Migration from Kwik3

Content Area

    application = 
   { 
        content  = 
        { 
             width = 768, 
             height = 1024, 
             fps = 60, 
             scale = kScale, 
             imageSuffix = {  
                ["@2"] = .5, 
             }  
        }, 
   } 

Kwik3's imageSuffix @2 does not come with x but Kwik4 uses normal convention as @2x

--calculate the aspect ratio of the device:
local aspectRatio = display.pixelHeight / display.pixelWidth
application = {
   content = {
      width = aspectRatio > 1.5 and 320 or math.ceil( 480 / aspectRatio ),
      height = aspectRatio < 1.5 and 480 or math.ceil( 320 * aspectRatio ),
      scale = "letterBox",
      fps = 30,
      imageSuffix = {
         ["@2x"] = 1.5,
         ["@4x"] = 3.0,
      },
   },
}