Hi,
As I wrote, adding units complicates things.
We would have two linked properties in what you have below and one
modifies the
interpretation of the other.
If we expose the number of spaces integer property today, I think we'd
have to add the units as a
separate property, but it might be that this is what you'd want anyway
unless right now, today
you add some new TabSize class which includes both and perhaps today
would support
only "spaces" or "ems" or something as the only value of the enum of sizes.
FWIW I assumed that CSS is using "ems" as an explicit name for the
default if you don't
specify units.
With TabSize there you could later add "pixels".
But I am not sure it is really worth supporting pixels but I raised it
because
we should have the discussion up front to know if we have a way to add
it later if it is needed.
If we aren't limiting the value, I see no reason to use short, since any
value > 100 or thereabouts
pretty much means " line break", or "clip" if there's no line breaking.
However I still prefer a sensible maximum.
Kevin noted off-line that clamping isn't completely off-base for ranges.
-phil.
On 10/17/19 10:40 AM, Scott Palmer wrote:
Hi Phil,
Thanks for taking a look. I was going to get back to this soon to attempt
adding the CSS property as you mention in your previous email. I considered
tabSize as a name as well. I don’t have a preference if we leave things as
representing tabs as a number of spaces. But it wouldn’t be too difficult to
support units, making it mostly compatible with CSS rules. The way I envision
that is having two properties, tabSize and tabUnit.
David mentioned javafx.css.SizeUnits… I looked quickly at the java docs for it,
and it’s basically undocumented . So I went to
https://www.w3.org/TR/css-values-3/#lengths and I see there is no CSS unit like
‘ems’ but meaning the width of a space in the current font. The problem with
that is it would leave out the possibility to set the tab width to anything
relative to the current implementation of 8 spaces. (In hindsight it should
have been implemented based on ‘ems’, which for a fixed width font as typically
used in a code editor would be the same as 8 spaces anyway)
Do we add something to SizeUnits so we can work around this? e.g. ‘fxsp’
(FX-space - fx prefix to avoid a potential collision with any future official
CSS units)
// Two tab-related properties
public void setTabSize(int size); // defaults to 8
public void setTabUnits(SizeUnits units); // ?? no unit for width of space in
current font
If we did the above, I would consider adding this for convenience:
public void setTabWidth(int size, TabUnits units);
As far as setting a range, I’m not sure there is any worthwhile benefit to
enforcing a maximum. If we want to store the value in a short instead of an
int to potentially save a couple bytes, sure. Otherwise, if someone wants to
set tabs to be 20 spaces or 100, why should we prevent it? If there isn't a
performance or memory impact, I wouldn’t enforce a maximum.
Ignoring any out of range values rather than clamping seems fine to me as well.
I was thinking of what happens if the value was bound to another value that
strayed out of range. Clamping would get you as close as possible to the bound
value, rather than stuck at the previously observed value. I just guessed that
would be preferred, but if ignoring is more consistent with other values, then
I agree it makes sense. As long as the behaviour is documented, I can’t think
of any significant downside either way.
Regards,
Scott
On Oct 17, 2019, at 12:45 PM, Phil Race <philip.r...@oracle.com> wrote:
Hi,
Some more points which I thought about but for whatever reason did not pen ..
First one minor thing: tabWidth is an OK name, but it does not
conjure up that the value you specify isn't a width in pixels but the
number of discrete space characters to use. FWIW CSS calls it tab-size.
But CSS then supports pixels and ems .. that complicates matters a lot.
https://developer.mozilla.org/en-US/docs/Web/CSS/tab-size
Thee rest is mostly to do with "legal or sensible values"
You have :
if (spaces < 0)
spaces = 0;
since negative values are not something we want to support!
But I think instead of clamping you could "ignore", any out of range value.
This is practiced elsewhere in FX where illegal values are ignored rather than
throwing an exception, although it might be that clamping is quite common
in range cases.
The follow on to that is that what is a sensible maximum value.
Currently we have int which is more than we need. For that matter so is short.
I think we should have a documented and enforced sensible maximum.
Perhaps it could be "8" meaning we only support reducing tab width as I
don't know if anyone really wants to increase it.
CSS doesn't have a limit that I can see but if we are already only supporting
it described as number of spaces, we can have this other limitation too.
If you think 8 is too small, then maybe 16 ?
Also remember we can compatibly relax it later but we can't compatibly tighten
it.
-phil.
On 10/15/19 12:17 PM, Phil Race wrote:
Hi,
I've looked over this and I don't see any issues - meaning gotchas.
