Charts

Add data visualizations to slides with Podium.add_chart/4. Podium supports 29 chart types with editable data backed by embedded Excel workbooks -- your audience can double-click any chart in PowerPoint and modify the underlying data.

Try it yourself

Run mix run demos/charts.exs to generate a presentation with all the examples from this guide.

alias Podium.Chart.ChartData

chart_data =
  ChartData.new()
  |> ChartData.add_categories(["Q1", "Q2", "Q3", "Q4"])
  |> ChartData.add_series("Revenue", [12_500, 14_600, 15_200, 18_100])

slide = Podium.add_chart(slide, :column_clustered, chart_data,
  x: {0.5, :inches}, y: {1, :inches},
  width: {9, :inches}, height: {5, :inches})

The Chart Data Model

Every chart starts with a data structure that defines the categories and series. Podium provides three data modules, each for a different family of chart types:

Module	Used For	Categories
`Podium.Chart.ChartData`	Column, bar, line, pie, area, doughnut, radar	Named categories (strings)
`Podium.Chart.XyChartData`	Scatter charts	Numeric X values per series
`Podium.Chart.BubbleChartData`	Bubble charts	Numeric X values + bubble sizes

ChartData

Podium.Chart.ChartData is the most common. You build it by adding categories (shared across all series) and then adding one or more named series with numeric values.

alias Podium.Chart.ChartData

data =
  ChartData.new()
  |> ChartData.add_categories(["Engineering", "Marketing", "Sales", "Support"])
  |> ChartData.add_series("Headcount", [230, 85, 120, 65], color: "4472C4")
  |> ChartData.add_series("Budget ($K)", [4200, 2100, 3500, 1800], color: "ED7D31")

Each series accepts these options:

Option	Type	Default	Description
`:color`	`String.t()`	`nil`	Hex RGB color for the series
`:pattern`	`keyword`	`nil`	Pattern fill (see Series Formatting)
`:marker`	`keyword`	`nil`	Marker options for line/scatter charts
`:point_colors`	`map`	`%{}`	Per-point color overrides by index
`:point_formats`	`map`	`%{}`	Per-point fill/line overrides by index
`:data_labels`	`map`	`nil`	Per-point data label overrides by index

A ChartData struct supports up to 25 series. All values must be numbers.

Adding a Chart

Use Podium.add_chart/4 to place a chart on a slide. The function takes the slide, chart type atom, chart data, and a keyword list of options. It returns the updated slide.

slide = Podium.add_chart(slide, :bar_clustered, data,
  x: {0.5, :inches}, y: {1, :inches},
  width: {12, :inches}, height: {5.5, :inches},
  title: "Department Overview",
  legend: :bottom)

Column clustered chart with axis config and data labels

Option	Type	Default	Description
`:x`	`emu_spec`	required	Horizontal position
`:y`	`emu_spec`	required	Vertical position
`:width`	`emu_spec`	required	Chart width
`:height`	`emu_spec`	required	Chart height
`:title`	`String.t()` or `keyword`	`nil`	Chart title
`:legend`	`atom` or `keyword` or `false`	`nil`	Legend configuration
`:data_labels`	`list` or `keyword`	`[]`	Data label configuration
`:category_axis`	`keyword`	`[]`	Category axis options
`:value_axis`	`keyword`	`[]`	Value axis options

Category Charts

Category charts use ChartData with string categories on one axis and numeric values on the other. Here are the available types grouped by family.

Column and Bar Charts

Column charts display vertical bars; bar charts display horizontal bars.

