- From: Cyril Concolato <cyril.concolato@enst.fr>
- Date: Thu, 16 Oct 2008 09:42:43 +0200
- To: Doug Schepers <schepers@w3.org>
- CC: SVG Working Group WG <public-svg-wg@w3.org>
Doug, Doug Schepers a écrit : > Hi, Cyril- > > Cyril Concolato wrote (on 10/16/08 2:56 AM): >>>>> * Section 5.9.1 The 'externalResourcesRequired' attribute What is the >>>>> rationale behind the sentence: >>>>> "If a node enters the error state then the document enters the error >>>>> state and progressive rendering stops." Is this behavior compatible >>>>> with traditional HTML processing? >>>> I've identified the following error states explicitely listed in the >>>> spec: >>>> - playbackOrder='all' and use of discard >>>> - circular references >>>> - eRR true but resource not fetched >>>> - a java class listed in SVG-Handler-Class does not implement >>>> EventListenerInitializer2 >>>> My problem is with the 3rd case. For example, if an image (in a group >>>> with eRR = true) is not fetched, the UA stops the rest of the rendering >>>> of the document. HTML browser don't stop rendering when an image link is >>>> broken and this is a more useful behavior. My suggestion is to say that >>>> if a node enters the error state (because of an unresolved link), then >>>> the UA should inform the user but keep rendering the rest of the >>>> document. >>> I'm not sure I agree. >>> >>> The more graceful error recovery is already the behavior when >>> externalResourcesRequired="false". externalResourcesRequired="true" >>> means exactly that: that the author considers the external resources to >>> be necessary to the proper viewing of the document. If the author >>> wishes to allow tolerant error recovery for broken links, then they need >>> only omit the externalResourcesRequired attribute (lacuna is "false") or >>> set it explicitly to "false". The behavior you suggest would defeat the >>> very purpose of the attribute. externalResourcesRequired is not a >>> conditional attribute, to hide or show an element based on the >>> availability of a resource. >>> >>> If you still disagree, please let us know why you would expect the other >>> behavior, and the SVG WG will discuss it. If this adequately explains >>> the rationale, please let us know that this is a satisfactory response. >> I understand your explanation, but eRR=true is actually doing 2 things: >> controlling the progressive rendering algorithm to stop the rendering >> until the resource is resolved; and controlling the resolution of the >> resources. I'm just wondering if it wouldn't be better to have 3 values: >> externalResourceRequired="none" (lacuna value, equivalent to false) >> externalResourceRequired="keep" (just pauses the rendering until the >> children are loaded but it continues rendering if a external resource >> link is broken) >> externalResourceRequired="strict" (equivalent to true in the current >> definition) >> >> However, if you think this is too much editing or a too big change, I >> agree to leave it as is. > > I do see your point, but this would be incompatible with SVG 1.1 [1], > and would indeed be too big a change to make at this point, for > relatively little gain. We already have existing implementations, and > this would change conformance requirements. I understand. In fact I did not remember this was in 1.1. > This may be something to look at in the SVG 2.0 Core timeframe, but > since you are satisfied with the explanation as is, we will not change > it for SVG 1.2 Tiny. Fine. Cyril -- Cyril Concolato Maître de Conférences/Associate Professor Groupe Mutimedia/Multimedia Group Département Traitement du Signal et Images /Dept. Signal and Image Processing Ecole Nationale Supérieure des Télécommunications 46 rue Barrault 75 013 Paris, France http://tsi.enst.fr/~concolat
Received on Thursday, 16 October 2008 07:43:22 UTC