OpenEuphoria

Re: JPEG Resolution

• Posted by Al Getz <Xaxo at aol.com> Mar 13, 2006
• 505 views

Brian Broker wrote:
> 
> Al Getz wrote:
> > 
> > Alex Chamberlain wrote:
> > > 
> > > Al Getz wrote:
> > > > 
> > > > Alex Chamberlain wrote:
> > > > > 
> > > > > Hi,
> > > > > 
> > > > > Can anyone help me by providing a function to tell me the resolution
> > > > > of
> a JPEG</font></i>
> > > > > File?
> > > > > 
> > > > > I'm using GD at the moment.
> > > > > 
> > > > > Thanks,
> > > > > 
> > > > > Alex
> > > > 
> > > > Hi there,
> > > > 
> > > > 
> > > > Are you talking about the DPI (dots per inch) ?
> > > > 
> > > > 
> > > > Al
> > > 
> > > Yeah!
> > 
> > 
> > Hi again Alex,
> > 
> > 
> > Sorry, i have an inch thick stack of notes on the jpg file format
> > and i cant seem to find anything on the dpi of the file.  It's 
> > been so long now since i've worked with this i dont remember how
> > to find or calculate this.  Maybe ask again or on another
> > forum?
> > 
> > 
> > Al
> > 
> > 
> > My bumper sticker: "I brake for LED's"
> 
> Correct me if I'm wrong but isn't DPI a measurement of an output device?
> 
> How big is a pixel?
> <a
> href="http://heim.ifi.uio.no/~gisle/photo/pixels.html">http://heim.ifi.uio.no/~gisle/photo/pixels.html</a>
> 
> -- Brian

Hi Brian,


What i was assuming was that he was after something like the bitmap
file header contains: PelsPerMeter for Vertical and Horizontal,
but couldnt find anything that had a unit of length in it.
It's possible to calculate (for jpg) but i cant seem to find the doc's on it.
I think it's because when i was doing my jpg decoder i had no use
for the resolution data because most of the time there's only one picture
to choose from and one monitor to choose from.
I think the last time i worked on my .jpg decoder (in the archives) was
around 1999 or so.


Take care,
Al

And, good luck with your Euphoria programming!

My bumper sticker: "I brake for LED's"