SKrellM User's Manual

The skrellm is a single process stack of system monitors which supports applying themes to match its appearance to your window manager, Gtk, or any other theme. It displays system resource monitors on your desktop, and it is a suckless rewrite of gkrellm, cured out of its glib and gtk illness. It is as dependency-free as possible, and also multiplatform.

SKrellM running on multiple platforms and using various themes

Advantages

very small codebase (ca. 6200 SLoC all in all), yet plenty of meters
unlike gkrellm, no obsolete library dependencies
platforms are detected automatically at compile-time
backends are detected automatically and linked in run-time (SDL, X11, GDI)
plugins are totally backend-independent and easy to write
themes are single image files, easier to share
layouts are theme and user customizable
supports HiDPI displays (kinda)

Disadvantages

no configuration GUI yet, you need to edit the config file with a text editor for now

Installation

No actual installation needed, SKrellM is a portable executable. On first run, configuration file will be created, which you can edit with any text editor.

Linux

Download the skrellm to /usr/bin
Make sure that it's executable: sudo chmod +x /usr/bin/skrellm

If your distro is debian based such as Ubuntu, then you can do this instead:

Download the deb package
Run the sudo dpkg -i skrellm_*.deb command in a terminal

Windows

Download the skrellm.exe to C:\Program Files\SKrellM

Compilation

Just run make in the src directory. No configure, no dependencies, suckless as it should be. The backends' header files are needed, but that's all, linking is done in run-time.

Command	Description
`make`	Compile the `skrellm` executable
`make mbedtls-bin`	Download a pre-compiled mbedtls library
`make mbedtls-src`	Download and compile the mbedtls library from source
`make install`	Install the compiled executable
`make deb`	Create a debian package from the compiled executable
`make clean`	Clean compiled files, but do not touch libraries
`make distclean`	Clean everything
`DEBUG=1 make`	Compile with debug information

If the mbedtls/mbedtls.a static library exists (first run make mbedtls-bin or make mbedtls-src to get it), then SKrellM is compiled automatically with https:// support in skm_load.

Customization

You can download additional themes and fonts and place them in the configuration directory.

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Configuration

On Linux the $HOME/.config/skrellm, and on Windows the %APPDATA%\Local\skrellm directory is used with the following files:

config

Warning

There's not much error checking, make sure the config file is syntactically correct!

This is a simple INI file with key=value pairs in each line. For example:

width=64
geometry=-0+32
refresh=250
levels=75,90,95
theme=default
plugins=hostname,uname,date,time,cpu,proc,net,disk,df,mem,bcdclock,uptime
time=%H:%M,%S
cpu=+
net=enp2s0,ath0

Key	Description
`backend`	(optional) you can disable the autodetection and force using a backend
`dock`	if `1` then tells the WM to threat its window as dock
`width`	width of the meters in pixels
`geometry`	where to place the window and gravity, `{+-}xpos{+-}ypos`
`refresh`	refresh rate in milliseconds, from 10 (1/100 secs) to 10000 (10 seconds)
`dpi_scale`	scale factor, from 1.0 to 10.0 (defaults to the `GDK_SCALE` env)
`levels`	three comma separated values: alert, warning, error percentage
`theme`	name of the theme to be used (without the `.png` extension)
`plugins`	comma separated list of enabled plugins, also defines their order
`uname`	a list of `snrvm` characters, same as the `uname` command flags
`date`	date display format string (see `strftime` for more details)
`time`	time display format string (see `strftime` for more details)
`mem`	a list of `m` (memory) and `s` (swap)
`cpu`	cpu load, composite list (`+` gives one meter, otherwise one per cpu core)
`disk`	disk activity, composite list (devices)
`df`	disk usage, composile list (mount points / drive letters)
`net`	net activity, composite list (network devices)
`battery`	battery capacity, compisite list (battery device)
`thermal`	temperature, composite list (sensor names)

Composite list: if not set, then lists all instances in their own separate meters. If set, then it's a comma separated list of instance names and only displays those that are listed; finally if it's a + then it shows one single composite meter for all.

