Skin development introduction
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Kodi is noted as having a very flexible and robust framework for its GUI, making theme-skinning and personal customization very accessible. Users can create their own skin (or modify an existing skin) and share it with others.
Kodi includes a new GUI library written from scratch. This library allows you to skin/change everything you see in Kodi, from the images, the sizes and positions of all controls, colours, fonts, and text, through to altering navigation and even adding new functionality. The skin system is quite complex, and this portion of the manual is dedicated to providing in depth information on how it all works, along with tips to make the experience a little more pleasant.
A skin called Confluence, which can be found in the Kodi GIT repo, is included with Kodi; the skin was originally created by Jezz_X and is kept up-to-date by Team Kodi. Any additional skins you create, or download must be placed in the addons sub-folder if you wish to have Kodi auto-detect the skin and allow you to load it from within the Appearance Settings. See Installing Skins for more.
You may wish to start by having a look through the Skinning Manual and the Skinning Tutorials articles, and try modifying a window or two by adding a button, or altering the textures or layout.
Anatomy of a Skin
Kodi skins once installed are located in userdata addons folder. This is the folder where all skins are placed and listed.
Any additional skins you create, or download from or be installed via zip Kodi will load and ask you if you would like to load the skin and also allow you to load them up from within the Appearance Settings. It is suggested that if you want to make your own skin, then starting by copying an existing skins files over into a new folder (let's say skin.myskin) is a good place to start. You can then edit each of the files as you become more familiar with the skinning system.
Each skin folder contains several subdirectorys, and several files:
- This contains the information that Kodi uses to find the other files that Kodi requires to describe it's skin. It also contains credits information, and versioning information.
- This is a resolution-specific directory. As Kodi can run in multiple resolutions, your skin can have multiple resolution folders. see: How Window XML Files Are Found
- optional folder containing the background images used in the skin
- contains a defaults.xml file which is used to define the colours used in the skin
- optional folder containing any additional items, that don't fit elsewhere
- This subdirectory contains all fonts used by the skin. you can add/replace fonts here
- contains several subfolders for each language (English/strings.po). you can define strings used in your skin in this file.
- This subdirectory contains all the media files (.png/.gif/.jpg...) You can replace/edit these as you like.
- optional folder for additional skin themes. Used to store textures in a different colour to create colour themes
- place 10 screenshots (1280x720) of your skin in here. Name them screenshot-01.jpg, screenshot-02.jpg ect. NOTE: You will need to reference these using the asset tag in the addon.xml
- a textfile detailing what has changed in every version of the skin
- a 1280x720 or 1920x1080 jpeg fanart image for your skin
- a 256x256 or 512x512 png image for your skin
- we recommend to include a Creative Commons license file in your skin: http://creativecommons.org/licenses/
The goal is to keep your skin folder structure as cleanly organized as possible as it makes it easier to troubleshoot problems; this is becomes very important if you are working as part of a Kodi skin creation team.
All the basic media files for a skin should be compressed into the Textures.xbt file, and placed in the media/ folder. You can use the tool TexturePacker for this. All the images that make up the default skin theme should be in the Textures.xbt file.
In addition to this, Kodi allows other .xbt files in the media/ folder, each one representing a different theme for your skin. For instance, you could tint all your main textures a red colour, and create a new theme package Red.xbt? – this gives users more choice in the look of a particular skin. Note that only the textures change when you change themes – the layout stays the same. If the user has selected a theme, then when a control requires a texture, Kodi will first look in the <themename>.xbt file for the texture. It will fall back to the Textures.xbt file if <themename>.xbt doesn't contain the image. This means that the theme .xbt files need only contain the changed textures – all other textures will fall-back to using Textures.xbt as usual.
When the user selects a theme, Kodi will automatically also select the themes default color set, based on the <themename>.xml file located in the colors/ folder. See below for more information.
A suggested method of creating a theme is as follows:
- Run TexturePacker.exe on the folder containing the default texture files, to generate Textures.xbt as you would normally do.