Type	Description
`:column_clustered`	Side-by-side vertical bars
`:column_stacked`	Stacked vertical bars
`:column_stacked_100`	Stacked vertical bars normalized to 100%
`:bar_clustered`	Side-by-side horizontal bars
`:bar_stacked`	Stacked horizontal bars
`:bar_stacked_100`	Stacked horizontal bars normalized to 100%

# Stacked bar chart showing channel breakdown
channel_data =
  ChartData.new()
  |> ChartData.add_categories(["Jan", "Feb", "Mar", "Apr", "May", "Jun"])
  |> ChartData.add_series("Email", [250, 230, 210, 200, 185, 170], color: "4472C4")
  |> ChartData.add_series("Chat", [180, 200, 220, 250, 280, 310], color: "ED7D31")
  |> ChartData.add_series("Phone", [100, 95, 90, 85, 80, 75], color: "A5A5A5")

slide = Podium.add_chart(slide, :bar_stacked, channel_data,
  x: {0.5, :inches}, y: {1, :inches},
  width: {12, :inches}, height: {5.5, :inches},
  title: "Support Tickets by Channel",
  legend: :right)

Stacked bar chart showing channel breakdown

Line Charts

Type	Description
`:line`	Lines without markers
`:line_markers`	Lines with data point markers
`:line_stacked`	Stacked lines
`:line_markers_stacked`	Stacked lines with markers
`:line_stacked_100`	Stacked lines normalized to 100%
`:line_markers_stacked_100`	Stacked lines with markers, normalized to 100%

trend_data =
  ChartData.new()
  |> ChartData.add_categories(["Jan", "Feb", "Mar", "Apr", "May", "Jun"])
  |> ChartData.add_series("Web", [45, 48, 52, 55, 60, 63], color: "4472C4")
  |> ChartData.add_series("Mobile", [30, 35, 38, 42, 50, 55], color: "ED7D31")

slide = Podium.add_chart(slide, :line_markers, trend_data,
  x: {0.5, :inches}, y: {1, :inches},
  width: {12, :inches}, height: {5.5, :inches},
  title: "Monthly Active Users",
  legend: :top,
  value_axis: [title: "Users (thousands)", major_gridlines: true])

Line chart with markers showing monthly active users

Pie and Doughnut Charts

Pie and doughnut charts show proportions. They do not have axes.

Type	Description
`:pie`	Standard pie chart
`:pie_exploded`	Pie with slices pulled out (25% explosion)
`:doughnut`	Ring chart with 50% hole
`:doughnut_exploded`	Ring chart with slices pulled out

market_data =
  ChartData.new()
  |> ChartData.add_categories(["North America", "Europe", "Asia Pacific", "Latin America"])
  |> ChartData.add_series("Revenue", [42, 28, 18, 12],
    point_colors: %{0 => "2E75B6", 1 => "BDD7EE", 2 => "ED7D31", 3 => "FBE5D6"})

slide = Podium.add_chart(slide, :pie, market_data,
  x: {2, :inches}, y: {1, :inches},
  width: {9, :inches}, height: {5.5, :inches},
  title: "Revenue by Region",
  legend: :right,
  data_labels: [:category, :percent])

Pie chart with per-point colors and category labels

Area Charts

Type	Description
`:area`	Standard area chart
`:area_stacked`	Stacked area
`:area_stacked_100`	Stacked area normalized to 100%

Radar Charts

Type	Description
`:radar`	Radar without markers
`:radar_markers`	Radar with data point markers
`:radar_filled`	Filled radar (spider chart)

skill_data =
  ChartData.new()
  |> ChartData.add_categories(["Speed", "Power", "Range", "Durability", "Precision"])
  |> ChartData.add_series("Model A", [80, 90, 70, 85, 75], color: "4472C4")
  |> ChartData.add_series("Model B", [70, 65, 95, 70, 90], color: "ED7D31")

slide = Podium.add_chart(slide, :radar_filled, skill_data,
  x: {2, :inches}, y: {1, :inches},
  width: {9, :inches}, height: {5.5, :inches},
  title: "Product Comparison",
  legend: :bottom)

Filled radar chart comparing two models

Chart Titles

Pass a string for a plain title, or a keyword list for formatted titles. Pass nil (the default) for no title.

# Plain title
Podium.add_chart(slide, :column_clustered, data,
  x: {0.5, :inches}, y: {1, :inches}, width: {12, :inches}, height: {5, :inches},
  title: "Quarterly Revenue")

# Formatted title
Podium.add_chart(slide, :column_clustered, data,
  x: {0.5, :inches}, y: {1, :inches}, width: {12, :inches}, height: {5, :inches},
  title: [text: "Quarterly Revenue", font_size: 18, bold: true, color: "003366", font: "Arial"])

Title formatting options: :text, :font_size, :bold, :italic, :color, :font.

