# Developer's Guide to Theming

This document provides information an application developer should know when developing plugins, actions, scripts, etc., that use colors, fonts, or icons. By following these guidelines, developers can easily make use of Ghidra's theming capabilities.

> > Most classes referenced in this document live in the `generic.theme` package.

## Theme Resource Types

When developing application code for Ghidra such as plugins, actions, etc., developers often want to use colors, fonts, and icons. The key idea to support theming is to never directly reference those resources. Instead, the developer should create an ID string for the resource and then in a `module.theme.properties` file, provide a default value for that ID. (Also, you may define an alternate "dark" default value that will be used if the current theme is considered a dark theme). The way you define and use these IDs is a bit different depending on whether the resource is a color, font, or icon. Colors and icons are similar in that developers use these types by creating either `GColor` or `GIcon`. Unfortunately, because of the way fonts are implemented, there is no equivalent `GFont`, so using fonts is a bit more involved.

> ### Colors

> For colors, developers should use the `GColor` class. Simply construct a new `GColor` object passing in the color resource ID as the argument. `GColor` is a subclass of `Color`, so it can be used anywhere a `Color` would be used. The developer then needs to provide a default value for that ID in the module's `module.theme.properties` file. So, for example:

> > > `panel.setBackground(Color.Red);`

> > becomes

> > > `panel.setBackground(new GColor("color.bg.abc"));`

> > and

> > > `public static final Color MY_COLOR = Color.BLUE;`

> > becomes

> > > `public static final Color MY_COLOR = new GColor("color.fg.xzy");`

> The `GColor` class uses a delegation model where all method calls to `GColor` get mapped to its delegate color. If ever the color associated with a `GColor`'s resource ID changes, the `GColor` is automatically updated by calling the `refresh()` method. This is done whenever the `Gui.setColor(id)` is called or a new theme is loaded.

> ### Icons

> Icons work just like colors, so you can just create a `GIcon(String id)`. So, for example,

> > > `public static final Icon MY_ICON = ResourceManager("images/balloon.png");`

> > becomes

> > > `public static final Icon MY_ICON = new GIcon("icon.text.bubble");`

> ### Fonts

> Unfortunately, fonts are unable to use the delegation model used for colors and icons. Therefore, there is no `GFont` class. Programming fonts requires a bit more work. If a font used directly, such as in renderer or in a paint method, simply get the font each time from the `Gui` class, as shown below. To set a font on a component, use `Gui.registerFont(Component, String)`. Once the component is registered, the application will automatically update the component if the font associated with that ID changes. So, for example:

> > > `Font font = new Font("Monospaced", Font.BOLD, 12);`

> > becomes

> > > `Font font = Gui.getFont("font.xyz");`

> > or

> > > `myLabel.setFont(new Font("Dialog", Font.PLAIN, 14)`

> > becomes

> > > `Gui.registerFont(myLabel, "font.xyz");`

> > ### Font Usage in Tables, Lists and Custom Painting

> > Ghidra makes great use of tables and to a lesser extent, lists. Both tables and lists use renderers to paint cell values.

> > - Java - By default, Java will use the font of the table/list as the font used during rendering.
> > - Ghidra Tables - Ghidra does not use the table's font for rendering by default. Instead, the renderer is initialized with the fonts used by `JLabel`, with additional fonts for bold and monospaced text.
> > - Ghidra Lists - Ghidra does not currently use custom rendering for lists. Thus, list cell rendering will make use of the list's font, which is Java's default behavior.

> > We point out this difference between Java and Ghidra here so that developers understand that changing fonts used for tables differs from Java. Specifically, calling

> > > >          table.setFont(newFont);

> > will not affect the font used when rendering the table. To programmatically change the fonts used for tables, you can set the font directly on each cell renderer. As with a any custom fonts used, be sure to define theme properties file and register then with the Gui class as outlined above.

> > The fonts used for any painting operations, including table and list cell rendering, as well as any code that overrides `paint` will work correctly within the theming environment as long as the fonts are derived from the default Look and Feel values or are obtained from the `Gui` class. In other words, as long as the fonts used in custom painting are not hard-coded, any changes to the fonts via the theming API will appear on the next call to paint the UI.

## Resource ID Strings

> Resource IDs are strings used to identify a color, font, or icon. These strings are created by the developer and should be chosen in a way that it is as self-describing as possible. So, for example, if you wanted the text color in some error message in some widget "abc", you might create the color ID "color.fg.abc.error". To help keep resource IDs consistent, we created a convention for IDs as follows:

> > >          [type].[category[...]].[client].[specialized uses]

> - type: color, font, or icon.
> - category: any value, examples include 'bg'(background), 'fg'(foreground), 'cursor'. There may be multiple dot-separated values.
> - client: the plugin name or feature name.
> - specialized uses: any key value here that applies to the client, such as 'vertex' for a graph client.

