Lingoworkshop :: Smooth Zoom and Pan

Smooth Zoom and Pan

Smooth Zoom and Pan. Click to change images.

This demo uses over-sized source images. Basically, the source image is over-sized relative to the output rect. The smooth movement is created by slowly moving a large rect across this over-sized image. This means that we can make 'sub-pixel' movement using Director's automatic dithering of images when they are scaled down when copypixeled to a smaller rect.

The basic behaviour is this:

property myCanvas, myDestRt, mySource, mySrcRect, toggler, myBlend


on beginSprite (me)
 myCanvas = (the stage).image
 myDestRt = rect(0,0,400,400)
 mySource = member("P1010128").image
 mySrcRect = rect(0,0,400,400).offset(600,600)
 mySrcRect = mySrcRect.inflate(300,300)
end


on exitFrame me
  go to the frame
end

on enterframe (me)
 if myBlend < 190 then myBlend = myBlend + 5
  myCanvas.copyPixels(mySource, myDestRt, mySrcRect, [#BlendLevel: myBlend])
  if mySrcRect.width > myDestRt.width then
   mySrcRect = mySrcRect.inflate(-1,-1)
   mySrcRect = mySrcRect.offset(1,0)
  else
   me.ToggleImages()
  end if
end

on mouseDown (me)
  me.ToggleImages()
end

on toggleImages (me)
 toggler = NOT(toggler)
 if toggler thenmySource = member("P1010034").image
 else mySource = member("P1010128").image
 mySrcRect = rect(0,0,400,400).offset(600,600)
 mySrcRect = mySrcRect.inflate(300,300)
 myBlend= 0
end