Very annoying Chrome bug with DrawImageRect

Monkey Targets Forums/HTML5/Very annoying Chrome bug with DrawImageRect

Fred	(Posted 2011) [#1]

Hello,
I'm experimenting a very annoying bug in Chrome: DrawImage called after a DrawImageRect WITH rotation are not stable ! I mean not drawn the same way.

Here is an example of a scaled down display that draws 6 (128x128) sprites with DrawImage. When the mouse is over a sprite I zoom and rotate it with DrawImageRect. Then the following sprites (drawing order) are moving a little bit depending on the rotation value and global scale !

With IE9 there is no problem, neither with all other targets (glfw, ...)

By the way if you use a 128x128 sprite with a one pixel thin grid in it you'll find interesting to see how good are different targets/browsers to handle scaled down bitmaps (in this case IE9 is surprisingly efficient)

Import mojo

global	ScreenScale:float = 0.625		' scale down 1024x768 to 640x480

global	MouseSelection:int = -1

Global	Sprite:Image
Global	SpriteRot:Float = 0.0

Function Main ()
	New Game
End

Class Game Extends App

	Method OnCreate()
		SetUpdateRate 60
		
		Sprite = LoadImage( "sprite.png" ) 			' 128x128
		Sprite.SetHandle 64.0, 64.0
	End

	Method OnUpdate()
	
		local	mx:float = TouchX(0) / ScreenScale
		local	my:float = TouchY(0) / ScreenScale
	
		if mx >= 20.0 And my >= 20.0 and mx < 20.0 + 160.0 * 6.0 And my < 128.0 + 20.0			
			MouseSelection = int( (mx-20.0)/160.0 )
		Else
			MouseSelection = -1		
		EndIf
		
		SpriteRot += 0.1
				
	End

	Method OnRender ()

		PushMatrix
		
		Scale ScreenScale, ScreenScale
			
		Cls 0, 0, 0
		
		Local	x:Float
		local	y:float = 20.0 + 64.0

		For Local n:Int = 0 to 5		
			x = 20.0 + 64.0 + float(n) * 160.0

			if n = MouseSelection
				DrawImageRect Sprite, x, y,    0,0,128,128,   SpriteRot, 1.3,1.3
			else
				DrawImage Sprite, x, y 
			endif
		next
		
		PopMatrix
		
	End

End

May be I'm doing something wrong ?