Examples

Examples

This page provides a gallery of examples to showcase the kinds of plots you can create with fplot. Each example includes the code in both Fennel and Lua, along with the resulting plot.

1. Line and Point Plot

A standard plot combining smooth lines and distinct data points.

Fennel

(local fplot (require :fplot))

(local data1 [])
(for [i 0 50]
  (let [x (* i 0.2)]
    (table.insert data1 [x (* (math.exp (* -0.1 x)) (math.cos x))])))

(local data2 [[1 0.5] [3 0.1] [5 -0.2] [7 -0.1] [9 0.05]])

(fplot.plot
  {:options {:title "Damped Oscillation with Data Points"
             :x-label "Time"
             :y-label "Amplitude"
             :grid true
             :key {:position "top right"}}
   :datasets [{:title "Model"
               :style "lines"
               :color "blue"
               :data data1}
              {:title "Measurements"
               :style "points"
               :color "red"
               :pointtype 7
               :data data2}]})

Lua

require("fennel").install()
local fplot = require("fplot")

local data1 = {}
for i = 0, 50 do
  local x = i * 0.2
  table.insert(data1, {x, math.exp(-0.1 * x) * math.cos(x)})
end

local data2 = {{1, 0.5}, {3, 0.1}, {5, -0.2}, {7, -0.1}, {9, 0.05}}

fplot.plot({
  options = {
    title = "Damped Oscillation with Data Points",
    x_label = "Time",
    y_label = "Amplitude",
    grid = true,
    key = {position = "top right"}
  },
  datasets = {
    {
      title = "Model",
      style = "lines",
      color = "blue",
      data = data1
    },
    {
      title = "Measurements",
      style = "points",
      color = "red",
      pointtype = 7,
      data = data2
    }
  }
})

(The resulting plot generated by fplot)

---

2. Bar Chart / Histogram

Creating a bar chart using the boxes style, which is great for categorical data.

Fennel

(local fplot (require :fplot))

(fplot.plot
  {:options {:title "Annual Production by Factory"
             :y-label "Units Produced"
             :x-range [0.5 4.5]
             :y-range [0 50000]
             :xtics [["North" 1] ["South" 2] ["East" 3] ["West" 4]]
             :extra-opts ["set style fill solid 0.8"]}
   :datasets [{:title "Production"
               :style "boxes"
               :data [[1 42000] [2 35000] [3 48000] [4 29000]]}]})

Lua

require("fennel").install()
local fplot = require("fplot")

fplot.plot({
  options = {
    title = "Annual Production by Factory",
    y_label = "Units Produced",
    x_range = {0.5, 4.5},
    y_range = {0, 50000},
    xtics = {{"North", 1}, {"South", 2}, {"East", 3}, {"West", 4}},
    extra_opts = {"set style fill solid 0.8"}
  },
  datasets = {
    {
      title = "Production",
      style = "boxes",
      data = {{1, 42000}, {2, 35000}, {3, 48000}, {4, 29000}}
    }
  }
})

(The resulting plot generated by fplot)

---

3. 3D Surface Plot

Using fplot.splot to visualize three-dimensional data.

Fennel

(local fplot (require :fplot))

(local data [])
(for [i -20 20]
  (let [x (* i 0.5)
        row []]
    (for [j -20 20]
      (let [y (* j 0.5)
            r (+ (math.sqrt (+ (* x x) (* y y))) 1e-6)
            z (/ (math.sin r) r)]
        (table.insert row [x y z])))
    (table.insert data row)))

(fplot.splot
  {:options {:title "Sinc Function"
             :z-label "z"
             :palette "viridis"}
   :datasets [{:data data
               :style "pm3d"
               :title ""}]})

Lua

require("fennel").install()
local fplot = require("fplot")

local data = {}
for i = -20, 20 do
  local x = i * 0.5
  local row = {}
  for j = -20, 20 do
    local y = j * 0.5
    local r = math.sqrt(x*x + y*y) + 1e-6
    local z = math.sin(r) / r
    table.insert(row, {x, y, z})
  end
  table.insert(data, row)
end

fplot.splot({
  options = {
    title = "Sinc Function",
    z_label = "z",
    palette = "viridis"
  },
  datasets = {
    {
      data = data,
      style = "pm3d",
      title = ""
    }
  }
})

(The resulting plot generated by fplot)

---

4. Logarithmic Scale Plot

Useful for visualizing data that spans several orders of magnitude.

Fennel

(local fplot (require :fplot))

(local data [])
(for [x 1 100]
  (table.insert data [x (* 1000 (math.exp (* -0.1 x)))]))

(fplot.plot
  {:options {:title "Exponential Decay"
             :x-label "Time"
             :y-label "Value"
             :log-scale "y"
             :grid true}
   :datasets [{:title "Decay"
               :style "lines"
               :data data}]})

Lua

require("fennel").install()
local fplot = require("fplot")

local data = {}
for x = 1, 100 do
  table.insert(data, {x, 1000 * math.exp(-0.1 * x)})
end

fplot.plot({
  options = {
    title = "Exponential Decay",
    x_label = "Time",
    y_label = "Value",
    log_scale = "y",
    grid = true
  },
  datasets = {
    {
      title = "Decay",
      style = "lines",
      data = data
    }
  }
})

(The resulting plot generated by fplot)

---