locX=getRawMouseX():locY=getRawMouseY()
dx=locX*canvasSize/windowSize:dy=locY*canvasSize/windowSize

setviewoffset(a,b)
z=(SIN(getrawmousewheel()*.5))*(GetRawMouseWheel()*.5)
SetViewZoom(z)
//this works but a point to note it begins at 0,0 scale 

// Project: WindowZoom 
// Created: 22-09-12

// show all errors

SetErrorMode(2)

// set window properties
SetWindowTitle( "WindowZoom" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 )


global renderImage as integer
global renderSprite as integer
global zoomValue as float


renderImage = CreateRenderImage(GetVirtualWidth(), GetVirtualHeight(), 0, 0)
renderSprite = CreateSprite(renderImage)

topLeft = 0.0
topRight = 0.0
zoomValue = 10.0


SetSpriteSize(renderSprite, 10, 10)
SetSpritePosition(renderSprite, (GetVirtualWidth() / 2) - (GetSpriteWidth(renderSprite) / 2), (GetVirtualHeight() / 2) - (GetSpriteHeight(renderSprite) / 2))

DrawToRenderImage()


do
	if GetRawKeyReleased(27) then exit
	
    Zoom(zoomValue)
    Sync()
    
loop


end




function DrawToRenderImage()
	local x1, y1
	local x2, y2
	local color as integer
	
	SetRenderToImage(renderImage, 0)
	
	color = MakeColor(255, 0, 0)
	x1 = 0
	y1 = 0
	x2 = x1 + (GetWindowWidth() / 2)
	y2 = y1 + (GetVirtualHeight() / 2)
	
	DrawBox(x1, y1, x2, y2, color, color, color, color, 1)
	
	color = MakeColor(0, 255, 0)
	x1 = (GetVirtualWidth() / 2)
	y1 = 0
	x2 = x1 + (GetWindowWidth() / 2)
	y2 = y1 + (GetVirtualHeight() / 2)
	
	DrawBox(x1, y1, x2, y2, color, color, color, color, 1)
	
	color = MakeColor(0, 0, 255)
	x1 = 0
	y1 = (GetVirtualHeight() / 2)
	x2 = x1 + (GetWindowWidth() / 2)
	y2 = y1 + (GetVirtualHeight() / 2)
	
	DrawBox(x1, y1, x2, y2, color, color, color, color, 1)
	
	color = MakeColor(255, 255, 255)
	x1 = (GetVirtualWidth() / 2)
	y1 = (GetVirtualHeight() / 2)
	x2 = x1 + (GetWindowWidth() / 2)
	y2 = y1 + (GetVirtualHeight() / 2)
	
	DrawBox(x1, y1, x2, y2, color, color, color, color, 1)
	
	color = MakeColor(255, 0, 255)
	x1 = (GetVirtualWidth() / 2) - (GetVirtualWidth() / 4)
	y1 = (GetVirtualHeight() / 2) - (GetVirtualHeight() / 4)
	x2 = x1 + (GetWindowWidth() / 2)
	y2 = y1 + (GetVirtualHeight() / 2)
	
	DrawBox(x1, y1, x2, y2, color, color, color, color, 1)
	
	SetRenderToScreen()
	
endfunction


function Zoom(value as float)
	local width as float
	local height as float
	local posX as float
	local posY as float
	
	width = GetSpriteWidth(renderSprite)
	height = GetSpriteHeight(renderSprite)
	
	inc width, value
	inc height, value
	
	SetSpriteSize(renderSprite, width, height)
	
	posX = (GetWindowWidth() / 2 - (GetSpriteWidth(renderSprite) / 2))
	posY = (GetWindowHeight() / 2 - (GetSpriteHeight(renderSprite) / 2))
	
	SetSpritePosition(renderSprite, posX, posY)
	
endfunction

SetVirtualResolution(1024,768)
type pos
	x as float
	y as float
endtype
//load background image - change to your own background image
LoadImage (1, "Bg.png")

//set background sprite
BG = CreateSprite (1)
SetSpritesize(Bg,GetVirtualWidth(),getvirtualHeight())
SetViewZoomMode(0)
//main loop
Do
   
    AlignWorld( getSpriteXByOffset( bg) , getSpriteXByOffset( bg ) , getVirtualWidth() * 0.5 , getVirtualHeight() * 0.5 , 2.0 )
    SetViewOffset (512,0)
    
	sync()
Loop

// Function to Align a point on the world plane with a point on the
// display plane at a given zoom level.
//
// Parameters: 
//   worldX# , worldY#       Point on world plane to align
//   displayX# , displayY#   Point on Display to Align to
//   worldZ#                 Zoom Level to align at
//

function AlignWorld( worldX# , worldY# , displayX# , displayY#, worldZ# )
  setViewZoom( worldZ# )
  setViewOffset( worldX# - ( displayX# / worldZ# ) , worldY# - ( displayY# / worldZ# ) )
endfunction


function SetSpritePixelSizeInPercentage(spriteID as integer, pixelWidth as float, pixelHeight as float)
    SetSpriteSize(spriteID, (pixelWidth/GetDeviceWidth())*100, (pixelHeight/GetDeviceHeight())*100)
endfunction

function getPositionAsPercentage(spr,x as integer,y as integer)
	pos as pos
	pos.x=getspriteX(spr)/GetVirtualWidth()
	pos.y=getspriteY(spr)/GetVirtualHeight()
endfunction pos