W3C home > Mailing lists > Public > www-svg@w3.org > February 2013

Re: minutes, Pyrmonth, Sydney SVG F2F Day 3 (05/02/2013)

From: Nikos Andronikos <nikos.andronikos@cisra.canon.com.au>
Date: Mon, 11 Feb 2013 12:03:21 +1100
Message-ID: <51184359.9020100@cisra.canon.com.au>
To: <public-svg-wg@w3.org>
CC: Richard Jacobs <richard.jacobs@cisra.canon.com.au>
Attached is a HTML version of the minutes.

On 6/02/2013 5:21 PM, Nikos Andronikos wrote:
> Hi all,
>
> Unfortunately RRSAgent wasn't invited to today's meeting.
> The raw log of the minutes is all that is available for now.
>
> 9:15:31 AM - Cyril: scribe: Cyril
> 9:15:49 AM - Cyril: Topic: Performances to transition in zooming and
> panning
> 9:15:50 AM - Cyril:
> http://www.w3.org/Graphics/SVG/WG/wiki/F2F/Sydney_2013/Agenda/Performances_to_transition_in_zooming_and_panning
>
> 9:16:08 AM - heycam: Meeting: SVG F2F Sydney 2013, Day 3
> 9:16:16 AM - Cyril: Chair: Cameron
> 9:16:34 AM - Cyril: heycam: Tagaki-san has a demo in WebKit
> 9:18:03 AM - Cyril: (takagi-san presenting)
> 9:19:03 AM - Cyril: birtles: 1st performance demo: zooming by changing
> the viewbox
> 9:19:20 AM - Cyril: ... 2nd demo, Bitmap in Canvas and zooming
> 9:19:32 AM - Cyril: ... same with panning
> 9:20:14 AM - Cyril: heycam: is that using the zoom and pan feature that
> some don't implement
> 9:20:22 AM - Cyril: AlexD: no, this is using scripting
> 9:20:37 AM - Cyril: heycam: if it was using built-in, then the
> application could choose
> 9:20:55 AM - krit [~krit@public.cloak] entered the room.
> 9:21:02 AM - Cyril: dirk: WebKit has built-in zooming and panning
> 9:21:12 AM - krit: s/dirk/krit/
> 9:21:56 AM - Cyril: heycam: I meant the built-in interaction on the root
> element
> 9:22:10 AM - Cyril: ... but it would be equivalent to controlling
> currentScale ... by script
> 9:22:19 AM - Cyril: birtles: is that optimized in any UA?
> 9:22:24 AM - Cyril: heycam: probably not
> 9:22:43 AM - Cyril: ... but this would be easier to optimize than the
> viewbox scripting
> 9:23:15 AM - Cyril: AlexD: performance difference between redrawing the
> entire tree vs. bitblitting a bitmap around
> 9:23:32 AM - Cyril: ed: we optimize that in Opera
> 9:23:43 AM - Cyril: AlexD: lazy redraw
> 9:24:04 AM - Cyril: ed: a viewbox change does mean you have to redraw
> everything
> 9:24:09 AM - Cyril: heycam: it changes %
> 9:24:24 AM - Cyril: AlexD: most implementation will say the root is dirty
> 9:24:32 AM - Cyril: ed: you could work out that it is a scale transform
> 9:24:37 AM - Cyril: AlexD: but that is very specific
> 9:24:52 AM - Cyril: birtles: you probably want to do a perf comparison
> vs using a transform
> 9:25:07 AM - Cyril: ... the second case is how you can create a Canvas
> 9:25:15 AM - Cyril: AlexD: that is very close to buffered rendering
> 9:25:39 AM - Cyril: krit: internally you do viewbox with a transform, so
> what's the difference ?
