# Manage Chart Data Labels in Presentations Using PHP

> Learn to add and format chart data labels in PowerPoint presentations using Aspose.Slides for PHP via Java for more engaging slides.

Source: https://docs.aspose.com/slides/php-java/chart-data-label/
Updated: 2026-08-05


## **Introduction**

Data labels on a chart show details about the chart data series or individual data points. They allow readers to quickly identify data series and they also make charts easier to understand.

## **Set Data Precision in Chart Data Labels**

This PHP code shows you how to set the data precision in a chart data label:

```php
  $pres = new Presentation();
  try {
    $chart = $pres->getSlides()->get_Item(0)->getShapes()->addChart(ChartType::Line, 50, 50, 450, 300);
    $chart->setDataTable(true);
    $chart->getChartData()->getSeries()->get_Item(0)->setNumberFormatOfValues("#,##0.00");
    $pres->save("output.pptx", SaveFormat::Pptx);
  } finally {
    if (!java_is_null($pres)) {
      $pres->dispose();
    }
  }
```

## **Display Percentage as Labels**
Aspose.Slides for PHP via Java allows you to set percentage labels on displayed charts. This PHP code demonstrates the operation:

```php
  # Creates an instance of the Presentation class
  $pres = new Presentation();
  try {
    # Gets the first slide
    $slide = $pres->getSlides()->get_Item(0);
    $chart = $slide->getShapes()->addChart(ChartType::StackedColumn, 20, 20, 400, 400);
    $categoryCount = java_values($chart->getChartData()->getCategories()->size());
    $total_for_Cat = array_fill(0, $categoryCount, 0.0);
    for($k = 0; $k < $categoryCount ; $k++) {
      for($i = 0; $i < java_values($chart->getChartData()->getSeries()->size()) ; $i++) {
        $total_for_Cat[$k] = $total_for_Cat[$k] + java_values($chart->getChartData()->getSeries()->get_Item($i)->getDataPoints()->get_Item($k)->getValue()->getData());
      }
    }
    $dataPontPercent = 0.0;
    for($x = 0; $x < java_values($chart->getChartData()->getSeries()->size()) ; $x++) {
      $series = $chart->getChartData()->getSeries()->get_Item($x);
      $series->getLabels()->getDefaultDataLabelFormat()->setShowLegendKey(false);
      for($j = 0; $j < java_values($series->getDataPoints()->size()) ; $j++) {
        $lbl = $series->getDataPoints()->get_Item($j)->getLabel();
        $dataPontPercent = java_values($series->getDataPoints()->get_Item($j)->getValue()->getData()) / $total_for_Cat[$j] * 100;
        $port = new Portion();
        $port->setText(sprintf("%.2f %%", $dataPontPercent));
        $port->getPortionFormat()->setFontHeight(8.0);
        $lbl->getTextFrameForOverriding()->setText("");
        $para = $lbl->getTextFrameForOverriding()->getParagraphs()->get_Item(0);
        $para->getPortions()->add($port);
        $lbl->getDataLabelFormat()->setShowSeriesName(false);
        $lbl->getDataLabelFormat()->setShowPercentage(false);
        $lbl->getDataLabelFormat()->setShowLegendKey(false);
        $lbl->getDataLabelFormat()->setShowCategoryName(false);
        $lbl->getDataLabelFormat()->setShowBubbleSize(false);
      }
    }
    # Saves the presentation containing the chart
    $pres->save("output.pptx", SaveFormat::Pptx);
  } finally {
    if (!java_is_null($pres)) {
      $pres->dispose();
    }
  }
```

