A question from a noob

[Flaccid_Jack]

When I am releasing resources such as with _GDIPlus_ImageDispose($hBitmap), if I am reusing $hBitmap many times, do i need to imagedispose for each instance?

Example:

_GDIPlus_Startup()
For $i = 0 To 100
    Global $hBitmap = _GDIPlus_ImageLoadFromFile($sBitmap)
    Global $hBitmap_Resized = _GDIPlus_ImageResize($hBitmap, 60, 60) ;resize image
    _GDIPlus_ImageSaveToFile ($hBitmap_Resized, @ScriptDir & "\MyBitmap.png" )
    $hImage = _GDIPlus_BitmapCreateFromFile(@ScriptDir & "\MyBitmap.png")
    ;removed content
Next
_GDIPlus_ImageDispose($hBitmap)
_GDIPlus_ImageDispose($hBitmap_Resized)
_GDIPlus_BitmapDispose($hImage)
_GDIPlus_Shutdown()

Will the above script cause memory leaks?

Thanks!

 

Edited September 26, 2020 by Flaccid_Jack

[zeenmakr]

51 minutes ago, Flaccid_Jack said:

Will the above script cause memory leaks?

it looks fine to me, btw why are you resizing the same image 100x (:

[JockoDundee]

Yes, I think it will leak, since only the resources pointed to by the last value of $hbitmap will be released.  The other 99 will still be out there somewhere, unreferenced.

[zeenmakr]

33 minutes ago, JockoDundee said:

Yes, I think it will leak, since only the resources pointed to by the last value of $hbitmap will be released.  The other 99 will still be out there somewhere, unreferenced.

my thought is it re-uses the $hBitmap and not create a new var each loop. or should Global $hBitmap be assigned before the for loop like so

_GDIPlus_Startup()
Global $hBitmap
Global $hBitmap_Resized
Global $hImage

For $i = 0 To 100
    $hBitmap = _GDIPlus_ImageLoadFromFile($sBitmap)
    $hBitmap_Resized = _GDIPlus_ImageResize($hBitmap, 60, 60) ;resize image
    _GDIPlus_ImageSaveToFile ($hBitmap_Resized, @ScriptDir & "\MyBitmap.png" )
    $hImage = _GDIPlus_BitmapCreateFromFile(@ScriptDir & "\MyBitmap.png")
    ;removed content
Next

 

Edited September 26, 2020 by zeenmakr

[JockoDundee]

3 hours ago, zeenmakr said:

my thought is it re-uses the $hBitmap and not create a new var each loop.

The problem is not with $hBitmap per se.  $hBitmap is just a handle pointing to the real bitmap created from the file.  And you create 100 of these bitmap in your loop, each time you call _GDIPlus_ImageLoadFromFile().  Same the for the other 2 calls that return new bitmaps.

In your original script, you only dispose of 3 of 300, in the last script 0 of 300.

[JockoDundee]

5 hours ago, Flaccid_Jack said:

Global $hBitmap, $hBitmap_Resized, $hImage

_GDIPlus_Startup()

For $i = 0 To 100
    $hBitmap = _GDIPlus_ImageLoadFromFile($sBitmap)
    $hBitmap_Resized = _GDIPlus_ImageResize($hBitmap, 60, 60) ;resize image
    _GDIPlus_ImageSaveToFile ($hBitmap_Resized, @ScriptDir & "\MyBitmap.png" )
    $hImage = _GDIPlus_BitmapCreateFromFile(@ScriptDir & "\MyBitmap.png")
    ;removed content

    _GDIPlus_ImageDispose($hBitmap)
    _GDIPlus_ImageDispose($hBitmap_Resized)
    _GDIPlus_BitmapDispose($hImage)
Next   
 
_GDIPlus_Shutdown()

 

do it like that...(Sorry didn’t mean to quote Flaccid_Jack, it’s my reworking 

Edited September 26, 2020 by JockoDundee

[zeenmakr]

5 hours ago, Flaccid_Jack said:

Will the above script cause memory leaks?

