# Interface (Zoom)
<!--Kit: Camera Kit-->
<!--Subsystem: Multimedia-->
<!--Owner: @qano-->
<!--SE: @leo_ysl-->
<!--TSE: @xchaosioda-->

> **NOTE**
>
> - The initial APIs of this module are supported since API version 10. Newly added APIs will be marked with a superscript to indicate their earliest API version.
> - The initial APIs of this interface are supported since API version 11.

Zoom inherits from [ZoomQuery](arkts-apis-camera-ZoomQuery.md).

It provides APIs related to zoom operations.

## Modules to Import

```ts
import { camera } from '@kit.CameraKit';
```

## setZoomRatio<sup>11+</sup>

setZoomRatio(zoomRatio: number): void

Sets a zoom ratio, with a maximum precision of two decimal places.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name      | Type                 | Mandatory| Description                                                                                                                             |
| --------- | -------------------- | ---- |---------------------------------------------------------------------------------------------------------------------------------|
| zoomRatio | number               | Yes  | Zoom ratio. The supported zoom ratio range can be obtained by calling [getZoomRatioRange](arkts-apis-camera-ZoomQuery.md#getzoomratiorange11). If the value passed in is not within the supported range, the value within the precision range is retained.<br>It takes some time for the zoom ratio to take effect at the bottom layer. To obtain the correct zoom ratio, you need to wait for one to two frames.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400103                |  Session not config.                                   |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function setZoomRatio(photoSession: camera.PhotoSession, zoomRatioRange: Array<number>): void {
  if (zoomRatioRange === undefined || zoomRatioRange.length <= 0) {
    return;
  }
  let zoomRatio = zoomRatioRange[0];
  try {
    photoSession.setZoomRatio(zoomRatio);
  } catch (error) {
    // If the operation fails, error.code is returned and processed.
    let err = error as BusinessError;
    console.error(`The setZoomRatio call failed. error code: ${err.code}`);
  }
}
```

## getZoomRatio<sup>11+</sup>

getZoomRatio(): number

Obtains the zoom ratio in use.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Return value**

| Type       | Description                         |
| ---------- | ----------------------------- |
| number    | Zoom ratio obtained. If the operation fails, an error code defined in [CameraErrorCode](arkts-apis-camera-e.md#cameraerrorcode) is returned.|

**Error codes**

For details about the error codes, see [Camera Error Codes](errorcode-camera.md).

| ID        | Error Message       |
| --------------- | --------------- |
| 7400103                |  Session not config.                                   |
| 7400201                |  Camera service fatal error.                           |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function getZoomRatio(photoSession: camera.PhotoSession): number {
  const invalidValue: number = -1;
  let zoomRatio: number = invalidValue;
  try {
    zoomRatio = photoSession.getZoomRatio();
  } catch (error) {
    // If the operation fails, error.code is returned and processed.
    let err = error as BusinessError;
    console.error(`The getZoomRatio call failed. error code: ${err.code}`);
  }
  return zoomRatio;
}
```

## setSmoothZoom<sup>11+</sup>

setSmoothZoom(targetRatio: number, mode?: SmoothZoomMode): void

Sets smooth zoom.

**Atomic service API**: This API can be used in atomic services since API version 19.

**System capability**: SystemCapability.Multimedia.Camera.Core

**Parameters**

| Name      | Type           | Mandatory| Description              |
| ------------ | -------------- | ---- | ----------------- |
| targetRatio  | number         | Yes  | Target zoom ratio.     |
| mode         | [SmoothZoomMode](arkts-apis-camera-e.md#smoothzoommode11) | No  | Smooth zoom mode.     |

**Example**

```ts
import { BusinessError } from '@kit.BasicServicesKit';

function setSmoothZoom(sessionExtendsZoom: camera.Zoom, targetZoomRatio: number, mode: camera.SmoothZoomMode): void {
  sessionExtendsZoom.setSmoothZoom(targetZoomRatio, mode);
}
```