If a plugin uses the Simple API's skm_layout, then its layout can be customized with

(plugin).layout=(type),(str),(str),(str),(str)

Here (type) is a space separated list of graph (show graph), 2vals (graph has two values), line (instead of columns), pbar (show progress bar), stat (show status bar) and stick (show percentage value with a stick icon on status bar).

The (str) values refer to the strings provided by the plugin (up to 4), and consist of two space separated words: the first word is a position tl (top left), tc (top center), tr (top right), bl (bottom left), bc (bottom center), br (bottom right) on graph, or l (left), c (center), r (right) on status bar. The second word specifies the font style, title, label, value, small (which font these use at which size and wether they have a shadow or not comes from the theme). For example:

net.layout=graph line 2vals stat,l small

This draws the network activity with lines and places the device's name on the status bar aligned to the left with the small font style.

self

This file only exists when SKrellM is running, and it is a plain text file with a single decimal number in it. Under Linux (and other POSIX systems) it contains the pid, and you can send signals to it: SIGHUP will make it reload the configuration, and SIGINT quits.

kill(value_from_self_file, SIGHUP);

Under Windows, this file contains the window handle, you can send WM_APP message to make it reload its configuration, and WM_CLOSE to make it quit.

PostMessage(value_from_self_file, WM_APP, 1, 1);

The primary purpose of this file is to allow an external configuration GUI to trigger the already running SKrellM instance.

Fonts (*.sfn)

Vector font files are used to display text and they must be in Scalable Screen Font format. They are loaded from this directory directly, so no system font registry plays part (no fontconfig mess, no whatever).

Fonts in TrueType, OpenType, X11 BDF, Console PSF2 etc. formats can be converted into .sfn with the sfnconv command line tool.

Themes (*.png)

All the other files must be special PNG files which hold SKrellM theme definitions. Themes might also contain an embedded font.

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Plugins

Plugins were carefully designed to be platform independent. Unlike in gkrellm, they don't need to know nor care about the actual backend. Similary to gkrellm, there's two API, one easy for simple plugins, and an advanced API for full control.

Writing plugins

To create a new plugin, one needs to pick a unique name plgname and create a plgname.c source file under src/plugins. In this file, the src/skm_plugin.h header must be included, and it must implement three functions (replace plgname with your actual unique plugin name in these):

plgname_init

void plgname_init(char *cfg)

Description

Should initialize the plugin. It receives a configuration string from the config file, which might be empty. Parsing this is up to the plugin, no restrictions (you can use skm_list on it for example).

Parameters

Argument	Description
cfg	configuration string

plgname_free

Description: Should free any memory that plgname_init has allocated.

plgname_draw

void plgname_draw(int full)

Description

Should gather meter data and use skm_*() functions to draw the meter.

Parameters

Argument	Description
full	set when doing a full refresh

Note

The actual refresh delay is user configurable. A full refresh is done once per second if the delay is smaller than a second, or every time if the delay is bigger. Without a full refresh, only the progress bars and the led indicators are updated.

Register

SKM_PLUGIN(plgname, desc, type, pos0, pos1, pos2, pos3, fnt0, fnt1, fnt2, fnt3)

Description

Finally, the source file must end with this line that informs SKrellM about the existence of the plugin and its default text placements and default styles (might be overriden by the theme and user config). Note, there's no ; semicolon after this.

Parameters

Argument	Description
plgname	unique name of the plugin
desc	description (displayed with `--help`)
type	default layout type (OR'd `TYPE_*` defines)
pos0-3	default text positions (one of `POS_*` defines)
fnt0-3	default text font styles (one of `FONT_*` defines)

Global Variables

There are some global read-only variables that plugins can access:

Variable	Description
`verbose`	verbosity level, by deafult 0
`width`	the width of the meters in pixels, 32 to 256
`height_graph`	the graph's height in pixels
`height_pbar`	the progress bar's height in pixels
`height_stat`	the status bar's height in pixels (also the icon's size)
`levels[]`	user configured alert levels (in percentage)
`colors[]`	theme defined colors, `uint32_t` array, index with `COLOR_*` defines
`lngcode`	string to the user specified language code (eg. `en` or `en_US`)

Misc API

Hint

These are just convenience functions, you can use stdio's, unistd's or string's functions as you like instead.

skm_load

void *skm_load(char *fn, int *len)

Description

Loads a file's content as a zero terminated string into a static buffer and returns the buffer address. DO NOT free the returned buffer when called with a local file. It loads bytes up to 64k, and works with /proc and /sys files as well (which usually report zero file size).

