RE: [dita] Suggestion for graphic scaling improvements in DITA 1.1

["Grosso, Paul" <pgrosso@ptc.com>]

Thanks for your support, Gershon.

As far as multiple settings for image size, when I
talked to our customers, they said they would rather
handle that need, when it arises, via profiling for
the various outputs.  

Given this workaround, and given the overall desire
not to make DITA 1.1 too complex, I think we might
want to defer your suggestion to a later release.

As an aside, I'd point out that Gershon's example
had a 40% scaling factor which is not included in
DITA's scale attribute's current enumerated list of
choices.  When I asked our customers if they could 
live with DITA's scale attribute's set of choices,
they said no way.  They often need to scale, say, 25% 
or 133% or whatever, which reinforces my suggestion
that we change the type of the scale attribute to NMTOKEN.

paul

> -----Original Message-----
> From: Gershon L Joseph [mailto:gershon@tech-tav.com] 
> Sent: Wednesday, 2006 January 25 5:09
> To: dita@lists.oasis-open.org
> Subject: RE: [dita] Suggestion for graphic scaling 
> improvements in DITA 1.1
> 
> I fully support Paul's suggestion, since our clients have 
> similar issues.
> 
> One additional issue I'd like to raise for discussion on the 
> list is whether
> we should support two settings for each image sizing 
> attribute. Many of our
> clients have expressed the need to specify *one* image size 
> for on-line
> (HTML) output and *another* image size for print/PDF output. 
> Since output
> generally falls into two categories -- online or print, we 
> probably don't
> need to make it infinitely scalable. However, some users may 
> also publish to
> hand-held devices that could arguably require a third image size...
> 
> The cleanest way to support setting graphic scaling for 
> multiple outputs is
> possibly to predefine the order in which the target media's 
> scaling appears,
> and allow for a character that represents no scaling for that 
> media. For
> example, <image scale="60 40" ...> would imply that 
> HTML-based output is
> scaled 60%, while for PDF output we'll scale the image to 40%. <image
> scale="* 40"> means we use a default scaling, (or no 
> scaling?) on the HTML
> output. The default value makes less sense on the scaling 
> attribute, since
> we could easily specify '100', but it does make sense when 
> setting specific
> width and height settings for the graphic. (In my case, one 
> client scales
> their graphic for print/PDF and has most of them full-size 
> for HTML output.
> So specifying * for width would apply no scaling to the width of the
> graphic.)
> 
> If the TC feels we should defer my suggestion to after DITA 
> 1.1, that's OK
> with me. I just wanted to get this point on the table for 
> discussion, and
> thought it could be done as part of Paul's suggestion.
> 
> Gershon
> 
> 
> -----Original Message-----
> From: Grosso, Paul [mailto:pgrosso@ptc.com] 
> Sent: Monday, January 23, 2006 10:31 PM
> To: dita@lists.oasis-open.org
> Subject: [dita] Suggestion for graphic scaling improvements 
> in DITA 1.1
> 
> I spoke to Don, and he suggested I send a specific suggestion 
> for a DITA 1.1
> work item to the list in the area of graphic scaling.
> 
> EXECUTIVE SUMMARY
> =================
> DITA's support for graphic sizing--which just allows a number 
> of pixels to
> be specified for the graphic image size via the image 
> element's height and
> width attributes--does not meet our customer requirements. 
> I suggest we make some upward compatible changes to address at least a
> subset of these requirements.
> 
> DETAILS
> =======
> 
> Current situation
> -----------------
> The DITA spec is vague on the topic of what are valid values 
> for the image
> element's height and width attributes and what are the 
> semantics of these
> values.
> 
> In checking both the toolkit and the collective IBM 
> knowledge, I understand
> that, for HTML generation, the image height and width values 
> are passed
> through as-is implying that DITA's image's height and width 
> attributes must
> be unitless integers giving the number of pixels to which to scale the
> graphic image (in each direction) in the browser displayed 
> results.  For IBM
> PDF processing, the pixel values are converted to points 
> (assuming 96 pixels
> per inch and 72 points per inch), and that value is used.
> 
> 
> Requirements for graphic scaling
> --------------------------------
> 
> 1. It should be possible for users to specify a percentage
>    value to which to scale the intrinsic size of the image.
> 
> 2. It should be possible for users to specify an absolute size
>    for the image height and/or width using a numeric value and
>    unit of measure.  Allowable units should include: pc (pica),
>    pt (point), px (pixels), in (inches), cm (centimeters), 
>    mm (millimeters), and em (ems) as allowed by CSS and XSL-FO.
> 
> 3. To aid in reuse and minimize hardwiring style to the source,
>    it may be a requirement to allow a user to request that an
>    image be scaled to some percentage of the "available space".
> 
> One specific proposal
> ---------------------
> 
> 1.  Add the "scale" attribute to the "image" element, and
>     change the declared type of the scale attribute to NMTOKEN.
>     Define the allowable value space of the scale attribute
>     to be any unsigned integer.  This would be an upward
>     compatible change.
> 
> 2.  No change needs to be made to the image element's height
>     and width DTD declarations, as NMTOKEN would allow all
>     values we wish to allow.  We would just augment the spec
>     to say that the value space of these attributes is a
>     length which is a real number with an optional unit
>     from the set of pc, pt, px, in, cm, mm, em.  An omitted
>     unit implies pixels so that existing documents will
>     continue to be treated the same way. 
> 
> 3.  This requirement could be met by allowing image element's
>     height and width attributes to take % values along with
>     some work to define what the "available space" is.  The
>     specific details of a suggested solution depend on the
>     exact user requirements which I'm still researching (and
>     would appreciate input from other users).
> 
> paul
> 
>