$spreadsheet = new Spreadsheet();
$worksheet = $spreadsheet->getActiveSheet();
// changed data to simulate a trend chart - Xaxis are dates; Yaxis are 3 meausurements from each date
$worksheet->fromArray(
    [
        ['', 'metric1', 'metric2', 'metric3'],
        ['=DATEVALUE("2021-01-01")', 12.1, 15.1, 21.1],
        ['=DATEVALUE("2021-04-01")', 56.2, 73.2, 86.2],
        ['=DATEVALUE("2021-07-01")', 52.2, 61.2, 69.2],
        ['=DATEVALUE("2021-10-01")', 30.2, 32.2, 24.2],
    ]
);
$worksheet->getStyle('A2:A5')->getNumberFormat()->setFormatCode('mm/dd/yyyy');
$worksheet->getColumnDimension('A')->setAutoSize(true);
$worksheet->setSelectedCells('A1');

// Set the Labels for each data series we want to plot
//     Datatype
//     Cell reference for data
//     Format Code
//     Number of datapoints in series
//     Data values
//     Data Marker (null)
//     Color (null)
$dataSeriesLabels = [
    new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$B$1', null, 1), // was 2010
    new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$C$1', null, 1), // was 2011
    new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$D$1', null, 1), // was 2012
];


// Set the X-Axis Labels
// changed from STRING to NUMBER
// added 2 additional x-axis values associated with each of the 3 metrics
// added FORMAT_CODE_NUMBER
// Number of datapoints in series
$xAxisTickValues = [
    //new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$A$2:$A$5', null, 4), // Q1 to Q4
		new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$A$2:$A$5', 
				Properties::FORMAT_CODE_DATE, 4),
    new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$A$2:$A$5', 
				Properties::FORMAT_CODE_DATE, 4),
    new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$A$2:$A$5', 
				Properties::FORMAT_CODE_DATE, 4),
];

// Set the Data values for each data series we want to plot
//     Datatype
//     Cell reference for data
//     Format Code
//     Number of datapoints in series
//     Data values
//     Data Marker
//     Data Marker Color fill/[fill,Border]
//     Data Marker size
//   Color(s) added
$dataSeriesValues = [
		new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$B$2:$B$5', 
			Properties::FORMAT_CODE_NUMBER, 4, null, 'diamond', null, 7),
		new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$C$2:$C$5', 
			Properties::FORMAT_CODE_NUMBER, 4, null, 'square', 'accent1', 7),  
		new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$D$2:$D$5', 
			Properties::FORMAT_CODE_NUMBER, 4, null, 'triangle', null, 7),
];

// series 1 
// marker details
$dataSeriesValues[0]->getMarkerColor1()->setColorProperties('0070C0',null,'srgbClr'); // diamond fill color
$dataSeriesValues[0]->getMarkerColor2()->setColorProperties('002060',null,'srgbClr'); // diamond border color

// line details - smooth line, connected
$dataSeriesValues[0]->setScatterLines(TRUE)
                    ->setSmoothLine(TRUE)
										->setLineColorProperties('accent1',40,'schemeClr');
                                           // value, alpha, type
// line style special effects: dashed, head arrow, end arrow 
$dataSeriesValues[0]->setLineStyleProperties(2.5,'tri','sysDash','sq','miter','arrow',4,'triangle',6);
//                                            width compound  dash    cap  join  headtype headsize(med,sm) endtype endsize(med,lg)


# series 2 - straight line - no special effects, connected, straight line
$dataSeriesValues[1]->getMarkerColor1()->setColorProperties('accent6',3,'schemeClr'); // square fill 
$dataSeriesValues[1]->getMarkerColor2()->setColorProperties('0FFF00',null,'srgbClr'); // square border 
$dataSeriesValues[1]->setScatterLines(TRUE)
                    ->setSmoothLine(FALSE)
										->setLineColorProperties('FF0000',80,'srgbClr');
$dataSeriesValues[1]->setLineWidth(2.0);

# series 3 - markers, no line
$dataSeriesValues[2]->getMarkerColor1()->setColorProperties('FFFF00',null,'srgbClr'); // triangle fill 
$dataSeriesValues[2]->getMarkerColor2()->setColorProperties('accent4',null,'schemeClr'); // triangle border 
$dataSeriesValues[2]->setScatterLines(FALSE); // points not connected 


// set Xaxis to m/d/yyyy dates instead of Excel-equivalent-year1900-numbers
$xAxis = new Axis();
$xAxis->setAxisNumberProperties(Properties::FORMAT_CODE_DATE );

// Build the dataseries
$series = new DataSeries(
    DataSeries::TYPE_SCATTERCHART, // plotType
    null, // plotGrouping (Scatter charts don't have grouping)
    range(0, count($dataSeriesValues) - 1), // plotOrder
    $dataSeriesLabels, // plotLabel
    $xAxisTickValues, // plotCategory
    $dataSeriesValues, // plotValues
    null, // plotDirection
		null, // smooth line
    DataSeries::STYLE_SMOOTHMARKER  // plotStyle
    //DataSeries::STYLE_MARKER  // plotStyle
);

// Set the series in the plot area
$plotArea = new PlotArea(null, [$series]);
// Set the chart legend
$legend = new ChartLegend(ChartLegend::POSITION_TOPRIGHT, null, false);

$title = new Title('Test Scatter Trend Chart');
$yAxisLabel = new Title('Value ($k)');

// Create the chart
$chart = new Chart(
    'chart1', // name
    $title, // title
    $legend, // legend
    $plotArea, // plotArea
    true, // plotVisibleOnly
    DataSeries::EMPTY_AS_GAP, // displayBlanksAs
    null, // xAxisLabel
    $yAxisLabel,  // yAxisLabel
    // added xAxis for correct date display
    $xAxis, // xAxis
);

// Set the position where the chart should appear in the worksheet
$chart->setTopLeftPosition('A7');
$chart->setBottomRightPosition('H20');
// Add the chart to the worksheet
$worksheet->addChart($chart);

// Save Excel 2007 file
$filename = '33_Chart_create_Color_scatter_newlib.xlsx';
$writer = IOFactory::createWriter($spreadsheet, 'Xlsx');
$writer->setIncludeCharts(true);
$writer->save($filename);