window-dragging.lua

-- **** copied from https://gist.github.com/spartanatreyu/850788a0441e1c5565668a35ed9a1dfc **** --

--required to be non zero for dragging windows to work some weird timing issue with hammerspoon fighting against osx events
hs.window.animationDuration = 0.00000001

--flag for dragging, 0 means no drag, 1 means dragging a window, -1 means dragging but not dragging the window
dragging = 0

--the window being dragged
dragging_window = nil

--the height of the window's title area in pixels, can change if you have different sized windows (might happen one day) or need a different window grabbing sensitivity
window_titlebar_height = 21

-- Exists because lua doesn't have a round function. WAT?!
function round(num)
	return math.floor(num + 0.5)
end

--based on kizzx2's hammerspoon-move-resize.lua
function get_window_under_mouse()
	-- Invoke `hs.application` because `hs.window.orderedWindows()` doesn't do it
	-- and breaks itself
	local _ = hs.application

	local my_pos = hs.geometry.new(hs.mouse.getAbsolutePosition())
	local my_screen = hs.mouse.getCurrentScreen()

	return hs.fnutils.find(hs.window.orderedWindows(), function(w)
		return my_screen == w:screen() and my_pos:inside(w:frame())
	end)
end


-------------------------------------------------------------------
--Window snapping with mouse, Windows style (Cinch Alternative)
-------------------------------------------------------------------

--Setup drag start and dragging
click_event = hs.eventtap.new({hs.eventtap.event.types.leftMouseDragged}, function(e)

	--if drag is just starting...
	if dragging == 0 then
		dragging_window = get_window_under_mouse()
		--if mouse over a window...
		if dragging_window ~= nil then

			local m = hs.mouse.getAbsolutePosition()
			local mx = round(m.x)
			local my = round(m.y)
			--print('mx: ' .. mx .. ', my: ' .. my)


			local f = dragging_window:frame()
			local screen = dragging_window:screen()
			local max = screen:frame()
			--print('fx: ' .. f.x .. ', fy: ' .. f.y .. ', fw: ' .. f.w .. ', fh: ' .. f.h)

			dragging_window_pos = { x = max.x, y = max.y }


			--if mouse inside titlebar horizontally
			if mx > f.x and mx < (f.x + f.w) then
				--print('mouse is inside titlebar horizontally')

				--if mouse inside titlebar vertically
				if my > f.y and my < (f.y + window_titlebar_height) then
					--print('mouse is inside titlebar')
			
					dragging = 1
					--print(' - start dragging - window: ' .. dragging_window:id())

				else
					--print('mouse is not inside titlebar')
					dragging = -1
					dragging_window = nil
				end
			else
				--print('mouse is not inside titlebar horizontally')
				dragging = -1
				dragging_window = nil
			end

		end
	--else if drag is already going
	--[[
	else
		if dragging_window ~= nil then
			local dx = e:getProperty(hs.eventtap.event.properties.mouseEventDeltaX)
			local dy = e:getProperty(hs.eventtap.event.properties.mouseEventDeltaY)
			local m = hs.mouse.getAbsolutePosition()
			local mx = round(m.x)
			local my = round(m.y)
			print(' - dragging: ' .. mx .. "," .. my .. ". window id: " .. dragging_window:id())
		end
	]]--
	end
end)

function setframe(frame, windowFrame, x, y, w, h)
    frame.x = windowFrame.x + (windowFrame.w * x)
    frame.y = windowFrame.y + (windowFrame.h * y)
    frame.w = windowFrame.w * w
    frame.h = windowFrame.h * h
    return frame
end

--Setup drag end
unclick_event = hs.eventtap.new({hs.eventtap.event.types.leftMouseUp}, function(e)
	local buffer_zone = 20

	--print('unclick, dragging: ' .. dragging)

	--if dragging the mouse
	if dragging == 1 then

		--if the mouse is dragging a window
		if dragging_window ~= nil then

			--print('letting go of window: ' .. dragging_window:id())

			local m = hs.mouse.getRelativePosition()
			local mx = round(m.x)
			local my = round(m.y)

			local win = dragging_window
			local f = win:frame()
			local screen = win:screen()
			local frame = screen:frame()

			print('mouse - x: ' .. m.x .. ', y: ' .. m.y)

			if m.y < buffer_zone then -- touching top
				if m.x < frame.w * .3 then
					win:setFrame(setframe(f, frame, 0, 0, .5, .5))
				elseif m.x > frame.w * .7 then
					win:setFrame(setframe(f, frame, .5, 0, .5, .5))
				else
					win:setFrame(setframe(f, frame, 0, 0, 1, 1))
				end
			elseif m.x < buffer_zone then -- touching left 
				if m.y < frame.h * .3 then
					win:setFrame(setframe(f, frame, 0, 0, .5, .5))
				elseif m.y > frame.h * .7 then
					win:setFrame(setframe(f, frame, 0, .5, .5, .5))
				else
					win:setFrame(setframe(f, frame, 0, 0, .5, 1))
				end
			elseif m.x > frame.w - buffer_zone then -- touching right
				if m.y < frame.h * .3 then
					win:setFrame(setframe(f, frame, .5, 0, .5, .5))
				elseif m.y > frame.h * .7 then
					win:setFrame(setframe(f, frame, .5, .5, .5, .5))
				else
					win:setFrame(setframe(f, frame, .5, 0, .5, 1))
				end
		    elseif m.y > frame.h - buffer_zone then -- bottom
				if m.x < frame.w * .3 then
					win:setFrame(setframe(f, frame, 0, .5, .5, .5))
				elseif m.x > frame.w * .7 then
					win:setFrame(setframe(f, frame, .5, .5, .5, .5))
				else
					win:setFrame(setframe(f, frame, 0, 0, 1, 1))
				end
		    end

		end
		--print("end dragging")
	end
	
	dragging = 0
	dragging_window = nil
end)

--Start watching for dragging (AKA: turn dragging on)
click_event:start()
unclick_event:start()