harmony 鸿蒙拍照
拍照
拍照是相机的最重要功能之一,拍照模块基于相机复杂的逻辑,为了保证用户拍出的照片质量,在中间步骤可以设置分辨率、闪光灯、焦距、照片质量及旋转角度等信息。
开发步骤
详细的API说明请参考Camera API参考。
- 导入image接口。创建拍照输出流的SurfaceId以及拍照输出的数据,都需要用到系统提供的image接口能力,导入image接口的方法如下。
import image from '@ohos.multimedia.image';
import camera from '@ohos.multimedia.camera';
import { BusinessError } from '@ohos.base';
- 获取SurfaceId。
通过image的createImageReceiver方法创建ImageReceiver实例,再通过实例的getReceivingSurfaceId方法获取SurfaceId,与拍照输出流相关联,获取拍照输出流的数据。
async function getImageReceiverSurfaceId(): Promise<string|undefined> {
let photoSurfaceId: string|undefined = undefined;
let receiver: image.ImageReceiver = image.createImageReceiver(640, 480, 4, 8);
console.info('before ImageReceiver check');
if (receiver !== undefined) {
console.info('ImageReceiver is ok');
photoSurfaceId = await receiver.getReceivingSurfaceId();
console.info(`ImageReceived id: ${JSON.stringify(photoSurfaceId)}`);
} else {
console.info('ImageReceiver is not ok');
}
return photoSurfaceId;
}
- 创建拍照输出流。
通过CameraOutputCapability类中的photoProfiles()方法,可获取当前设备支持的拍照输出流,通过createPhotoOutput()方法传入支持的某一个输出流及步骤一获取的SurfaceId创建拍照输出流。
function getPhotoOutput(cameraManager: camera.CameraManager, cameraOutputCapability: camera.CameraOutputCapability, photoSurfaceId: string): camera.PhotoOutput|undefined {
let photoProfilesArray: Array<camera.Profile> = cameraOutputCapability.photoProfiles;
if (!photoProfilesArray) {
console.error("createOutput photoProfilesArray == null||undefined");
}
let photoOutput: camera.PhotoOutput|undefined = undefined;
try {
photoOutput = cameraManager.createPhotoOutput(photoProfilesArray[0], photoSurfaceId);
} catch (error) {
let err = error as BusinessError;
console.error(`Failed to createPhotoOutput. error: ${JSON.stringify(err)}`);
}
return photoOutput;
}
- 参数配置。
配置相机的参数可以调整拍照的一些功能,包括闪光灯、变焦、焦距等。
function configuringSession(captureSession: camera.CaptureSession): void {
// 判断设备是否支持闪光灯
let flashStatus: boolean = false;
try {
flashStatus = captureSession.hasFlash();
} catch (error) {
let err = error as BusinessError;
console.error(`Failed to hasFlash. error: ${JSON.stringify(err)}`);
}
console.info(`Promise returned with the flash light support status: ${flashStatus}`);
if (flashStatus) {
// 判断是否支持自动闪光灯模式
let flashModeStatus: boolean = false;
try {
let status: boolean = captureSession.isFlashModeSupported(camera.FlashMode.FLASH_MODE_AUTO);
flashModeStatus = status;
} catch (error) {
let err = error as BusinessError;
console.error(`Failed to check whether the flash mode is supported. error: ${JSON.stringify(err)}`);
}
if (flashModeStatus) {
// 设置自动闪光灯模式
try {
captureSession.setFlashMode(camera.FlashMode.FLASH_MODE_AUTO);
} catch (error) {
let err = error as BusinessError;
console.error(`Failed to set the flash mode. error: ${JSON.stringify(err)}`);
}
}
}
// 判断是否支持连续自动变焦模式
let focusModeStatus: boolean = false;
try {
let status: boolean = captureSession.isFocusModeSupported(camera.FocusMode.FOCUS_MODE_CONTINUOUS_AUTO);
focusModeStatus = status;
} catch (error) {
let err = error as BusinessError;
console.error(`Failed to check whether the focus mode is supported. error: ${JSON.stringify(err)}`);
}
if (focusModeStatus) {
// 设置连续自动变焦模式
try {
captureSession.setFocusMode(camera.FocusMode.FOCUS_MODE_CONTINUOUS_AUTO);
} catch (error) {
let err = error as BusinessError;
console.error(`Failed to set the focus mode. error: ${JSON.stringify(err)}`);
}
}
// 获取相机支持的可变焦距比范围
let zoomRatioRange: Array<number> = [];
try {
zoomRatioRange = captureSession.getZoomRatioRange();
} catch (error) {
let err = error as BusinessError;
console.error(`Failed to get the zoom ratio range. error: ${JSON.stringify(err)}`);
}
if (zoomRatioRange.length <= 0 ) {
return;
}
// 设置可变焦距比
try {
captureSession.setZoomRatio(zoomRatioRange[0]);
} catch (error) {
let err = error as BusinessError;
console.error(`Failed to set the zoom ratio value. error: ${JSON.stringify(err)}`);
}
}
- 触发拍照。
通过photoOutput类的capture()方法,执行拍照任务。该方法有两个参数,第一个参数为拍照设置参数的setting,setting中可以设置照片的质量和旋转角度,第二参数为回调函数。
function capture(captureLocation: camera.Location, photoOutput: camera.PhotoOutput): void {
let settings: camera.PhotoCaptureSetting = {
quality: camera.QualityLevel.QUALITY_LEVEL_HIGH, // 设置图片质量高
rotation: camera.ImageRotation.ROTATION_0, // 设置图片旋转角度0
location: captureLocation, // 设置图片地理位置
mirror: false // 设置镜像使能开关(默认关)
};
photoOutput.capture(settings, (err: BusinessError) => {
if (err) {
console.error(`Failed to capture the photo. error: ${JSON.stringify(err)}`);
return;
}
console.info('Callback invoked to indicate the photo capture request success.');
});
}
状态监听
在相机应用开发过程中,可以随时监听拍照输出流状态,包括拍照流开始、拍照帧的开始与结束、拍照输出流的错误。
- 通过注册固定的captureStart回调函数获取监听拍照开始结果,photoOutput创建成功时即可监听,拍照第一次曝光时触发,该事件返回此次拍照的captureId。
function onPhotoOutputCaptureStart(photoOutput: camera.PhotoOutput): void {
photoOutput.on('captureStart', (err: BusinessError, captureId: number) => {
console.info(`photo capture stated, captureId : ${captureId}`);
});
}
- 通过注册固定的captureEnd回调函数获取监听拍照结束结果,photoOutput创建成功时即可监听,该事件返回结果为拍照完全结束后的相关信息CaptureEndInfo。
function onPhotoOutputCaptureEnd(photoOutput: camera.PhotoOutput): void {
photoOutput.on('captureEnd', (err: BusinessError, captureEndInfo: camera.CaptureEndInfo) => {
console.info(`photo capture end, captureId : ${captureEndInfo.captureId}`);
console.info(`frameCount : ${captureEndInfo.frameCount}`);
});
}
- 通过注册固定的error回调函数获取监听拍照输出流的错误结果。callback返回拍照输出接口使用错误时的对应错误码,错误码类型参见CameraErrorCode。
function onPhotoOutputError(photoOutput: camera.PhotoOutput): void {
photoOutput.on('error', (error: BusinessError) => {
console.info(`Photo output error code: ${error.code}`);
});
}
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