79 lines
2.9 KiB
Swift
79 lines
2.9 KiB
Swift
// Copyright 2018-2020 Tokamak contributors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Created by Max Desiatov on 07/10/2018.
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//
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/** Renderer protocol that renderers for all platforms must implement.
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It's up to a specific renderer to provide an initializer with an arbitrary
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signature that works well for that platform. Methods required by this
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protocol are used by a reconciler (`StackReconciler` instance) to notify
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the renderer about updates in the view tree.
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*/
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public protocol Renderer: AnyObject {
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typealias Mounted = MountedElement<Self>
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typealias MountedHost = MountedHostView<Self>
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/** Views are rendered to platform-specific targets with a renderer.
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Usually a target is a simple view (`UIView` and `NSView` for `UIKit`
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and `AppKit` respectively).
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*/
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associatedtype TargetType: Target
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/** Function called by a reconciler when a new target instance should be
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created and added to the parent (either as a subview or some other way, e.g.
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installed if it's a layout constraint).
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- parameter parent: Parent target that will own a newly created target instance.
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- parameter view: The host view that renders to the newly created target.
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- returns: The newly created target.
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*/
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func mountTarget(
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before sibling: TargetType?,
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to parent: TargetType,
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with host: MountedHost
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) -> TargetType?
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/** Function called by a reconciler when an existing target instance should be
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updated.
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- parameter target: Existing target instance to be updated.
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- parameter view: The host view that renders to the updated target.
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*/
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func update(
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target: TargetType,
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with host: MountedHost
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)
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/** Function called by a reconciler when an existing target instance should be
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unmounted: removed from the parent and most likely destroyed.
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- parameter target: Existing target instance to be unmounted.
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- parameter parent: Parent of target to direct interaction with parent.
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- parameter task: The state associated with the unmount.
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*/
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func unmount(
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target: TargetType,
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from parent: TargetType,
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with task: UnmountHostTask<Self>
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)
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/** Returns a body of a given pritimive view, or `nil` if `view` is not a primitive view for
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this renderer.
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*/
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func primitiveBody(for view: Any) -> AnyView?
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/** Returns `true` if a given view type is a primitive view that should be deferred to this
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renderer.
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*/
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func isPrimitiveView(_ type: Any.Type) -> Bool
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}
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