> 9:26:04 AM - Cyril: AlexD: you'd have to add logic to detect that the
> transform does not need a whole redraw
> 9:26:59 AM - Cyril: shane: doing that without doing a Canvas would be to
> use CSS 3D Transforms
> 9:27:42 AM - Cyril: ... changing the perspective via CSS will treat the
> SVG as an image
> 9:28:06 AM - Cyril: krit: in browser we have the backing store but it's
> not in the rendering layer
> 9:28:34 AM - Cyril: shanestephens_: CSS Transforms will do go performance
> 9:29:01 AM - Cyril: AlexD: if you'd have buffered rendering on the root
> and CSS 2D Transform (not accelerated) you'd generate a bitmap
> 9:29:10 AM - stakagi: how you can create canvas :
> http://www.w3.org/Graphics/SVG/WG/wiki/F2F/Sydney_2013/Agenda/Performances_to_transition_in_zooming_and_panning#Existing_implementation
>
> 9:29:30 AM - Cyril: AlexD: if you're doing that in Script, you're
> synchronous
> 9:29:45 AM - Cyril: ... but you want the zoom to be independent of the
> scripting
> 9:30:16 AM - Cyril: heycam: they couldn't say scale the bitmap and when
> there is a free cycle, render the rest
> 9:30:42 AM - Cyril: AlexD: as long as the zoom is handled by the UA and
> not the script, you'd have no problem
> 9:31:11 AM - Cyril: ... with script as part of the web content, they
> block each other, because the DOM is single threaded
> 9:31:57 AM - Cyril: shanestephens_: Tab has a proposal
> 9:32:15 AM - Cyril: cabanier: some people objected
> 9:32:41 AM - Cyril: shanestephens_: yes objected because not a priority
> at that time
> 9:32:59 AM - plinss is now known as plinss_away.
> 9:33:01 AM - Cyril: birtles: we've seen that there are other ways to
> render faster than using canvas
> 9:33:24 AM - Cyril: ... but the second issue is: is it still useful to
> be able to render SVG within a Canvas ?
> 9:33:30 AM - Cyril: ... there is a section in the proposal
> 9:33:39 AM - Cyril: ... it shows one way people are doing it now
> 9:33:54 AM - shanestephens_: (Tab's proposal:
> http://lists.w3.org/Archives/Public/www-style/2012Nov/0496.html)
> 9:34:01 AM - Cyril: ... by serializing SVG out, and giving that to a
> Canvas
> 9:34:07 AM - plinss_away is now known as plinss.
> 9:34:17 AM - Cyril: ... which is not very elegant
> 9:34:45 AM - Cyril: ... is it worth pursuing a more elegant way
> 9:35:09 AM - Cyril: heycam: you can't get the pixels out of the canvas
> 9:35:22 AM - Cyril: ... and I'm a bit surprised, data URI shouldn't
> taint the canva
> 9:35:41 AM - Cyril: krit: it's because it's SVG and SVG can have links
> ...
> 9:35:51 AM - Cyril: ... and you could check visited links ...
> 9:36:03 AM - Cyril: AlexD: there is a security reference in the paper
> 9:36:11 AM - AlexD: See
> http://www.svgopen.org/2010/papers/62-From_SVG_to_Canvas_and_Back/index.html
>
> 9:36:14 AM - cabanier: link:
> http://www.svgopen.org/2010/papers/62-From_SVG_to_Canvas_and_Back/index.html
>
> 9:36:38 AM - Cyril: shanestephens_: I don't understand how the proposed
> methods are safer
> 9:36:55 AM - Cyril: heycam: It doesn't claim to be safer ?
> 9:37:20 AM - Cyril: ... most uses of that would look at the rendering
> 9:37:28 AM - Cyril: ... access to the pixels
> 9:38:17 AM - Cyril: krit: browsers have logic to prevent access to
> unwanted pixels
> 9:38:28 AM - Cyril: ... they don't do it in an interoperable way
> 9:38:44 AM - Cyril: ... Firefox don't show links (in black), links are
> not links anymore
> 9:39:32 AM - Cyril: cabanier: sounds like a bug in Firefox
> 9:39:45 AM - Cyril: AlexD: is there a reason that currentTranslate is
> read-only
> 9:40:00 AM - Cyril: ed: you can modify the inside (currentTranslate.x)
> 9:40:18 AM - Cyril: AlexD: so you should be able to use them with good
> performance
> 9:41:09 AM - Cyril: shanestephens_: it seems that if we remove the
> restriction on getImageData, that would make it easier
> 9:42:34 AM - Cyril: Cyril: is there a way to know that the data URI was
> generated
> 9:42:39 AM - Cyril: heycam: no
> 9:42:48 AM - Cyril: Cyril: maybe a blobURI could be used
> 9:43:05 AM - Cyril: cabanier: you could use drawImage with SVGSVGElement
> 9:43:10 AM - Cyril: ... it would be easier
> 9:43:18 AM - Cyril: ed: yes we support it
> 9:44:04 AM - Cyril: heycam: about the links in Firefox, the default
> styles are not applied but if you have your own :link, it works
> 9:44:09 AM - Cyril: ... so it looks like a bug
> 9:44:29 AM - Cyril: ed: I did propose drawImage (SVGSVGElement) but it
> was not accepted
> 9:44:36 AM - Cyril: ... there are some undefined things
> 9:44:46 AM - Cyril: krit: Opera doesn't style visited links
> 9:45:12 AM - Cyril: ed: mixing foreignObject and nesting can be tricky
> 9:45:41 AM - Cyril: krit: svg + foreignObject + html in Firefox works,
> and Opera (with problems)
> 9:46:01 AM - krit: and not at all in WebKit
> 9:46:48 AM - Cyril: heycam: how do you size the SVG element ?
