// Copyright 2017 The Fuchsia Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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library fuchsia.ui.gfx;
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// Reports metrics information.
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// This event type is only reported for node resources.
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const uint32 kMetricsEventMask = 1;
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const uint32 kSizeChangeHintEventMask = 2;
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// These are all of the types of events which can be reported by a |Session|.
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// Use |SetEventMaskCmd| to enable event delivery for a resource.
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union Event {
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// Events which are controlled by a mask.
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MetricsEvent metrics;
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SizeChangeHintEvent size_change_hint;
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// Events which are always delivered, regardless of mask.
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ImportUnboundEvent import_unbound;
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ViewConnectedEvent view_connected;
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ViewDisconnectedEvent view_disconnected;
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ViewHolderDisconnectedEvent view_holder_disconnected;
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ViewAttachedToSceneEvent view_attached_to_scene;
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ViewDetachedFromSceneEvent view_detached_from_scene;
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ViewPropertiesChangedEvent view_properties_changed;
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ViewStateChangedEvent view_state_changed;
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};
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// Provides rendering target metrics information about the specified node.
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//
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// This event is delivered when the following conditions are true:
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// - The node is a descendant of a |Scene|.
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// - The node has |kMetricsEventMask| set to an enabled state.
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// - The node's metrics have changed since they were last delivered, or since
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// |kMetricsEventMask| transitioned from a disabled state to an enabled state.
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//
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// Subscribe to this event to receive information about the scale factors you
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// should apply when generating textures for your nodes.
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struct MetricsEvent {
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uint32 node_id;
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Metrics metrics;
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};
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// Delivered in response to a size change hint from a parent node
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// (SendSizeChangeHintCmd).
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//
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// This event is delivered when the following conditions are true:
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// - The node has |kSizeChangeEventMask| set to an enabled state.
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// - A parent node has sent a SendSizeChangeHintCmd.
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//
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// Subscribe to this event to receive information about how large textures you
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// will need in the near future for your nodes. The canonical use case is to
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// pre-allocate memory to avoid repeated re-allocations.
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struct SizeChangeHintEvent {
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uint32 node_id;
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float32 width_change_factor;
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float32 height_change_factor;
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};
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// Delivered when the imported resource with the given ID is no longer bound to
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// its host resource, or if the imported resource can not be bound because
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// the host resource is not available.
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struct ImportUnboundEvent {
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uint32 resource_id;
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};
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// Delivered to a ViewHolder's Session when its peer View is connected.
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struct ViewConnectedEvent {
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uint32 view_holder_id;
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};
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// Delivered to a ViewHolder's Session when its peer View is disconnected or
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// destroyed.
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//
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// If the View is destroyed before the connection is established, then this
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// event will be delivered immediately when the ViewHolder attempts to connect.
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struct ViewDisconnectedEvent {
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uint32 view_holder_id;
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};
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// Delivered to a View's Session when its peer ViewHolder is disconnected or
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// destroyed.
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//
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// If the ViewHolder is destroyed before the connection is established, then
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// this event will be delivered immediately when the View attempts to connect.
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struct ViewHolderDisconnectedEvent {
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uint32 view_id;
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};
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// Delivered to a View's Session when the parent ViewHolder for the given View
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// becomes a part of a Scene.
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//
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// A ViewHolder is considered to be part of a Scene if there is an unbroken
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// chain of parent-child relationships between the Scene node and the
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// ViewHolder node.
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struct ViewAttachedToSceneEvent {
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uint32 view_id;
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ViewProperties properties;
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};
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// Delivered to a View's Session when the parent ViewHolder for the given View
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// is no longer part of a scene.
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//
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// This can happen if the ViewHolder is detached directly from the scene, or
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// if one of its parent nodes is.
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//
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// A ViewHolder is considered to be part of a Scene if there is an unbroken
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// chain of parent-child relationships between the Scene node and the
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// ViewHolder node.
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struct ViewDetachedFromSceneEvent {
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uint32 view_id;
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};
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// Delivered when the parent ViewHolder for the given View makes a change to
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// the View's properties.
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struct ViewPropertiesChangedEvent {
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uint32 view_id;
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ViewProperties properties;
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};
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// Delivered to a ViewHolder's Session when its peer View's state has changed.
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struct ViewStateChangedEvent {
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uint32 view_holder_id;
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ViewState state;
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};
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