Re: [oiic-formation-discuss] My perspective. display perferct?

[jose lorenzo <hozelda@yahoo.com>]

--- On Mon, 6/30/08, Dave Pawson <dave.pawson@gmail.com> wrote:

> From: Dave Pawson <dave.pawson@gmail.com>
> Subject: Re: [oiic-formation-discuss] My perspective. display perferct?
> To: oiic-formation-discuss@lists.oasis-open.org
> Date: Monday, June 30, 2008, 5:26 AM
> 2008/6/30 Thomas Zander <zander@kde.org>:
> > There is a difference between different odf-features.
> 
> > Then we have features like table borders, in OOo (at
> least 2 years ago, when I
> > tested it) table borders were drawn above the
> cell-separator while in the
> > spec it was suppost to on the cell separator.  So a
> border of 2pt was drawn
> > 1pt too high up.
> > This kind of details certainly can be tested and
> marked as wrong; they are in
> > the spec.
> 
> How would you define an objective test for measuring +-2pt?
> Is that practical?
> This seems to be moving towards 'pixel perfect'
> which seemed
> to be impractical.

I know some have questioned the need for pixel perfect. I am not making a judgment on that, but thought I'd point out something which may end up being useful in other tests.

2 pixels is twice as thick as 1 pixel, ie, 100% extra thick. So you can create a series of lines across the screen (acid test) that are spaced by 1 or by 2 pixels and test the item. I don't know the details of this situation, but I am sure you can get to a point where you either have 1/2 the screen colored or only 1/3 of it or something along those lines. That should be noticeable to the eye. If not, you can then do a sampling of a screen area and see if roughly the shaded area is 50%, 33% 25% or whatever else would be the case.

So while 1 pixel is small, we do have 1 pixel resolution. We can multiply the effect of that one pixel to be tens of thousands of pixels difference when we consider the whole screen. Ie, we blow up the small detail to a scale where 1 pixel scales to half the screen or something like that (like magnification. Yes, an amoeba is small, but not when looked at through a microscope).

Also an even more stark contrast is between 1px and 0px which are still 1 pixel difference. If you repeat this line width for the height of the screen, you end up with 1*height = 100% shaded or 0*height = 0% shaded. Thus, if you reduce the test to 1 pixel or 0 pixel and can repeat that pattern, the result is a clearly distinguishable fully shaded screen (eg, in red) or completely empty screen (eg, white). .. and you need not do to the whole screen to see this. Just dedicate an mxn square on the screen for this particular test (acid test). Though the full screen example does make it extremely easy to use a program to automatically do the test (no fuzziness or high precision needed).

BTW, to actually carry something like this out for the case of table cells, perhaps use a cell (internal) height of 0, cell border of 1, cell margin of 0 or 1 (I am guessing from memory and html/css.. not sure about odf). Then stack cells on top of each other (rows in table). Either you can cram as many cells as the height of the screen, more or less, or else you would get an infinite number of cells which is easy to catch (cellnum>100,000).