> 9:47:11 AM - Cyril: ed: the drawimage can provide the area but not
> always, that's a problem
> 9:47:50 AM - Cyril: krit: same thing as img with no width and height
> attribute, Firefox uses a default size
> 9:47:54 AM - Cyril: ... we could have that for SVG
> 9:48:17 AM - Cyril: birtles: I thought this was specified in replaced
> content image values
> 9:48:32 AM - birtles: http://dev.w3.org/csswg/css3-images/
> 9:49:06 AM - Cyril: s/replaced content image values/CSS Image Values and
> Replaced Content/
> 9:49:57 AM - Cyril: birtles: at the end of the proposal, there is text
> to create the image
> 9:50:32 AM - Cyril: krit: (reading a note in the CSS images)
> 9:51:11 AM - Cyril: heycam: the proposal is not clear about whether
> createSVGimage is meant to create a rasterized image or an independent
> clone
> 9:51:17 AM - Cyril: ... with styles
> 9:52:27 AM - Cyril: Cyril: the note says for animation it is uncertain,
> so it sounds like a snapshot more than a clone
> 9:52:48 AM - Cyril: heycam: you need to snapshot the computed style of
> the SVG elements in the tree that you are cloning
> 9:53:32 AM - Cyril: heycam: erik, do you think the Canvas spec should
> allow drawing with SVGSVGElement
> 9:53:44 AM - Cyril: ed: yes, but with security constraints
> 9:53:54 AM - Cyril: ... and we need to define the behavior of transforms
> 9:54:12 AM - Cyril: ... I've seen cases of SVG being pixelated when drawn
> 9:54:30 AM - Cyril: krit: the Canvas spec has been changed regarding the
> zooming
> 9:55:03 AM - Cyril: cabanier: maybe you should propose it again and see
> what happens
> 9:55:31 AM - Cyril: heycam: it seems that people would rather have
> drawImage with SVGSVGElement support than a new method
> 9:56:21 AM - Cyril: ACTION: ed to propose drawImage with SVGSVGElement
> to the public canvas mailing list
> 9:56:22 AM * trackbot is creating a new ACTION.
> 9:56:22 AM - trackbot: Created ACTION-3435 - Propose drawImage with
> SVGSVGElement to the public canvas mailing list [on Erik Dahlström - due
> 2013-02-12].
> 9:57:04 AM - Cyril: heycam: if you drawImage an image element with
> animated content in it, does it snapshot ?
> 9:57:09 AM - Cyril: cabanier: it should
> 9:57:17 AM - Cyril: ed: we snapshot at t=0
> 9:57:30 AM - Cyril: AlexD: use the snapshotTime from Tiny
> 9:57:45 AM * birtles looking up default sizing: CSS 2.1 sets width:auto
> to 300px when it can't be determined
> (http://www.w3.org/TR/CSS21/visudet.html#inline-replaced-width) and
> height to 150px
> (http://www.w3.org/TR/CSS21/visudet.html#inline-replaced-height)
> 9:58:11 AM - birtles: looking up default sizing: CSS 2.1 sets width:auto
> to 300px when it can't be determined
> (http://www.w3.org/TR/CSS21/visudet.html#inline-replaced-width) and
> height to 150px
> (http://www.w3.org/TR/CSS21/visudet.html#inline-replaced-height)
> 9:58:27 AM - Cyril: Topic: non scaling objects
> 9:58:40 AM - Cyril: CSS Image Values and Replaced Content
> 9:58:51 AM - birtles:
> http://www.w3.org/Graphics/SVG/WG/wiki/F2F/Sydney_2013/NonScalingObject
> 9:59:05 AM - Cyril: s/CSS Image Values and Replaced Content//
> 9:59:30 AM - Cyril: birtles: this is following from an action from the
> last F2F
> 9:59:38 AM - Cyril: AlexD: this is constrained transformed, isnt it?