Legends

Control legend visibility and position. Pass false or nil for no legend, an atom for position only, or a keyword list for full formatting.

# Position only
legend: :bottom

# Formatted legend
legend: [position: :bottom, font_size: 10, bold: true, font: "Arial", color: "333333"]

Legend positions: :left, :right, :top, :bottom.

Data Labels

Data labels display values directly on chart elements. Pass a list of atoms to control what information appears, or a keyword list for full configuration.

# Show category names and percentages (common for pie charts)
data_labels: [:category, :percent]

# Show values with positioning and number format
data_labels: [show: [:value], position: :outside_end, number_format: "$#,##0"]

# White labels for dark backgrounds
data_labels: [show: [:value], color: "FFFFFF"]

Available label content: :value, :category, :series, :percent. Use :color with a hex string to set the text color (useful for charts on dark backgrounds).

Position	Description
`:center`	Centered on the data point
`:inside_end`	Inside the bar, near the end
`:inside_base`	Inside the bar, near the base
`:outside_end`	Outside the bar end
`:top`	Above the point
`:bottom`	Below the point
`:left`	Left of the point
`:right`	Right of the point
`:best_fit`	PowerPoint chooses the position

Category Axis

Customize the category (horizontal) axis with the :category_axis option.

slide = Podium.add_chart(slide, :column_clustered, data,
  x: {0.5, :inches}, y: {1, :inches}, width: {12, :inches}, height: {5, :inches},
  category_axis: [
    title: "Quarter",
    label_rotation: -45,
    major_tick_mark: :cross,
    minor_tick_mark: :in
  ])

Option	Type	Default	Description
`:title`	`String.t()` or `keyword`	`nil`	Axis title (plain string or formatted)
`:label_rotation`	`number`	`nil`	Label rotation in degrees
`:reverse`	`boolean`	`false`	Reverse axis direction
`:visible`	`boolean`	`true`	Show or hide the axis
`:major_tick_mark`	`atom`	`nil`	`:out`, `:in`, `:cross`, or `:none`
`:minor_tick_mark`	`atom`	`nil`	`:out`, `:in`, `:cross`, or `:none`
`:crosses`	`atom` or `number`	`nil`	Where the value axis crosses: `:auto_zero`, `:min`, `:max`, or a number
`:color`	`String.t()`	`nil`	Hex color for tick label text (e.g. `"FFFFFF"`)
`:line_color`	`String.t()`	`nil`	Hex color for the axis line
`:type`	`:date`	`nil`	Set to `:date` for date axis mode

Axis titles support the same formatting options as chart titles: :text, :font_size, :bold, :italic, :color, :font.

category_axis: [title: [text: "Quarter", font_size: 12, bold: true, color: "333333"]]

Value Axis

Customize the value (numeric) axis with the :value_axis option.

slide = Podium.add_chart(slide, :column_clustered, data,
  x: {0.5, :inches}, y: {1, :inches}, width: {12, :inches}, height: {5, :inches},
  value_axis: [
    title: "Amount ($)",
    number_format: "$#,##0",
    major_gridlines: true,
    min: 0,
    max: 20_000,
    major_unit: 5000
  ])

