Basalt/docs/objects/Object/onDrag.md

onDrag

onDrag(self, event, button, x, y, xOffset, yOffset)
The computercraft event which triggers this method is mouse_drag.

Here is a example on how to add a onDrag event to your button:

local basalt = require("basalt")

local main = basalt.createFrame()
local button = main:addButton()
  :setPosition(3,3)
  :setSize(12,3)
  :setText("Click")

function buttonOnDrag(self, button, x, y, xOffset, yOffset)
  basalt.debug("Someone drags me (i know i wont reposition myself)!")
end
button:onDrag(buttonOnDrag)