Remove White Spaces in image

[darkshark]

Hi, everyone!

I have some pictures on my computer that I need to "remove the white parts".

Basically I need to crop images only where it has some content ...

I wrote this code that seems to work, but, it is very very slow ...

I wonder if there is any other alternative to do this service!

Attached I left the image used as test and what I expect result!

If anyone could help me I would be very happy.

Thank you very much

 

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#include <File.au3>
#Include <GDIPlus.au3>


Global $iMinX = 0
Global $iMinY = 0
Global $iMaxX = 0
Global $iMaxY = 0


_GDIPlus_Startup()

Local $hImage = _GDIPlus_ImageLoadFromFile(@ScriptDir & "\test.png")
Local $iHeight =  _GDIPlus_ImageGetHeight($hImage)
Local $iWidth = _GDIPlus_ImageGetWidth($hImage)


For $x = 0 To $iWidth
    For $y = 0 To $iHeight
        Local $iPixelColor = _GDIPlus_BitmapGetPixel($hImage, $x, $y)
        If $iPixelColor <> 4294967295 Then
            If $x < $iMinX or $iMinX = 0 Then
                $iMinX = $x
            EndIf
            If $x > $iMaxX Then
                $iMaxX = $x
            EndIf
            If $y < $iMinY or $iMinY = 0 Then
                $iMinY = $y
            EndIf
            If $y > $iMaxY Then
                $iMaxY = $y
            EndIf
        EndIf
    Next
Next

 $hClone = _GDIPlus_BitmapCloneArea($hImage, $iMinY, $iMaxX, $iMaxY, $GDIP_PXF24RGB)
_GDIPlus_ImageSaveToFile($hClone, @ScriptDir & "\croped.png")
_GDIPlus_ImageDispose($hClone)
_GDIPlus_ImageDispose($hImage)


_GDIPlus_ShutDown ()

 

 

 

Edited December 11, 2016 by darkshark

[UEZ]

Reading directly from the bitmap is much faster:

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#include <File.au3>
#Include <GDIPlus.au3>


Global $iMinX = 0xFFFF
Global $iMinY = 0xFFFF
Global $iMaxX = 0
Global $iMaxY = 0


_GDIPlus_Startup()

Local $hImage = _GDIPlus_ImageLoadFromFile(@ScriptDir & "\test.png")

Local $iHeight =  _GDIPlus_ImageGetHeight($hImage)
Local $iWidth = _GDIPlus_ImageGetWidth($hImage)
Local $hClone = _GDIPlus_BitmapCloneArea($hImage, 0, 0, $iWidth, $iHeight, $GDIP_PXF01INDEXED)


;version darkshark
Local $iPixelColor, $fTimer = TimerInit()
For $x = 0 To $iWidth - 1
    For $y = 0 To $iHeight - 1
        $iPixelColor = _GDIPlus_BitmapGetPixel($hClone, $x, $y)
        If $iPixelColor = 4278190080 Then
            If $x < $iMinX Then $iMinX = $x
            If $y < $iMinY Then $iMinY = $y
            If $x > $iMaxX Then $iMaxX = $x
            If $y > $iMaxY Then $iMaxY = $y
        EndIf
    Next
Next
ConsoleWrite("Took " & Round(TimerDiff($fTimer), 2) & " ms." & @CRLF)
Local $hCropped1 = _GDIPlus_BitmapCloneArea($hImage, $iMinX, $iMinY, $iMaxX - $iMinX + 1, $iMaxY - $iMinY + 1)
_GDIPlus_ImageSaveToFile($hCropped1, @ScriptDir & "\cropped1.png")


;version reading directly from the bitmap

$iMinX = 0xFFFF
$iMinY = 0xFFFF
$iMaxX = 0
$iMaxY = 0
$fTimer = TimerInit()
Local $tBitmapData = _GDIPlus_BitmapLockBits($hClone, 0, 0, $iWidth, $iHeight)
Local $tPixel = DllStructCreate("int[" & $iWidth * $iHeight & "];", DllStructGetData($tBitmapData, "Scan0"))
Local $iRowOffset, $iPixel
For $y = 0 To $iHeight - 1
    $iRowOffset = $y * $iWidth + 1
    For $x = 0 To $iWidth - 1
        If DllStructGetData($tPixel, 1, $iRowOffset + $x) = 0xFF000000 Then
            If $x < $iMinX Then $iMinX = $x
            If $y < $iMinY Then $iMinY = $y
            If $x > $iMaxX Then $iMaxX = $x
            If $y > $iMaxY Then $iMaxY = $y
        EndIf
    Next
Next
_GDIPlus_BitmapUnlockBits($hImage, $tBitmapData)
ConsoleWrite("Took " & Round(TimerDiff($fTimer), 2) & " ms." & @CRLF)
Local $hCropped2 = _GDIPlus_BitmapCloneArea($hImage, $iMinX, $iMinY, $iMaxX - $iMinX + 1, $iMaxY - $iMinY + 1)
_GDIPlus_ImageSaveToFile($hCropped2, @ScriptDir & "\cropped2.png")


_GDIPlus_ImageDispose($hClone)
_GDIPlus_ImageDispose($hImage)
_GDIPlus_ImageDispose($hCropped1)
_GDIPlus_ImageDispose($hCropped2)


_GDIPlus_ShutDown ()

 

The fastest solution is using inline assembler which I don't want to code now 'cause it's too late here (11pm).

