electron/docs/api/native-image.md

nativeImage

Create tray, dock, and application icons using PNG or JPG files.

In Electron, for the APIs that take images, you can pass either file paths or nativeImage instances. An empty image will be used when null is passed.

For example, when creating a tray or setting a window's icon, you can pass an image file path as a String:

const appIcon = new Tray('/Users/somebody/images/icon.png');
let win = new BrowserWindow({icon: '/Users/somebody/images/window.png'});

Or read the image from the clipboard which returns a nativeImage:

const image = clipboard.readImage();
const appIcon = new Tray(image);

Supported Formats

Currently PNG and JPEG image formats are supported. PNG is recommended because of its support for transparency and lossless compression.

On Windows, you can also load ICO icons from file paths, to get best visual effects it is recommended to include at least followings sizes in the icon:

• 16x16
• 32x32
• 64x64
• 256x256

High Resolution Image

On platforms that have high-DPI support, you can append @2x after image's base filename to mark it as a high resolution image.

For example if icon.png is a normal image that has standard resolution, then icon@2x.png will be treated as a high resolution image that has double DPI density.

If you want to support displays with different DPI densities at the same time, you can put images with different sizes in the same folder and use the filename without DPI suffixes. For example:

images/
├── icon.png
├── icon@2x.png
└── icon@3x.png

let appIcon = new Tray('/Users/somebody/images/icon.png');

Following suffixes for DPI are also supported:

• @1x
• @1.25x
• @1.33x
• @1.4x
• @1.5x
• @1.8x
• @2x
• @2.5x
• @3x
• @4x
• @5x

Template Image

Template images consist of black and clear colors (and an alpha channel). Template images are not intended to be used as standalone images and are usually mixed with other content to create the desired final appearance.

The most common case is to use template images for a menu bar icon so it can adapt to both light and dark menu bars.

Note: Template image is only supported on macOS.

To mark an image as a template image, its filename should end with the word Template. For example:

• xxxTemplate.png
• xxxTemplate@2x.png

Methods

The nativeImage class has the following methods:

nativeImage.createEmpty()

Creates an empty nativeImage instance.

nativeImage.createFromPath(path)

• path String

Creates a new nativeImage instance from a file located at path.

const nativeImage = require('electron').nativeImage;

let image = nativeImage.createFromPath('/Users/somebody/images/icon.png');

nativeImage.createFromBuffer(buffer[, scaleFactor])

• buffer Buffer
• scaleFactor Double (optional)

Creates a new nativeImage instance from buffer. The default scaleFactor is 1.0.

nativeImage.createFromDataURL(dataURL)

• dataURL String

Creates a new nativeImage instance from dataURL.

Instance Methods

The following methods are available on instances of nativeImage:

image.toPNG()

Returns a Buffer that contains the image's PNG encoded data.

image.toJPEG(quality)

• quality Integer (required) - Between 0 - 100.

Returns a Buffer that contains the image's JPEG encoded data.

image.toDataURL()

Returns the data URL of the image.

image.getNativeHandle() macOS

Returns a Buffer that stores C pointer to underlying native handle of the image. On macOS, a pointer to NSImage instance would be returned.

Notice that the returned pointer is a weak pointer to the underlying native image instead of a copy, so you must ensure that the associated nativeImage instance is kept around.

image.isEmpty()

Returns a boolean whether the image is empty.

image.getSize()

Returns the size of the image.

image.setTemplateImage(option)

• option Boolean

Marks the image as template image.

image.isTemplateImage()

Returns a boolean whether the image is a template image.