harmony 鸿蒙@ohos.effectKit (Image Effects)

  • 2022-08-09
  • 浏览 (733)

@ohos.effectKit (Image Effects)

The EffectKit module provides basic image processing capabilities, including brightness adjustment, blurring, grayscale adjustment, and color picker.

This module provides the following classes:

  • Filter: a class that adds a specified effect to the image source.
  • Color: a class used to store the color picked.
  • ColorPicker: a smart color picker.

NOTE

The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import effectKit from '@ohos.effectKit';

effectKit.createEffect

createEffect(source: image.PixelMap): Filter

Creates a Filter instance based on a pixel map.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name Type Mandatory Description
source image.PixelMap Yes PixelMap instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see Image Overview.

Return value

Type Description
Filter Head node of the filter linked list without any effect. If the operation fails, null is returned.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  let headFilter = effectKit.createEffect(pixelMap);
})

effectKit.createColorPicker

createColorPicker(source: image.PixelMap): Promise<ColorPicker>

Creates a ColorPicker instance based on a pixel map. This API uses a promise to return the result.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name Type Mandatory Description
source image.PixelMap Yes PixelMap instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see Image Overview.

Return value

Type Description
Promise<ColorPicker> Promise used to return the ColorPicker instance created.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}

image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap).then(colorPicker => {
    console.info("color picker=" + colorPicker);
  }).catch( (reason : BusinessError) => {
    console.error("error=" + reason.message);
  })
})

effectKit.createColorPicker10+

createColorPicker(source: image.PixelMap, region: Array<number>): Promise<ColorPicker>

Creates a ColorPicker instance for the selected region based on a pixel map. This API uses a promise to return the result.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name Type Mandatory Description
source image.PixelMap Yes PixelMap instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see Image Overview.
region Array<number> Yes Region of the image from which the color is picked.
The array consists of four elements, representing the left, top, right, and bottom positions of the image, respectively. The value of each element must be in the range [0, 1]. The leftmost and topmost positions of the image correspond to 0, and the rightmost and bottom positions correspond to 1. In the array, the third element must be greater than the first element, and the fourth element must be greater than the second element.
If no value is passed, the default value [0, 0, 1, 1] is used, indicating that the color region is the entire image.

Return value

Type Description
Promise<ColorPicker> Promise used to return the ColorPicker instance created.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}

image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap).then(colorPicker => {
    console.info("color picker=" + colorPicker);
  }).catch( (reason : BusinessError) => {
    console.error("error=" + reason.message);
  })
})

effectKit.createColorPicker

createColorPicker(source: image.PixelMap, callback: AsyncCallback<ColorPicker>): void

Creates a ColorPicker instance based on a pixel map. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name Type Mandatory Description
source image.PixelMap Yes PixelMap instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see Image Overview.
callback AsyncCallback<ColorPicker> Yes Callback used to return the ColorPicker instance created.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
    }
  })
})

effectKit.createColorPicker10+

createColorPicker(source: image.PixelMap, region:Array<number>, callback: AsyncCallback<ColorPicker>): void

Creates a ColorPicker instance for the selected region based on a pixel map. This API uses an asynchronous callback to return the result.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name Type Mandatory Description
source image.PixelMap Yes PixelMap instance created by the image module. An instance can be obtained by decoding an image or directly created. For details, see Image Overview.
region Array<number> Yes Region of the image from which the color is picked.
The array consists of four elements, representing the left, top, right, and bottom positions of the image, respectively. The value of each element must be in the range [0, 1]. The leftmost and topmost positions of the image correspond to 0, and the rightmost and bottom positions correspond to 1. In the array, the third element must be greater than the first element, and the fourth element must be greater than the second element.
If no value is passed, the default value [0, 0, 1, 1] is used, indicating that the color region is the entire image.
callback AsyncCallback<ColorPicker> Yes Callback used to return the ColorPicker instance created.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
    }
  })
})

Color

A class that stores the color picked.

System capability: SystemCapability.Multimedia.Image.Core

Name Type Readable Writable Description
red number Yes No Value of the red component. The value range is [0x0, 0xFF].
green number Yes No Value of the green component. The value range is [0x0, 0xFF].
blue number Yes No Value of the blue component. The value range is [0x0, 0xFF].
alpha number Yes No Value of the alpha component. The value range is [0x0, 0xFF].

ColorPicker

A class used to obtain the color from an image. Before calling any method of ColorPicker, use createColorPicker to create a ColorPicker instance.

