nativeImage

使用 PNG 或 JPG 文件创建托盘、dock和应用程序图标。

进程： Main, Renderer

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.

例如, 创建托盘或设置窗口图标时, 你可以传递 String 格式的图片路径

const { BrowserWindow, Tray } = require('electron')
const appIcon = new Tray('/Users/somebody/images/icon.png')
const win = new BrowserWindow({ icon: '/Users/somebody/images/window.png' })
console.log(appIcon, win)

Or read the image from the clipboard, which returns a NativeImage:

const { clipboard, Tray } = require('electron')
const image = clipboard.readImage()
const appIcon = new Tray(image)
console.log(appIcon)

支持的格式

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. For best visual quality, it is recommended to include at least the following sizes in the:

• 小图标
  • 16x16 (100% DPI scale)
  • 20x20 (125% DPI scale)
  • 24x24 (150% DPI scale)
  • 32x32 (200% DPI scale)
• 大图标
  • 32x32 (100% DPI scale)
  • 40x40 (125% DPI scale)
  • 48x48 (150% DPI scale)
  • 64x64 (200% DPI scale)
  • 256x256

在这篇文章.aspx)中查看 尺寸说明 的章节

高分辨率

在具有高 DPI 支持的平台 (如 Apple 视网膜显示器) 上, 可以在图像的基本文件名之后追加 @ 2x 以将其标记为高分辨率图像。

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. 例如：

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

const { Tray } = require('electron')
const appIcon = new Tray('/Users/somebody/images/icon.png')
console.log(appIcon)

The following suffixes for DPI are also supported:

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

模板图片

Template images consist of black and an alpha channel. 模板图片不是单独使用的, 它通常与其他内容混合以创建期望的最终效果

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.

注意: 仅在 macOS 上支持Template image。

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

• xxxTemplate.png
• xxxTemplate@2x.png

方法

nativeImage 模块具有以下方法, 它们都返回 nativeImage 类的实例:

nativeImage.createEmpty()

返回 NativeImage

创建一个空的 NativeImage 实例。

nativeImage.createThumbnailFromPath(path, maxSize) macOS Windows

• path String - path to a file that we intend to construct a thumbnail out of.
• maxSize Size - the maximum width and height (positive numbers) the thumbnail returned can be. The Windows implementation will ignore maxSize.height and scale the height according to maxSize.width.

Returns Promise<NativeImage> - fulfilled with the file’s thumbnail preview image, which is a NativeImage.

nativeImage.createFromPath(path)

• path String

返回 NativeImage

从位于 path 的文件创建新的 NativeImage 实例。 如果 path 不存在，，无法读取或不是有效图像，方法将返回空图像, 。

const nativeImage = require('electron').nativeImage
const image = nativeImage.createFromPath('/Users/somebody/images/icon.png')
console.log(image)

nativeImage.createFromBitmap(buffer, options)

• buffer Buffer
• 选项 对象
  • width Integer
  • height Integer
  • scaleFactor Double (optional) - Defaults to 1.0.

返回 NativeImage

Creates a new NativeImage instance from buffer that contains the raw bitmap pixel data returned by toBitmap(). The specific format is platform-dependent.

nativeImage.createFromBuffer(buffer[, options])

• buffer Buffer
• options Object (可选)
  • width Integer (optional) - Required for bitmap buffers.
  • height Integer (optional) - Required for bitmap buffers.
  • scaleFactor Double (optional) - Defaults to 1.0.

返回 NativeImage

从 buffer 创建新的 NativeImage 实例。 Tries to decode as PNG or JPEG first.

nativeImage.createFromDataURL(dataURL)

• dataURL String

返回 NativeImage

从 dataURL 创建新的 NativeImage 实例。

nativeImage.createFromNamedImage(imageName[, hslShift]) macOS

• imageName String
• hslShift Number[] (optional)

返回 NativeImage

从映射到给定图像名称的 NSImage 创建一个 NativeImage 实例。 See System Icons for a list of possible values.

使用以下规则将hslShift应用于图像:

• hsl_shift[0] (hue): The absolute hue value for the image - 0 and 1 map to 0 and 360 on the hue color wheel (red).
• hsl_shift[1] (saturation): A saturation shift for the image, with the following key values: 0 = remove all color. 0.5 = 保持不变。 1 = fully saturate the image.
• hsl_shift[2] (lightness): A lightness shift for the image, with the following key values: 0 = remove all lightness (make all pixels black). 0.5 = 保持不变。 1 = 全亮 (所有像素点设置为白色)。

这意味着 [-1, 0, 1] 将使图像完全变白，[-1, 1, 0]将使图像完全变黑.

