json:"crossing"`
 	MajorGridlines      bool    `json:"major_grid_lines"`
+	MinorGridlines      bool    `json:"minor_grid_lines"`
 	MajorTickMark       string  `json:"major_tick_mark"`
 	MinorTickMark       string  `json:"minor_tick_mark"`
 	MinorUnitType       string  `json:"minor_unit_type"`