Speed up Process (PixelGetColor)

[flatt83]

Hi, 
I want to know if there exists a way to speed up this process?

Local $update[50][50]

$tStart = TimerInit()
For $x = 493 To 529 Step 1
    For $y = 263 To 271 Step 1
        $Color = PixelGetColor($x, $y)
        $p1 = $x - 493
        $p2 = $y - 263
        $update[$p1][$p2] = $Color
    Next
Next
MsgBox(0, "t", TimerDiff($tStart))
$update = 0

Edited April 27, 2014 by flatt83

[BrewManNH]

How long is it taking for you? It took 8 seconds for me. It has to run the loops 288 times, it's going to take some time to do that.

[flatt83]

on the laptop of my gf it takes also more than 8secs but on my pc less than 6 but thats not the problem.

i'm trying to build an imagesearch-function and this is what i wanted to use to get the specific image saved to an array, which i wanted to search onscreen the same way, but this would need  way more time than it should. i know that there already exists a prebuild ImageSearch.au3 in this forum but that also has a precompiled dll, which is not readable in source this way, that is why i wanted to build this up myself.

[Werty]

I dont know if I'm doing something wrong, but I can run the above script 1900 times in 8 seconds.

Local $update[50][50]

$tStart = TimerInit()
For $Loop = 1 To 1900
For $x = 493 To 529 Step 1
    For $y = 263 To 271 Step 1
        $Color = PixelGetColor($x, $y)
        $p1 = $x - 493
    ;   ConsoleWrite(TimerDiff($tStart) & " " & $x & " " & $y & " " & $color & @CRLF)
        $p2 = $y - 263
        $update[$p1][$p2] = $Color
    Next
 Next
 Next

;MsgBox(0, "t", TimerDiff($tStart))
ConsoleWrite(TimerDiff($tStart))
$update = 0

7771.99788037979>Exit code: 0    Time: 8.006

i5-750 (2.4ghz)

I'm not sure my computer is 1900 times faster than your guys.

[flatt83]

could u pls tell what's the difference between the two of us?

and i know it's not your cpu, because i ran that code on an i7-2600k (3.4 gHz).

[binhnx]

@Werty, @BrewManNH:

It's not the about the computer or GPU speed. Two you disable the DWM (aka. Aero Glass), don't you? It seems that the OP have an DWM enabled desktop. And PixelGetColor slow speed is totally expected.

PixelGetColor is a wrapper of WinAPI function GetPixel.

When DWM is disabled, Windows maintains the bitmap of all windows in a on-screen buffer, which is displayed later by the graphics card (GPU). GetPixel read the color data from the on-screen buffer. Although reading data from video memory is considered slow, it's still not too slow and you can get a desired performance.

When DWM is enabled, Windows asks each application to draw in a off-screen bitmap. Then all the bitmap will be gathered and "composed" together to the on-screen buffer. After that, GPU display the buffer to your screen. This approach solve the tearing problem and has many advantages, but it also has some problem :

When you call GetPixel then it force rendering all off-screen buffer to the on-screen buffer, and read the data from that bitmap. The extra work of rendering make it's much slower than get data from the on-screen buffer only.

So, the workaround, you should capture your window first, to a memory bitmap, get the HDC of the bitmap, then call GetPixel (using DllCall, not the AutoIt PixelGetColor, since you cannot use PixelGetColor to read color from a specified HDC)

[Werty]

Yes, I'm running Win7 32bit using the old "Classic" theme without Aero/DWM

[czardas]

If you are comparing one image against several other images, you don't necessarily need to test every pixel of every image. Test one pixel and if no match is found then there are no results. Test the second pixel with all the matching images found if they exist. Use ExitLoop when you hit a mismatch.

Another method might be to use the hash values and test them instead of using pixels - this won't work with different file types though. It's just a thought. You can probably narrow down your search using various tricks: FileGetSize etc...

Edited April 27, 2014 by czardas

[BrewManNH]

PixelChecksum might be a better idea than pixel searching every pixel in an area.

[flatt83]

These Lines Are just Run to Save the colors of the Button for later implementing them into the original program. I was just curious why it Takes so Long to get the colors. Its a picture of a Button in a hwnd_wrapper which i cant get Control of. I wanted to search for the first Pixel, and if found to keep searching for the Rest of the Array.

Sry for Bad english, i'm not naturally speaking english and i'm half asleep on my Way to work.