useful_android_code/cameraFocus.java at main · seohyunni/useful_android_code · GitHub

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public boolean onTouchEvent(MotionEvent event) {
        if (event.getPointerCount() == 1) {
            handleFocusMetering(event, mCamera);
        } else {
            switch (event.getAction() & MotionEvent.ACTION_MASK) {
                case MotionEvent.ACTION_POINTER_DOWN:
                    oldDist = getFingerSpacing(event);
                    break;
                case MotionEvent.ACTION_MOVE:
                    float newDist = getFingerSpacing(event);

                    oldDist = newDist;
                    break;
            }
        }
        return true;
    }

    private void handleFocusMetering(MotionEvent event, Camera camera) {
        int viewWidth = getWidth();
        int viewHeight = getHeight();
        Rect focusRect = calculateTapArea(event.getX(), event.getY(), 1f, viewWidth, viewHeight);
        Rect meteringRect = calculateTapArea(event.getX(), event.getY(), 1.5f, viewWidth, viewHeight);

        camera.cancelAutoFocus();
        Camera.Parameters params = camera.getParameters();
        if (params.getMaxNumFocusAreas() > 0) {
            List<Camera.Area> focusAreas = new ArrayList<>();
            focusAreas.add(new Camera.Area(focusRect, 800));
            params.setFocusAreas(focusAreas);
        } else {
            //focus areas not support
            return;
        }
        if (params.getMaxNumMeteringAreas() > 0) {
            List<Camera.Area> meteringAreas = new ArrayList<>();
            meteringAreas.add(new Camera.Area(meteringRect, 800));
            params.setMeteringAreas(meteringAreas);
        } else {
            //metering areas not support
            return;

        }

        if(params.getMaxNumFocusAreas() > 0 && params.getMaxNumMeteringAreas() > 0){
            final String currentFocusMode = params.getFocusMode();
            params.setFocusMode(Camera.Parameters.FOCUS_MODE_MACRO);
            camera.setParameters(params);

            camera.autoFocus(new Camera.AutoFocusCallback() {
                @Override
                public void onAutoFocus(boolean success, Camera camera) {
                    Camera.Parameters params = camera.getParameters();
                    params.setFocusMode(currentFocusMode);
                    camera.setParameters(params);
                    //focus mode = macro
                }
            });
        }

        else if(params.getMaxNumFocusAreas() ==0 && params.getMaxNumMeteringAreas()==0){
            return;
        }

        else{
            final String currentFocusMode = params.getFocusMode();
            params.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
            camera.setParameters(params);

            camera.autoFocus(new Camera.AutoFocusCallback() {
                @Override
                public void onAutoFocus(boolean success, Camera camera) {
                    Camera.Parameters params = camera.getParameters();
                    params.setFocusMode(currentFocusMode);
                    camera.setParameters(params);
                    //focus mode = auto
                }
            });
        }
    }

    private static float getFingerSpacing(MotionEvent event) {
        float x = event.getX(0) - event.getX(1);
        float y = event.getY(0) - event.getY(1);
        return (float) Math.sqrt(x * x + y * y);
    }

    private static Rect calculateTapArea(float x, float y, float coefficient, int width, int height) {
        float focusAreaSize = 300;
        int areaSize = Float.valueOf(focusAreaSize * coefficient).intValue();
        int centerX = (int) (x / width * 2000 - 1000);
        int centerY = (int) (y / height * 2000 - 1000);

        int halfAreaSize = areaSize / 2;
        RectF rectF = new RectF(clamp(centerX - halfAreaSize, -1000, 1000)
                , clamp(centerY - halfAreaSize, -1000, 1000)
                , clamp(centerX + halfAreaSize, -1000, 1000)
                , clamp(centerY + halfAreaSize, -1000, 1000));
        return new Rect(Math.round(rectF.left), Math.round(rectF.top), Math.round(rectF.right), Math.round(rectF.bottom));
    }

    private static int clamp(int x, int min, int max) {
        if (x > max) {
            return max;
        }
        if (x < min) {
            return min;
        }
        return x;
    }

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