Class (PathIterator)

Implements a path operation iterator. You can read path operation instructions by traversing the iterator.

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.

The initial APIs of this class are supported since API version 18.

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';

constructor¹⁸⁺

constructor(path: Path)

Creates an iterator and binds it with a path.

System capability: SystemCapability.Graphics.Drawing

Parameters

Name	Type	Mandatory	Description
path	Path	Yes	Path object bound to the iterator.

Example

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

let path: drawing.Path = new drawing.Path();
let iter: drawing.PathIterator = new drawing.PathIterator(path);

next¹⁸⁺

next(points: Array<common2D.Point>, offset?: number): PathIteratorVerb

Retrieves the next operation in this path and moves the iterator to that operation.

System capability: SystemCapability.Graphics.Drawing

Parameters

Name	Type	Mandatory	Description
points	Array<common2D.Point>	Yes	Array of coordinate points. The array length must be at least the offset plus 4 to ensure that the array can hold all types of path data. After the operation is executed, this array is overwritten. The number of coordinate points to be filled depends on the operation type. Specifically, for MOVE, fill one coordinate; for LINE, fill two coordinates; for QUAD, fill three coordinates; for CONIC, fill three coordinates and one weight value (a total of 3.5 groups); for CUBIC, fill four coordinates; for CLOSE and DONE, do not fill any coordinate points.
offset	number	No	Offset from the start of the array where writing begins. The default value is 0. The value range is [0, size - 4], where size is the length of the coordinate point array.

Returns

Type	Description
PathIteratorVerb	Path operation type contained in the iterator.

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; 3. Parameter verification failed.

Example

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

let path: drawing.Path = new drawing.Path();
path.moveTo(10, 20);
let iter: drawing.PathIterator = new drawing.PathIterator(path);
let verbStr: Array<string> = ["MOVE", "LINE", "QUAD", "CONIC", "CUBIC", "CLOSE", "DONE"];
let pointCount: Array<number> = [1,2,3,4,4,0,0];
let points: Array<common2D.Point> = [{x: 0, y: 0}, {x: 0, y: 0}, {x: 0, y: 0}, {x: 0, y: 0}];
let offset = 0;
let verb = iter.next(points, offset);
let outputMessage: string = "pathIteratorNext: ";
outputMessage += "verb =" + verbStr[verb] + "; has " + pointCount[verb] + " pairs: ";
for (let j = 0; j < pointCount[verb] + offset; j++) {
  outputMessage += "[" + points[j].x + ", " + points[j].y + "]";
}
console.info(outputMessage);

peek¹⁸⁺

peek(): PathIteratorVerb

Retrieves the next operation in this path, without moving the iterator.

System capability: SystemCapability.Graphics.Drawing

Returns

Type	Description
PathIteratorVerb	Path operation type contained in the iterator.

Example

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

let path: drawing.Path = new drawing.Path();
let iter: drawing.PathIterator = new drawing.PathIterator(path);
let res = iter.peek();

hasNext¹⁸⁺

hasNext(): boolean

Checks whether there is any next operation in the path operation iterator.

System capability: SystemCapability.Graphics.Drawing

Returns

Type	Description
boolean	Check result. true means yes; false otherwise.

Example

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

let path: drawing.Path = new drawing.Path();
let iter: drawing.PathIterator = new drawing.PathIterator(path);
let res = iter.hasNext();