DatumHuePlatform v0.0.24datumhue.com
Contents

handle3 methods, 1 field

Brush

Returned by area:brush(...). The active brush gesture on one plot area — read the committed selection off selection, reconfigure it in place, clear it, or remove it.

Obtained from
PlotArea:brush

The examples on this page start from:

lua
local color = datumhue.color
local canvas = datumhue.draw.new({ width = 400, height = 300 })
canvas:mount({ width = 400, height = 300 })
local plot = canvas:chart({ margin = { left = 40, bottom = 40 } })
local brush = plot:brush()

Fields 1

FieldTypeAccessDescription
selectionchart.BrushSelection?read-onlyData-space bounds of the committed brush selection; nil when nothing is selected or the brush was removed.

Methods 3

Brush:update

method
Brush:update(options: chart.BrushOptions)

Reconfigure the brush in place; passing on_brush replaces the callback. Changing axis clears any committed selection (without firing on_brush). Raises after remove.

Example
-- A new axis clears the selection; on_brush replaces the callback.
brush:update({
    axis = "both",
    color = color("#dbbc7f"),
    on_brush = function(selection)
        print(brush.selection == nil, selection == nil)
    end,
})

options chart.BrushOptions options 4 keys Omitted keys keep their current value.

KeyTypeDescription
axis"x" | "y" | "both"Which axes the brush selects on. Single-axis brushes span the full plot on the other axis.
button"left" | "right" | "middle" | "back" | "forward"Mouse button that drags the brush.
colorColorSelection region fill.
on_brushfun(selection: chart.BrushSelection?)Fires when a selection commits (bounds table) or a click clears it (nil).

Brush:clear

method
Brush:clear()

Clear the committed selection and its region without firing on_brush.

Brush:remove

method
Brush:remove()

Remove the brush, its selection region, and its on_brush callback. The area can then construct a new one. Safe to call more than once.

Types 1

chart.BrushSelection

record

record 4 keys

KeyTypeDescription
x_min?numberSelection lower x bound in data space (epoch-ms on time scales). Absent when the brush axis is y.
x_max?numberSelection upper x bound in data space. Absent when the brush axis is y.
y_min?numberSelection lower y bound in data space. Absent when the brush axis is x.
y_max?numberSelection upper y bound in data space. Absent when the brush axis is x.

Used by: Brush.selection

Nested in: chart.BrushOptions

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Victor Mono is licensed under the SIL Open Font License 1.1
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This Font Software is licensed under the SIL Open Font License, Version 1.1.
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