DrawAlphaImage - drawing in wrong order

[KianV]

Hi all,
I have created 4 transparent images which need to be layered in a specific order.
When I draw them onto the background using the following code:

Code: Select all

      DrawAlphaImage(ImageID(#calque1),(188),100)
      DrawAlphaImage(ImageID(#calque2),(188),100)
      DrawAlphaImage(ImageID(#calque3),(188),100)
      DrawAlphaImage(ImageID(#calque4),(188),100)         

the final layer 'calque4' always appears behind the others.
I have even tried drawing layer 4 onto layer 3 first, but still the same behaviour

Can anyone provide an explanation for this ?

Thanks in advance,
Kian

[STARGÅTE]

I can't confirm this report.

In this code, the drawing order is exactly the oder of the call of DrawAlphaImage()

Code: Select all

Enumeration
	#Window
	#Gadget
	#Image1
	#Image2
	#Image3
	#Image4
EndEnumeration

Define Image.i

For Image = #Image1 To #Image4
	If CreateImage(Image, 128, 128, 32, #PB_Image_Transparent)
		If StartDrawing(ImageOutput(Image))
			DrawingMode(#PB_2DDrawing_AlphaBlend)
			Select Image
				Case #Image1
					Box(0, 0, 128, 128, $FF0000FF)
				Case #Image2
					Box(16, 16, 96, 96, $FF00FF00)
				Case #Image3
					Box(32, 32, 64, 64, $FFFF0000)
				Case #Image4
					Box(48, 48, 32, 32, $FF000000)
			EndSelect
			StopDrawing()
		EndIf
	EndIf
Next

OpenWindow(#Window, 0, 0, 800, 450, "Canvas Gadget", #PB_Window_MaximizeGadget|#PB_Window_MaximizeGadget|#PB_Window_SizeGadget|#PB_Window_ScreenCentered)
CanvasGadget(#Gadget, 0, 0, WindowWidth(#Window), WindowHeight(#Window), #PB_Canvas_Keyboard)
If StartDrawing(CanvasOutput(#Gadget))
	DrawAlphaImage(ImageID(#Image1), 64, 64)
	DrawAlphaImage(ImageID(#Image2), 64, 64)
	DrawAlphaImage(ImageID(#Image3), 64, 64)
	DrawAlphaImage(ImageID(#Image4), 64, 64)
	StopDrawing()
EndIf

Repeat
	Select WaitWindowEvent()
		Case #PB_Event_CloseWindow
			Break
	EndSelect
ForEver

End

[KianV]

Your code works correctly for me also.
I don't know if it makes any difference but the 'background' I am merging them onto is another (non.transparent) image, rather than a canvas.

[Little John]

As always: Posting a short executable code that demonstrates the problem would help a lot.

[KianV]

Unfortunately I cannot create a small bit of code which does the same.
I did indeed write a small example, but it behaves exactly as it should. The program which it is part of is very large.
I was hoping that at some point someone had come across something similar and had a eureka moment.

[IceSoft]

Unfortunately I cannot create a small bit of code which does the same.
I did indeed write a small example, but it behaves exactly as it should. The program which it is part of is very large.
I was hoping that at some point someone had come across something similar and had a eureka moment.

Check your code. There is the problem. I think you draw sprites anywhere again.

[RASHAD]

Hi
Most probably you have a conflict with enumeration or you are using ImageID(#calque4) in other place before or after
Check your ImageID()

[KianV]

IceSoft was kind of right and lead me to the solution.
The code which drew the layers was erroneously called twice. The first time was after drawing the 'top' layer (calque4). Essentially the program is reversing the order of the layers, so it drew the top layer, added it to the background. cleared the layer graphics then it drew the lower layers before outputting them on top.
My thanks to everyone who contributed to what was a slightly vaguely presented problem.