> 10:00:13 AM - Cyril: heycam: do we have transform="ref" in SVG
> 10:00:34 AM - Cyril: ed: not yet, but adding it just to SVG 2 (not CSS
> Transform) is hard
> 10:00:41 AM - Cyril: ... is it useful outside of SVG 2
> 10:00:54 AM - Cyril: AlexD: yes, itcan be useful in general for Webapps
> 10:01:24 AM - Cyril: Cyril: I don't understand the example with text
> 10:02:10 AM - Cyril: krit: there is a flowing/exclusion thing
> 10:02:39 AM - Cyril: Cyril: ok the text hasn't changed font size but
> since the shape has increased, you can fit more text in it
> 10:02:56 AM - Cyril: shanestephens_: sounds like this makes constrained
> transforms more complicated
> 10:03:19 AM - Cyril: birtles: we discussed some things related yesterday
> 10:03:25 AM - Cyril: Cyril: flip invariant text
> 10:03:31 AM - Cyril: heycam: pinned transforms
> 10:04:10 AM - Cyril: krit: should we look at 1.1 for the next version of
> CSS Transforms
> 10:04:28 AM - Cyril: heycam: 1.1 is change the position but not the scale
> 10:04:35 AM - Cyril: Cyril: that's pinned transform
> 10:05:01 AM - Cyril: birtles: there are 5 cases in section 1
> 10:05:06 AM - Cyril: ... case 1 is not scaling
> 10:05:12 AM - Cyril: ... case 2 is non scaling stroke
> 10:05:21 AM - Cyril: case 3 is non scaling objects
> 10:05:47 AM - Cyril: s/case 1 is not scaling/case 1 is regular scaling/
> 10:06:07 AM - Cyril: ... case 4: there is a difference between scaling
> the content vs the viewport
> 10:06:23 AM - Cyril: heycam: I don't understand this one
> 10:06:39 AM - Cyril: shanestephens_: I think case 4 is like case 1
> (current behavior)
> 10:06:39 AM - stakagi: 1.2 is pointed out by alex three years before
> 10:07:29 AM - Cyril: shanestephens_: case 5 is the same as case 3 but
> rather than the CTM being changed it is the viewport being changed
> 10:07:57 AM - Cyril: heycam: one is scaling because of hte transform
> stack and the other one is the viewbox thing outside of the transform
> 10:08:40 AM - Cyril: heycam: the requirement could be set in the same
> way for both things: changing the aspect but keep the positing
> 10:10:29 AM - Cyril: heycam: for cases with UI control, whatever the
> positioning and scaling mechanism used, it should be on the content and
> on the UI
> 10:10:38 AM - Cyril: ... the UI should be in a different element
> 10:11:04 AM - Cyril: ... so that you don't have to undo the transform on
> the UI stuff
> 10:11:20 AM - Cyril: ed: maybe it's because in Tiny you can't nest SVG
> elements
> 10:11:47 AM - Cyril: heycam: if currentTranslate and currentScale don't
> work on inner svg elements, we should make it work
> 10:12:03 AM - Cyril: ... for POI element, it's a different story,
> because it's part of the content
> 10:12:10 AM - Cyril: ... it's a valid use case
> 10:14:30 AM - Cyril: ACTION: shane to investigate the model for
> constrained transforms
> 10:14:30 AM * trackbot is creating a new ACTION.
> 10:14:30 AM - trackbot: Created ACTION-3436 - Investigate the model for
> constrained transforms [on Shane Stephens - due 2013-02-12].
> 10:14:53 AM - Cyril: ACTION: shane to investigate currentTranslate and
> currentScale on inner svg elements
> 10:14:53 AM * trackbot is creating a new ACTION.
> 10:14:53 AM - trackbot: Created ACTION-3437 - Investigate
> currentTranslate and currentScale on inner svg elements [on Shane
> Stephens - due 2013-02-12].
> 10:15:28 AM - Cyril: heycam: currentTranslate and currentScale can be
> modified by script but are also affected by the user transforms
> 10:16:16 AM - Cyril: birtles: case 4 and case 5 if you resize a window
> that contains SVG, the viewbox to viewport ratio is adjusted and this is
> not accessible in the DOM
> 10:16:32 AM - Cyril: ... case 5 is for when you resize the window, you
> want some objects not scaled
> 10:16:56 AM - stakagi: In other words, 1.2 case 5 can be said fixed size
> in physical unit.
