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VB Forum / Win API / December 2007Garbage collect (or what?)
Hello, Using XL97VBA/WIN98 and SendKeys and Appactivate and Shell, I'm successfully able to make thumbnails with either Paint or Photoshop Elements. But, after processing 100 or so images, it seems the system gets bogged down or something, and Paint gets "out of memory" errors and Photoshop also gets a problem, I don't know what. I've run "Accesories/System Monotor" and know that memory allocation is high and swap usage is high. Q's: 1) Can I call some kind of "Garbage Collect" API every once in awhile to keep things cleaner? 2) Can I call some kind of "Memory Usage" or "Swap Usage" API and maybe terminate/re-shell the program based on that? I haven't tried to terminate/re-shell on a regular basis -- maybe that's a solution. TIA, D-C Dave hi Dave, It sounds like all those graphic images are piling up in memory, and then forcing "virtualization" (or expanding real memory by creating virtual memory -- your disk swapfile). Are you processing them all-at-once(?), i.e., as in making up a page of thumbnails? If so, then the application is loading your graphic images in memory, but is not having any opportunity to release the memory. And, there is no garbage collection if the graphic image memory doesn't get released. If that is the case, I would suggest processing the images one-at-a-time, save the thumbnail to disk, and then close your app. That way, the app (should) release the memory allocated to your graphic. Finally, re-assemble your thumbnails. In general, my impression is that "garbage collection" is not invoked until the system runs out of memory. It will then start releasing blocks or memory as needed that have been de-allocated, the oldest one first. If there are no de-allocated blocks, then it will start swapping out memory to the swap file. Perhaps there are more knowledgeable folks here who can provide a more accurate and precise description of "garbage collection". However, my impression from what you said is that when your system starts "thrashing" that it is not "garbage collection", rather it is the failure to release memory that is the problem. cheers, jw > Hello, > [quoted text clipped - 19 lines] > > TIA, D-C Dave Thanks for your response. I missed making an important point: >Are you processing them all-at-once(?) No, I am doing them one at a time and saving to disk, so only one is in memory at any time. I have many DoEvents sprinkled about in my code. 1) I will try a second or so of DoEvents (or Sleep?) in between each image (or 10 images). 2) I will try terminating and re-shelling the program in between each image (or 10 images). Thanks again, Dave D-C >hi Dave, > [quoted text clipped - 55 lines] >> >> TIA, D-C Dave > Thanks for your response. I missed making an important point: >>Are you processing them all-at-once(?) [quoted text clipped - 8 lines] > > Thanks again, Dave D-C Why don't you just write some code yourself to resize the images? Michael > No, I am doing them one at a time and saving to disk, so > only one is in memory at any time. [quoted text clipped - 4 lines] > 2) I will try terminating and re-shelling the program > in between each image (or 10 images). I agree with MC, you'd get more control over the process by writting the code yourself than shelling out to other applications. LFS "Michael C" <mike@nospam.com> wrote: >Why don't you just write some code yourself to resize the images? >I agree with MC, you'd get more control over the process by >writting the code yourself than shelling out to other applications. ARE YOU GUYS SERIOUS!? OK, seriously, You've inspired me to look at that. I assume I'll have to do this in VB6 and not XL-VBA (right?). No problem. In the past I have called a VB6 routine from VBA by compiling a routine Sub1 in a class module Class1 in a ActiveX DLL and doing Dim ObjPtr as New Class1 ' and then ObjPtr.Sub1() ' does the job. But all want is a simple Call Sub1(). But that is a separate issue. So I'll have an Image in a Form and do a LoadPicture and something like Image1.Width = w and Image1.Height = h and then SavePicture (as jpg)? http://search.microsoft.com/results.aspx?q=savepicture+jpg&qsc0=0&SearchBtn0=Sea rch&FORM=QBME1&l=1&mkt=en-US&PageType=99 I probably won't be using APIs much. Where else do you guys hang around when I have questions on this? Thanks so much. mr_unreliable <kindlyReplyToNewsgroup@notmail.com> wrote: >Here are a couple of tutorials on garbage collection > http://msdn.microsoft.com/msdnmag/issues/1100/GCI/default.aspx > http://msdn.microsoft.com/msdnmag/issues/1200/GCI2/default.aspx Thanks again, I'll look at those. D-C Dave > "Michael C" <mike@nospam.com> wrote: > >Why don't you just write some code yourself to resize the images? [quoted text clipped - 7 lines] > I assume I'll have to do this in VB6 and not XL-VBA (right?). > No problem. <...