It just provides a way to over-ride the hard-coded 8,
whether using a Text node directly or a TextFlow.
Two observations of what one might call limitations
1) This is a rendering time property, which is controlled by the program.
A document containing tabs saved and re-rendered somewhere else
won't be helped.
2) This just provides API on the scene graph node types, not any of the UI
controls
which use Text nodes. Something like a CSS property may be the way to go if
you wanted that.
Text has a nested class StyleableProperties for CSS properties with which it
plays nice : font, underline, strikethrough, text-alignment
So creating an fx-tabWidth (or similar name) CSS property could be propagated
through to there in a similar way.
-phil.
On 9/30/19 9:48 AM, Scott Palmer wrote:
Okay, current work relocated to a clone of the new official Git repo.
My initial implementation is here:
https://github.com/swpalmer/jfx/commit/cc6193451bf8a693093f3ded5dcbe47af2fcbe8f
<https://github.com/swpalmer/jfx/commit/cc6193451bf8a693093f3ded5dcbe47af2fcbe8f>
I would submit it as a pull request but that seems premature since there hasn’t
been any real discussion of challenges I’ve overlooked. All I have are the
famous last words, “It works for me.”
I saw in the archives a concern about tab width vs tab stops. For some reason I
didn’t get the email. Anyway, I don’t think arbitrary tab stop positions, at
different intervals that is, are what was asked for. That certainly would
require a significantly different implementation.
Would love to keep some momentum going on this before I become busy with other
things and won’t have time for it.
Scott
On Sep 23, 2019, at 3:57 PM, Scott Palmer <swpal...@gmail.com> wrote:
My current work is here
https://github.com/javafxports/openjdk-jfx/compare/develop...swpalmer:jdk-8130738?expand=1
<https://github.com/javafxports/openjdk-jfx/compare/develop...swpalmer:jdk-8130738?expand=1>
While writing a unit test I realized that the StubToolkit isn’t really running
the Prism layout code, so I’m not sure how that gets tested. I made it work
with StubTextLayout for now.
Regards,
Scott
On Sep 20, 2019, at 12:57 PM, Scott Palmer <swpal...@gmail.com
<mailto:swpal...@gmail.com>> wrote:
Thanks Kevin.
My current implementation appears to be working for TextFlow and Text, with the
TextFlow overriding the tabWidth of the child Text nodes. This seems to work
out naturally from the way TextFlow overrides the TextLayout instance used by
the Text node.
If there are tricky corner-cases that I’m missing, I guess figuring out all the
cases it will need to handle is part of this discussion. It didn’t seem to be
that challenging so far, so perhaps I am missing something (hopefully not). I
wrote a small test app to visually see that things were working as I expected.
I have not yet written the unit tests.
Cheers,
Scott
On Sep 20, 2019, at 10:58 AM, Kevin Rushforth <kevin.rushfo...@oracle.com
<mailto:kevin.rushfo...@oracle.com>> wrote:
Hi Scott,
I'm sure Phil will have more comments on this. While the API seems simple
enough on the surface, I suspect that this will be a challenging feature to
implement correctly for all of the cases it will need to handle. It would need
careful review and testing as well. My only comment on the API itself is that
if we do accept this feature, it should probably go on both Text and TextFlow,
and be one of the attributes of Text that is ignored / overridden when a Text
node is in a TextFlow.
-- Kevin
On 9/18/2019 6:14 PM, Scott Palmer wrote:
I would like to implement this feature, being able to adjust the tab size in a TextFlow or
Text node (JDK-8130738 <https://bugs.openjdk.java.net/browse/JDK-8130738
<https://bugs.openjdk.java.net/browse/JDK-8130738>>). It involves new public API,
so I want to start a discussion about it here. (My motivation is that RichTextFX suggests
an entirely unacceptable workaround of substituting actual spaces when the tab character is
typed and cites the lack of this API.)
I’ve already jumped the gun and taken a crack at an implementation. It is
currently incomplete as I was just poking around to see if it was going to be
easy enough to not take up too much of my time. It boils down to:
TextFlow and Text get a new property for tab width, an integer representing the
number of spaces taken by a tab. (The value is only used to initialize the tab
width for the TextLayout when needed.)
TextLayout interface gets a new method: boolean setTabWidth(int spaces)
TextLayout gets a new constant: DEFAULT_TAB_WIDTH = 8;
PrismTextLayout implements the new setTabWidth API.
I’m not sure that the Text node needs this new property. I figured it would be
rarely used on that class, so I had implemented it via an added property in the
private TextAttributes class. Maybe it isn’t needed at all.
What’s the next step?
Regards,
Scott