> 10:17:37 AM - Cyril: heycam: you wouldn't want to specify physical units
> because they are not really physcial unit
> 10:17:47 AM - Cyril: ... you want the initial size to remain the same
> after interaction
> 10:18:05 AM - Cyril: heycam: what about section 2 items
> 10:18:16 AM - Cyril: birtles: I think shane will look at it in his
> actions
> 10:18:19 AM - Cyril: shanestephens_: partly
> 10:18:29 AM - Cyril: ... there are more issues than constrained
> transforms
> 10:18:36 AM - Cyril: ... there are some layout issues
> 10:19:02 AM - Cyril: heycam: 2.1 you could do media queries and switching
> 10:19:13 AM - Cyril: birtles: if you have suitable media queries
> 10:19:19 AM - Cyril: heycam: do they exist?
> 10:19:33 AM - Cyril: birtles: no, there is the proposal for zoom
> 10:19:42 AM - Cyril: heycam: what about the picture element
> 10:20:04 AM - Cyril: birtles: the thing that was showed was part of the
> iframe proposal not of the picture element
> 10:20:27 AM - Cyril: heycam: with max-zoom, min-zoom media queries you
> could probably do it
> 10:20:48 AM - Cyril: shanestephens_: would you be able to do it with
> foreign content
> 10:20:54 AM - Cyril: ... and text overflow
> 10:21:04 AM - Cyril: heycam: we've made text overflow work on text in SVG
> 10:21:27 AM - Cyril: shanestephens_: overflow of boxes in CSS is
> different
> 10:21:49 AM - Cyril: ... the spirit of that proposal is automatic change
> of text
> 10:22:34 AM - Cyril: ... my concern with media queries, you'd need to
> guess where the swithc points should be and that'd be hard to do
> 10:22:45 AM - Cyril: ... but the browser knows the switch point
> 10:23:03 AM - Cyril: ... but just displaying "Sydney in" would not be
> good either
> 10:23:54 AM - Cyril: birtles: I suspect media queries could do a
> reasonnable job for now
> 10:24:22 AM - Cyril: shanestephens_: media queries could produce the
> wrong results
> 10:24:27 AM - Cyril: heycam: if you don't know the exact font
> 10:24:42 AM - Cyril: shanestephens_: and script might be better
> 10:24:50 AM - Cyril: ... I don't think we should add new features for now
> 10:25:06 AM - Cyril: heycam: solving as part of extending text overflow
> seems to be right approach
> 10:25:34 AM - Cyril: shanestephens_: hard things are hard
> 10:26:49 AM - Cyril: heycam: (showing a tool to produce adpative
> diagrams)
> 10:27:33 AM - Cyril: --- break ---
> 10:29:12 AM - jun has left the room (Quit: jun).
> 10:29:19 AM - shanestephens_ has left the room (Quit: shanestephens_).
> 10:33:03 AM - stakagi has left the room (Quit: Ping timeout: 60 seconds).
> 10:37:54 AM - dmitry [~Adium@public.cloak] entered the room.
> 10:41:15 AM - heycam is now known as heycam|away.
> 10:49:49 AM - shanestephens_ [~shanestephens@public.cloak] entered the
> room.
> 10:50:08 AM - AlexD has left the room (Quit: "http://www.kiwiirc.com/ -
> A hand crafted IRC client").
> 10:52:51 AM - shanestephens_ has left the room (Quit: shanestephens_).
> 10:53:47 AM - heycam|away is now known as heycam.
> 10:55:08 AM - shanestephens_ [~shanestephens@public.cloak] entered the
> room.
> 10:56:34 AM - jun [~fujisawa@public.cloak] entered the room.
> 10:57:59 AM - stakagi [~stakagi@public.cloak] entered the room.
> 10:59:23 AM - nikos has left the room (Quit: Ping timeout: 60 seconds).
> 11:00:02 AM - nikos [~Thunderbird@public.cloak] entered the room.
> 11:00:09 AM - nikos: scribenick: nikos
> 11:00:25 AM - nikos: Topic: Testing
> 11:00:47 AM - heycam: ACTION: stakagi to specify how the zoom media
> query would work with HTML as well
> 11:00:48 AM * trackbot is creating a new ACTION.
> 11:00:48 AM - trackbot: Created ACTION-3438 - Specify how the zoom media
> query would work with HTML as well [on Satoru Takagi - due 2013-02-13].
> 11:01:05 AM - nikos: heycam: So
> 11:01:28 AM - nikos: ... We have TTWF on Friday night and I wanted to
> get Shepherd running so we could commit tests
> 11:01:44 AM - nikos: ... I got instructions from Peter Linss, but it
> requires some admin changes to the server
> 11:01:57 AM - nikos: ... I asked JWatt if he could do that but he's
> unsure if we should continue using his machine
> 11:02:02 AM - glenn has left the room (Quit: Client closed connection).
