[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [RFC] Reading images

From: Pete French
Subject: Re: [RFC] Reading images
Date: Mon, 22 Sep 2003 12:29:05 +0100

> When is a screen device ever assumed to be 72 dpi? I don't assume that

Next black hardware ? Plus I thought 72 points per inch was the assumed
default resolution for PostScript. e.g. the following file should always
produce a 1inch black square should it not ?

0 setgray
72 72 moveto  0 72 rlineto 72 0 rlineto 0 -72 rlineto closepath fill

...thats probably where the screen assumption comes from thinking about
it, assuming the DPS engine also fires up with that assumption.

> Depends. If you just want to use it to render back to the device, it's a
> good thing that the image is in device resolution. If you want an image
> with a specific size in pixels, you'll need to figure out the
> transformation between user space and image space (that's the 'Matrix'
> entry) so you know what size the original rectangle you draw in should
> be.

O.K., I'm convinced my code is wrong :-) Will go back and take a look
at it and see if I can find a nice easy way round it.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]