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Battery improvements in kde plasma 4.4

The battery applet in KDE Plasma 4.4 has gotten some nice improvements. First of all, I wasn’t really happy with the layout of its popup dialog. It looked messy and didn’t scale well with bigger fonts. During Tokamak3 in September, I started improving this. To make it look calmer, I reduced the amount of edges widgets are aligned to. The previous version used nested layouts, which lead to widgets not properly aligned with each other. This creates a rather messy look. For 4.4, I’ve reworked the layout and reduced everything to only one layout and attached the battery in the popup off-layout in the top-right corner. I thought about using an AnchorLayout for this, but a simple setGeometry() to position the battery top-right would work as well, so I went for KISS. I also replaced the text on the "Configure Power Management" button with a tooltip, reducing visual clutter but keeping this handy in-context shortcut to easily get at the more advanced power managment settings.

The battery popup now resembles a FormLayout more closely, which should make it more consistent with how other dialogs in KDE are designed, so that’s a bonus in consistency. The two screenshots show the old and the new version of the applet side-by-side.

One wish came up more than once over the past months. Some (very vocal) users would like to see the battery showing the remaining time when it’s running on battery. Normally, the applet would show the charge percentage, which is a rather abstract number. (How long is 37%?) Now unfortunately, there’s no way to give an accurate estimation oft the time that’s left, since it largely depends on the usage patterns. You check the battery, it says "10 minutes left", then you start some app that exercises your CPU and disk and suddenly the machine goes into suspend after 3 minutes. Quite possible, and the usage scenarios and differences in modern portable hardware are such that there’s really no way to accurately predict the remaining battery lifetime. In the Plasma team, we decided that we rather not show the user unreliable information, since there’s only a very small group that understands that this number is almost black magic, and often simply wrongly reported by HAL. There’s well over 200 emails on that subject, mainly on the Plasma mailinglist and everytime this topic comes up we hear how much KDE must suck if this tiny little feature isn’t available. We’ve made this feature available in KDE 4.3, as a hidden config option (meaning that you cannot enable it using the configuration UI, but it’s there if you enable it in the configuration file. I had tentatively disabled this code during the larger part of the 4.4 development cycle to see if I’d get away with ditching it, and it didn’t quite fit in with the new layouting for the popup.

Lately, the same discussion came up again, hopefully for the last time, since I submitted a patch yesterday night that brings the remaining time back (still as hidden config option, and that’s about as far as we will go). No, there won’t be a checkbox since I don’t want to confront users with information that’s most likely bogus and highly depends on what you’re doing at this very moment. As the option needs a power user to understand what this info really means (i.e. an estimation that’s completely off or not, depending on what your BIOS or ACPI subsystem reports), I think we can reasonable expect that adding a line to a config file is easy enough for those who really, really, really want it.

So, for reference, here’s how you get the remaining time display in the battery applet.

  • Install KDE Plasma 4.4, at least trunk from today
  • kquitapp plasma-desktop (to stop your plasma shell, as long as it’s running, it can’t pick up config changes, if you stop it after you changed the config file, it will happily overwrite your hand-made changes on quit)
  • Open your plasma-desktop config file, (mine is ~/.kde4/share/config/plasma-desktop-appletsrc, YMMV)
  • Locate the section for the battery applet, in the below example, you’ll find the plugin=battery line, choose the section that adds [Configuration] to the identifier. This section might not exist if you’re using default settings, in that case, it’s easiest to check the “show charge information” checkbox in the battery’s config (you might need to restart plasma-desktop for that, don’t kill it afterwards but use kquitapp). Then locate the showBatteryString= line and add another line in the same section:
    Save the edited config file, restart plasma-desktop


The remaining time will now be shown if it’s non-zero (obviously bogus since the machine would be off then) and the battery is discharging. If in doubt, use “plasmaengineexplorer –engine powermanagement” to check wether Solid reports the remaining time at all, and that it’s non-zero. The remaining time could also be shown while charging, but this apparently isn’t supported by my setup, so I can’t test it.

Also during Tokamak3, Dario fixed a bug that would switch the display’s brightness back to 100% after it was dimmed because the machine had been idle. So if you’d set it to 50%, and it would then dim after some minutes of idle time, you’d move the mouse and it pops back to 100%, while it should go back to 50%. That’s fixed as well, and the patch has also been backported to KDE 4.3. You probably are already running with this fix.

source: About.com Linux

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About Hugo Repetto

Ubuntu is a Linux distribution that offers an operating system predominantly focused on desktop computers but also provides support for servers. Based on Debian GNU / Linux, Ubuntu focuses on ease of use, freedom in usage restriction, regular releases (every 6 months) and ease of installation.
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