> 11:02:07 AM - nikos: ... it might be better to move it to somewhere else
> (perhaps Cam's) host
> 11:02:29 AM - nikos: heycam: I will co-ordinate to do that but it means
> the repository won't be ready Friday
> 11:02:39 AM - plinss is now known as plinss_away.
> 11:02:46 AM - nikos: ... but we can store tests on a shared drive or
> dropbox for TTWF
> 11:03:18 AM - nikos: Cyril: we didn't use a repository for Paris because
> it takes too long for the attendees to setup
> 11:03:28 AM - nikos: ... in Paris there were no topics on SVG, so no SVG
> test were created
> 11:03:39 AM - nikos: ... the topics were CSS, HTML, mobile, indexDB
> 11:03:46 AM - nikos: ... is it planned to have one in Sydney?
> 11:04:00 AM - nikos: heycam: yes, the web page lists SVG and some CSS
> 11:04:23 AM - nikos: krit: CSS filters and transforms
> 11:05:07 AM - nikos: heycam: as part of the moving process I will
> reorganise the repository so we can add new specs there
> 11:05:32 AM - nikos: Topic: improved bbox methods
> 11:06:03 AM - heycam:
> http://lists.w3.org/Archives/Public/www-svg/2013Jan/0057.html
> 11:06:29 AM - nikos: heycam: in the spec atm we have getbbox which
> includes the fill and the stroke as separate methods
> 11:06:48 AM - nikos: s/getbbox/getStrokeBbox
> 11:07:03 AM - nikos: ... firstly I'm not sure about the name as the spec
> seems to include markers
> 11:07:27 AM - nikos: ... and it might be useful if you can control
> exactly which of fill, stroke, and marker are included
> 11:07:42 AM - nikos: krit: you pass a dictionary, would it be possible
> to pass a set of keywords?
> 11:07:55 AM - nikos: ed: that would be good, dictionary makes it verbose
> 11:08:04 AM - nikos: ... I'm not sure if the enum values we had are
> better
> 11:08:13 AM - nikos: heycam: the alternative is possibly an array of
> strings?
> 11:08:22 AM - nikos: ... or variatic, take string ...
> 11:08:28 AM - nikos: ... might be a bit hacky
> 11:08:39 AM - nikos: cabanier: what do JS people like?
> 11:08:46 AM - nikos: heycam: this method is pretty common
> 11:09:04 AM - nikos: ... you could do fill:expression which is evaluated
> to true or false
> 11:09:27 AM - nikos: krit: it must be backwards compatible so no option
> would mean just fill
> 11:09:41 AM - nikos: heycam: dictionaries are always optional
> 11:09:54 AM - nikos: ... maybe it doesn't make sense to control whether
> the fill contributes?
> 11:10:01 AM - nikos: ... is it a useful feature?
> 11:10:09 AM - nikos: krit: if it's not useful, why are libraries doing
> it?
> 11:10:18 AM - nikos: ... you can get the bounding box and you can get
> the stroke bounding box
> 11:10:30 AM - nikos: ... stroke bounding box does not include the
> bounding box
> 11:11:05 AM - dmitry: Suggestion of bounding box to include
> transformation inside. this is very useful for JS people
> 11:11:52 AM - nikos: heycam: I think we discussed a get transformed
> bounding box function
> 11:12:26 AM - nikos: ... so it would be the bounding box of the
> transformed shape, rather than the transformed bounding box
> 11:12:43 AM - dmitry: Yes, of course
> 11:13:26 AM - nikos: krit: we have a discussion tomorrow, there are
> problems with transforms
> 11:13:53 AM - nikos: heycam: we could have an additional argument, which
> is the element whose co-ordinate space the returned bounding box is in
> 11:14:09 AM - nikos: ... I may have written up a proposal on the wiki
> about this
> 11:14:20 AM - nikos: cabanier: how does that work with non-scaling
> stroke?
> 11:14:23 AM - heycam:
> http://www.w3.org/Graphics/SVG/WG/wiki/Proposals/getBBoxOf
> 11:15:00 AM - nikos: krit: There shouldn't be a difficulty working out
> the bounding box
> 11:15:27 AM - nikos: cabanier: that would be the bounding box of there
> rendered object
> 11:15:31 AM - nikos: krit: that's what you want
> 11:16:05 AM - nikos: cabanier: can you create a detached SVG element and
> ask for it's bbox?
