Hi Marius, On 09/10/2010 02:52 PM, Marius Dumitru Florea wrote: > Hi Alex, > > On 09/09/2010 11:35 PM, Alex Busenius wrote: >> Hi, >> >> >> Currently we simply copy-paste the attributes into the generated HTML, >> which makes the syntax ambiguous. E.g. it is possible to write something >> like >> >> [[image:logo.jpg||width="100px" height="50%" style="width: 45%; height: >> 100px"]] > > I don't understand why do you say the syntax is ambiguous. I guess you > consider XHTML syntax ambiguous too, because: > Yes, thats what I meant.
> <img src="logo.jpg" alt="logo" width="100px" height="50%" style="width: > 45%; height: 100px" /> > > is perfectly valid. You can specify image size either using the > attributes or using CSS (be it in-line, though the style attribute, or > in a style sheet). CSS (both in-line and style sheet) always takes > precedence over the size attributes. Thus in your example, the final > image size in the browser is 45% x 100px. Note that there is a > difference in what you can specify with the size attributes and what you > can specify with CSS: width/height attributes accept only pixels or > percent, so CSS (i.e. the style attribute) is more powerful. > >> >> Using the size information for resizing pictures sound interesting, but >> regarding the example above: >> > >> What will happen if the user specifies width or height in percent? > > If the unit ( http://www.w3schools.com/css/css_units.asp ) of > width/height is not pixel then I continue as if the width/height hasn't > been specified. For instance, if image width/height limit is set to > 800x600 in configuration then: > > width:30%; height:3cm => ?width=800&height=600&keepAspectRatio=true > > width:70px; height:3in => ?width=70 > > width:6em; height:20px => ?height=20 > > width:35px; height:15px => ?width=35&height=15 > Ok, makes sense. >> What if pixel and percent numbers are mixed (e.g. width is in px and >> height in %)? > > Only the dimension expressed in pixels is used. Width and height are > "read" from image parameters independent of each other. > I see. >> What takes precedence, width attribute or CSS style attribute? > > Always the CSS (be it in-line or from a style sheet). > Ok. >> Will the size information XWiki uses to resize images be the same as >> various browsers use to display the image? > > Most of the time the image will be resized just once, on the server. > There are some cases though when the image will be resized both on the > server and on the client (by the browser). For instance: > > * if width and height are not expressed in pixels then the server will > limit the image size based on configuration and the browser will resize > the image based on specified width/height > > * if one of the dimensions is expressed in pixels and the other in > percent (or any other unit different than pixel) then the server will > scale the image using the pixel dimension and the browser will adjust > the other based on the specified value. > > * if width and height are specified in pixels but there is an external > style sheet that enforces a different image size then the server will > scale the image based on the specified width/height and the browser will > resize the returned image based on the external style sheet. > Sounds reasonable. >> >> >> In general, I think copy-pasting the attributes is bad (esp. from >> security PoV). I'd prefer having a fixed set of supported attributes >> (subset of HTML/CSS) that are handled in a fully deterministic way. This >> would for example allow to specify how exactly the width information is >> parsed and transform the example above into a non-ambiguous form on save. > > I think you are referring to the XHTML renderer here, but my change > targets all the renderers. A renderer doesn't know how to assemble the > URL for an attachment or a document so it asks the WikiModel. Thomas and > I discussed about adding a: > > String getImageURL(String documentName, String fileName, Map<String, > String> parameters) > > method to WikiModel, that can be used by any renderer. XWikiWikiModel > (our implementation) will look at the passed parameters map and if image > width/height is specified them it will add this information to the query > string of the attachment download URL. The fact that we look for the > "width", "height" and "style" parameters is a convention. It's not > related to HTML. The fact that the style image parameter contains CSS is > also unrelated to HTML (CSS can be used on other types of structured > content). > > Regarding copy-pasting custom parameters from XWiki syntax to the > rendered HTML (by the XHTML renderer) I don't have a strong opinion. I > don't see why it is bad from security PoV. I'll let Thomas and Vincent > comment on this. > >> >> Since your change would introduce parsing for the parameters, it might >> be a good point to start going into this direction, WDYT? > > This needs to be discussed in a separate thread. > Yes, this is a larger topic, to be discussed later. +1 for A and B Thanks, Alex > Thanks for your feedback, > Marius > >> >> >> Thanks, >> Alex >> >> On 09/08/2010 10:40 PM, Marius Dumitru Florea wrote: >>> Hi devs, >>> >>> Currently the image plugin [1] allows us to create image thumbnails by >>> specifying the image width and/or height in the query string of the >>> image attachment download URL: >>> >>> /xwiki/bin/download/Spage/Page/image.jpg?width=100 >>> >>> I propose that we: >>> >>> (A) Use the image width and/or height (when they are specified in the >>> image syntax using pixel unit) to resize the image on the server side. >>> For instance: >>> >>> [[image:logo.jpg||width="100px"]] >>> >>> will be linked to >>> >>> /xwiki/bin/download/Spage/Page/logo.jpg?width=100 >>> >>> and >>> >>> [[image:logo.jpg||style="height: 50px; width: 70px"]] >>> >>> will be linked to >>> >>> /xwiki/bin/download/Spage/Page/logo.jpg?width=70&height=50 >>> >>> The image plugin also accepts a quality parameter that controls the >>> compression quality when encoding jpeg images. The default value of this >>> parameter (i.e. when not specified in the URL) is configurable. I >>> propose we use 0.3 by default, 1 representing the best quality. >>> >>> (B) Add the ability to limit the image dimensions (preserving aspect >>> ratio) when the image width and/or height are not specified in the image >>> syntax (or when they are not using pixel unit). The width and height >>> limit will be configurable and -1 by default (i.e. no limitation). For >>> instance: >>> >>> image:logo.jpg >>> >>> will be linked to >>> >>> /xwiki/bin/download/Spage/Page/logo.jpg?width=1024 >>> >>> when width limit is 1024, and to >>> >>> /xwiki/bin/download/Spage/Page/logo.jpg?width=1024&height=768&keepAspectRatio=true >>> >>> when width limit is 1024 and height limit is 768. Note that in this case >>> the image aspect ratio is preserved. The image is resized to best fit >>> the limits. If the user want to bypass the limit he has to specify the >>> image width/height in the image syntax. >>> >>> I'm +1 for both (A) and (B). WDYT? >>> >>> Thanks, >>> Marius >>> >>> [1] >>> http://svn.xwiki.org/svnroot/xwiki/platform/core/trunk/xwiki-core/src/main/java/com/xpn/xwiki/plugin/image/ >>> _______________________________________________ >>> devs mailing list >>> [email protected] >>> http://lists.xwiki.org/mailman/listinfo/devs >>> >> _______________________________________________ >> devs mailing list >> [email protected] >> http://lists.xwiki.org/mailman/listinfo/devs > _______________________________________________ > devs mailing list > [email protected] > http://lists.xwiki.org/mailman/listinfo/devs > _______________________________________________ devs mailing list [email protected] http://lists.xwiki.org/mailman/listinfo/devs
