实施相机的“轻按对焦"的正确方法是什么? [英] What's the correct way to implement Tap To Focus for camera?

问题描述

我正在开发一个具有自定义相机屏幕的应用程序，为此我应该对其进行轻拍对焦，例如Android(更具体地讲，Galaxy S4)相机应用程序.

I'm working on an app which has a custom camera screen, for which I'm supposed to implement tap to focus, like in the Android(more specifically, the Galaxy S4) camera app.

我尝试使用此处中概述的步骤，但是它似乎不会引起任何明显的聚焦.对焦模式设置为连续图片(我们仅支持特定设备).

I've tried using the steps outlined here, but it doesn't seem to cause any noticeable focusing. The Focus Mode is set to Continuous Picture(we are supporting only a specific device).

当用户点击相机预览时，我需要专注于图像的上半部分.为此，我使用代码片段

When the user taps on the camera preview, I need to be focusing on the top half of the image. For this, I use the code snippet

Parameters parameters = mCamera.getParameters();

if (parameters.getMaxNumFocusAreas() > 0) {

    ArrayList<Area> focusAreas = new ArrayList<Camera.Area>(1);
    focusAreas.add(new Area(new Rect(-1000, -1000, 1000, 0), 750));

    parameters.setFocusAreas(focusAreas);
    mCamera.setParameters(parameters);
}

我不希望使用自动对焦，因为对焦时间太长.我只对图像的上半部分感兴趣.有没有人成功实现了点按对焦和连续图片模式?

I do NOT want AutoFocus as it takes too long to focus on the image. I am interested only in the top half of the image. Has anybody successfully implemented Tap to Focus along with Continuous Picture mode?

推荐答案

最近涉及到此问题.正如MatheusJardimB所说，这个问题很有帮助.

Bumped into this issue recently. As MatheusJardimB said, this question helps a lot.

但是，就我而言，我想从ContinuousPicture模式开始，然后能够轻按以进行对焦，然后继续使用ContinuousPicture模式.

However, in my case, I wanted to start in the ContinuousPicture mode then be able to tap to focus and then continue with the ContinuousPicture mode.

我设法通过使用Camera.AutoFocusCallback()的onAutoFocus方法使其工作.我不确定这是最好的方法还是最漂亮的方法，但是它似乎有效.

I managed to get it to work by using the onAutoFocus method of the Camera.AutoFocusCallback(). I'm not sure if it's the best or the prettiest way of doing it, but it seems to work.

代码如下:

setOnTouchListener(new View.OnTouchListener() {         
    @Override
        public boolean onTouch(View v, MotionEvent event) {
            if (mCamera != null) {
                Camera camera = mCamera.getCamera();
                camera.cancelAutoFocus();
                Rect focusRect = calculateTapArea(event.getX(), event.getY(), 1f);

                Parameters parameters = camera.getParameters();
                parameters.setFocusMode(Parameters.FOCUS_MODE_MACRO);

                if (parameters.getMaxNumFocusAreas() > 0) {
                    List<Area> mylist = new ArrayList<Area>();
                    mylist.add(new Camera.Area(focusRect, 1000));
                    parameters.setFocusAreas(mylist);
                }

                camera.setParameters(parameters);
                camera.autoFocus(new Camera.AutoFocusCallback() {                   
                    @Override
                    public void onAutoFocus(boolean success, Camera camera) {
                        camera.cancelAutoFocus();
                        Parameters params = camera.getParameters();
                        if (!params.getFocusMode().equals(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
                            params.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
                            camera.setParameters(params);
                        }
                    }
                });
            }
            return true;
        }
        return false;
    });

您可以将焦点区域更改为

You could just change the focus area to

ArrayList<Area> focusAreas = new ArrayList<Camera.Area>(1);
focusAreas.add(new Area(new Rect(-1000, -1000, 1000, 0), 750));

它应该可以工作.

更新

我最近购买了三星S5并对其进行了测试.它不能很好地工作，所以我添加了一些修改，并且现在可以工作了.这也已在Galaxy S6和Galaxy Note4上成功测试.

I recently acquired a Samsung S5 and tested this out on it. It didn't work that well, so I added a few modifications and it's working now. This was also successfully tested on the Galaxy S6 and Galaxy Note4.

这是修改后的代码:

setOnTouchListener(new View.OnTouchListener() {
    @Override
    public boolean onTouch(View v, MotionEvent event) {
        if (mCamera != null) {
            Camera camera = mCamera.getCamera();
            camera.cancelAutoFocus();
            Rect focusRect = calculateTapArea(event.getX(), event.getY(), 1f);

            Parameters parameters = camera.getParameters();
            if (parameters.getFocusMode().equals(
                    Camera.Parameters.FOCUS_MODE_AUTO) {
                parameters.setFocusMode(Parameters.FOCUS_MODE_AUTO);
            }

            if (parameters.getMaxNumFocusAreas() > 0) {
                List<Area> mylist = new ArrayList<Area>();
                mylist.add(new Camera.Area(focusRect, 1000));
                parameters.setFocusAreas(mylist);
            }

            try {
                camera.cancelAutoFocus();
                camera.setParameters(parameters);
                camera.startPreview();
                camera.autoFocus(new Camera.AutoFocusCallback() {
                    @Override
                    public void onAutoFocus(boolean success, Camera camera) {
                        if (!camera.getParameters().getFocusMode().equals(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE)) {
                            Parameters parameters = camera.getParameters();
                            parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE);
                            if (parameters.getMaxNumFocusAreas() > 0) {
                                parameters.setFocusAreas(null);
                            }
                            camera.setParameters(parameters);
                            camera.startPreview();
                        }
                    }
                });
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return true;
    }
});

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