Option	Type	Default	Description
`:title`	`String.t()` or `keyword`	`nil`	Axis title
`:number_format`	`String.t()`	`nil`	Excel-style number format (e.g. `"$#,##0"`)
`:major_gridlines`	`boolean`	`true`	Show major gridlines
`:minor_gridlines`	`boolean`	`false`	Show minor gridlines
`:min`	`number`	`nil`	Minimum axis value
`:max`	`number`	`nil`	Maximum axis value
`:major_unit`	`number`	`nil`	Major unit step
`:minor_unit`	`number`	`nil`	Minor unit step
`:crosses`	`atom` or `number`	`nil`	Where the category axis crosses
`:label_rotation`	`number`	`nil`	Label rotation in degrees
`:reverse`	`boolean`	`false`	Reverse axis direction
`:visible`	`boolean`	`true`	Show or hide the axis
`:major_tick_mark`	`atom`	`nil`	`:out`, `:in`, `:cross`, or `:none`
`:minor_tick_mark`	`atom`	`nil`	`:out`, `:in`, `:cross`, or `:none`
`:color`	`String.t()`	`nil`	Hex color for tick label text (e.g. `"FFFFFF"`)
`:line_color`	`String.t()`	`nil`	Hex color for the axis line
`:major_gridlines_color`	`String.t()`	`nil`	Hex color for major gridlines
`:minor_gridlines_color`	`String.t()`	`nil`	Hex color for minor gridlines

Series Formatting

Colors

Set a series color with the :color option on ChartData.add_series/4:

ChartData.add_series(data, "Revenue", [100, 200, 300], color: "4472C4")

Pattern Fills

Use pattern fills instead of solid colors:

ChartData.add_series(data, "Email", [250, 230, 210],
  pattern: [type: :dn_diag, foreground: "4472C4", background: "FFFFFF"])

Pattern fills and per-point formatting on columns

The :type must be one of the 54 pattern presets from Podium.Pattern (e.g. :dn_diag, :lt_horz, :dk_vert, :sm_grid, :cross).

Markers

For line and scatter charts, customize data point markers:

ChartData.add_series(data, "Trend", [20, 35, 45, 50, 55, 70],
  color: "4472C4",
  marker: [style: :diamond, size: 10, fill: "4472C4", line: "002060"])

Marker styles: :circle, :square, :diamond, :triangle, :star, :x, :plus, :dash, :dot, :none.

Per-Point Formatting

Override the appearance of individual data points within a series.

Point Colors

Color specific points by index:

ChartData.add_series(data, "Revenue", [42, 28, 18, 35, 22],
  point_colors: %{0 => "2E75B6", 3 => "ED7D31"})

Point Formats

Apply fill and line formatting to specific points:

ChartData.add_series(data, "Revenue", [42, 28, 18, 35, 22],
  point_formats: %{
    0 => [fill: "2E75B6", line: [color: "001133", width: {2, :pt}]],
    3 => [fill: "ED7D31", line: [color: "7F3300", width: {2, :pt}]]
  })

Per-Point Data Labels

Show data labels on specific points only:

ChartData.add_series(data, "Revenue ($K)", [42, 28, 18, 35, 22],
  data_labels: %{
    0 => [show: [:value], position: :outside_end, number_format: "$#,##0K"],
    3 => [show: [:value, :category], position: :outside_end]
  })

XY (Scatter) Charts

Scatter charts plot data as X/Y coordinate pairs. Use Podium.Chart.XyChartData instead of ChartData -- there are no shared categories, each series provides its own X and Y value lists.

alias Podium.Chart.XyChartData

xy_data =
  XyChartData.new()
  |> XyChartData.add_series("Series A", [1, 2, 3, 4, 5], [2.3, 4.1, 3.7, 5.2, 4.8],
    color: "4472C4")
  |> XyChartData.add_series("Series B", [1, 2, 3, 4, 5], [1.5, 3.2, 2.8, 4.5, 3.9],
    color: "ED7D31")

slide = Podium.add_chart(slide, :scatter, xy_data,
  x: {0.5, :inches}, y: {1, :inches},
  width: {12, :inches}, height: {5.5, :inches},
  title: "Scatter Analysis")

Scatter chart with two series

Type	Description
`:scatter`	Points only (no connecting lines)
`:scatter_lines`	Points connected with straight lines
`:scatter_lines_no_markers`	Straight lines, no point markers
`:scatter_smooth`	Points connected with smooth curves
`:scatter_smooth_no_markers`	Smooth curves, no point markers

XyChartData.add_series/5 takes the series name, X values list, Y values list, and optional formatting options. The X and Y lists must have the same length, and all values must be numbers.

