Camera框架
图片.png
Camera拍照流程
拍照采用ImageReader来作为中介保存图片例子参考android-Camera2Basic
首先是创建ImageReader
static void ImageReader_init(JNIEnv* env, jobject thiz, jobject weakThiz,
jint width, jint height, jint format, jint maxImages)
{
status_t res;
int nativeFormat;
android_dataspace nativeDataspace;
sp<JNIImageReaderContext> ctx(new JNIImageReaderContext(env, weakThiz, clazz, maxImages));
sp<IGraphicBufferProducer> gbProducer;
sp<IGraphicBufferConsumer> gbConsumer;
BufferQueue::createBufferQueue(&gbProducer, &gbConsumer); // 创建BufferQueue作为相机与 ImageReader的buffer
sp<BufferItemConsumer> bufferConsumer;
String8 consumerName = String8::format("ImageReader-%dx%df%xm%d-%d-%d",
width, height, format, maxImages, getpid(),
createProcessUniqueId());
uint32_t consumerUsage = GRALLOC_USAGE_SW_READ_OFTEN;
bufferConsumer = new BufferItemConsumer(gbConsumer, consumerUsage, maxImages,
/*controlledByApp*/true);
ctx->setBufferConsumer(bufferConsumer);
bufferConsumer->setName(consumerName);
ctx->setProducer(gbProducer);
bufferConsumer->setFrameAvailableListener(ctx); // 消费者是ImageReader，有新图像到来时会通知onFrameAvailable，再--> postEventFromNative --> App注册的Listener
ImageReader_setNativeContext(env, thiz, ctx);
ctx->setBufferFormat(nativeFormat);
ctx->setBufferDataspace(nativeDataspace);
ctx->setBufferWidth(width);
ctx->setBufferHeight(height);
// Set the width/height/format/dataspace to the bufferConsumer.
res = bufferConsumer->setDefaultBufferSize(width, height);
res = bufferConsumer->setDefaultBufferFormat(nativeFormat);
res = bufferConsumer->setDefaultBufferDataSpace(nativeDataspace);
}
图片.png
- 从上图可以看出Surface仅仅是个接口壳，多有的操作都是针对BufferQueue的
- BufferQueueCore中有个成员是mSlots，这个就是用来存放garlloc分配的buffer的handle，类型为
