Implement charge meter.

src/meter.lua

@@ -0,0 +1,42 @@
+import "CoreLibs/graphics"
+import "CoreLibs/object"
+import "CoreLibs/math"
+
+local gfx <const> = playdate.graphics
+
+class("Meter").extends(gfx.sprite)
+
+function Meter:init(value, w, h, vertical)
+   Meter.super.init(self)
+
+   self.vertical = vertical or true
+   self:setSize(w, h)
+   self:setZIndex(999)
+   self:setValue(value)
+end
+
+function Meter:setValue(value)
+   local img = gfx.image.new(self:getSize())
+   gfx.pushContext(img)
+      gfx.drawRect(0, 0, self:getSize())
+      local x, y, w, h = 0
+      if self.vertical then
+         x = 0
+         w = self.width
+         y = self.height - playdate.math.lerp(0, self.height, value / 100)
+         print(y)
+         h = self.height - y
+         print(h)
+      else
+         y = 0
+         h = self.height
+         x = 0
+         w = self.width - playdate.math.lerp(0, self.width, value / 100)
+      end
+      gfx.setColor(gfx.kColorWhite)
+      gfx.fillRect(1, 1, self.width-2, self.height-2)
+      gfx.setColor(gfx.kColorBlack)
+      gfx.fillRect(x, y, w, h)
+   gfx.popContext()
+   self:setImage(img)
+end