Class (TextBlob)

Defines a block consisting of one or more characters with the same font.

NOTE

The initial APIs of this module are supported since API version 11. Newly added APIs will be marked with a superscript to indicate their earliest API version.

This module uses the physical pixel unit, px.

The module operates under a single-threaded model. The caller needs to manage thread safety and context state transitions.

Modules to Import

import { drawing } from '@kit.ArkGraphics2D';

makeFromPosText¹²⁺

static makeFromPosText(text: string, len: number, points: common2D.Point[], font: Font): TextBlob

Creates a TextBlob object from the text. The coordinates of each font in the TextBlob object are determined by the coordinate information in the points array.

System capability: SystemCapability.Graphics.Drawing

Parameters

Name	Type	Mandatory	Description
text	string	Yes	Content to be used for drawing the text blob.
len	number	Yes	Number of glyphs, which is an integer obtained from countText.
points	common2D.Point[]	Yes	Array of points, which are used to specify the coordinates of each font. The array length must be the same as the value of len.
font	Font	Yes	Font object.

Returns

Type	Description
TextBlob	TextBlob object.

Error codes

For details about the error codes, see Universal Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified;2. Incorrect parameter types.

Example

import { RenderNode } from '@kit.ArkUI';
import { drawing,common2D} from '@kit.ArkGraphics2D';

class DrawingRenderNode extends RenderNode {
  draw(context : DrawContext) {
    const canvas = context.canvas;
    let text : string = 'makeFromPosText';
    let font : drawing.Font = new drawing.Font();
    font.setSize(100);
    let length = font.countText(text);
    let points : common2D.Point[] = [];
    for (let i = 0; i !== length; ++i) {
      points.push({ x: i * 35, y: i * 35 });
    }
    let textblob : drawing.TextBlob =drawing.TextBlob.makeFromPosText(text, points.length, points, font);
    canvas.drawTextBlob(textblob, 100, 100);
  }
}

uniqueID¹²⁺

uniqueID(): number

Obtains the unique, non-zero identifier of this TextBlob object.

System capability: SystemCapability.Graphics.Drawing

Returns

Type	Description
number	Unique, non-zero identifier of this TextBlob object.

Example

import {drawing} from "@kit.ArkGraphics2D";

let text : string = 'TextBlobUniqueId';
let font : drawing.Font = new drawing.Font();
font.setSize(100);
let textBlob = drawing.TextBlob.makeFromString(text, font, 0);
let id = textBlob.uniqueID();
console.info("uniqueID---------------" +id);

makeFromString

static makeFromString(text: string, font: Font, encoding?: TextEncoding): TextBlob

Converts a value of the string type into a TextBlob object.

System capability: SystemCapability.Graphics.Drawing

Parameters

Name	Type	Mandatory	Description
text	string	Yes	Content to be used for drawing the text blob.
font	Font	Yes	Font object.
encoding	TextEncoding	No	Encoding type. The default value is TEXT_ENCODING_UTF8. Currently, only TEXT_ENCODING_UTF8 takes effect, and other encoding types are treated as TEXT_ENCODING_UTF8.

Returns

Type	Description
TextBlob	TextBlob object.

Error codes

For details about the error codes, see Universal Error Codes.

ID	Error Message
401	Parameter error.Possible causes:1.Mandatory parameters are left unspecified;2.Incorrect parameter types.

Example

import { RenderNode } from '@kit.ArkUI';
import { drawing } from '@kit.ArkGraphics2D';

class DrawingRenderNode extends RenderNode {
  draw(context : DrawContext) {
    const canvas = context.canvas;
    const brush = new drawing.Brush();
    brush.setColor({alpha: 255, red: 255, green: 0, blue: 0});
    const font = new drawing.Font();
    font.setSize(20);
    const textBlob = drawing.TextBlob.makeFromString("drawing", font, drawing.TextEncoding.TEXT_ENCODING_UTF8);
    canvas.attachBrush(brush);
    canvas.drawTextBlob(textBlob, 20, 20);
    canvas.detachBrush();
  }
}

makeFromRunBuffer

static makeFromRunBuffer(pos: Array<TextBlobRunBuffer>, font: Font, bounds?: common2D.Rect): TextBlob

Creates a TextBlob object based on the RunBuffer information.

System capability: SystemCapability.Graphics.Drawing

Parameters

Name	Type	Mandatory	Description
pos	Array<TextBlobRunBuffer>	Yes	TextBlobRunBuffer array.
font	Font	Yes	Font object.
bounds	common2D.Rect	No	Bounding box. If this parameter is not set, there is no bounding box.

Returns

Type	Description
TextBlob	TextBlob object.

Error codes

For details about the error codes, see Universal Error Codes.

ID	Error Message
401	Parameter error.Possible causes:1.Mandatory parameters are left unspecified;2.Incorrect parameter types.

Example

import { RenderNode } from '@kit.ArkUI';
import { common2D, drawing } from '@kit.ArkGraphics2D';

class DrawingRenderNode extends RenderNode {
  draw(context : DrawContext) {
    const canvas = context.canvas;
    const font = new drawing.Font();
    font.setSize(20);
    let runBuffer : Array<drawing.TextBlobRunBuffer> = [
      { glyph: 65, positionX: 0, positionY: 0 },
      { glyph: 227, positionX: 14.9, positionY: 0 },
      { glyph: 283, positionX: 25.84, positionY: 0 },
      { glyph: 283, positionX: 30.62, positionY: 0 },
      { glyph: 299, positionX: 35.4, positionY: 0}
    ];
    const textBlob = drawing.TextBlob.makeFromRunBuffer(runBuffer, font, null);
    const brush = new drawing.Brush();
    brush.setColor({alpha: 255, red: 255, green: 0, blue: 0});
    canvas.attachBrush(brush);
    canvas.drawTextBlob(textBlob, 20, 20);
    canvas.detachBrush();
  }
}

bounds

bounds(): common2D.Rect

Obtains the rectangular bounding box of the text blob.

System capability: SystemCapability.Graphics.Drawing

Returns

Type	Description
common2D.Rect	Rectangular bounding box.

Example

import { common2D, drawing } from '@kit.ArkGraphics2D';

const font = new drawing.Font();
font.setSize(20);
const textBlob = drawing.TextBlob.makeFromString("drawing", font, drawing.TextEncoding.TEXT_ENCODING_UTF8);
let bounds = textBlob.bounds();