Important

If mbedtls is compiled in, then fn might start with https://, and in this case the returned buffer is allocated and can be any size. When called with an URL, then it is the caller's responsibility to call free on the returned buffer.

Parameters

Argument	Description
fn	file name, absolute path or `https://` URL
len	(optional, can be `NULL`) variable to store the number of bytes loaded

Return Value

Returns NULL on error otherwise the contents of the file and its size in the len variable.

skm_json

char *skm_json(char *json, char *key)

Description

Returns a pointer to a value in json for a key. In case https:// is enabled and a plugin wishes to use a REST API of some service (like a weather forecast).

Parameters

Argument	Description
json	zero terminated JSON string
key	path to a value, like `"0.6.0.1"` or `"result.items.0.name"`

Return Value

Returns NULL if key not found, otherwise pointer to the value.

skm_list

int skm_list(char *needle, char *haystack)

Description

Checks if needle is listed in the comma separated haystack list.

Parameters

Argument	Description
needle	string to look for
haystack	comma separated list or `+`

Return Value

Returns 0 if not listed, 1 if found and -1 if list is composite.

String parsing

char *skm_eol(char **s, char *end, char sep); char *skm_name(char **s, char *e, char sep); int64_t skm_int(char **s, char *e, char sep, int base); void skm_skip(char **s, char *e, char sep);

Description

First one returns the end of the line, the second a name string, the third an integer number, and the last skips a column.

Parameters

Argument	Description
s	string to parse
e	end of the line (returned by `skm_line`)
end	end of the entire string
sep	column separator character (most likely space)
base	either 2, 8, 10 or 16

Return Value

In case of skm_int an integer, otherwise a string pointer. The functions adjust s to the next column.

Simple API

This is really-really simple, the plugin doesn't have to care about displaying anything, it just needs to fill in the fields in the layout and do a single function call.

skm_layout

void skm_layout(layout_t *lyt)

Description

Outputs a layout, should be called from *_draw. A plugin can call this multiple times if there are multiple meters of its kind.

Parameters

Argument	Description
lyt	filled in layout

Field	Description
`type`	a bitfield that tells which part of the layout should be drawn
`value[0]`	progress bar and graph's value (input, read, receive, etc.)
`value[1]`	second graph value (output, write, sent, etc.)
`min` / `max`	fixed graph scale, minimum and maximum values (optional)
`icon_l`	icon on the left on the status bar (optional, 0 if none)
`icon_r`	icon on the right on the status bar (optional, 0 if none)
`str[4]`	strings to display (optional, `NULL` if none)

Layout

The bitfield in type tells which parts to draw and how, for example TYPE_GRAPH | TYPE_2VALS | TYPE_PBAR | TYPE_STAT will display a graph with columns and two values on top of each other, a progress bar, and a status bar as well. The values are passed in the value[] array. If min and max is set, then the graph is drawn accordingly to that scale, otherwise if both zero, then min and max calculated automatically from the last 256 values.

+----------------------------+
| POS_TL    POS_TC    POS_TR |  TYPE_GRAPH
|                            |  TYPE_2VALS
| POS_BL    POS_BC    POS_BR |  TYPE_LINE
+----------------------------+
| percentage                 |  TYPE_PBAR
+----------------------------+
| POS_L     POS_C      POS_R |  TYPE_STAT
| icon_l              icon_r |  TYPE_STICK
+----------------------------+

A layout can display additionally 4 strings, their default position (graph or status bar, left or right, etc.) and font style is specififed in SKM_PLUGIN, but the theme might override and the user can alter these too in the config file. For the available defines, see skm_text's description below.

