Automatically crop image boundaries

[XverhelstX]

Hey,

I'm using the following code to automatically crop an image to it's boundaries.

'Define the boundaries of the image
Sub DefineBoundaries
   Dim color As Int
   Dim top(2), bottom(2), left(2), right(2) As Int
   
   Log("-------TOP--------")
   'Define from top
   For i=0 To btmpCrop.Width-1 
      For j=0 To btmpCrop.Height-1
         color = btmpCrop.GetPixel(i,j)
         If color <> Colors.RGB(255,255,255) Then
            Log("No Color white from top!")
            Log("x: " & i)
            Log("y: " & j)
            top(0) = i
            top(1) = j
            i = btmpCrop.Width
            Exit
         End If
      Next
   Next
   
   Log("-------Left--------")
   'Define from left
   For i=0 To btmpCrop.Height-1 
      For j=0 To btmpCrop.Width-1
         color = btmpCrop.GetPixel(j,i)
         If color <> Colors.RGB(255,255,255) Then
            Log("No Color white from left!")
            Log("x: " & j)
            Log("y: " & i)
            left(0) = j
            left(1) = i
            i = btmpCrop.Height
            Exit
         End If
      Next
   Next

   Log("-------Bottom--------")
   'Define from bottom
   For i=btmpCrop.Width-1 To 0 Step -1
      For j=btmpCrop.Height-1 To 0 Step -1
         color = btmpCrop.GetPixel(i,j)
         If color <> Colors.RGB(255,255,255) Then
            Log("No Color white from bottom!")
            Log("x: " & i)
            Log("y: " & j)
            bottom(0) = i
            bottom(1) = j
            i = 0
            Exit
         End If
      Next
   Next
   
   
   Log("-------Right--------")
   'Define from right
   For i=btmpCrop.Height-1 To 0 Step -1
      For j=btmpCrop.Width-1 To 0 Step -1
         color = btmpCrop.GetPixel(j,i)
         If color <> Colors.RGB(255,255,255) Then
            Log("No Color white from right!")
            Log("x: " & j)
            Log("y: " & i)
            right(0) = j
            right(1) = i
            i = 0
            Exit
         End If
      Next
   Next

   AutoCrop(left, right, top, bottom)
End Sub

,

I created the code from the pseudocode here:
java - Automatically crop image boundaries - Stack Overflow

I want to know how i could improve (the speed) of the getPixel method with getPixels. (from BitmapExtended or RSImageProcessing library.)
Any example would be great.

Regards,
Tomas

 

[thedesolatesoul]

If you can read a whole row of pixels that would be good and then perform some kind of and_reduce to compare them.
Not sure how though

Sent from my GT-I9000 using Tapatalk 2

 

[vb1992]

Not sure if these will help

download - Downloading the android source, *not* via git/repo - Stack Overflow

https://github.com/biokys/cropimage