Android系统Camera图片反转的一个问题
一、问题提出
目前遇到项目问题，Camera预览图像是反的，于是考虑设置180度反转以便正常。
通过如下两种方式：
params.setRotation(180); //java部分
p.set(CameraParameters::KEY_ROTATION,180); //C部分
发现应用部分takepicture出来数据都没有变化。
代码片段如下：
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
/*
Matrix matrix = new Matrix();
matrix.setRotate(180);
int width = bitmap.getWidth();
int height = bitmap.getHeight();
bitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
*/
File out = new File("/data/");
if (!out.exists()) {
out.mkdirs();
}
out = new File("/data/", "1.jpg");
try {
FileOutputStream outStream = new FileOutputStream(out);
bitmap.compress(CompressFormat.JPEG, 100, outStream);
outStream.close();
} catch (Exception e) {
e.printStackTrace();
}二、逐层排查
1.frameworks/av/services/camera/libcameraservice/CameraClient.cpp
void CameraClient::dataCallback(int32_t msgType,
const sp& dataPtr, camera_frame_metadata_t *metadata, void* user) {
int takepicture_fd;
takepicture_fd = open("/data/tankai.jpg",O_WRONLY|O_CREAT,00700);
ALOGD("TK---------->>>>JPEG,dataPtr->size() is %d,takepicture_fd is %d\n",dataPtr->size(),takepicture_fd);
ALOGD("TK---------->>>>JPEG,dataPtr->size() is 0x%x\n",dataPtr->pointer());
int write_len = write(takepicture_fd, dataPtr->pointer(), dataPtr->size());
close(takepicture_fd);
ALOGD("TK--------_>>>>>>ok\n");
} void Camera::dataCallback(int32_t msgType, const sp& dataPtr,
camera_frame_metadata_t *metadata)
{
int takepicture_fd;
takepicture_fd = open("/data/tankai_CPP.jpg",O_WRONLY|O_CREAT,00700);
ALOGD("TK---CPP------->>>>JPEG,dataPtr->size() is %d,takepicture_fd is %d\n",dataPtr->size(),takepicture_fd);
ALOGD("TK->>>>CPP---->>>>>dataPtr->pointer() is 0x%x",dataPtr->pointer());
int write_len = write(takepicture_fd, dataPtr->pointer(), dataPtr->size());
close(takepicture_fd);
ALOGD("TK---CPP-----_>>>>>>ok\n");
} void JNICameraContext::copyAndPost(JNIEnv* env, const sp& dataPtr, int msgType)
{
jbyteArray obj = NULL;
obj = env->NewByteArray(size);
//add by tankai
int takepicture_fd;
takepicture_fd = open("/data/tankai_jni2.jpg",O_WRONLY|O_CREAT,00700);
ALOGD("TK-------JNI2--->>>>JPEG,size is %d,takepicture_fd is %d\n",size,takepicture_fd);
ALOGD("TK----->>>>JNI2------>>>>>>data is 0x%x",data);
int write_len = write(takepicture_fd, data, size);
close(takepicture_fd);
ALOGD("TK----JNI2----_>>>>>>ok\n");
//end tankai
env->SetByteArrayRegion(obj, 0, size, data);
//add by tankai
takepicture_fd = open("/data/tankai_jni3.jpg",O_WRONLY|O_CREAT,00700);
ALOGD("TK-------JNI3--->>>>JPEG,size is %d,takepicture_fd is %d\n",size,takepicture_fd);
jbyte * olddata = (jbyte*)env->GetByteArrayElements(obj, 0);
char* bytearr = (char*)olddata;
ALOGD("TK----->>>>JNI3------>>>>>>obj is 0x%x,bytearr is 0x%x",obj,bytearr);
write_len = write(takepicture_fd, bytearr, size);
close(takepicture_fd);
ALOGD("TK----JNI3----_>>>>>>ok\n");
//end tankai
//调用mCameraJClass的fields.post_event方法，参数为后边的5个
env->CallStaticVoidMethod(mCameraJClass, fields.post_event,
mCameraJObjectWeak, msgType, 0, 0, obj);
} public void handleMessage(Message msg) {
case CAMERA_MSG_COMPRESSED_IMAGE:
//add by tankai
Log.d(TAG,"TK-------->>>>>>java callback");
Bitmap bitmap = BitmapFactory.decodeByteArray(((byte[])msg.obj), 0, ((byte[])msg.obj).length);
Log.d(TAG,"TK----->>>>((byte[])msg.obj) is 0x%x" + ((byte[])msg.obj));
String path = "/data/";
String fileName = "tankai_java.jpg";
File out = new File(path);
if (!out.exists()) {
out.mkdirs();
}
out = new File(path, fileName);
try {
FileOutputStream outStream = new FileOutputStream( out);
bitmap.compress(CompressFormat.JPEG, 100,outStream);
outStream.close();
Log.d(TAG,"TK-------->>>>>>java callback>>>>ok");
} catch (Exception e) {
Log.d(TAG,"TK-------->>>>>>java callback>>>>fail");
e.printStackTrace();
}
//end tankai
}三、原因
1.java部分使用bitmap存文件，没有直接保存；可能是这个原因。
2.修改应用程序中存JPEG文件的方式：
File ret = null;
BufferedOutputStream stream = null;
try {
ret = new File("/data/1.jpg");
FileOutputStream fstream = new FileOutputStream(ret);
stream = new BufferedOutputStream(fstream);
stream.write(data);
} catch (Exception e) {
// log.error("helper:get file from byte process error!");
e.printStackTrace();
} finally {
if (stream != null) {
try {
stream.close();
} catch (IOException e) {
// log.error("helper:get file from byte process error!");
e.printStackTrace();
}
}
}3.结论
问题出在bitmap转换上。
四、读取JPEG文件EXIF信息的ORIENTATION字段
1.源码
private int getBitmapDegree(String path) {
int degree = 0;
try {
// 从指定路径下读取图片，并获取其EXIF信息
ExifInterface exifInterface = new ExifInterface(path);
// 获取图片的旋转信息
int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION,
ExifInterface.ORIENTATION_NORMAL);
switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_90:
degree = 90;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
degree = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_270:
degree = 270;
break;
}
} catch (IOException e) {
e.printStackTrace();
}
return degree;
}
result = getBitmapDegree("/data/tankai_CPP.jpg");
Log.d("TKTK","TK------>>>>>>>/data/tankai_CPP is " + result);
result = getBitmapDegree("/data/tankai_jni.jpg");
Log.d("TKTK","TK------>>>>>>>/data/tankai_jni1 is " + result);
result = getBitmapDegree("/data/tankai_jni2.jpg");
Log.d("TKTK","TK------>>>>>>>/data/tankai_jni2 is " + result);
result = getBitmapDegree("/data/tankai_jni3.jpg");
Log.d("TKTK","TK------>>>>>>>/data/tankai_jni3 is " + result);
result = getBitmapDegree("/data/tankai_java.jpg");
Log.d("TKTK","TK------>>>>>>>/data/tankai_java is " + result);
result = getBitmapDegree("/data/1.jpg");
Log.d("TKTK","TK------>>>>>>>/data/1.jpg is " + result);正常显示时该字段为180，没有变正的该字段为0。
五、结论
Android系统中Camera拍照时setRotation在各个平台功能不统一：有些平台会直接操作图片的存储地址，将数据反写；但绝大多数平台只是修改了JPEG编码时EXIF头部的ORIENTATION字段。