- Identify the textures you wish to have themed and copy them to a separate folder.
- Create a separate folder for each theme outside of your normal skin work area, and place the altered copies of each of the textures in them.
- Run TexturePacker.exe on each of the theme folders created in step 3 to create the themed .xbt files (note you can use the -output switch with TexturePacker.exe to name the theme appropriately).
- Place Textures.xbt and each of the theme .xbt files in the media/ folder of your skin. Kodi will automatically pick them up.
The XML files contained in the colors/ folder contain the different colour themes for the skin. This allows you the skinner to define the colours that you'll use for text and images once in terms of English names (rather than hex codes) and potentially allows you to have different colour themes.
Each additional colour theme has a single XML file, where the filename should be the same as the name of the colour theme (e.g. orange.xml). The default colours should be placed in defaults.xml - this is a fallback file that is used when the user hasn't requested another colour theme, or when their selected colour theme doesn't contain a particular colour assignment.
The layout is as follows (note that the hex code is in ARGB format):
<colors> <color name="white">ffffffff</color> <color name="grey">7fffffff</color> <color name="green">ff00ff7f</color> </colors>
You can then use <textcolor>white</textcolor> within the main skin files to refer to which colour you want. This allows you to easily change all the colouring in the skin by just adding a new XML file to the colors/ folder.
There's one special file called Font.xml. This file contains a list of all fonts the skin uses. kodi will load all the fonts mentioned in this file from the /myskin/fonts directory first, and if that fails, will attempt to load them from Kodi/media/fonts. In the event that Kodi is unable to locate the specified font, it will default to "font13". You can modify this file as you like and add/delete/change fonts. The user friendly font name is referenced by the other xml files mentioned below.
Format of the Font.xml File
The Font.xml file is divided into font sets, which includes a set of fonts used by the skin. Every font set must contain the same font names in order for the skin to work with all font sets.
<?xml version="1.0" encoding="UTF-8"?> <fonts> <fontset id="Default" idloc="31390"> <font> .... </font> <font> .... </font> .... </fontset> <fontset id="Arial" idloc="31391"> <font> .... </font> .... </fontset> </fonts>
A font set has the following attributes:
- Name of the font set. Displayed to the user. Can have any value.
- Refers to a string in the Skins' language file, so font names can be localized.
It is possible to use includes (eg. <include>MonoSpace</include>) in Font.xml There has to be at least one font set with the unicode attribute set to true else languages like Chinese or Korean will not display properly. There is a font called Arialuni.TTF with a size of 20MB. It is a unicode True Type Font and works with all languages Kodi supports.
Note: Kodi will automatically switch to the first available unicode font set if the user selects a language that needs one. This switch will not be made if the currently loaded font set already supports unicode.
True type Fonts
True type fonts must have a .ttf suffix. For a true type font it is possible to define the size (default 20) and a style normal, bold, italics, or bolditalics. Frodo also includes lowercase or uppercase. Isengard includes capitalize. Jarvis includes lighten.
Note: Multiple styles can be used by separating them with a space.
<font> <name>font12</name> <filename>arial.ttf</name> <size>12</size> <style>uppercase lowercase capitalize bold lighten</style> <aspect>0.75</aspect> <linespacing>1.0</linespacing> </font>
The <aspect> tag specifies the aspect ratio of the font. An aspect of 0.75 means that the width of the font will be 0.75 of the height. By default the aspect is 1.0 for all but the SD 16x9 modes (PAL16x9, NTSC16x9 and 480p16x9) where the aspect ratio is 0.75, due to the stretched pixels.
The <linespacing> tag defines height of each line (sometimes called leading or inteline spacing). By default linespacing is set to 1.0.
The other special (and arguably the most important skinning file of all) is includes.xml. This is, as its title suggests, a place from which you can define the default look, size, and positioning of controls, to save you replicating many of the control's attributes throughout the window .xml files. For instance, you can setup the size, and textures used for a button control, thus allowing you to leave those details out in the rest of the skin files, unless ofcourse you want to override the default look or size etc. in a particular window.
