feat: 新增护眼距离和行走抖动检测提醒功能

app/src/main/java/com/aoleyun/sn/view/FaceOverlayView.java

@@ -0,0 +1,95 @@
+package com.aoleyun.sn.view;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.graphics.PointF;
+import android.util.AttributeSet;
+import android.view.View;
+
+import androidx.annotation.Nullable;
+
+import java.util.Locale;
+
+public class FaceOverlayView extends View {
+    private Paint pointPaint;
+    private Paint textPaint;
+    private PointF leftEye;
+    private PointF rightEye;
+    private double distance;
+    private int imageWidth;
+    private int imageHeight;
+
+    public FaceOverlayView(Context context) {
+        super(context);
+        init();
+    }
+
+    public FaceOverlayView(Context context, @Nullable AttributeSet attrs) {
+        super(context, attrs);
+        init();
+    }
+
+    private void init() {
+        pointPaint = new Paint();
+        pointPaint.setColor(Color.RED);
+        pointPaint.setStyle(Paint.Style.FILL);
+        pointPaint.setStrokeWidth(10f);
+
+        textPaint = new Paint();
+        textPaint.setColor(Color.YELLOW);
+        textPaint.setTextSize(60f);
+        textPaint.setFakeBoldText(true);
+        textPaint.setShadowLayer(5, 0, 0, Color.BLACK);
+    }
+
+    public void updateData(double distance, PointF leftEye, PointF rightEye, int imageWidth, int imageHeight) {
+        this.distance = distance;
+        this.leftEye = leftEye;
+        this.rightEye = rightEye;
+        this.imageWidth = imageWidth;
+        this.imageHeight = imageHeight;
+        postInvalidate();
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        super.onDraw(canvas);
+        if (leftEye == null || rightEye == null || imageWidth <= 0 || imageHeight <= 0) {
+            canvas.drawText("未检测到人脸", 50, 100, textPaint);
+            return;
+        }
+
+        // 1. 获取 View 的尺寸
+        float viewWidth = getWidth();
+        float viewHeight = getHeight();
+
+        // 2. 计算缩放比例 (适配 PreviewView 的 FILL_CENTER 逻辑)
+        // FILL_CENTER：取宽高缩放比例中较大的一个，使图像填满 View 且不拉伸，多出的部分被裁剪
+        float scale = Math.max(viewWidth / imageWidth, viewHeight / imageHeight);
+
+        // 3. 计算偏移量（由居中裁剪产生）
+        float postScaleWidth = imageWidth * scale;
+        float postScaleHeight = imageHeight * scale;
+        float offsetX = (viewWidth - postScaleWidth) / 2f;
+        float offsetY = (viewHeight - postScaleHeight) / 2f;
+
+        // 4. 坐标映射并处理镜像
+        // CameraX 的 PreviewView 显示前置摄像头时默认是镜像的
+        // 映射公式： viewX = viewWidth - (imageX * scale + offsetX)
+        float lx = viewWidth - (leftEye.x * scale + offsetX);
+        float ly = leftEye.y * scale + offsetY;
+        float rx = viewWidth - (rightEye.x * scale + offsetX);
+        float ry = rightEye.y * scale + offsetY;
+
+        // 绘制眼睛点位
+        canvas.drawCircle(lx, ly, 15, pointPaint);
+        canvas.drawCircle(rx, ry, 15, pointPaint);
+
+        // 绘制连线，更直观
+        canvas.drawLine(lx, ly, rx, ry, pointPaint);
+
+        canvas.drawText(String.format(Locale.getDefault(), "瞳距: %.2f", distance), 50, 100, textPaint);
+    }
+}