> 11:17:05 AM - nikos: krit: you will get an empty rect
> 11:17:18 AM - nikos: heycam: that may not be specced
> 11:17:44 AM - nikos: ed: so you couldn't ask for a bounding box of
> something in a def?
> 11:17:53 AM - nikos: cabanier: or display:none
> 11:17:58 AM - nikos: heycam: that doesn't work
> 11:18:13 AM - nikos: ed: if we don't have it we calculate it, it's not
> that expensive
> 11:18:56 AM - nikos: heycam: so getting back to the design of the get
> bbox method
> 11:19:15 AM - nikos: ... do people think it makes sense to add the
> functionality to getBBox rather than have a new method?
> 11:19:24 AM - nikos: cabanier: I think people like dictionaries
> 11:19:36 AM - nikos: ed: what about for multiple stroking, do we want to
> say which are included?
> 11:20:01 AM - nikos: heycam: you could always add a new dictionary
> member which specifies which
> 11:20:23 AM - nikos: birtles: so the default is fill:true and everything
> else false?
> 11:20:57 AM - nikos: heycam: the way the optional dictionaries are done
> in WebIDL is that you can assume they have been filled in as an empty
> dictionary. So we would say the default of fill is true and if you
> wanted to override it you would have to say fill:false
> 11:21:12 AM - nikos: ... so it would have the opposite behaviour of the
> other arguments
> 11:21:53 AM - nikos: birtles: it's not unreasonable to have authors say
> fill:false stroke:true if that's what they want
> 11:22:17 AM - nikos: ... with dashing that will give a different
> bounding box to fill:true stroke:true
> 11:22:31 AM - nikos: heycam: do we want the dashes taken into account?
> that's difficult
> 11:22:51 AM - nikos: ed: it's cheaper to approximate the stroke
> 11:23:23 AM - nikos: heycam: that's what we do internally
> 11:23:27 AM - nikos: cabanier: cabanier: do you ignore miters-limit
> value?
> 11:23:28 AM - nikos: heycam: not sure
> 11:23:46 AM - dmitry has left the room (Quit: "Leaving.").
> 11:23:59 AM - nikos: krit: so if I set miter-limit to 1000 will that
> result in poor performance because of massive bounding boxes?
> 11:24:31 AM - nikos: heycam: if you are only interested in approximating
> the stroke, authors can do it themselves
> 11:24:50 AM - nikos: ed: I'm wondering how neccessary it is that it is
> exact
> 11:24:59 AM - nikos: ... could provide an option to specify accuracy
> 11:27:00 AM - nikos: cabanier: accuracy is affected by whether you use
> the shape of the marker or the marker bounding box to calculate the
> overall bounding box
> 11:27:10 AM - nikos: ... it's not a tight bounding box if you use the
> marker's bounding box
> 11:28:11 AM - nikos: cabanier: so should we have an option to select
> tight or not?
> 11:28:33 AM - nikos: heycam: I would assume people are only interested
> in the tight version
> 11:30:15 AM - nikos: krit: if we don't require the exact tight bounding
> box the result may be different across bounding boxes
> 11:30:39 AM - nikos: ed: it probably doesn't matter too much
> 11:31:19 AM - nikos: krit: will we have the tight property or will we
> always assume it's tight?
> 11:31:30 AM - nikos: ... should we add a new attribute to the dictionary?
> 11:31:55 AM - nikos: birtles: I think for when you don't want tight -
> for performance reasons you will probably do the calculations yourself
> 11:32:05 AM - nikos: cabanier: it seems slower to do it yourself
> 11:32:21 AM - nikos: birtles: but with games and things you will
> probably know enough information that you can approximate well enough
> 11:32:28 AM - nikos: ... I have done that myself
> 11:33:01 AM - dmitry [~Adium@public.cloak] entered the room.
> 11:33:51 AM - nikos: ... what I'm saying is that I have a hunch that the
> non tight bounding box may not be necessary and we should look at the
> use cases to see if they are valid before adding it
> 11:34:06 AM - nikos: cabanier: it seems like something that would be
> easy to implement
> 11:34:16 AM - nikos: birtles: but it complicates the api and you need to
> test, etc
> 11:34:32 AM - nikos: cabanier: the default should be tight
> 11:34:50 AM - nikos: ed: is it possible to get the tight bbox from all
> the graphics libraries?
