Adobe Illustrator - Vertical and horizontal lines antialiased at export (and i don't

Author

Vertical and horizontal lines antialiased at export (and i don't

Philours

2006-06-08, 6:18 pm

Hello !
I've made a vector template into illustrator (CS2) and want to export it
into photoshop (CS2 too) for web purpose.
I noticed that each time i export a vector into a bitmap with
antialiased turned on it smooth *all* of the document, wich would be
fine and ok in theory except it also smooths the pure vertical and
horizontal lines (which do not require any type of antialiasing as they
are purely straight).
I've tried exporting the document with and without background, and into
various type of formats (PSD, BMP, EPS, PDF, etc.) and tried also to
directly import the .AI into photoshop (worst result).
Is there something i missed into the export preferences or something
i've done wrong ?
I precise that the document setup size into illustrator (the artboard
size in pixels) matches the final result i aimed at into photoshop (and
the color space is the same ie:RGB).
Of course i need to export it with antialiased turned on because of non
straight elements into the template...
Thanks in advance for your help.
Philours.

Philours

2006-06-08, 6:18 pm

jbl a écrit :
> On Thu, 08 Jun 2006 14:48:31 +0200, Philours
> <Philours@-NoSpam-philours.com> wrote:
>
>
> There is no way to export or save vector objects from illustrator to
> photoshop without them being rasterized. Even purely "straight" lines.
>
> It is a simple matter to "clean up" the straight horizontal and
> vertical lines with the photoshop pencil tool.
> jbl
Yes that's what i've done by the end but i still think that
rasterization would not have to antialiased purely straight lines (don(t
you ? :) ).
Anyway, thanks for the help. :)

Philours

2006-06-08, 6:18 pm

Doug Winger a écrit :
> In article <4488414c$0$19186$626a54ce@news.free.fr>,
> Philours <Philours@-NoSpam-philours.com> wrote:
>
>
> Your trouble arises from the antialiasing algorithm having to deal with
> fractional pixels. If you're using, I assume, the 'standard' 72 dpi for
> display screen resolution, unless the bezier line lies exactly along the
> center of a pixel, the algorithm will spread the joy to the next cell.
>
> The partial cure is to make sure that there's no fractional measures in
> the line's location, and that end resolution matches line weights, e.g.
> making sure that box's lines locations 'line up' along whole numbers
> with no fractional component (unless the line weight requires it) and
> the line weights translate directly into a pixel.
>
> The above is one of the reasons that many people use 72 DPI when
> figuring on screen display. Illustrator's point measure translates
> directly into pixels. It makes 'lining up' lines with pixels during
> later translation a lot easier.
>
>
> - Doug
Nice point Doug, it's absolutely relevant in this case. I noticed that
the vector shapes in photoshop do the same as they are not aligned
precisely.
Do you mean i have to use the grid with pixels in unit and aligne each
of my lines to grid separation ? I assume it would solve the problem in
this case right ?

Philours

2006-06-11, 3:18 am

Doug Winger a écrit :
> In article <448852ca$0$6978$636a55ce@news.free.fr>,
> Philours <Philours@-NoSpam-philours.com> wrote:
>
>
>
> Partly. The key to this is making the line edges match a pixel's 'edge'.
> For instance, when using a one point line in Illustrator with 72 DPI
> your final destination, you have to make sure that the line itself
> 'splits' the pixel: that it centers on a 0.5 point dimension so that the
> 'edges' of the line lie on the desired pixel edges after conversion,
> while a two point line needs to line up 'on the grid' so that its edges
> fill the two pixels it traverses. Odd number size strokes can be a
> headache, as they just don't 'fit' properly or easily. Thankfully,
> simple filled objects just have to line up on whole number dimensions
> and are easier to lay down.
>
> It's primarily thinking ahead, setting up for end resolution, some
> simple math, trying to work at final size and always keeping in mind
> that you have to treat strokes as if they were actually rectangles
> (which they are, to postscript :). Using guidelines, a grid (with nudge
> set to provide any necessary fractional moves), move and the Transform
> make things a lot easier.
>
>
> - Doug
Thanks a lot for all these precious advices Doug !
:)