> > Examples:

> > - color.bg
> > - color.bg.listing
> > - color.bg.functiongraph.vertex.group
> > - font.listing
> > - font.listing.header
> > - icon.error
> > - icon.delete
> > - icon.plugin.byteviewer.provider

> - System IDs: The following resource IDs are created and used by the system. For a description of how these IDs are used internally by the application, see the `UiDefaultsMapper` class . The `system.*` keys allow users to quickly change many Look and Feel values via these high-level concepts. The `laf.*` properties are for internal use and do not need to be changed by the user. A description of the system properties can be found in the `SystemThemeIds` class.

> > - laf.color.*
> > - laf.font.*
> > - laf.icon.*
> > - system.color.*
> > - system.font.*

> > The `system` property names use the standard property names, such as `font, bg` and `fg`. These properties introduce these additional terms: `control, view, menu and tooltip`. `control` refers to items that generally control the state of the application, such as buttons and check boxes. `view` refers to widgets that display data, such as trees, tables and text fields. `menu` and `tooltip` work with the items after which they are named.

## Theme Property Files

> The default values for resource IDs are defined in files that reside a module's data directory (not all modules define this file). These files all are named to end in `theme.properties` and begin with the module's name. Some modules make use of multiple files in order to better manage the volume of IDs. In this case, the name of each properties file offers a clue as to its contents. Thus, for small modules, those without many resource IDs in use, one theme properties file is sufficient to easily define and manage all required IDs. But, we recommend larger modules use multiple files, one for each sub-feature. The application will find all theme property files as long as they exist in a module's data directory and are named with the `.theme.properties` suffix.

> ### Theme Properties File Naming Convention

> To promote consistency, theme property files should use the following naming convention:

> > >           module name[.additional name]].theme.properties

> > Examples:

> > - base.theme.properties
> > - base.listing.theme.properties

> ### Theme Properties File Format

> Theme files uses a very simple format for specifying theme property values. Each line specifies a property ID (sometimes referred to as the key) and a value, separated by an "=". A theme properties file consists of two sections: the standard defaults section and a section for specifying defaults for "dark" themes.

> > `

> >     [Defaults]

> >     [property id 1] = [some value]
> >     [property id 2] = [some value]
> >     [property id 3] = [some value]
> >     ...

> >     [Dark Defaults]

> >     [property id 1] = [some value]
> >     [property id 2] = [some value]
> >     ...

> > `

> Example:

> >     [Defaults]

> >     color.bg = white
> >     color.bg.listing = color.bg

> >     color.fg.listing.address = black
> >     color.fg.listing.bytes = #00ff00

> >     font.global = courier-BOLD-12
> >     font.global.listing = font.global

> >     icon.error = defaultError.png

> >     [Dark Defaults]

> >     color.bg = black

> >     color.fg.listing.address = gray
> >     color.fg.listing.bytes = orange

> NOTE: The `[Dark Defaults]` section is for optionally overriding values defined in the standard `[Defaults]` section. If a property ID is not given a value in the defaults section, it is an error. If a value is not defined in the `[Dark Defaults]` section, then the value defined in the `[Defaults]` section will be used in a dark theme.

## Theme Property Values

> The values specified in the theme properties files can be specified in a variety of ways, including ways to modify other property values. For example, an icon's size can be modified directly in the theme properties file. A font value can specified as a reference to another defined font, but with a different size or style.

> Also, any value can also be a reference to some other ID of the same type. So, for example, a reference color entry might be something like "color.bg.listing = color.bg". This says that the listing's background color should be whatever "color.bg" is defined to be. Note that all of the application's defined properties start with either "color.", "font.", or "icon.".

> Properties defined by the theming system do not follow this pattern. To reference a property that does not have a standard prefix, an ID can be prefixed with `[color]` , `[font]`, or `[icon]` as appropriate to allow the theme property parser to recognize the values as IDs to other properties. For example, to refer to a system property named `system.color.bg.view`, you would use the following definition:

> `color.bg.tree = [color]system.color.bg.view`

### Color Values

Color values supports the following formats:

> - #rrggbb
> - #rrggbbaa
> - 0xrrggbb
> - 0xrrggbbaa
> - rgb(red, green, blue)
> - rgba(red, green, blue, alpha)
> - web color name // the case-insensitive name of a web color such as red, olive, or purple

Examples:

            color.foo = #0000ff             // blue
            color.foo = #ff000080           // red with half transparency
            color.foo = 0x00ff00            // green
            color.foo = 0xff000080          // red with half transparency
            color.foo = rgb(0, 0, 255)      // blue
            color.foo = rgba(255,0, 0, 128) // red with half transparency
            color.foo = blue                // web color defined as 0x0000FF
            color.foo = LawnGreen           // web color defined as 0x7CFC00

### Font Values

Font values are specified using the following format:

>           family name-style-size

> - family name: the font name such as `monospaced`, `dialog`, `courier`.
> - style: One of `PLAIN`, `BOLD`, `ITALIC`, or `BOLDITALIC`.
> - size: the font point size. 12 is very common.

