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Clodoaldo
clodoaldo.pinto.neto at gmail.com
Tue Mar 20 14:53:33 EST 2007
2007/3/20, Kenneth Loafman <kenneth at loafman.com>: > Clodoaldo wrote: > > 2007/3/20, Kenneth Loafman <kenneth at loafman.com>: > >> Clodoaldo wrote: > >> > 2007/3/20, Kenneth Loafman <kenneth at loafman.com>: > >> >> I'm using mod_python under Ubuntu Edgy 64, doing some basic plots of > >> >> data and allowing users to select a point to center on a region and > >> gen > >> >> the next plot. All of that works as long as the user moves forward. > >> >> The problem comes in the use of the back button. The browser merely > >> >> displays the last page rather than rebuilding it, or at least > >> restoring > >> >> the variables. This leads to a lot of confusion because the server is > >> >> on one set of plot values and the browser is now on another. This > >> seems > >> >> to be a common problem. Is there a solution, or should I just warn > >> the > >> >> user not to use the browser back button? > >> > > >> > How does the user select the point? Entering it in a form field? If so > >> > save the plot values (the page state) on the page using a hidden field > >> > inside the form: > >> > <input type="hidden" name="variable_1" value="99.9"> > >> > <input type="hidden" name="variable_2" value="33.3"> > >> > > >> > When the form is submitted those values will be available to your > >> script. > >> > >> What I am doing is this: > >> > >> def regen_plot(req): > >> <plot logic snipped> > >> return """\ > >> %s > >> <div align="center"> > >> <a href="/demo/index/display_hit"> > >> <img src="/demo/%s.gif" ismap border=0></a> > >> <p>X range is %d through %d seconds</p> > >> </div> > >> %s > >> """ % (_head, dbname, xrng[0], xrng[1], _tail(req)) > >> > >> Then when the user hits a point on the plot, display_hit is called. I > >> translate the x,y args from the URL into plot space, center the point > >> around a smaller region, and plot again. Going forward, it all works. > >> Session() vars work, but since I'm not in a form, and there's no submit > >> button, the hidden values don't work. req.form.get('x') fails. > >> > >> Is it possible to get <form> to use an <img ... ismap> tag in lieu of > >> the submit button? > > > > I don't know. What if you just set the the values in the URL? This way > > the user could even bookmark each frame of his interest.: > > > >> <a href="/demo/index/display_hit?var_1=99.9&var_2=33.3"> > > I tried that and the values just go away. The <img...ismap> tag appends > the x,y values of the mouse to the url, so what you see in the status > bar is: > > /demo/index/display_hit?var_1=99.9&var_2=33.3?5,9 > > When the mouse is clicked, the first ?... goes away before being passed. > > /demo/index/display_hit?5,9 I tried this and it worked in Firefox 1.5: <html> <body> <form method="get" action=""> <input type="image" name="my_image" src="ado_net_costas.png"> <input type="hidden" name="x" value="99.9"> <input type="hidden" name="y" value="33.3"> </form> </body> </html> When I click the image this URL is sent: http://teste.s0/python/imagemap.html?my_image.x=293&my_image.y=222&x=99.9&y=33.3 -- Clodoaldo Pinto Neto
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