This is extremely valuable as it allows you to greatly simplify a lot of the work in building a skin. For one thing, it means that once you have include files setup, many of the default parameters for a different resolution can be done by just altering the parameters within the include file(s) for the different resolution.
With the 2.1 skinning engine, you can infact have more than one include file - you can specify the file attribute when including from a different file, allowing you to have an include file dedicated to a particular set of attributes.
The layout of an includes file is as follows.
<?xml version="1.0" encoding="UTF-8"?> <includes> <include name="whitetext"> <textcolor>ffffffff</textcolor> </include> <include file="listdefaults.xml" /> <default type="button"> <include>whitetext</include> </default> <constant name="leftedge">50</constant> </includes>
You'll notice in the above example that we have 4 different types of includes. The first <include> tag basically allows a substitution of the tags underneath it whenever it occurs. For instance, if in a window .xml file you have this:
<control type="togglebutton"> <include>whitetext</include> ... other tags go here </control>
Then it would substitute the <textcolor> tag for where the include tag is. You can have as many includes as you like, and as many tags can be inside an include - even complete controls, or complete control groups.
The second <include> tag in the example demonstrates how to include from a different file. As there is no include name specified, it will include the contents of the entire file at that point.
The <default> tag is similar to an include, except that it is used in every control of that type - even if you don't specify that the control is to use includes. Thus every buttoncontrol will have the whitetext include in it. Note that you can override this by specifying the <textcolor> tag in the buttoncontrol.
And finally, the <constant> tag allows you to define a numeric (floating point) constant by name for use in place of numeric values (<left>, height="" etc.) would otherwise be used. This allows alignment of items using the same position values which can then easily be altered in one place.
The Window XML Files
The other xml files each define the skin for a single window. They all have the same basic layout, allowing you to place different controls on the window, and define how navigation should operate.
The list of all window .xml files and what they represent is be found in the Window ID's section.
The important thing to remember is that each window has a unique identifying number (id). This is how Kodi identifies the window from within the source code. Furthermore, many of the controls within each window should have a unique id as well, unless they're just used as images or labels where navigation is unimportant and Kodi does not need to be able to identify them uniquely. The window id's are all listed in the window list.
The structure of the window .xml files can be found in the Window Structure section.
Controls are the substance of your skin. They define everything from buttons, to text labels, to visualization placement. The Controls section will explain each and every control in detail.
Kodi's skinning engine versatility is based apon the fact that the skinner can display and hide portions of the skin using a variety of conditional statements that can be combined to create very user friendly UI implementations. For further information of available variable and how they can be applied see the Conditional Visibility section.
Animating Your Skin
The Kodi skinning engine supports animations of any control allowing them to rotate, slide, fade or any combination there-of. Combining animations with conditional statements ensure your skin will have stunning effects that appear as professional as a 1st party product. For further information, see the Animating Your Skin section.
This Skinning Tutorials section is designed to help both people who are new to skinning Kodi get to grips with how the system works, as well as dealing with a few things that the old timers may find useful.
This Skinning Manual section is designed to give quick overview of all current skin code available to help the developers using the full extend of the possibilities.
See Category:Skin_development for a list of information
When writing Skins one often needs Kodi to reload the current Skin. To avoid the tedious procedure of loading another Skin and reloading yours or even close and reopen Kodi in order to see changes, you can map a key to refreshing the skin. This is done by modifying keyboard.xml.
This example keyboard.xml maps F4 to reloading the Skin, F4 followed by F5 to show the Skin specific debuginfo and F6 to showing a popup notification (DialogKaiToast.xml)
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <keymap> <global> <keyboard> <F4>Skin.ToggleDebug</F4> <F5>ReloadSkin()</F5> <F6>Notification(Testing 123,Hello world)</F6> </keyboard> </global> </keymap>