BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  TJPEGImage; can I dispose the interal BMP-buffer?          BorlandTalk.com Forum Index -> C++ Builder (Graphics) View previous topic :: View next topic   Author Message wwwim Guest Posted: Tue Jan 20, 2004 9:42 pm    Post subject: TJPEGImage; can I dispose the interal BMP-buffer? Hi, I programmed an image viewer. It read some 300 JPEG images in a list of TJPEGImage objects. This hardly uses memory, each jpeg file is about 20 kbyte. However, if I draw the jpeg objects to an TImage in my form, I see the amount of memory used grows to over 150 Megabyte. I tried deleting the TImage and creating a new one for each jpeg-image, but it didn't help. I discovered that TJPEGImage has an internal buffer in which it keeps the bitmap of the image. I could not discover a way to remove this buf. I would rather have the PC again decode the jpeg to a bmp than using this huge amount of memory. Any solutions for this? Thank you! Back to top Hans Galema Guest Posted: Wed Jan 21, 2004 8:08 am    Post subject: Re: TJPEGImage; can I dispose the interal BMP-buffer? wwwim wrote: Quote: I discovered that TJPEGImage has an internal buffer in which it keeps the bitmap of the image. I could not discover a way to remove this buf. Why would you remove the buf of the TJPEGIMage ? First you said that it occupied hardly any memory. Or did I miss something. Did you tell that with assigning it to a TImage that internal bujffer first grew ? And if you cannot remove that buf separately you could still delete the TJPEGIMage instance itself? Please explain. Hans. Back to top Detlef Guest Posted: Wed Jan 21, 2004 8:24 am    Post subject: Re: TJPEGImage; can I dispose the interal BMP-buffer? I think JPEG is a compressing algorithm. If you expand this ( writing to an image) it will use more memory. The only solution for this is not to show all images. Detlef "wwwim" <wbardoelREMOVEUPPERCASE (AT) yahoo (DOT) com> schrieb im Newsbeitrag news:400da0bf (AT) newsgroups (DOT) borland.com... Quote: Hi, I programmed an image viewer. It read some 300 JPEG images in a list of TJPEGImage objects. This hardly uses memory, each jpeg file is about 20 kbyte. However, if I draw the jpeg objects to an TImage in my form, I see the amount of memory used grows to over 150 Megabyte. I tried deleting the TImage and creating a new one for each jpeg-image, but it didn't help. I discovered that TJPEGImage has an internal buffer in which it keeps the bitmap of the image. I could not discover a way to remove this buf. I would rather have the PC again decode the jpeg to a bmp than using this huge amount of memory. Any solutions for this? Thank you! Back to top wwwim Guest Posted: Wed Jan 21, 2004 7:06 pm    Post subject: Re: TJPEGImage; can I dispose the interal BMP-buffer? Sorry for not being completely clear in what I want to achieve (although you guessed it quite well!) Indeed, my conclusion is that as soon as you assign a TJPEGImage to an TImage, the size of TJPEGImage grows. As far as I understood from other postings, this is due to an internal buffer in which it decodes the jpeg to a bitmap. I want to display only one image at a time, and want to be able to quickly and randomly switch between images. I use only one TImage to display the jpeg. I prefer not to use the harddisk and because the jpegs are roughtly 20 - 40k Byte each, I thought this would not be a problem. However, due to the internal buf in TJPEGImage, at the time I've seen all images, all internal buffs are filled and they total to 200MByte for some 300 jpeg images! "Hans Galema" <dontusethis (AT) dontusethis (DOT) nl> wrote Quote: wwwim wrote: I discovered that TJPEGImage has an internal buffer in which it keeps the bitmap of the image. I could not discover a way to remove this buf. Why would you remove the buf of the TJPEGIMage ? First you said that it occupied hardly any memory. Or did I miss something. Did you tell that with assigning it to a TImage that internal bujffer first grew ? And if you cannot remove that buf separately you could still delete the TJPEGIMage instance itself? Please explain. Hans. "Hans Galema" <dontusethis (AT) dontusethis (DOT) nl> wrote Quote: wwwim wrote: I discovered that TJPEGImage has an internal buffer in which it keeps the bitmap of the image. I could not discover a way to remove this buf. Why would you remove the buf of the TJPEGIMage ? First you said that it occupied hardly any memory. Or did I miss something. Did you tell that with assigning it to a TImage that internal bujffer first grew ? And if you cannot remove that buf separately you could still delete the TJPEGIMage instance itself? Please explain. Hans. Back to top wwwim Guest Posted: Wed Jan 21, 2004 7:08 pm    Post subject: Re: TJPEGImage; can I dispose the interal BMP-buffer? Hi Detlef, Even if you don't show all images (which I don't do, I display only one) it will use a lot of memory, You can see more details in my reply to Hans Galema, Wim "Detlef" <detlef.stute (AT) seatec-gmbh (DOT) com> wrote Quote: I think JPEG is a compressing algorithm. If you expand this ( writing to an image) it will use more memory. The only solution for this is not to show all images. Detlef "wwwim" <wbardoelREMOVEUPPERCASE (AT) yahoo (DOT) com> schrieb im Newsbeitrag news:400da0bf (AT) newsgroups (DOT) borland.com... Hi, I programmed an image viewer. It read some 300 JPEG images in a list of TJPEGImage objects. This hardly uses memory, each jpeg file is about 20 kbyte. However, if I draw the jpeg objects to an TImage in my form, I see the amount of memory used grows to over 150 Megabyte. I tried deleting the TImage and creating a new one for each jpeg-image, but it didn't help. I discovered that TJPEGImage has an internal buffer in which it keeps the bitmap of the image. I could not discover a way to remove this buf. I would rather have the PC again decode the jpeg to a bmp than using this huge amount of memory. Any solutions for this? Thank you! Back to top Hans Galema Guest Posted: Wed Jan 21, 2004 7:22 pm    Post subject: Re: TJPEGImage; can I dispose the interal BMP-buffer? wwwim wrote: Quote: I want to display only one image at a time, and want to be able to quickly and randomly switch between images. I use only one TImage to display the jpeg. I prefer not to use the harddisk and because the jpegs are roughtly 20 - 40k Byte each, I thought this would not be a problem. However, due to the internal buf in TJPEGImage, at the time I've seen all images, all internal buffs are filled and they total to 200MByte for some 300 jpeg images! Then I suggest to add one TJPEGImage instance (named JPEGexpander) more. If you need a specific jpg then first assign it from the unexpanded TJPEGImage instance to JPEGexpander. Then from the JPEGexpander assign it to the TImage. Please report if this works. Hans. Back to top wwwim Guest Posted: Wed Jan 21, 2004 7:37 pm    Post subject: Re: TJPEGImage; can I dispose the interal BMP-buffer? Yep, It works. Ignored to carefully read the help on Assign. It states clearly that one can a assign a TJPEGImage to another TJPEGImage. Goed gedaan Hans! "Hans Galema" <dontusethis (AT) dontusethis (DOT) nl> wrote Quote: wwwim wrote: I want to display only one image at a time, and want to be able to quickly and randomly switch between images. I use only one TImage to display the jpeg. I prefer not to use the harddisk and because the jpegs are roughtly 20 - 40k Byte each, I thought this would not be a problem. However, due to the internal buf in TJPEGImage, at the time I've seen all images, all internal buffs are filled and they total to 200MByte for some 300 jpeg images! Then I suggest to add one TJPEGImage instance (named JPEGexpander) more. If you need a specific jpg then first assign it from the unexpanded TJPEGImage instance to JPEGexpander. Then from the JPEGexpander assign it to the TImage. Please report if this works. Hans. 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