electron/docs/api/native-image.md

NativeImage

In Electron for the APIs that take images, you can pass either file paths or NativeImage instances. When passing null, an empty image will be used.

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

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

Or read the image from clipboard:

var clipboard = require('clipboard');
var image = clipboard.readImage();
var appIcon = new Tray(image);

Supported formats

Currently PNG and JPEG are supported, and it is recommended to use PNG because it supports alpha channel and image is usually not compressed.

High resolution image

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

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

If you want to support displays with different DPI denses at the same time, you can put images with different sizes in the same folder, and use the filename without DPI suffixes, like this:

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

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

Following suffixes as DPI denses 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 image for menu bar icon so it can adapt to both light and dark menu bars.

Template image is only supported on Mac.

To mark an image as template image, its filename should end with the word Template, examples are:

• xxxTemplate.png
• xxxTemplate@2x.png

nativeImage.createEmpty()

Creates an empty NativeImage instance.

nativeImage.createFromPath(path)

• path String

Creates a new NativeImage instance from file located at path.

nativeImage.createFromBuffer(buffer[, scaleFactor])

• buffer Buffer
• scaleFactor Double

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

nativeImage.createFromDataUrl(dataUrl)

• dataUrl String

Creates a new NativeImage instance from dataUrl.

Class: NativeImage

This class is used to represent an image.

NativeImage.toPng()

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

NativeImage.toJpeg(quality)

• quality Integer

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

NativeImage.toDataUrl()

Returns the data URL of image.

NativeImage.isEmpty()

Returns whether the image is empty.

NativeImage.getSize()

Returns the size of the image.

NativeImage.setTemplateImage(option)

• option Boolean

Marks the image as template image.