Similarly, the status bar might have text on it, but it might also have icons, these can be found in the skm_icon's description. The actual images for these icons come from the theme.

When the TYPE_PBAR type is set, then there's a progress bar indicating value[0] which must be a percentage. This will be color coded, from normal to alert, warning and error. If value[0] is negative, then its absolute value is used and the color code is reversed (so 100% will be normal not 0%), this is mostly used for battery levels only.

If there's no TYPE_PBAR, but there's TYPE_STICK then the status bar has a "stick" icon at value[0] percentage.

Advanced API

This is selected if the plugin calls skm_pbuf instead of skm_layout.

Warning

Direct manipulation of the pixel buffer is certainly possible, but ill advised. The pixel buffer lines usually have more bytes than four times width, therefore rows must be addressed by a pitch value (stride). The advanced API functions also take care not to write outside of the valid width x h area (doing so would certainly ruin the frame or might even cause segfault).

skm_pbuf

uint32_t *skm_pbuf(int h, int *p);

Description

Expands the pixel buffer vertically by h pixels and returns the pixel buffer's address and pitch. Each row starts at multiple of this pitch, and the returned buffer's size is width x h pixels. Each pixel is 4 bytes ARGB, with the blue channel in the least significant byte, and alpha in the most. This format is always the same, regardless to the platform and the actual backend.

Parameters

Argument	Description
h	the requested height
p	the returned pitch in bytes (not pixels!)

Return Value

The pixel buffer's address and number of bytes in a row in p.

skm_draw

void skm_draw(int x, int y, uint32_t color)

Description

Draws one pixel. This alpha blends the pixel with the existing one, and keeps the bigger alpha.

Parameters

Argument	Description
x	the X coordinate to draw to, in pixels
y	the Y coordinate to draw to, in pixels
color	an ARGB color, blue in least significant byte

skm_line

void skm_line(int x0, int y0, int x1, int y1, uint32_t color)

Description

Draws a line. This alpha blends the pixel with the existing one, and keeps the bigger alpha.

Parameters

Argument	Description
x0	the X coordinate to draw from, in pixels
y0	the Y coordinate to draw from, in pixels
x1	the X coordinate to draw to, in pixels
y1	the Y coordinate to draw to, in pixels
color	an ARGB color, blue in least significant byte

skm_plot

void skm_plot(int x, int y, uint32_t color)

Description

Plots one pixel, this just blindly overwrites the old pixel. This can be used to clear the alpha channel.

Parameters

Argument	Description
x	the X coordinate to draw to, in pixels
y	the Y coordinate to draw to, in pixels
color	an ARGB color, blue in least significant byte

skm_rect

void skm_rect(int x, int y, int w, int h, uint32_t color)

Description

Draws a filled rectangle, blindly overwriting any existing pixels. This can be used to clear the alpha channel.

Parameters

Argument	Description
x	the X coordinate to draw to, in pixels
y	the Y coordinate to draw to, in pixels
w	width of the rectangle in pixels
h	height of the rectangle in pixels
color	an ARGB color, blue in least significant byte

skm_icon

void skm_icon(int x, int y, int icon)

Description

Blits a theme icon onto the pixel buffer.

Parameters

Argument	Description
x	the X coordinate to draw to, in pixels
y	the Y coordinate to draw to, in pixels
icon	one of the `ICON_*` defines

Define	Description
`ICON_NONE`	no icon displayed (with `icon_l` and `icon_r`)
`ICON_STICK`	only with skm_icon(), `TYPE_STICK`'s stick
`ICON_LED_OFF`	a gray inactive led
`ICON_LED_IN`	an active led with input / read color
`ICON_LED_OUT`	an active led with output / write color
`ICON_LED_0`	an alternative led, inactive
`ICON_LED_1`	an alternative led, active
`ICON_MAIL_NONE`	an empty mailbox icon
`ICON_MAIL_NEW`	a mailbox with new, unread mail icon
`ICON_ALERT`	an alert icon (needs user attention)
`ICON_WARN`	a warning icon (the meter is at a dangerous level)
`ICON_ERROR`	an error icon (meter indicates a malfunction)
`ICON_CHARGING`	a battery is charging icon
`ICON_SUNNY`	weather sunny (clear day)
`ICON_CLOUDY`	weather cloudy
`ICON_RAINY`	weather rainy
`ICON_STORM`	weather storm
`ICON_SNOWY`	weather snowy
`ICON_WINDY`	weather windy
`ICON_WINDSTORM`	weather windstorm
`ICON_NIGHT`	weather clear night

skm_pbar

void skm_pbar(int x, int y, int w, int percent)