getMainColor

getMainColor(): Promise<Color>

Obtains the main color from the image and writes the result to a Color instance. This API uses a promise to return the result.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type Description
Promise<Color> Promise used to return the color value of the main color. If the operation fails, an error message is returned.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

export function test06(): void {
  const color = new ArrayBuffer(96);
  let opts: image.InitializationOptions = {
    editable: true,
    pixelFormat: 3,
    size: {
      height: 4,
      width: 6
    }
  }
  image.createPixelMap(color, opts).then((pixelMap) => {
    effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
      if (error) {
        console.log('Failed to create color picker.');
      } else {
        console.log('Succeeded in creating color picker.');
        colorPicker.getMainColor().then(color => {
          console.log('Succeeded in getting main color.');
          console.info(`color[ARGB]=${color.alpha},${color.red},${color.green},${color.blue}`);
        })
      }
    })
  })
}

getMainColorSync

getMainColorSync(): Color

Obtains the main color from the image and writes the result to a Color instance. This API returns the result in synchronous mode.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type Description
Color Color value of the main color. If the operation fails, null is returned.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let color = colorPicker.getMainColorSync();
      console.log('get main color =' + color);
    }
  })
})

en-us_image_Main_Color.png

getLargestProportionColor10+

getLargestProportionColor(): Color

Obtains the color with the largest proportion from the image and writes the result to a Color instance. This API returns the result in synchronous mode.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type Description
Color Color value of the color with the largest proportion. If the operation fails, null is returned.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let color = colorPicker.getLargestProportionColor();
      console.log('get largest proportion color =' + color);
    }
  })
})

en-us_image_Largest_Proportion_Color.png

getHighestSaturationColor10+

getHighestSaturationColor(): Color

Obtains the color with the highest saturation from the image and writes the result to a Color instance. This API returns the result in synchronous mode.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type Description
Color Color value of the color with the highest saturation. If the operation fails, null is returned.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts: image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let color = colorPicker.getHighestSaturationColor();
      console.log('get highest saturation color =' + color);
    }
  })
})

en-us_image_Highest_Saturation_Color.png

getAverageColor10+

getAverageColor(): Color

Obtains the average color from the image and writes the result to a Color instance. This API returns the result in synchronous mode.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type Description
Color Average color value. If the operation fails, null is returned.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts: image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let color = colorPicker.getAverageColor();
      console.log('get average color =' + color);
    }
  })
})

en-us_image_Average_Color.png

isBlackOrWhiteOrGrayColor10+

isBlackOrWhiteOrGrayColor(color: number): boolean

Checks whether a color is black, white, and gray.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name Type Mandatory Description
color number Yes Color to check. The value range is [0x0, 0xFFFFFFFF].

Return value

Type Description
boolean Returns true if the image is black, white, and gray; returns false otherwise.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts: image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
}
image.createPixelMap(color, opts).then((pixelMap) => {
  effectKit.createColorPicker(pixelMap, (error, colorPicker) => {
    if (error) {
      console.log('Failed to create color picker.');
    } else {
      console.log('Succeeded in creating color picker.');
      let bJudge = colorPicker.isBlackOrWhiteOrGrayColor(0xFFFFFFFF);
      console.log('is black or white or gray color[bool](white) =' + bJudge);
    }
  })
})

Filter

A class used to add a specified effect to an image. Before calling any method of Filter, use createEffect to create a Filter instance.

blur

blur(radius: number): Filter

Adds the blur effect to the filter linked list, and returns the head node of the linked list.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name Type Mandatory Description
radius number Yes Blur radius, in pixels. The blur effect is proportional to the configured value. A larger value indicates a more obvious effect.

Return value

Type Description
Filter Final image effect.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
};
image.createPixelMap(color, opts).then((pixelMap) => {
  let radius = 5;
  let headFilter = effectKit.createEffect(pixelMap);
  if (headFilter != null) {
    headFilter.blur(radius);
  }
})

en-us_image_Add_Blur.png

brightness

brightness(bright: number): Filter

Adds the brightness effect to the filter linked list, and returns the head node of the linked list.

System capability: SystemCapability.Multimedia.Image.Core

Parameters

Name Type Mandatory Description
bright number Yes Brightness value, ranging from 0 to 1. When the value is 0, the image brightness remains unchanged.

Return value

Type Description
Filter Final image effect.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
};
image.createPixelMap(color, opts).then((pixelMap) => {
  let bright = 0.5;
  let headFilter = effectKit.createEffect(pixelMap);
  if (headFilter != null) {
    headFilter.brightness(bright);
  }
})

en-us_image_Add_Brightness.png

grayscale

grayscale(): Filter

Adds the grayscale effect to the filter linked list, and returns the head node of the linked list.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type Description
Filter Final image effect.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
};
image.createPixelMap(color, opts).then((pixelMap) => {
  let headFilter = effectKit.createEffect(pixelMap);
  if (headFilter != null) {
    headFilter.grayscale();
  }
})

en-us_image_Add_Grayscale.png

getPixelMap

getPixelMap(): image.PixelMap

Obtains image.PixelMap of the source image to which the filter linked list is added.

System capability: SystemCapability.Multimedia.Image.Core

Return value

Type Description
image.PixelMap image.PixelMap of the source image.

Example

import image from "@ohos.multimedia.image";
import effectKit from "@ohos.effectKit";

const color = new ArrayBuffer(96);
let opts : image.InitializationOptions = {
  editable: true,
  pixelFormat: 3,
  size: {
    height: 4,
    width: 6
  }
};
image.createPixelMap(color, opts).then((pixelMap) => {
  let pixel = effectKit.createEffect(pixelMap).grayscale().getPixelMap();
  console.log('getPixelBytesNumber = ', pixel.getPixelBytesNumber());
})

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