Raw pixel performance version 1.11 to 1.35 slowdown?

Below is a code sample that runs much slower on versions 1.35 and 1.34 compared to version 1.11.

Basically it uses ReadPixelFast and WritePixelFast on an image bufer and the canvas.

The numbers I get are
version 1.11 - 1900 millisecs
version 1.35 - 14500 millisecs

That's about 7x slower.

I thought perhaps it was the canvas operations, but commenting out the write to the canvas is still slower.
version 1.11 - 600 millisecs
version 1.35 - 900 millisecs

I suspect I'm doing something wrong but I don't know what.


; Simple Speed test of read and write pixels

Const EVENT_MOUSEDOWN = $201
Const EVENT_CLOSE = $803

Const IMAGE_WIDTH = 400
Const IMAGE_HEIGHT = 400

; Create a main window
window = CreateWindow ("Speed Test of raw pixel ops", 0, 0, ClientWidth(Desktop()), ClientHeight(Desktop()))

If window

; Create panel
panel = CreatePanel (0, 0, ClientWidth(window), ClientHeight(window), window, 1)
SetPanelColor panel, 64, 64, 64
SetGadgetLayout panel, 1, 1, 1, 1

; Create drawing canvas
canvas = CreateCanvas (0, 0, IMAGE_WIDTH, IMAGE_HEIGHT, panel)
SetGadgetLayout canvas,1,1,1,1

; Create image buffer
ibuffer = CreateImage (IMAGE_WIDTH, IMAGE_HEIGHT)
SetBuffer ImageBuffer (ibuffer)

; Main event loop...
Repeat

; Wait for a window event...
e = WaitEvent ()

; Process the event...
If e = EVENT_MOUSEDOWN Then

LockBuffer CanvasBuffer(canvas)
LockBuffer ImageBuffer(ibuffer)

startTime = MilliSecs()

For count = 0 To 100
For y = 0 To IMAGE_HEIGHT
For x = 0 To IMAGE_WIDTH
rrgb = ReadPixelFast(x,y)
WritePixelFast x,y,rrgb

SetBuffer CanvasBuffer (canvas)
WritePixelFast x,y,rrgb
SetBuffer ImageBuffer (ibuffer)
Next
Next
Next

UnlockBuffer CanvasBuffer(canvas)
UnlockBuffer ImageBuffer(ibuffer)

endTime = MilliSecs()
Print endTime - startTime

FlipCanvas (canvas)
EndIf
If e = EVENT_CLOSE Then End
Forever

Else
Notify ("Failed to create window!", True)
End
EndIf