Description

Blits a progress bar onto the pixel buffer. If percent is negative, then its absolute value is used, and the level color codes will be reversed (so 100% will be normal, and 0% will be an error).

Parameters

Argument	Description
x	the X coordinate to draw to, in pixels
y	the Y coordinate to draw to, in pixels
w	width of the progress bar in pixels
percent	percentage to represent

skm_blit

void skm_blit(int x, int y, int w, int item)

Description

Blits a theme item onto the pixel buffer.

Parameters

Argument	Description
x	the X coordinate to draw to, in pixels
y	the Y coordinate to draw to, in pixels
w	width of the item in pixels (height for sides)
item	one of the `ITEM_*` defines

Define	Description
`ITEM_LEFT`	frame left side (`w` is height)
`ITEM_RIGHT`	frame right side (`w` is height)
`ITEM_TOP`	frame top
`ITEM_BOTTOM`	frame bottom
`ITEM_METER`	meter background (an empty panel)
`ITEM_GRAPH`	graph background (panel with chart)
`ITEM_PBAR`	progress bar background
`ITEM_PN`	progress indicator normal
`ITEM_PA`	progress indicator alert
`ITEM_PW`	progress indicator warning
`ITEM_PE`	progress indicator error
`ITEM_STAT`	status bar background
`ITEM_SINGLE`	isolated status bar

skm_copy

1
2

void skm_copy(int x, int y, int w, int h, uint32_t *src, int sp, int sx, int sy, int sw, int sh)

Description

Blits another pixel buffer onto the pixel buffer. If w is bigger than sw or h is bigger than sh, then it repeats the source image.

Parameters

Argument	Description
x	the X coordinate to draw the image to, in pixels
y	the Y coordinate to draw the image to, in pixels
w	destination width to draw in pixels
h	destination height of draw in pixels
src	source pixel buffer
sp	source pitch
sx	source X coordinate to take the image from, in pixels
sy	source Y coordinate to take the image from, in pixels
sw	source width of the image in pixels
sh	source height of the image in pixels

skm_text

void skm_text(int x, int y, int font, int ha, int va, const char *str)

Description

Draws a string as text to the pixel buffer. The typeface, font size, text color and padding is defined by the theme.

Parameters

Argument	Description
x	the X coordinate to draw the text to, in pixels
y	the Y coordinate to draw the text to, in pixels
font	one of the `FONT_*` defines
ha	horizontal alignment: -1 right, 0 centered, 1 left
va	vertical alignment: -1 top, 0 middle, 1 bottom
str	a zero terminated UTF-8 string

Define	Description
`FONT_TITLE`	title font style
`FONT_LABEL`	label font style
`FONT_VALUE`	value font style
`FONT_SMALL`	small font style
`FONT_GRTIT`	title font style on graph
`FONT_GRLAB`	label font style on graph
`FONT_GRVAL`	value font style on graph
`FONT_GRSML`	small font style on graph

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Theme

A SKrellM theme is a single image, which can be easily created in CLI mode.

File Manipulation

skrellm --unpack <theme.png>

Extracts a theme image into multiple files to a directory (same name as the image, but without the .png).

skrellm --pack <directory>

Packs directory contents into a single theme image file (same name as the directory, but .png added).

Hint

These also look for the theme in the configuration directory. To use the current working directory, prefix with ./.

Theme Structure

The theme directory must contain one plain text file and several PNG images with fixed names. The SKrellM window is constructed using these images.

+-------+  frame top
|.+---+.|
| |   | |  meter
|.+---+.|
| |   | |  meter
|.+---+.|
|.+---+.|  meter
| |   | |  meter
|.+---+.|
+-------+  frame bottom

The layout is various meters arranged on a vertical stack, surrounded by a frame.

