Loading ...
Sorry, an error occurred while loading the content.

Re: [XSL-FO] How is Baseline Position Determined?

Expand Messages
  • G. Ken Holman
    ... The only quantity that has messed me up in the past is the half-leading, as the default leading value is implementation defined. I ve taken control by
    Message 1 of 3 , Jan 24, 2006
    • 0 Attachment
      At 2006-01-24 16:34 -0600, Eliot Kimber wrote:
      >I'm trying to translate design specs that specify baseline-to-baseline
      >into reliable FO specifications and I'm finding that it may not be possible.
      >
      >What I need to be able to do is predict where the baseline for a given
      >line of text, usually the first line in a block, will fall relative to
      >the before or after edge of the block.
      >
      >If I understand the spec, the "baseline start point" is formatter
      >determined (Clause 4.5 Line-areas).
      >
      >If this is the case then there doesn't seem to be a reliable way to
      >predict where the baseline will fall.

      The only quantity that has messed me up in the past is the
      half-leading, as the default leading value is implementation
      defined. I've taken control by specifying line height explicitly and
      then obtained closer results between tools.

      But I confess that I haven't had to count pixels, so I don't know if
      there is a nuance I've missed.

      >Is my analysis correct (that baseline is unpredicatable) or have I
      >missed a subtlety somewhere?

      Before and after each line the formatter will allocate half of the
      leading (a kewl method of accommodating successive lines with
      different font sizes).

      I wonder if you changed line height to "1" (scalars are allowed as
      indications of factor of the font size) if you would get closer
      results because there would then be no leading.

      I hope this helps.

      . . . . . . . . . . . . Ken

      --
      Upcoming XSLT/XSL-FO hands-on courses: Denver,CO March 13-17,2006
      World-wide on-site corporate, govt. & user group XML/XSL training.
      G. Ken Holman mailto:gkholman@...
      Crane Softwrights Ltd. http://www.CraneSoftwrights.com/f/
      Box 266, Kars, Ontario CANADA K0A-2E0 +1(613)489-0999 (F:-0995)
      Male Cancer Awareness Aug'05 http://www.CraneSoftwrights.com/f/bc
      Legal business disclaimers: http://www.CraneSoftwrights.com/legal
    • Eliot Kimber
      ... I just realized that it doesn t really matter where the baseline as long as you know the line-height of the lines in the blocks involved. For example,
      Message 2 of 3 , Jan 24, 2006
      • 0 Attachment
        Eliot Kimber wrote:
        > I'm trying to translate design specs that specify baseline-to-baseline
        > into reliable FO specifications and I'm finding that it may not be possible.

        I just realized that it doesn't really matter where the baseline as long
        as you know the line-height of the lines in the blocks involved.

        For example, imagine you have two blocks, one with a line height of 12
        points and one with a line height of 18 points and you want a nominal
        baseline-to-baseline distance of 36 points between the last line of the
        first block (block A) and the first line of the second block (B). I
        think that this formula will always work:

        b-to-b - (line-height-A/2 + line-height-B/2)

        This is because the relative positioning of the baselines of both lines
        involved will be the same, regardless of where they actually are placed.

        The bigger challenge would be when the layout is designed in terms of
        distances from a fixed edge to the baseline, top of x-height, or top of
        cap height of a line. That seems to still be unknowable.

        Cheers,

        Eliot
        --
        W. Eliot Kimber
        Professional Services
        Innodata Isogen
        9390 Research Blvd, #410
        Austin, TX 78759
        (512) 372-8841

        ekimber@...
        www.innodata-isogen.com
      Your message has been successfully submitted and would be delivered to recipients shortly.