From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <50152B04.6070101@xenomai.org> Date: Sun, 29 Jul 2012 14:22:28 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <500FEB0F.9000308@xenomai.org> <201207282127.33575.paul_c@tuxcnc.org> <50144E93.5050109@xenomai.org> <201207291044.22418.paul_c@tuxcnc.org> <501519E8.3040509@piments.com> <50151B8D.10307@xenomai.org> <50151D82.7080203@piments.com> <50151F4C.2070006@xenomai.org> <5015284F.3020204@piments.com> In-Reply-To: <5015284F.3020204@piments.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] Heads up: I-pipe patch status on ARM List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenophile Cc: xenomai@xenomai.org On 07/29/2012 02:10 PM, xenophile wrote: > On 07/29/12 13:32, Gilles Chanteperdrix wrote: >> On 07/29/2012 01:24 PM, xenophile wrote: >> >>> On 07/29/12 13:16, Gilles Chanteperdrix wrote: >>>> On 07/29/2012 01:09 PM, xenophile wrote: >>>> >>>>> bitmap rendered graphs should be a relic of the 1990's ;) >>>> >>>> >>>> On the other hand, a bitmap is rendered once and only once, which really >>>> makes sense for a static page, will appear the same in all navigators, >>>> including those which do not support svg. >>>> >>> >>> How often it is rendered depends upon the viewer. I don't see how this >>> relates to whether the page is "static". (I'm assuming you are talking >>> about static vs dyanamic content at the server end). >>> >>> I don't see any fundamental difference in whether you _create_ (as >>> opposed to render) a graphic in svg , png or jpeg. >>> >>> There is nothing about svg/svgz that means you have to create it on the >>> fly each time you serve a page. It is an XML format but as I said it can >>> be embedded (hence the svg part can be pre-made). >>> >>> I do this on a 200MHz embedded ARM system running lighttpd. The pseudo >>> real-time output is created in svg every 15min or on demand. The >>> surrounding html template is static. >> >> >> As far as I understand, the rendering (I am talking about the graphical >> rendering) is done by every client which wants to view the graph, which >> is stupid if it is always the same graph (that is what I meant by >> static). And has a number of issue. >> >> I do not understand why you do not want to do the rendering on a 200 MHz >> ARM, but if the machine serving the page is powerful enough, and the >> graph not updated frequently, I find it makes a lot of sense to do the >> rendering only once. >> >>> Gnuplot runs on the ARM. >> >> I do not discuss the fact that getting gnuplot to generate an svg will >> consume less power. But overall, it will get all viewer to consume power >> to do the rendering, which the static bitmap file avoids. >> > > The whole point of SVG is the S: scalable. If you "render" it to a > bitmap on the server no one scale it in their viewer (web browser in > this case). > > Now whether decoding png or jpeg compression of an image (including much > blank white area) and then interpolating to the final screen rendered > size raster image in the users browser is more or less "power efficient" > that sending a textual vector description that the viewer draws line by > line I have no idea. > > Since the PC is probably consuming about 150W just sitting there I'm not > sure what the point aiming for is. I mean "processing power". Intuitively, generating a text file after reading points from other text files seems more economic, than drawing the lines to a bitmap in memory, rendering the text, and compressing with png. But you are right, this is not even obvious. > > SVG, basically gives the browser and the user total freedom of what size > to scale the output. rather than sending a series of dots which have a > predetermined resolution. > > My reason for using SVG on the ARM is not save power or because it could > not handle producing a png , it is to give the viewer of the graphic the > ability to zoom in to any desired level and benefit from things like > toggling off lines that obscure the one he's interested in and getting > cursor readout of data points on the graph. > > No way is that sort of thing possible with png. > > I don't quite think you are appreciating all the differences between > vectorial and bitmap formats. Hopefully, I've explained some of our > confusion over the term "render". The image is only rendered in the > viewer, Both vector and bitmap are descriptions of what has to be rendered. Ok, ok, I am convinced, you can send the patch, now. -- Gilles.