There's a frame top and bottom, and each meter has its own frame left and frame right. The meters in the middle all have the same width pixels width, although their height might be different. This is independent to the frame side widths (meter's width is defined by the user, while frame side widths come from the theme images).

Meta Data

Warning

There's not much error checking, make sure the meta file is syntactically correct!

The text file in the directory is called meta, which is a simple INI file with key=value pairs in each line. For example:

author=John Doe
copyright=MIT
padding=1 2
back=101010ff
fore=7e7e7eff
input=007e00ff
output=00007eff
grid=202020ff
title=7e7e7eff 2020207f 16 FreeSans
label=7e7e7eff 2020207f 12 FreeSans
value=7e7e7eff 2020207f 12 FreeSans
small=7e7e7eff 00000000 10 FreeSans

Key	Description
`author`	theme author's name
`copyright`	theme's copyright
`padding`	space separated vertical and horizontal padding in pixels
`back`	panel background color (RGBA, HTML color code)
`fore`	panel foreground color
`input`	graph input color
`output`	graph output color
`grid`	graph grid color
`title`	centered font style (HTML color, shadow, size, font name)
`label`	left / right font style
`value`	left / right font style
`small`	small text font style
`grtit`	centered font style on graph
`grlab`	left / right font style on graph
`grval`	left / right font style on graph
`grsml`	small text font style on graph
`(plugin).layout`	override plugin styles, same format as in config

Frame top

+----+------+----+
| tl |  tc  | tr |
+----+------+----+
   <--width-->

The frame top is constructed from tl.png, tc.png and tr.png. These must be of the same height. The left part is placed once, the right part likewise, then the gap between is filled by horizontally repeating the center image.

Note that the left and right image widths are independent to the actual width. The only assumption is, that the entire block's width equals to width plus frame side widths.

Frame sides

+----+---------+----+
| lt |         | rt |
+----+  meter  +----+
| lc |<------->| rc |
+----+  width  +----+
| lb |         | rb |
+----+---------+----+

For both sides, the frame is constructed from three images. On the left lt.png, lc.png and lb.png, and on the right rt.png, rc.png and rb.png. Images of the left and right must have the same width. First the top image is placed, then the one at the bottom, finally the gap is filled in by repeating the center part vertically.

Horizontally the middle part is width pixels wide and it contains the meter.

Frame bottom

   <--width-->
+----+------+----+
| bl |  bc  | br |
+----+------+----+

Just like top, the frame bottom is contructed from bl.png, bc.png and br.png. These must be of the same height. The left part is placed once, the right part likewise, then the gap between is filled by horizontally repeating the center image.

Note that the left and right image widths are independent to the actual width. The only assumption is, that the entire block's width equals to width plus frame side widths.

Meter background

<------width----->
+----+------+----+
|    |      |    |
| ml |  mc  | mr |
|    |      |    |
+----+------+----+

The empty meter's background is also constructed from three images of the same height, ml.png, mc.png and mr.png, similarily placing left and right first, then filling the gap by repeating horizontally the center piece.

Here the entire block's width is width pixels. This is never used by SKrellM, but plugins might want an empty background when they use the Advanced API.

Graph meter

<------width----->
+----+------+----+
|    |      |    |
| gl |  gc  | gr |
|    |      |    |
+----+------+----+

The graph area's background is also constructed from three images of the same height, gl.png, gc.png and gr.png, similarily placing left and right first, then filling the gap by repeating horizontally the center piece.

Here the entire block's width is width pixels. The graph's height is usually much larger than the other meter heights.

Progress bar meter

<------width----->
+----+------+----+
| pl |  pc  | pr |  progress bar background
+----+------+----+
  +--+------+--+
  |nl|  nc  |nr|    normal bar
  +--+------+--+
  |al|  ac  |ar|    alert bar
  +--+------+--+
  |wl|  wc  |wr|    warning bar
  +--+------+--+
  |el|  ec  |er|    error bar
  +--+------+--+

All of these images must have the same height. The progress bar's background is drawn using pl.png, pc.png and pr.png. As for the progress indicator, there are four different kinds, and note that their left and right widths should be smaller than the background's left and right.