## **Set the Percentage Sign with Chart Data Labels**
This PHP code shows you to set the percentage sign for a chart data label:

```php
  # Creates an instance of the Presentation class
  $pres = new Presentation();
  try {
    # Gets a slide's reference through its index
    $slide = $pres->getSlides()->get_Item(0);
    # Creates the PercentsStackedColumn chart on a slide
    $chart = $slide->getShapes()->addChart(ChartType::PercentsStackedColumn, 20, 20, 500, 400);
    # Sets the NumberFormatLinkedToSource to false
    $chart->getAxes()->getVerticalAxis()->setNumberFormatLinkedToSource(false);
    $chart->getAxes()->getVerticalAxis()->setNumberFormat("0.00%");
    $chart->getChartData()->getSeries()->clear();
    $defaultWorksheetIndex = 0;
    # Gets the chart data worksheet
    $workbook = $chart->getChartData()->getChartDataWorkbook();
    # Adds new series
    $series = $chart->getChartData()->getSeries()->add($workbook->getCell($defaultWorksheetIndex, 0, 1, "Reds"), $chart->getType());
    $series->getDataPoints()->addDataPointForBarSeries($workbook->getCell($defaultWorksheetIndex, 1, 1, 0.3));
    $series->getDataPoints()->addDataPointForBarSeries($workbook->getCell($defaultWorksheetIndex, 2, 1, 0.5));
    $series->getDataPoints()->addDataPointForBarSeries($workbook->getCell($defaultWorksheetIndex, 3, 1, 0.8));
    $series->getDataPoints()->addDataPointForBarSeries($workbook->getCell($defaultWorksheetIndex, 4, 1, 0.65));
    # Sets the fill color of series
    $series->getFormat()->getFill()->setFillType(FillType::Solid);
    $series->getFormat()->getFill()->getSolidFillColor()->setColor(java("java.awt.Color")->RED);
    # Sets the LabelFormat properties
    $series->getLabels()->getDefaultDataLabelFormat()->setShowValue(true);
    $series->getLabels()->getDefaultDataLabelFormat()->setNumberFormatLinkedToSource(false);
    $series->getLabels()->getDefaultDataLabelFormat()->setNumberFormat("0.0%");
    $series->getLabels()->getDefaultDataLabelFormat()->getTextFormat()->getPortionFormat()->setFontHeight(10);
    $series->getLabels()->getDefaultDataLabelFormat()->getTextFormat()->getPortionFormat()->getFillFormat()->setFillType(FillType::Solid);
    $series->getLabels()->getDefaultDataLabelFormat()->getTextFormat()->getPortionFormat()->getFillFormat()->getSolidFillColor()->setColor(java("java.awt.Color")->WHITE);
    $series->getLabels()->getDefaultDataLabelFormat()->setShowValue(true);
    # Adds new series
    $series2 = $chart->getChartData()->getSeries()->add($workbook->getCell($defaultWorksheetIndex, 0, 2, "Blues"), $chart->getType());
    $series2->getDataPoints()->addDataPointForBarSeries($workbook->getCell($defaultWorksheetIndex, 1, 2, 0.7));
    $series2->getDataPoints()->addDataPointForBarSeries($workbook->getCell($defaultWorksheetIndex, 2, 2, 0.5));
    $series2->getDataPoints()->addDataPointForBarSeries($workbook->getCell($defaultWorksheetIndex, 3, 2, 0.2));
    $series2->getDataPoints()->addDataPointForBarSeries($workbook->getCell($defaultWorksheetIndex, 4, 2, 0.35));
    # Sets Fill type and color
    $series2->getFormat()->getFill()->setFillType(FillType::Solid);
    $series2->getFormat()->getFill()->getSolidFillColor()->setColor(java("java.awt.Color")->BLUE);
    $series2->getLabels()->getDefaultDataLabelFormat()->setShowValue(true);
    $series2->getLabels()->getDefaultDataLabelFormat()->setNumberFormatLinkedToSource(false);
    $series2->getLabels()->getDefaultDataLabelFormat()->setNumberFormat("0.0%");
    $series2->getLabels()->getDefaultDataLabelFormat()->getTextFormat()->getPortionFormat()->setFontHeight(10);
    $series2->getLabels()->getDefaultDataLabelFormat()->getTextFormat()->getPortionFormat()->getFillFormat()->setFillType(FillType::Solid);
    $series2->getLabels()->getDefaultDataLabelFormat()->getTextFormat()->getPortionFormat()->getFillFormat()->getSolidFillColor()->setColor(java("java.awt.Color")->WHITE);
    # Writes the presentation to disk
    $pres->save("SetDataLabelsPercentageSign_out.pptx", SaveFormat::Pptx);
  } finally {
    if (!java_is_null($pres)) {
      $pres->dispose();
    }
  }
```

## **Set Label Distance from an Axis**
This PHP code shows you how to set the label distance from a category axis when you are dealing with a chart plotted from axes:

```php
  # Creates an instance of the Presentation class
  $pres = new Presentation();
  try {
    # Gets a slide's reference
    $sld = $pres->getSlides()->get_Item(0);
    # Creates a chart on the slide
    $ch = $sld->getShapes()->addChart(ChartType::ClusteredColumn, 20, 20, 500, 300);
    # Sets the label distance from an axis
    $ch->getAxes()->getHorizontalAxis()->setLabelOffset(500);
    # WriteS the presentation to disk
    $pres->save("output.pptx", SaveFormat::Pptx);
  } finally {
    if (!java_is_null($pres)) {
      $pres->dispose();
    }
  }
```

## **Adjust Label Location**

When you create a chart that does not rely on any axis such as a pie chart, the chart's data labels may end up being too close to its edge. In such a case, you have to adjust the location of the data label so that the leader lines get displayed clearly.

This PHP code shows you how to adjust the label location on a pie chart:

```php
  $pres = new Presentation();
  try {
    $chart = $pres->getSlides()->get_Item(0)->getShapes()->addChart(ChartType::Pie, 50, 50, 200, 200);
    $series = $chart->getChartData()->getSeries();
    $label = $series->get_Item(0)->getLabels()->get_Item(0);
    $label->getDataLabelFormat()->setShowValue(true);
    $label->getDataLabelFormat()->setPosition(LegendDataLabelPosition->OutsideEnd);
    $label->setX(0.71);
    $label->setY(0.04);
    $pres->save("pres.pptx", SaveFormat::Pptx);
  } finally {
    if (!java_is_null($pres)) {
      $pres->dispose();
    }
  }
```

![pie-chart-adjusted-label](pie-chart-adjusted-label.png)

## **FAQ**

### How can I prevent data labels from overlapping on dense charts?

Combine automatic label placement, leader lines, and reduced font size; if necessary, hide some fields (for example, the category) or show labels only for extreme/key points.

### How can I disable labels only for zero, negative, or empty values?

Filter data points before enabling labels and turn off display for values of 0, negative values, or missing values according to a defined rule.

### How can I ensure a consistent label style when exporting to PDF/images?

Explicitly set fonts (family, size) and verify that the font is available on the rendering side to avoid fallback.