In some cases, the NSImageName doesn’t match its string representation; one example of this is NSFolderImageName, whose string representation would actually be NSFolder. Therefore, you’ll need to determine the correct string representation for your image before passing it in. This can be done with the following:

echo -e '#import <Cocoa/Cocoa.h>\nint main() { NSLog(@"%@", SYSTEM_IMAGE_NAME); }' | clang -otest -x objective-c -framework Cocoa - && ./test

where SYSTEM_IMAGE_NAME should be replaced with any value from this list.

类: NativeImage

本机图像，如托盘、dock栏和应用图标。

进程： Main, Renderer

实例方法

以下方法可用于 NativeImage 类的实例:

image.toPNG([options])

• options Object (可选)
  • scaleFactor Double (optional) - Defaults to 1.0.

返回 Buffer-一个包含图像 PNG 编码数据的 Buffer 。

image.toJPEG(quality)

• quality Integer - Between 0 - 100.

返回 Buffer-一个包含图像 JPEG 编码数据的 Buffer 。

image.toBitmap([options])

• options Object (可选)
  • scaleFactor Double (optional) - Defaults to 1.0.

返回 Buffer-一个包含图像的原始位图像素数据副本的 Buffer 。

image.toDataURL([options])

• options Object (可选)
  • scaleFactor Double (optional) - Defaults to 1.0.

返回 String-图像的数据 URL。

image.getBitmap([options])

• options Object (可选)
  • scaleFactor Double (optional) - Defaults to 1.0.

返回 Buffer-一个包含图像原始位图像素数据的 Buffer 。

The difference between getBitmap() and toBitmap() is that getBitmap() does not copy the bitmap data, so you have to use the returned Buffer immediately in current event loop tick; otherwise the data might be changed or destroyed.

image.getNativeHandle() macOS

返回 Buffer-一个 Buffer , 它将 C 指针存储在图像的基础本机句柄上。 在 macOS 上, 将返回指向 NSImage 实例的指针。

请注意, 返回的指针是指向基础本机映像而不是副本的弱指针, 因此 必须 确保关联的 nativeImage 实例保留在周围。

image.isEmpty()

返回 Boolean-图像是否为空。

image.getSize([scaleFactor])

• scaleFactor Double (optional) - Defaults to 1.0.

Returns Size.

If scaleFactor is passed, this will return the size corresponding to the image representation most closely matching the passed value.

image.setTemplateImage(option)

• option Boolean

将图像标记为模板图像。

image.isTemplateImage()

返回 Boolean-图像是否为模板图像。

image.crop(rect)

• rect Rectangle -要裁剪的图像区域.

返回 NativeImage-裁剪的图像。

image.resize(options)

• 选项 对象
  • width Integer (optional) - Defaults to the image’s width.
  • height Integer (可选) - 默认值为图片高度.
  • quality String (optional) - The desired quality of the resize image. Possible values are good, better, or best. 默认值为best. 这些值表示期望的 质量/速度 的权衡。 They are translated into an algorithm-specific method that depends on the capabilities (CPU, GPU) of the underlying platform. It is possible for all three methods to be mapped to the same algorithm on a given platform.

返回 NativeImage-裁剪的图像。

如果只指定height或width，那么当前的长宽比将保留在缩放图像中。

image.getAspectRatio([scaleFactor])

• scaleFactor Double (optional) - Defaults to 1.0.

返回 Float - 图像的长宽比.

If scaleFactor is passed, this will return the aspect ratio corresponding to the image representation most closely matching the passed value.

image.getScaleFactors()

Returns Float[] - An array of all scale factors corresponding to representations for a given nativeImage.

image.addRepresentation(options)

• 选项 对象
  • scaleFactor Double - The scale factor to add the image representation for.
  • width Integer (可选) - 默认值为 0. Required if a bitmap buffer is specified as buffer.
  • height Integer (可选) - 默认值为 0. Required if a bitmap buffer is specified as buffer.
  • buffer Buffer (可选) - 包含原始图像数据的缓冲区.
  • dataURL String (optional) - The data URL containing either a base 64 encoded PNG or JPEG image.

Add an image representation for a specific scale factor. This can be used to explicitly add different scale factor representations to an image. This can be called on empty images.

实例属性

nativeImage.isMacTemplateImage macOS

A Boolean property that determines whether the image is considered a template image.

Please note that this property only has an effect on macOS.