intellij-sdk-code-samples/topics/reference_guide/work_with_icons_and_images.md

Icons and images are used widely by IntelliJ Platform plugins. Plugins need icons mostly for actions, custom components renderers, tool windows, and so on.

Plugin Icons, which represent a plugin itself, have different requirements than icons and images used within a plugin. For more information see the Plugin Icon page.

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Plugins should reuse existing platform icons whenever possible, see Icons list and AllIcons. A detailed design guideline is available for creating custom icons.

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How to organize and how to use icons?

The best way to deal with icons and other image resources is to put them to a dedicated source root marked as Resources Root, say icons or resources.

The getIcon() method of IconLoader can be used to access the icons.

The path to the icon passed in as argument to IconLoader.getIcon() must start with leading /

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Then define a class/interface in a top-level package called icons holding icon constants as static fields:

package icons;

public interface DemoPluginIcons {
  Icon DemoAction = IconLoader.getIcon("/icons/demoAction.png", DemoPluginIcons.class);
  Icon StructureToolWindow = IconLoader.getIcon("/icons/toolWindowStructure.png", DemoPluginIcons.class);
  Icon FileType = IconLoader.getIcon("/icons/myLangFileType.png", DemoPluginIcons.class);
}

When using Kotlin, fields must be annotated with @JvmField:

package icons

object DemoPluginIcons {
  
  @JvmField
  val DemoAction = IconLoader.getIcon("/icons/demoAction.png", javaClass)

  // ...
}

Use these constants inside plugin.xml as well when specifying icon attribute for <action> or extension points. Note that the package name icons will be automatically prefixed and must not be added manually.

<actions>
    <action id="DemoPlugin.DemoAction"
            icon="DemoPluginIcons.DemoAction" [...] />
</actions>

<extensions defaultExtensionNs="com.intellij">
    <toolWindow id="CustomStructure"
                icon="DemoPluginIcons.StructureToolWindow" [...] />
</extensions>

Image Formats

IntelliJ Platform supports Retina displays and has dark theme called Darcula. Thus, every icon should have a dedicated variant for Retina devices and Darcula theme. In some cases, you can skip dark variants if the original icon looks good under Darcula.

Required icon sizes depend on the usage as listed in the following table:

Usage	Icon Size (pixels)
Node, Action, Filetype	16x16
Tool window	13x13
Editor gutter	12x12

SVG Format

SVG icons are supported since 2018.2.

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As SVG icons can be scaled arbitrarily, they provide better results on HiDPI environments or when used in combination with bigger screen fonts (e.g., in presentation mode).

A base size denoting the size (in the user space) of the rendered image in 1x scale should be provided. The size is set via the width and height attributes omitting the size units. If unspecified, it defaults to 16x16 pixels.

A minimal SVG icon file:

<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16">
 <rect width="100%" height="100%" fill="green"/>
</svg>

The naming notation used for PNG icons (see below) is still relevant. However, the @2x version of an SVG icon should still provide the same base size. The icon graphics of such an icon can be expressed in more details via double precision. If the icon graphics are simple enough so that it renders perfectly in every scale, then the @2x version can be omitted.

For generating the SVG icons suited for the IntelliJ-based IDEs, you may also use the third-party web tool – IntelliJ Icon Generator.

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PNG Format

Please consider using SVG icons if your plugin targets 2018.2+.

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All icon files must be placed in the same directory following this naming pattern (replace .png with .svg for SVG icons):

• iconName.png W x H pixels (Will be used on non-Retina devices with default theme)
• iconName@2x.png 2*W x 2*H pixels (Will be used on Retina devices with default theme)
• iconName_dark.png W x H pixels (Will be used on non-Retina devices with Darcula theme)
• iconName@2x_dark.png 2*W x 2*H pixels (Will be used on Retina devices with Darcula theme)

The IconLoader class will load the icon that matches the best depending on the current environment.

Here are examples of toolWindowStructure.png icon representations:

Theme/Resolution	File name	Image
Default	toolWindowStructure.png
Darcula	toolWindowStructure_dark.png
Default + Retina	toolWindowStructure@2x.png
Darcula + Retina	toolWindowStructure@2x_dark.png