SurfaceFinger layer创建过程

SurfaceFinger layer创建过程

引言

本篇博客重点分析app创建Surface时候，SurfaceFlinger是如何构建对应的Layer的主要工作有那些！

这里参考的Android源码是Android 13 aosp！

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app端创建Surface

其核心流程可以分为如下接部分:

• app使用w,h,format等参数，调用SurfaceComposerClient::createSurface

• createSurface调用SurfaceComposerClient::createSurfaceChecked；createSurfaceChecked调用mClient->createSurface；mClient是surfaceflinger client的代理；mClient的初始化还没介绍，后面单独写一篇介绍。

• mClient->createSurface会调用到android12\frameworks\native\services\surfaceflinger\Client.cpp 中Client::createSurface

• Client::createSurface调用mFlinger->createLayer

核心逻辑代码如下:

surfaceComposerClient->createSurface(String8("SurfaceTestDemo"), resolution.getWidth(),
                  resolution.getHeight(), PIXEL_FORMAT_RGBA_8888,
                  ISurfaceComposerClient::eFXSurfaceBufferState,
                  /*parent*/ nullptr);
                  
sp<SurfaceControl> SurfaceComposerClient::createSurface(const String8& name, uint32_t w, uint32_t h,
                                      PixelFormat format, uint32_t flags,
                                      const sp<IBinder>& parentHandle,
                                      LayerMetadata metadata,
                                      uint32_t* outTransformHint) {
   
    sp<SurfaceControl> s;
    createSurfaceChecked(name, w, h, format, &s, flags, parentHandle, std::move(metadata),
                         outTransformHint);
    return s;
}