 

34 minutes ago, JockoDundee said:

The problem is not with $hBitmap per se.  $hBitmap is just a handle pointing to the real bitmap created from the file.  And you create 100 of these bitmap in your loop, each time you call _GDIPlus_ImageLoadFromFile().  Same the for the other 2 calls that return new bitmaps.

mystery solved, each loop creates a new object hence new handle - dispose is must for each cycle. it does not reassign var such as e.g $i += 1 as i was assuming. see screenshot for quick test

#include <GDIPlus.au3>

Global $sBitmap = @DesktopDir &'\test.png'
Global $hBitmap

_GDIPlus_Startup()
For $i = 1 To 10
    $hBitmap = _GDIPlus_ImageLoadFromFile($sBitmap)
    ConsoleWrite('-->'&@ScriptLineNumber&' | '&$i&': $hBitmap= '&$hBitmap&''&@CRLF) ;Yellow/Orange
;~     _GDIPlus_ImageDispose($hBitmap)
Next
_GDIPlus_Shutdown()

 

 

[JockoDundee]

1 hour ago, zeenmakr said:

does not reassign var such as e.g $i += 1 as i was assuming

but the var $hbitmap does get reassigned, just like $i.

its just that $hBitmap is not a bitmap.  It’s just a pointer to a bitmap.  And the bitmap is where the big memory usage is.

 

 

[zeenmakr]

5 minutes ago, JockoDundee said:

but the var $hbitmap does get reassigned, just like $i.

its just that $hBitmap is not a bitmap.  It’s just a pointer to a bitmap.  And the bitmap is where the big memory usage is.

i understand, just didn't take the time to explain myself (:

[JockoDundee]

Another question would be, does memory usage increase with each loop iteration?  
Like in the OP:

For $n = 1 To 100
 Global $m=$n
Next

or even

For $n = 1 To 100
  Local $m=$n
Next

In autoit at least, I don’t think it does ...

Edited September 27, 2020 by JockoDundee

[Flaccid_Jack]

_GDIPlus_Startup()
For $i = 0 To 100
    Local $sBitmap = $ObjectImage[$i] ;accidently edited this out from first post <-----------------------
    Global $hBitmap = _GDIPlus_ImageLoadFromFile($sBitmap)
    Global $hBitmap_Resized = _GDIPlus_ImageResize($hBitmap, 60, 60) ;resize image
    _GDIPlus_ImageSaveToFile ($hBitmap_Resized, @ScriptDir & "\MyBitmap.png" )
    $hImage = _GDIPlus_BitmapCreateFromFile(@ScriptDir & "\MyBitmap.png")
    ;removed content
Next
_GDIPlus_ImageDispose($hBitmap)
_GDIPlus_ImageDispose($hBitmap_Resized)
_GDIPlus_BitmapDispose($hImage)
_GDIPlus_Shutdown()

Sorry, in attempt to cut the fat from my first post for readability, i left out the declaration of $sBitmap. 

 

I'm sorry, @JockoDundee and @zeenmakr; but I am not sure what the consensus was.

 

I am currently doing as Jocko had suggested (disposing of resources every loop). I made this post because I want to optimize my script and didn't know if I was wasting processing time by doing so.

[JockoDundee]

3 hours ago, Flaccid_Jack said:

_GDIPlus_Startup()
For $i = 0 To 100
    Local $sBitmap = $ObjectImage[$i] ;accidently edited this out from first post <-----------------------
    Global $hBitmap = _GDIPlus_ImageLoadFromFile($sBitmap)
    Global $hBitmap_Resized = _GDIPlus_ImageResize($hBitmap, 60, 60) ;resize image
    _GDIPlus_ImageSaveToFile ($hBitmap_Resized, @ScriptDir & "\MyBitmap.png" )
    $hImage = _GDIPlus_BitmapCreateFromFile(@ScriptDir & "\MyBitmap.png")
    ;removed content
Next
_GDIPlus_ImageDispose($hBitmap)
_GDIPlus_ImageDispose($hBitmap_Resized)
_GDIPlus_BitmapDispose($hImage)
_GDIPlus_Shutdown()

Sorry, in attempt to cut the fat from my first post for readability, i left out the declaration of $sBitmap. 

 

I'm sorry, @JockoDundee and @zeenmakr; but I am not sure what the consensus was.

 

I am currently doing as Jocko had suggested (disposing of resources every loop). I made this post because I want to optimize my script and didn't know if I was wasting processing time by doing so.

Yes, but declaring in the loop doesn’t actually do anything, except save a few characters of source code.

On the other hand, I found this UDF that disposes objects for you automatically on the call to GDI Shutdown.  Probably doesn’t make much difference in total execution, and you would still temporarily use a lot of memory, but you wouldn’t have to dispose along the way, and the files might appear slightly quicker.