Hi Jürgen On 14.01.2011 13:03:39 Juergen Birkle wrote: > > Hallo Pete, > > The print is nearly perfect, but has the same minimal difference as the > screen.
Nearly? I haven't heard any indication, yet, that this problem appears in print. > The antialiasing at the screens is ALLWAYS 1px, no matter what zoom-factor > you use at the reader. With the effect that the difference get less as you > increase the zoom-factor. > > But my main problem is, that the view of the reader looks bad in a > zoom-range of 50% to 200%! > > A line of 2px at 100% is displayed with 3 different kinds: > 1. with antialiasing from top and bottom ==> displays as "light grey" line > 2. with antialiasing from top or bottom ==> displays as "dark grey" line > 3. with not antialiasing (solid) ==> displays as "black" line > > If you reduce the zoom-factor to 75% or 50%, the line of 1. becomes > invisible and 2. becomes a lighter appearance. > > Print of the page is ok, but only because the printer has a much higher > resolution. No, because no anti-aliasing happens on a printer. The anti-aliasing is only done on computer screens to improve the subjective resolution. And Adobe's approach seems to have some drawbacks here. > I have generated PDF with Excel and with it the borders are all drawn as > solid lines. You can see the difference with Acrobat reader at 6400%. FOP > generated files have different types of lines. The shapes are displayed with > a thin "object-line" in the middle of the black border and antialiasing, the > solid lines are displayed without this "object-line" and without > antialiasing. The mixing of this two objects in one PDF file results in a > bad display in the reader. > > If there is a possibility to disable the usage of shapes (or rectangle > object) in FOP and only use solid lines it would help me and others very > much. Because with the mixing of this two objects in one PDF no good looking > PDF at the screen is possible! There is currently no switch that makes this go away. The current approach was selected to support all different border styles in XSL-FO and the border collapsing model. That has that precise drawback that you see in Acrobat. Of course, it would theoretically be possible to combine the various border segments where this is possible, for example when two adjacent border segments have the same color. I remember back when Karen and Keiron discussed combining border segments during the FOP redesign (2003/2004). Apparently, this business is quite tricky. A simple approach might be to fall back to FOP 0.20.5's approach that simply painted solid lines (but didn't support all border styles). But even that sometimes looked ugly in Acrobat (or even in print). > If you want me to show you the difference let me know, I will post the > Screenshots at 6400% of Acrobat reader. We know all about how it looks. This has come up several times. Disable anti-aliasing in Acrobat and the problem goes away. Unsatisfying, I know. Anyway, implementing a better border painting strategy with border segment combination will be a tricky thing. I don't think you can expect a short-term solution from anyone here, except if you give it a shot yourself. But I doubt it is worth the effort just to improve how the borders look in Adobe Acrobat. <snip/> Jeremias Maerki --------------------------------------------------------------------- To unsubscribe, e-mail: fop-users-unsubscr...@xmlgraphics.apache.org For additional commands, e-mail: fop-users-h...@xmlgraphics.apache.org