> > So I'll have an Image in a Form and do a LoadPicture and > something like Image1.Width = w and Image1.Height = h > and then SavePicture (as jpg)? Getting the image reduced to the size you want is no problem in VB, its the saving the image as a jpg that is unsupported. Post the following code into a new form. It loads an image on to the form (the form's icon), then scales that image upwards, prints text on it, and scales it back down again. You might use two pictureboxes, one to load the image, and a second to adjust to the size you want that recieves the scaled down (thumbnail) version. From there, you can easily save the image as a BMP file, but to save as JPG you'll need a bit more code. Here is some free code you can add to your project to do that.... http://www.planetsourcecode.com/vb/scripts/ShowCode.asp?txtCodeId=50065&lngWId=1 Depending on the quality you want for the thumbnails, the PaintPicture method may work for you if you are not that picky about quality. Otherwise, some API work would allow for even more control, and help to produce better quality thumbnails. But, get the basics working first, then see if you need to tweak it for better performance.... HTH LFS Private Sub Form_Load() ' Init Me.ScaleMode = vbPixels Me.AutoRedraw = True Me.Font.Bold = True Me.Font.Size = 18 Me.ForeColor = vbRed Show ' Original Me.Picture = Me.Icon ' Scale up Me.PaintPicture Me.Picture, 0, 40, 128, 128, 0, 0, 32, 32 Me.PSet (10, 100), Me.Point(10, 100) Me.Print "THUMB" Me.Picture = Me.Image ' Scale down Me.PaintPicture Me.Picture, 0, 200, 32, 32, 0, 40, 128, 128 End Sub Here are a couple of tutorials on garbage collection (past and present): http://msdn.microsoft.com/msdnmag/issues/1100/GCI/default.aspx http://msdn.microsoft.com/msdnmag/issues/1200/GCI2/default.aspx O.K., before you flamers start flaming me because the net framework is mentioned, there is some more general discussion in those articles which is applicable to any garbage collection scenario. As to the op's question, if the graphics are being processed one-at-a-time, then in all likelihood the original app has a "memory leak". I don't especially like that term, but in plain English it means that some app has failed to release system resources (such as memory, bitmaps, icons, etc). You can find various "memory monitors" or "resource monitors" which will graphically show available memory and/or system resources being consumed in real time. If the op brings up one of these monitors and then runs his job, then he can get a picture of system memory and/or system resource utilization and potential "memory leaks". What to do about it is another matter. If the original app is not releasing allocated memory and/or system resources, then yes -- you are eventually going to come to a grinding stop. You can suggest that the app vendor fix his/her app, or you can "roll-yer-own", i.e., do-it-yourself. Or, find another app. There are a number of apps out there which will create thumbnails for you -- even apps created by microsoft (who can be relied upon to provide 100% reliable and error-free code). cheers, jw > Hello, > [quoted text clipped - 19 lines] > > TIA, D-C Dave mr_unreliable <kindlyReplyToNewsgroup@notmail.com> schrieb im Beitrag <#59Q0icNIHA.4656@TK2MSFTNGP03.phx.gbl>... > who can be relied upon to provide 100% reliable and error-free code Yeah, and our earth is in fact a disk...  Signature---------------------------------------------------------------------- THORSTEN ALBERS Universität Freiburg albers@ uni-freiburg.de ---------------------------------------------------------------------- Save yourself a lot of hassle and use the free IrfanView: www.irfanview.com It will batch process 100 thumbnails in about the time it took you to read this. SignatureSteve Easton > Hello, > [quoted text clipped - 19 lines] > > TIA, D-C Dave Thanks for the recommendation. I'm now using it. But not to make my thumbnails for my application. It will "Save selected thumbs as single images" at various sizes, but they are square and not exactly what I want. But I'll look more at irfanview as well as making my own [thumbnails]. >Save yourself a lot of hassle and use the free IrfanView: >www.irfanview.com >It will batch process 100 thumbnails in about the time it took you to >read this. |
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