#1925 First zoom fault in date / time plot using canvas term

[Anonymous]

I created time-series graph (x-axis) by canvas term for viewing it from web-browser.
When I try to zoom that graph on browser by right-drag, data points disappear.
But, data reappaer by rezoom.

The same thing seems to happen to demo-page(at least, in my computer).
http://gnuplot.sourceforge.net/demo_canvas_5.0/timedat.html

gnuplot version: 5.0.6
OS: Mac (10.12.4)
Browser: Safari and Firefox.

[Karl Ratzsch]

Just checked on win7/firefox (with the demo linked above), and the zooming sometimes works, and sometimes all data points disappear.

[Ethan Merritt]

It turns out that all canvas term plots are affected by this bug. It is particularly noticeable for time coordinates because the magnitude of the raw coordinates is very large.
Fixed for 5.0 and 5.1
I've updated the demo collection for 5.1 but left the 5.0 demos as they were for now.

[Ethan Merritt]

I have added a work-around in gnuplot_mouse.js that corrects for the initialization error in canvas plots created with gnuplot 5.0 through patchlevel 6. This corrected version is now on the demo page, so even though the [dem].js files contain an error, the error is hidden by the mousing code.

**Important: ** This means you can "fix" your old plots by using the new gnuplot_mouse.js without rebuilding gnuplot from source to get a fixed canvas terminal driver.