Bubble Charts

Bubble charts extend scatter charts with a third dimension: bubble size. Use Podium.Chart.BubbleChartData.

alias Podium.Chart.BubbleChartData

bubble_data =
  BubbleChartData.new()
  |> BubbleChartData.add_series("Region A",
    [1, 3, 5, 7], [10, 25, 15, 30], [5, 12, 8, 15],
    color: "4472C4")
  |> BubbleChartData.add_series("Region B",
    [2, 4, 6, 8], [20, 15, 30, 10], [10, 6, 14, 8],
    color: "ED7D31")

slide = Podium.add_chart(slide, :bubble, bubble_data,
  x: {0.5, :inches}, y: {1, :inches},
  width: {12, :inches}, height: {5.5, :inches},
  title: "Market Opportunity Analysis")

Bubble chart with sized data points

Type	Description
`:bubble`	Standard bubble chart
`:bubble_3d`	Bubble chart with 3D effect

BubbleChartData.add_series/6 takes the series name, X values, Y values, bubble sizes, and optional formatting options. All three lists must have the same length.

Date Axes

When your categories represent dates, set the category axis type to :date to get proper date-based spacing and formatting.

date_data =
  ChartData.new()
  |> ChartData.add_categories(["2025-01", "2025-04", "2025-07", "2025-10", "2026-01"])
  |> ChartData.add_series("Sales", [120, 145, 190, 210, 250], color: "4472C4")

slide = Podium.add_chart(slide, :line_markers, date_data,
  x: {0.5, :inches}, y: {1, :inches},
  width: {12, :inches}, height: {5.5, :inches},
  title: "Quarterly Sales",
  category_axis: [
    type: :date,
    title: "Date",
    base_time_unit: :months,
    major_time_unit: :months,
    major_unit: 3
  ],
  value_axis: [title: "Sales ($K)", major_gridlines: true])

Date axis options:

Option	Type	Description
`:base_time_unit`	`:days`, `:months`, or `:years`	Base time unit for date axis
`:major_time_unit`	`:days`, `:months`, or `:years`	Major tick time unit
`:minor_time_unit`	`:days`, `:months`, or `:years`	Minor tick time unit
`:major_unit`	`number`	Number of time units between major ticks
`:minor_unit`	`number`	Number of time units between minor ticks

Chart Type Reference

All 29 chart types supported by Podium:

Category	Type Atom	Data Module
Column	`:column_clustered`	`ChartData`
Column	`:column_stacked`	`ChartData`
Column	`:column_stacked_100`	`ChartData`
Bar	`:bar_clustered`	`ChartData`
Bar	`:bar_stacked`	`ChartData`
Bar	`:bar_stacked_100`	`ChartData`
Line	`:line`	`ChartData`
Line	`:line_markers`	`ChartData`
Line	`:line_stacked`	`ChartData`
Line	`:line_markers_stacked`	`ChartData`
Line	`:line_stacked_100`	`ChartData`
Line	`:line_markers_stacked_100`	`ChartData`
Pie	`:pie`	`ChartData`
Pie	`:pie_exploded`	`ChartData`
Area	`:area`	`ChartData`
Area	`:area_stacked`	`ChartData`
Area	`:area_stacked_100`	`ChartData`
Doughnut	`:doughnut`	`ChartData`
Doughnut	`:doughnut_exploded`	`ChartData`
Radar	`:radar`	`ChartData`
Radar	`:radar_markers`	`ChartData`
Radar	`:radar_filled`	`ChartData`
Scatter	`:scatter`	`XyChartData`
Scatter	`:scatter_lines`	`XyChartData`
Scatter	`:scatter_lines_no_markers`	`XyChartData`
Scatter	`:scatter_smooth`	`XyChartData`
Scatter	`:scatter_smooth_no_markers`	`XyChartData`
Bubble	`:bubble`	`BubbleChartData`
Bubble	`:bubble_3d`	`BubbleChartData`

For even more charting power, see Combo Charts to combine multiple chart types in a single plot area.

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