Android Camera开发入门第十篇：Camera2 zoom变焦

本文主要是介绍Android Camera开发入门第十篇：Camera2 zoom变焦，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

【小驰笔记】【Android Camera开发】【Android Camera2】【camera2】

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关于数码变焦，前面专门写过一篇文章：

https://mp.weixin.qq.com/s/XZzQytKVz-F0sUMW61FFRQ

一、获取支持的最大数码变焦倍数

CameraCharacteristics.SCALER_AVAILABLE_MAX_DIGITAL_ZOOM

二、请求裁剪范围

CaptureRequest.SCALER_CROP_REGION

三、示例代码

/*** 进行镜头缩放* @param zoom 缩放系数（0~1.0）**/
public void applyZoom(float zoom) {float old = mZoomValue;mZoomValue = zoom;if(mCameraCharacteristics != null){float maxZoom = mCameraCharacteristics.get(CameraCharacteristics.SCALER_AVAILABLE_MAX_DIGITAL_ZOOM);// converting 0.0f-1.0f zoom scale to the actual camera digital zoom scale// (which will be for example, 1.0-10.0)float calculatedZoom = (mZoomValue * (maxZoom - 1.0f)) + 1.0f;Rect newRect = getZoomRect(calculatedZoom, maxZoom);mPreviewBuilder.set(CaptureRequest.SCALER_CROP_REGION, newRect);mPreviewSession.setRepeatingRequest(mPreviewBuilder.build(), null, mBackgroundHandler);}}/*** 获取缩放矩形**/
private Rect getZoomRect(float zoomLevel, float maxDigitalZoom) {Rect activeRect = new Rect();activeRect = mCameraCharacteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);int minW = (int) (activeRect.width() / maxDigitalZoom);int minH = (int) (activeRect.height() / maxDigitalZoom);int difW = activeRect.width() - minW;int difH = activeRect.height() - minH;// When zoom is 1, we want to return new Rect(0, 0, width, height).// When zoom is maxZoom, we want to return a centered rect with minW and minHint cropW = (int) (difW * (zoomLevel - 1) / (maxDigitalZoom - 1) / 2F);int cropH = (int) (difH * (zoomLevel - 1) / (maxDigitalZoom - 1) / 2F);returnnew Rect(cropW, cropH, activeRect.width() - cropW,activeRect.height() - cropH);
}