 

[darkshark]

24 minutes ago, UEZ said:

Reading directly from the bitmap is much faster:

expandcollapse popup

#include <File.au3>
#Include <GDIPlus.au3>


Global $iMinX = 0xFFFF
Global $iMinY = 0xFFFF
Global $iMaxX = 0
Global $iMaxY = 0


_GDIPlus_Startup()

Local $hImage = _GDIPlus_ImageLoadFromFile(@ScriptDir & "\test.png")

Local $iHeight =  _GDIPlus_ImageGetHeight($hImage)
Local $iWidth = _GDIPlus_ImageGetWidth($hImage)
Local $hClone = _GDIPlus_BitmapCloneArea($hImage, 0, 0, $iWidth, $iHeight, $GDIP_PXF01INDEXED)


;version darkshark
Local $iPixelColor, $fTimer = TimerInit()
For $x = 0 To $iWidth - 1
    For $y = 0 To $iHeight - 1
        $iPixelColor = _GDIPlus_BitmapGetPixel($hClone, $x, $y)
        If $iPixelColor = 4278190080 Then
            If $x < $iMinX Then $iMinX = $x
            If $y < $iMinY Then $iMinY = $y
            If $x > $iMaxX Then $iMaxX = $x
            If $y > $iMaxY Then $iMaxY = $y
        EndIf
    Next
Next
ConsoleWrite("Took " & Round(TimerDiff($fTimer), 2) & " ms." & @CRLF)
Local $hCropped1 = _GDIPlus_BitmapCloneArea($hImage, $iMinX, $iMinY, $iMaxX - $iMinX + 1, $iMaxY - $iMinY + 1)
_GDIPlus_ImageSaveToFile($hCropped1, @ScriptDir & "\cropped1.png")


;version reading directly from the bitmap

$iMinX = 0xFFFF
$iMinY = 0xFFFF
$iMaxX = 0
$iMaxY = 0
$fTimer = TimerInit()
Local $tBitmapData = _GDIPlus_BitmapLockBits($hClone, 0, 0, $iWidth, $iHeight)
Local $tPixel = DllStructCreate("int[" & $iWidth * $iHeight & "];", DllStructGetData($tBitmapData, "Scan0"))
Local $iRowOffset, $iPixel
For $y = 0 To $iHeight - 1
    $iRowOffset = $y * $iWidth + 1
    For $x = 0 To $iWidth - 1
        If DllStructGetData($tPixel, 1, $iRowOffset + $x) = 0xFF000000 Then
            If $x < $iMinX Then $iMinX = $x
            If $y < $iMinY Then $iMinY = $y
            If $x > $iMaxX Then $iMaxX = $x
            If $y > $iMaxY Then $iMaxY = $y
        EndIf
    Next
Next
_GDIPlus_BitmapUnlockBits($hImage, $tBitmapData)
ConsoleWrite("Took " & Round(TimerDiff($fTimer), 2) & " ms." & @CRLF)
Local $hCropped2 = _GDIPlus_BitmapCloneArea($hImage, $iMinX, $iMinY, $iMaxX - $iMinX + 1, $iMaxY - $iMinY + 1)
_GDIPlus_ImageSaveToFile($hCropped2, @ScriptDir & "\cropped2.png")


_GDIPlus_ImageDispose($hClone)
_GDIPlus_ImageDispose($hImage)
_GDIPlus_ImageDispose($hCropped1)
_GDIPlus_ImageDispose($hCropped2)


_GDIPlus_ShutDown ()

 

The fastest solution is using inline assembler which I don't want to code now 'cause it's too late here (11pm).

 

UEZ

Thanks a lot for the help, really doing it this way is much faster!

I really would not be able to do it in assembly since I do not know anything about that language.

I'll use this code you sent me!

Thank you and good night!

[jchd]

It's as late here but if your source image is always a rectangle horizontally centered (or anything close to that) you can certainly remain within AutoIt to speed this up by a factor.

Test center pixel of the image line by line until you encounter <something which isn't white enough> This is the top line of the rectangle. From there test pixels on the same line until you hit <something which is white enough> on the left (leftmost column) and then on the right (rightmost column). From there test pixels on the same (rightmost) column until you hit <something which is white enough> and you have the bottom line of the bounding rectangle of your picture.

Adjust <colour match values> to something good enough for your actual use cases.

 

[darkshark]

5 minutes ago, jchd said:

It's as late here but if your source image is always a rectangle horizontally centered (or anything close to that) you can certainly remain within AutoIt to speed this up by a factor.

Test center pixel of the image line by line until you encounter <something which isn't white enough> This is the top line of the rectangle. From there test pixels on the same line until you hit <something which is white enough> on the left (leftmost column) and then on the right (rightmost column). From there test pixels on the same (rightmost) column until you hit <something which is white enough> and you have the bottom line of the bounding rectangle of your picture.

Adjust <colour match values> to something good enough for your actual use cases.

 

Thanks for the answer, I understood your reasoning, but not always an image will be a rectangle, sometimes it will have text, some other image ...

[jchd]

Ha, much harder then. I was focused on the test case you submitted.

Yet you can enhance UEZ' code significantly. Redeclare the bitmap DllStruct as a 2D array, then if your background is homogenously white (or some fixed color) then just compare successive rows until the last one differs, giving the top. Do the same for the bottom, comparing rows upwards. That saves a lot of comparisons.

EDIT: I just tried some code implementing the idea but forget it. That won't work reliably as I discovered that the image is heavily watermarked.

Edited December 12, 2016 by jchd

[UEZ]

Btw, the images above don't have a homogene white background, thus you cannot check easily for 0xFFFFFFFF. That's the reason using 1-bit images. Of course this method might not be very precise because you cannot set the threshold of white/black.