OOP: Extended types get upgraded and not forgotten

BlitzMax Forums/BlitzMax Beginners Area/OOP: Extended types get upgraded and not forgotten

Hotcakes

(Posted 2008) [#1]

Here's an interesting testbed:

Type TUnscaled
	Field	Image:TImage
	
	Method	Load(file$)
		Image	=	LoadImage(file$)
	End Method
	
	Method	Draw(x:Int,y:Int)
		DrawImage Image,x,y
	End Method
End Type

Type TScaled Extends TUnscaled
	Field	scale:Int	 = 	4
	
	Method	Draw(x:Int , y:Int) 
		SetScale scale , scale
		Super.Draw x,y
		SetScale 1 , 1
	End Method
End Type


Type TTester
	Method	DoIt() 
	End Method
End Type


Type TGame
	Field	Image:TUnscaled	 = 	New TUnscaled
		
	Method	CallNextTest(test:TTester,x:Int,y:Int) 
		test.DoIt
		Image.Draw x,y
	End Method
End Type


Type TTest1 Extends TTester
	Method	DoIt()
		Game.Image.Load "image.png"
	End Method
End Type

Type TTest2 Extends TTester
	Field	Image:TScaled		 = 	New TScaled
	
	Method	DoIt()
		Image.Load "image.png"
		Game.Image=Image
	End Method
End Type

' phew!

Local	ShouldNotDrawScaled:TTest1
Local	ShouldDrawScaled:TTest2
Global	Game:TGame	 = 	New TGame
Graphics 800,600
ShouldNotDrawScaled	 = 	New TTest1
Game.CallNextTest ShouldNotDrawScaled,100,100

ShouldDrawScaled	 = 	New TTest2
Game.CallNextTest ShouldDrawScaled,200,200

ShouldNotDrawScaled	 = 	New TTest1
Game.CallNextTest ShouldNotDrawScaled,400,400
Flip
WaitMouse
End

Well, well. I am enjoying my OOP. This testbed needs a (small; under 50x50) image file called image.png.

What I think SHOULD happen is the first image is drawn at the original size, the second image at 4 times larger and then the third image at the original size again. Well, that was the intent.

What actually happens is the third image is also drawn scaled.

I believe I understand what is actually happenning, but I wondered is this actually correct behaviour? If it is correct, is there an easy way around it? I can't set the scale while loading the image associated with for ShouldNotDrawScaled because it throws a compiler error of course.

What do y'all think?

Warpy

(Posted 2008) [#2]

You're not resetting Game.Image after the second image is drawn. It's still a TScaled object.

Hotcakes

(Posted 2008) [#3]

Yup, that's what I thought. Thanks.