Feature: flip yuv when it is front camera

Live/src/main/java/com/frank/live/camera/Camera2Helper.java

@@ -593,6 +593,10 @@ public class Camera2Helper {
                     } else {
                         YUVUtil.YUV420pRotate180(dstData, yuvData, width, height);
                     }
+                    // front camera need to flip
+                    if (CAMERA_ID_FRONT.equals(mCameraId)) {
+                        YUVUtil.flipYUV(dstData, width, height, rotation == 90, rotation == 180);
+                    }
                     if (camera2Listener != null) {
                         camera2Listener.onPreviewFrame(dstData);
                     }

Live/src/main/java/com/frank/live/util/YUVUtil.java

@@ -126,4 +126,29 @@ public class YUVUtil {
         }
     }
 
+    private static void swap(byte[] a, int i, int j) {
+        byte temp = a[i];
+        a[i] = a[j];
+        a[j] = temp;
+    }
+
+    public static void flipYUV(byte[] dst, int width, int height, boolean flipX, boolean flipY) {
+        if (dst == null || width <= 0 || height <= 0)
+            return;
+        if (flipY) {
+            for (int i=0; i<height; i++) {
+                for (int j=0; j<width/2; j++) {
+                    swap(dst, j, width - j - 1);
+                }
+            }
+        }
+        if (flipX) {
+            for (int i=0; i<width; i++) {
+                for (int j=0; j<height/2; j++) {
+                    swap(dst, j, height - j - 1);
+                }
+            }
+        }
+    }
+
 }

app/src/main/cpp/yuv/yuv_converter.cpp

@@ -28,7 +28,7 @@
 // U = (-38 * R - 74 * G + 112 * B) >> 8 + 128
 // V = (112 * R - 94 * G - 18 * B) >> 8 + 128
 
-static void rgba_to_yuv420p(int *argb, int8_t *yuv, int width, int height) {
+static void rgba_to_yuv420p(const int *argb, int8_t *yuv, int width, int height) {
     int frameSize = width * height;
     int index = 0;
     int yIndex = 0;

app/src/main/cpp/yuv/yuv_converter.h

@@ -7,7 +7,7 @@
 
 #include <cstdint>
 
-static void rgba_to_yuv420p(int *argb, int8_t *yuv, int width, int height);
+static void rgba_to_yuv420p(const int *argb, int8_t *yuv, int width, int height);
 
 static void yuv420p_to_argb(const int8_t *yuv, int *argb, int width, int height);