> 11:34:57 AM - nikos: krit: core graphics has some bugs with that
> 11:35:08 AM - nikos: ... I wouldn't assume it will be exactly the same
> from all graphics libraries
> 11:35:13 AM - nikos: ... but should be within a tolerance
> 11:35:19 AM - nikos: ... will never be smaller - that would be bad
> 11:35:36 AM - nikos: ed: that would mean that you would have to involve
> the rendering library to get the area
> 11:36:00 AM - nikos: birtles: I wonder what the use cases are for
> getting the bbox that include stroke but not markers?
> 11:36:21 AM - nikos: krit: assuming it's not expensive for browsers, you
> might as well let people specify what they want
> 11:36:35 AM - nikos: birtles: I think we should do the minimum that is
> useful and add more functionality later
> 11:36:42 AM - nikos: ... it makes it easier to maintain in future
> 11:37:26 AM - nikos: ed: if you don't want the markers included in the
> bounding box ask for the bbox without them applied
> 11:38:11 AM - nikos: heycam: do people still want a fuzzy bounding box?
> 11:39:29 AM - nikos: birtles: I think generally the author can calculate
> that separately if performance is important
> 11:40:03 AM - nikos: ed: Is it useful to have the full repaint bbox that
> includes filters and everything?
> 11:40:28 AM - nikos: ... I think I agree that the tight bounding box is
> the most useful
> 11:40:37 AM - nikos: ... for setting the viewbox for example
> 11:42:07 AM - nikos: heycam: I would prefer to have tight for now and
> extend later if required
> 11:42:13 AM - nikos: ... it makes sense for the default to be tight
> 11:42:28 AM - nikos: ed: tight would mean dashes are taken into account?
> 11:42:29 AM - nikos: heycam: yes
> 11:42:50 AM - nikos: heycam: that is a a question I would like answered
> 11:43:26 AM - nikos: ... I can think of a stroke area where the dashing
> happens inside and that whole area is included in the bbox
> 11:43:39 AM - nikos: ed: I think I would take dashes into account if I
> was asking for the tight bbox
> 11:43:43 AM - nikos: ... which might be harder
> 11:44:20 AM - nikos: heycam: dash capping, etc, included makes sense. It
> might be a bit difficult to compute.
> 11:45:06 AM - nikos: birtles: I also raised the question - when would
> you ever want the bbox with the stroke but not the markers?
> 11:45:10 AM - nikos: ... what are the use cases for that?
> 11:46:51 AM - nikos: heycam: not sure. But I can imagine cases where you
> have a fill with the stroke around it and the markers are decorative so
> not really part of the shape in the context
> 11:47:38 AM - nikos: ... if we had the dictionary of options, and we
> ignore markers at the moment. Stroke would imply markers?
> 11:48:35 AM - nikos: birtles: from a feature point of view, if we don't
> want a fuzzy bbox and we don't differentiate between stroke and markers
> then it would suggest that from an interface point of view it might be
> sufficient to have getBBox and getStrokeBBox as separate functions
> 11:49:20 AM - nikos: nikos: that's less flexible later
> 11:49:31 AM - nikos: heycam: I like the idea of using getBBox
> 11:51:20 AM - nikos: ... my preference is one function, tight, markers
> included
> 11:51:37 AM - nikos: ... we could include the co-ordinate system in the
> dictionary or as a separate argument
> 11:51:55 AM - nikos: ... when I say markers included, I mean controllable
> 11:52:31 AM - nikos: heycam: does anyone strongly prefer the other
> option?
> 11:52:35 AM - nikos: all: no
> 11:53:56 AM - nikos: RESOLUTION: We will add dictionary arguments for
> controlling inclusion of fill, stroke, and markers to getBBox(). The
> tight bounding box will be returned and there will be a method to
> control the co-ordinate system for the bounding box.
> 11:54:21 AM - nikos: action: cameron to add dictionary arguments for
> controlling inclusion of fill, stroke, and markers to getBBox(). The
> tight bounding box will be returned and there will be a method to
> control the co-ordinate system for the bounding box.
> 11:54:21 AM * trackbot is creating a new ACTION.
> 11:54:21 AM - trackbot: Created ACTION-3439 - Add dictionary arguments
> for controlling inclusion of fill, stroke, and markers to getBBox(). The
> tight bounding box will be returned and there will be a method to
> control the co-ordinate system for the bounding box. [on Cameron
> McCormack - due 2013-02-13].
>
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Received on Monday, 11 February 2013 01:04:25 GMT

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