Android Graphics模块中的各种State和重要类普法

Android Graphics模块中的各种State和重要类普法

引言

尼玛，这Android Graphics图形栈蛋疼啊，更新太快了。机会是每年一个版本，前进的胶布不能停啊，继续干。这边博客，我们的核心是理一理Android Graphics中各种State状态类。

这里分析的Android版本是Android 13 aosp！

一. Layer中State

先不解释，先直接上代码，后分析:

//frameworks/native/services/surfaceflinger/Layer.h
    //struct android::Layer::State
    struct State {
   
        Geometry active_legacy;
        Geometry requested_legacy;
        int32_t z;

        ui::LayerStack layerStack;

        uint32_t flags;
        uint8_t reserved[2];
        int32_t sequence; // changes when visible regions can change
        bool modified;

        // Crop is expressed in layer space coordinate.
        Rect crop;
        Rect requestedCrop;

        // the transparentRegion hint is a bit special, it's latched only
        // when we receive a buffer -- this is because it's "content"
        // dependent.
        Region activeTransparentRegion_legacy;
        Region requestedTransparentRegion_legacy;

        LayerMetadata metadata;

        // If non-null, a Surface this Surface's Z-order is interpreted relative to.
        wp<Layer> zOrderRelativeOf;
        bool isRelativeOf{
   false};

        // A list of surfaces whose Z-order is interpreted relative to ours.
        SortedVector<wp<Layer>> zOrderRelatives;

        half4 color;
        float cornerRadius;
        int backgroundBlurRadius;

        gui::WindowInfo inputInfo;
        wp<Layer> touchableRegionCrop;

        // dataspace is only used by BufferStateLayer and EffectLayer
        ui::Dataspace dataspace;

        // The fields below this point are only used by BufferStateLayer
        uint64_t frameNumber;
        uint32_t width;
        uint32_t height;
        ui::Transform transform;

        uint32_t bufferTransform;
        bool transformToDisplayInverse;

        Region transparentRegionHint;

        std::shared_ptr<renderengine::ExternalTexture> buffer;
        client_cache_t clientCacheId;
        sp<Fence> acquireFence;
        std::shared_ptr<FenceTime> acquireFenceTime;
        HdrMetadata hdrMetadata;
        Region surfaceDamageRegion;
        int32_t api;

        sp<NativeHandle> sidebandStream;
        mat4 colorTransform;
        bool hasColorTransf