====== X11 driver ======

{{:X11:xlcd4linux.png}}

The driver opens a X11 window based on the geometry specified in the config file. This window cannot be resized. The contents of the window will be redrawn every tick msec.

The driver uses very low cpu time, and requires low bandwitdh, because only modified pixels are redrawn.

===== Configuration: =====

The driver needs/supports the following entries in lcd4linux.conf:

**Display**: must be "X11" \\\

**size**: [[:columns]]x[[:rows]], e.g. "20x4" \\\

**font**: [[:xrex]]x[[:yres]], at the moment only "5x8" and "6x8" supported. \\\

**pixel**: [[:pixelsize]]+[[:pixelgap]], e.g. "5+1" \\\

**gap**: [[:row|gap]]x[[:column|gap]], e.g. "3x3" \\\

**border**: border width \\\

**foreground**: color of an active LCD Pixel, must be #rrggbb \\\

**halfground**: color of an inactive LCD Pixel, must be #rrggbb \\\

**background**: backlight color, must be #rrggbb \\\


This may look weird, but it is weird. Let's explain this a bit further:

The X11 driver tries to emulate a real LC display. A real LCD has a size of //columns*rows// characters. Each character consists of //xres*yres// LCD cells. One single cell will be represented by a rectangle of //pixelsize*pixelsize// pixels.

If you want to, you can emulate the gap between this lcd cells by specifying a //pixelgap// greater than zero.

{{:X11:dump1.png}}
<code>
size "3x1"
border 10
font "5x8"
pixel "8+2"
gap "-1x-1"
</code>


{{:X11:dump2.png}}
<code>
size "3x1"
border 10
font "5x8"
pixel "10+0"
gap "-1x-1"
</code>


Sometimes there's a //gap// between characters, too. You can specify this gap (in pixels again) horizontally and vertically. Usually this gap is the same size as a cell (which is //pixelsize+pixelgap//). If you specify either the row gap or the column gap as -1, this cell size will be used instead.

{{:X11:dump3.png}}
<code>
size "3x1"
border 10
font "5x8"
pixel "8+2"
gap "20x20"
</code>


If you use a font of 5x8, some characters may use the first and the last pixel. So you should specify a column gap, otherwise the caracters may touch. On the other hand, the 6x8 font never uses the first pixel. So you can omit the //column gap//, and will get the same text layout, but uninterupted bars!

{{:X11:dump4.png}}
<code>
size "3x1"
border 10
font "6x8"
pixel "8+2"
gap "0x-1"
</code>


After all: don't try to understand this unless you have tried it out!

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