[Zamoth_bg]

Hello everyone!

I have done this school project for Visual User Interface class.
It is pretty cool but I do not like that the way I have done the animation everything is blinking and it does not look good.
I wonder if there is anyway to remove this flicker by using backbuffer or similar thing so it can be drawn before displaying.
If anyone can give me a hint that will be great.

I use blit() function of the canvas class.

Is there a better way?

I have uploaded everything you need to run it in emulator.

Put the "shoes.rar" in a directory /shoes of your python directory.
http://www.box.net/shared/zy7gb39c0c
and thses are the two modules:
http://www.box.net/shared/ssyldn9yck
http://www.box.net/shared/iphqu3sdcc

Here is a small snippet from the code:

def Draw(self,key,level,moveInDirection=None,frame=None):
		"""Drawing of the current item and its neigbour if possible."""
		global targetRecHandler
		if (level > 0):
			if(moveInDirection == None): #check if we are in the process of animation
				target = targetRecHandler.GetMeRectangle(zoomLvl=itemHandler.currentZoomLevel,key=key) #gets the rectangle needed
				if(target is not None): #check if we actually have an rectangle
					canvas.blit(self.picture, #takes current picture
					target=target,scale = 1)#draws current item
			else:
				if ((moveInDirection != "+") & (moveInDirection != "-")):
					animKey = key + str(itemHandler.currentZoomLevel-1) + "->" + key + moveInDirection + str(itemHandler.currentZoomLevel-1) #creates the animation key
					animKey = animKey.replace("ns","") #fixing some string problems with animation
					animKey = animKey.replace("sn","")
					animKey = animKey.replace("ew","")
					animKey = animKey.replace("we","")
				elif moveInDirection == "+":
					animKey = key + str(itemHandler.currentZoomLevel-1)  + "->" + key + str(itemHandler.currentZoomLevel-2)
				else:
					animKey = key + str(itemHandler.currentZoomLevel-1)  + "->" + key + str(itemHandler.currentZoomLevel)
				target = targetRecHandler.GetMeRectangle(key=animKey,frame=frame) #gets the rectangle needed
				if(target is not None): #check if we actually have an rectangle
					canvas.blit(self.picture,target=target,scale = 1)#draws current item
				
			self.__DrawNeighbours(key,level,moveInDirection,frame)

[shubhendra]

Hi Zamoth_bg,
Did try your application, is really cool one.
Now about that blinking part is because image is being redrawn continuously.I think if you want the GUI types of maybe Apple's OS X then you need to use some graphics libraries.

The experts maybe will be able to elaborate more, i am really newbie in this GUI part.

[Zamoth_bg]

Thank you for the nice words. No I am saying if I can work on the same platform, same language if I can connect it to graphical API. Something to hack the code so it can dispaly stuff better.

[JOM]

Use double buffering, never ever draw directly on the canvas. In worst cases you can use also triple buffering.

Cheers,

--jouni sorry for being busy

[Zamoth_bg]

I know but, how? Point me to what I need to use and a possible solution.

[JOM]

Originally Posted by Zamoth_bg

I know but, how? Point me to what I need to use and a possible solution.

Double Buffering is so easy, it's hard to think of example.. Possible surely and I should write a sample, but time is limited and it's more fun to do other things

Just updated Rol-a-Bol to version 1.4, wanted to experiment with triple buffering

http://jouni.miettunen.googlepages.com/rol-a-bol

Double Buffering:

• Never draw on canvas
• Create temporary empty image exactly similar to canvas
• Draw everything on temp image, exactly like on canvas
• Blit temp image on canvas
• That's it

That's good enough for simple cases, no problems. In more demanding cases you have to optimize:

• Create permanent "temp" image (off-screen)
• Protect your draw routines (atomize)
• Update screen as little as possible i.e. not full screen

Cheers,

--jouni

[Zamoth_bg]

There is no real support of back buffer? I just create empty image and "draw" on it. Then just blip the image? Ok.

[JOM]

Originally Posted by Zamoth_bg

There is no real support of back buffer? I just create empty image and "draw" on it. Then just blip the image? Ok.

Yep,

It's just as easy as you said: create your own empty image, draw everything on it and blit on top of canvas.

Enjoy,

--jouni