AutoIT script - Compare Paint's Rotated Image with GDI's rotated image - image

Question

I have an image and rotate it with both MS Paint and GDI. I want to show that the rotated image from both methods are the same.
Here is the code I have to rotate image with GDI
#include <GDIPlus.au3>
_GDIPlus_Startup()
$hImage1 = _GDIPlus_ImageLoadFromFile(#ScriptDir & "\Picture.gif")
$hGraphic1 = _GDIPlus_ImageGetGraphicsContext($hImage1)
$hImage2 = _GDIPlus_BitmapCreateFromGraphics(_GDIPlus_ImageGetWidth($hImage1), _GDIPlus_ImageGetHeight($hImage1), $hGraphic1)
$hGraphic2 = _GDIPlus_ImageGetGraphicsContext($hImage2)
$matrix = _GDIPlus_MatrixCreate()
_GDIPlus_MatrixRotate($matrix,90)
_GDIPlus_GraphicsSetTransform($hGraphic2, $matrix)
_GDIPlus_GraphicsDrawImage($hGraphic2, $hImage1, 0, -590)
_GDIPlus_ImageSaveToFile($hImage2, #ScriptDir & "\out.gif")
_GDIPlus_MatrixDispose($matrix)
_GDIPlus_GraphicsDispose($hGraphic1)
_GDIPlus_GraphicsDispose($hGraphic2)
_GDIPlus_ImageDispose($hImage1)
_GDIPlus_ImageDispose($hImage2)
_GDIPlus_ShutDown ()
Then I used this code to compare 2 images:
$bm1 = _GDIPlus_ImageLoadFromFile(#ScriptDir & "\Picture1.gif")
$bm2 = _GDIPlus_ImageLoadFromFile(#ScriptDir & "\out.gif")
if ComparePicture($bm1, $bm2) == True Then
MsgBox(0, "Test result", "Same image!")
Else
MsgBox(0, "Test result", "Different image!")
EndIf
_GDIPlus_ImageDispose($bm1)
_GDIPlus_ImageDispose($bm2)
_GDIPlus_Shutdown()
Func ComparePicture($bm1, $bm2)
$Bm1W = _GDIPlus_ImageGetWidth($bm1)
$Bm1H = _GDIPlus_ImageGetHeight($bm1)
$BitmapData1 = _GDIPlus_BitmapLockBits($bm1, 0, 0, $Bm1W, $Bm1H, $GDIP_ILMREAD, $GDIP_PXF08INDEXED )
$Stride = DllStructGetData($BitmapData1, "Stride")
$Scan0 = DllStructGetData($BitmapData1, "Scan0")
$ptr1 = $Scan0
$size1 = ($Bm1H - 1) * $Stride + ($Bm1W - 1) * 4
$Bm2W = _GDIPlus_ImageGetWidth($bm2)
$Bm2H = _GDIPlus_ImageGetHeight($bm2)
$BitmapData2 = _GDIPlus_BitmapLockBits($bm2, 0, 0, $Bm2W, $Bm2H, $GDIP_ILMREAD, $GDIP_PXF08INDEXED)
$Stride = DllStructGetData($BitmapData2, "Stride")
$Scan0 = DllStructGetData($BitmapData2, "Scan0")
$ptr2 = $Scan0
$size2 = ($Bm2H - 1) * $Stride + ($Bm2W - 1) * 4
$smallest = $size1
If $size2 < $smallest Then $smallest = $size2
$call = DllCall("msvcrt.dll", "int:cdecl", "memcmp", "ptr", $ptr1, "ptr", $ptr2, "int", $smallest)
_GDIPlus_BitmapUnlockBits($bm1, $BitmapData1)
_GDIPlus_BitmapUnlockBits($bm2, $BitmapData2)
Return ($call[0]=0)
EndFunc
I tried changing the file type, color depth, etc. but I could not get the code to show that they are the same. When I do not rotate the picture i.e
_GDIPlus_MatrixRotate($matrix,0)
then it recognize the same image. When I rotate right 90, it doesn't. Does anyone knows what might be going on?
Thanks
For reference, this question has also been asked on the AutoIt forums here.

Answer 1

I think $GDIP_PXF08INDEXED is modifying the images differently. Try it without setting it and it should work.
Furthermore, you can use this code to flip the image:
$hImage1 = _GDIPlus_ImageLoadFromFile(#ScriptDir & "\Picture1.gif")
_GDIPlus_ImageRotateFlip($hImage1, 1) ;90°
_GDIPlus_ImageSaveToFile($hImage1, #ScriptDir & "\out.gif")
_GDIPlus_ImageDispose($hImage1)
Br,
UEZ