/spacey

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1 by Josh C
zoetrope 1.4
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-- Class: Button
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-- A button is a composite sprite made of two things: a label (e.g.
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-- some text like "OK") and a background (e.g. a graphic or fill).
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-- A button's dimensions, e.g. its clickable area, is determined by
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-- its background's dimensions.
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--
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-- The x and y position of the label sprite is relative to the button's
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-- top-left corner. The background sprite is always drawn at the button's
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-- top-left corner. The label is always drawn on top of the background.
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--
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-- Extends:
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--		<Sprite>
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--
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-- Event: onMouseOver
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-- Called each frame the mouse is over the button.
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--
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-- Event: onMouseEnter
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-- Called during the first frame the user moves the mouse over the button.
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--
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-- Event: onMouseExit
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-- Called during the first frame the user moves the mouse off of the button.
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--
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-- Event: onMouseDown
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-- Called during the first frame the user is clicking the mouse when it is over the button.
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--
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-- Event: onMouseUp
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-- Called when the user releases the mouse over the button.
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Button = Sprite:extend
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{
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	-- Property: background
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	-- The background <Sprite> of the button.
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	-- Propetrty: label
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	-- The label <Sprite> of the button.
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	-- Property: enabled
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	-- If false, then no events will fire for this object, even just
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	-- mouse enter/exit ones. It also forces the <mouseOver> property to
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	-- false. This does not change the appearance of the button
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	-- on its own; that's up to you.
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	enabled = true,
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	-- Property: mouseOver
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	-- Tracks whether the user's mouse is over the button this frame.
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	mouseOver = false,
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	-- Property: beingClicked
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	-- Tracks whether the user has the mouse button down and started
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	-- clicking the mouse inside the button.
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	beingClicked = false,
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	draw = function (self, x, y)
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		local bg = self.background
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		local label = self.label
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		x = x or self.x
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		y = y or self.y
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		if bg then bg:draw(x + bg.x, y + bg.y) end
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		if label then label:draw(x + label.x, y + label.y) end
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		Sprite.draw(self, x, y)
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	end,
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	update = function (self, elapsed)
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		local bg = self.background
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		local label = self.label
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		-- keep dimensions in sync with background
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		if bg then
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			self.width = bg.width
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			self.height = bg.height
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		end
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		-- call hooks for mouse movement events
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		if self.enabled then
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			local overBefore = self.mouseOver
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			self.mouseOver = self:intersects(the.mouse.x, the.mouse.y)
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			if self.mouseOver then self:callHook('onMouseOver') end
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			if self.mouseOver and not overBefore then self:callHook('onMouseEnter') end
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			if not self.mouseOver and overBefore then self:callHook('onMouseExit') end
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			-- check for clicks
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			if self.mouseOver and the.mouse:justPressed() then
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				self.beingClicked = true
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				self:callHook('onMouseDown')
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			end
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			if self.beingClicked and the.mouse:justReleased() then
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				if self.mouseOver then
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					self:callHook('onMouseUp')
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				else
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					if label and label.onMouseUp then label:onMouseUp() end
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					if bg and bg.onMouseUp then label:onMouseUp() end
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					if self.onMouseUp then self:onMouseUp() end
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				end
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				self.beingClicked = false
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			end
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		else
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			self.mouseOver = false
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		end
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		-- let label and background update
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		if bg then bg:update(elapsed) end
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		if label then label:update(elapsed) end
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		Sprite.update(self, elapsed)
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	end,
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	callHook = function (self, name)
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		local label = self.label
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		local bg = self.background
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		if label and label[name] then label[name](label) end
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		if bg and bg[name] then bg[name](bg) end
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		if self[name] then self[name](self) end
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	end
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}