having to help Rev (was: Re: Memory Leak on export png????)

Dave dave at looktowindward.com
Fri Mar 23 11:56:42 EDT 2007


Hi,

Here is the original script:

on doExport
   local tNum
   local twID
   local tFol
   local tDest
   local myImageData

   put text of fld "number" into tNum
   put the windowID of this stack into twID
   put text of fld "export folder" into tFol
   if there is not a folder tFol then
     answer "Export folder not found!"
     exit to top
   end if
   set the defaultfolder to tFol

   repeat with x = 1 to (0 + tNum)
     put "F-" & x & ".png" into tDest

     put x into field "FieldCounter" of group "GroupCounter"

     set the alwaysBuffer of the templateImage to false
	
     --export snapshot from group "GroupCounter" to file tDest as PNG

     export snapshot from group "GroupCounter" to myImageData as PNG
   end repeat

   answer "Done!"
end doExport

I still get the error at file 289, is this what you thought would  
happen?

Thanks a lot for this
All the Best
Dave

On 23 Mar 2007, at 15:38, J. Landman Gay wrote:

> Dave wrote:
>
>> Took me 10 minutes to build the test for the export snapshot  
>> command and 2 minutes to run it.
>
> And, as it turns out, we were all wrong. There is a leak, and they  
> will fix it, but the reason there is a leak makes perfect sense.
>
> The bug I posted about this problem only a day or two ago has  
> already been verified and answered. This is a *strong*  
> recommendation that those of you who don't want to submit reports  
> should change your mind. Since I was the submitter, the respone  
> came directly to my inbox. If Dave had submitted, he'd have  
> received the response instead.

It's not that I don't want to, it's that I can't log on from here and  
when I get home at the weekends I am so tired and busy catching up  
with "home" stuff that it's hard to find the time.
>
> Here is what they said, and now that I think of it, I'm almost  
> embarrassed that I didn't think of the reason myself:
>
>> The memory leak that has been observed here occurs for all forms  
>> of 'export
>> snapshot' and any image format - however, it *only* occurs if the  
>> alwaysBuffer
>> of the templateImage is set to true.
>> To eliminate the leak:
>>   set the alwaysBuffer of the templateImage to false
>> Before using the export command.
>> The setting of this property is set differently in the Revolution  
>> and MC IDE's
>> and in standalones (and on Mac OS X and Windows) - explaining the  
>> difficulty in
>> reproducing it for some people.
>
> While I admit the leak needs to be fixed, the reason for it become  
> obvious; alwaysbuffer reserves memory space for the image in an  
> offscreen buffer. The bug does not show up on some platforms, and  
> the alwaysbuffer setting varies from one IDE to another. It would  
> be difficult to stress-test this bug; it only seems to occur in one  
> very specific circumstance, in only one IDE, and only on one OS.
>
> Dave, your original script should work just fine if you change the  
> alwaysbuffer of the templateimage to false.






More information about the use-livecode mailing list