Yeah, but jpg doesn't record pixels like that. What you suggest could work with a bitmap, but a jpg is different. Don't ask me the techie details, but I think of it as recording a start position, colour value, then the number of adjacent pixels of that colour. So building up a picture means it is necessary to decode the whole file. Progressive jpgs obviously work a bit differently - perhaps recrding 2 images with alternate rows in each image, then interlacing them?
Anyways, what you say is not easy or perhaps even possible for a standard jpg... > -----Original Message----- > From: vr [mailto:[EMAIL PROTECTED] > Sent: 02 April 2004 11:00 > To: [EMAIL PROTECTED] > Subject: Re: New *ist D review - Imaging Resource > > > > > John Francis wrote: > > > > not to display some of the pixels if they were available, > and there's > > no reasonable way to get some of the pixels from an image without > > getting all of them (except, as noted, if it were a > progressive JPEG). > > > > how is that? > you can give an order to address and read every 4th pixel from file.. > > what do you think modern databases work like where ypou can > get desired > bits from huge file in seconds if the file is indexed?? > > though to be faster or more reasonable compared to readin > everything the > gap should not be every 4th pixel, but much wider.. > > i guess > > viljar > > > > >