The indicator images should look the same, and they should only differ in color, indicating normal progress bar, alert, warning and error levels. Only one of these is used on a meter at any given time.

Status bar meter

<------width----->
+----+------+----+
| sl |  sc  | sr |
+----+------+----+
+----+------+----+
| il |  ic  | ir |
+----+------+----+

The status bar's background is also constructed from three images of the same height, sl.png, sc.png and sr.png (when there's a graph or progressbar) or il.png, ic.png and ir.png (when it's isolated), similarily placing left and right first, then filling the gap with by repeating horizontally the center piece.

Icons

The theme icons must have the same width and height, and that also has to match the status bar's height.

stick.png - the percent indicator "stick"
led_off.png - a gray inactive led
led_in.png - an active led with input / read color
...etc.

These have the same name as the ICON_* defines, just in lowercase and without the prefix.

Font

The font.sfn file is optional. If it exists, then it will be embedded in the theme, and will be used regardless to what font name was specified. If it's missing, then fonts are loaded from the file system.

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Theme File

It is a normal PNG file, just with a special smTh chunk in it, with the following data:

Offset	Size	Description
0	2	theme version (0 for now)
2	1	vertical padding
3	1	horizontal padding
4	12	frame left
16	12	frame right
28	12	frame top
40	12	frame bottom
52	12	empty meter background
64	12	graph (chart) background
76	12	progress bar background
88	12	progress indicator normal
100	12	progress indicator alert
112	12	progress indicator warning
124	12	progress indicator error
136	12	status bar background
148	12	single status bar background
160	3*12	reserved for future use
196	32	title font style
228	32	label font style
260	32	value font style
292	32	small font style
324	32	graph title font style
356	32	graph label font style
388	32	graph value font style
420	32	graph small font style
452	8*32	reserved for future use
708	4	background color
712	4	foreground color
716	4	input graph color
720	4	output graph color
724	4	grid graph color
728	3*4	reserved for future use
740	64	author
804	64	copyright
868	2*64	reserved for future use
996	16*24	plugin style overrides

As for the items, each record looks like (sides store width, height, height, height; but the same structure, all the others store height, width, width, width):

Offset	Size	Description
0	2	x
2	2	y
4	2	height / width
6	2	left width / top height
8	2	middle width / middle height
10	2	right width / bottom height

Font styles:

Offset	Size	Description
0	4	text color
4	4	shadow color (or 0 if none)
8	1	size (8 to 192)
9	23	font's name

Colors are stored as blue channel in the least significant byte, alpha in the most.

The author and copyright are zero terminated UTF-8 strings.

Finally the plugin style overrides look like:

Offset	Size	Description
0	15	plugin name
15	1	type override
16	1	string #1 position override
17	1	string #2 position override
18	1	string #3 position override
19	1	string #4 position override
20	1	string #1 style override
21	1	string #2 style override
22	1	string #3 style override
23	1	string #4 style override

If the PNG chunk is bigger than this fixed size (1380 bytes) structure, then there's an embedded font, and data in SFN format follows (could be gzip compressed).

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Licenses

The SKrellM is Free and Open Source software available under the GPLv3+ or any later version of that license.

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

Advantages

Disadvantages

Getting Started

Installation

Linux

Windows

Compilation

Customization

Configuration

config

self

Fonts (*.sfn)

Themes (*.png)

Plugins

Writing plugins

plgname_init

plgname_free

plgname_draw

Register

Global Variables

Misc API

skm_load

skm_json

skm_list

String parsing

Simple API

skm_layout

Advanced API

skm_pbuf

skm_draw

skm_line

skm_plot

skm_rect

skm_icon

skm_pbar

skm_blit

skm_copy

skm_text

Theme

File Manipulation

Theme Structure

Meta Data

Frame top

Frame sides

Frame bottom

Meter background

Graph meter

Progress bar meter

Status bar meter

Icons

Font

Theme File

Licenses