Examples:

            font.foo = monospaced-PLAIN-12
            font.foo = courier-BOLD-14
            font.foo = SansSerif-ITALIC-10

#### Font Modifiers

When referencing another font, the referenced font can be modified using the following format:

>           font.ref[family name][style][size]

> - font.ref: the theme property ID of some other font
> - family name: use the size and style of the reference font, but use this font family.
> - style: use the same font as the reference font, but with this style. One of `PLAIN`, `BOLD`, `ITALIC`, or `BOLDITALIC`.
> - size: use the same font as the reference font, but with this size.

Examples:

            font.foo = SansSerif-PLAIN-12   // standard font spec
            font.bar = font.foo[BOLD]       // results in SansSerif-BOLD-12
            font.bar = font.foo[15]         // results in SansSerif-PLAIN-15
            font.bar = font.foo[monospaced] // results in monospaced-PLAIN-12
            font.bar = font.foo[ITALIC][15] // results in SansSerif-ITALIC-15

### Icon Values

Icon are specified by simply entering the name of an icon that is in the classpath. However, an icon value can get complicated because it can be modified in a number of ways, such as scaling, disabling, even overlaying other icons. The format is as follows:

>           iconName[size(width,height)][disabled]{overlayIconName[size(width,height)[disabled][move(x,y)]}{...}

> - iconName: the name the base icon
> - size(width,height): optional modifier to scale the image to the given size.
> - disabled: optional modifier to create a disabled version of the icon.
> - {...}: optional modifier to overlay an icon on the base icon. It is recursively defined using the standard icon format.
> - move(x,y): optional modifier on overlays to position them relative to the base icon.

Examples:

            icon.foo = house.png               // using the icon house.png found as an image resource on the classpath
            icon.foo = house.png[size(10,10)]  // uses the house.png icon, but scales it to 10x10
            icon.foo = house.png[disabled]     // creates a disabled version of house.png
            icon.foo = house.png[16,16]{hammer.png[size(4,4)][move(12,12)]}
                                                    // creates a 16x16 version of the house icon with a 4x4 scaled
                                                    // hammer.icon overlayed in its lower right corner

To create stand-alone icon suitable for dynamically overlaying other icons, there is special syntax for specifying an empty base icon. Use the empty icon along with another overlay icon in some specific area of the empty icon to create a final icon that can be used as an overlay for other icons. For example, to create an overlay icon that would add a flag to the bottom-right corner of any other icon:

            icon.overlay.flag = EMPTY_ICON[size(16,16)]{flag.png[size(6,6)][move(10,10)]}

## Useful Concepts

### GThemeDefaults

> This class contains many common application theme values for developers to use, such as the default background color. These values can be used directly so developers do not have to instantiate theme objects using theme IDs.

### Icons

> When adding icons to the application, consider using standard icons provided by the `Icons` class. Many generic concepts that require icons are in this class.

### Palette Colors

> A list of palette colors has been defined in `gui.palette.theme.properties`. These palette colors values are meant to be used by developers to reduce the total number of colors used in the application. These color ids and values are viewable in the Theme Editor Dialog.

> One of the benefits of using the palette system is that it is easy for end-users to change one palette color to update all widgets in the application.

> We recommend you use the existing palette colors when picking colors for your widgets.

### HTML Foreground Colors in Messages

> Some developers use HTML messages in labels, tables, tooltips, and in calls to system APIs, like `Msg`. Using HTML text allows clients to control the formatting of the text, including the usage of color. If you use color in your HTML, then we suggest you do so using GColors, like this:

>         String message = "Some text: <FONT COLOR=\"" + Messages.ERROR + "\">" + errorText + "";

> In this example, an HTML message is created and part of that text is colored with the standard error message color, which is red in a light mode theme. You can also use your own `GColor` object in your HTML messages. Using standard system colors or GColors allows these colors to be updated as the theme changes. We do not recommend the use of hard-coded color values.

### Options Usage of Colors and Fonts

> The `Options` class in Ghidra facilitates user-configurable options in the application. Previously, developers could use options to allow end-users to control color values. In the new theme-based system, all colors are controlled via theming. However, to make the transition to theming easier for developers, we added methods to the options class that allow the developer to bind color editing via the options UI. These color options will write any changes directly to the theme system.

> See: `Options.registerThemeColorBinding()` and `Options.registerThemeFontBinding()`

### UiDefaultsMapper

> This class discusses some of the plumbing the application uses to unify the various Look and Feel concepts presented by the different LaFs.

### SystemThemeIds

> This class is used by the `UiDefaultsMapper` class and presents a set of resource IDs common across all LaFs. These values can be changed by the user. See also the description of System IDs in this document.

### Known Issues

> Sometimes switching between themes does not reset all widgets. When this happens, you may notice odd UI artifacts. These will go away when the application is restarted and often when you again switch the theme.

Provided by: Theme Manager

Related Topics

- Theming Overview
- Theming User's Guide
- Theming Architecture