// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
module viz.mojom;
import "cc/mojom/element_id.mojom";
import "cc/mojom/layer_type.mojom";
import "skia/public/mojom/skcolor4f.mojom";
import "ui/gfx/geometry/mojom/geometry.mojom";
import "ui/gfx/mojom/transform.mojom";
// Details about a cc::LayerImpl that has been added to a tree or modified in
// some interesting way since a prior tree update.
struct Layer {
// The layer's assigned ID. This is an arbitrary integer value which is
// guaranteed to be (a) unique across all layers currently in the tree and
// (b) consistent for the lifetime of each layer. When a LayerTreeUpdate
// contains a Layer with a previously unseen ID, the Layer is being added to
// the tree; otherwise an existing layer's properties are changing.
int64 id;
// The type of this layer. If this structure is updating an existing layer,
// the type here must match that of the existing layer.
cc.mojom.LayerType type;
// Bounds of the layer, generally in layer space. If this is the root layer,
// bounds are in viewport space, including device scale factor.
gfx.mojom.Size bounds;
// Optimization hints indicating whether the layer is fully opaque, or at
// least opaque wherever text is drawn.
bool contents_opaque;
bool contents_opaque_for_text;
// Indicates whether the layer produces any visual output for the compositor.
bool is_drawable;
// The background color (and safe opaque background color) used by this Layer.
// See comments for equivalent fields on cc::Layer.
skia.mojom.SkColor4f background_color;
skia.mojom.SkColor4f safe_opaque_background_color;
// Optional stable identifier that may be referenced in property trees and
// animations. Identifies a client-side object which can be represented by
// multiple layers over time but only by a single layer at once.
cc.mojom.ElementId? element_id;
// Current cumulative dirty rect for the layer since last update, in layer
// space.
gfx.mojom.Rect update_rect;
// The post-transform position of this layer.
gfx.mojom.Vector2dF offset_to_transform_parent;
// Property tree node IDs. Each of these IDs is bound to the range [0, N) for
// a property tree with N nodes.
int32 transform_tree_index;
int32 clip_tree_index;
int32 effect_tree_index;
int32 scroll_tree_index;
};
// See blink::AnchorPositionScrollData, from which the fields here are derived.
struct AnchorPositionScrollData {
array<cc.mojom.ElementId> adjustment_container_ids;
gfx.mojom.Vector2d accumulated_scroll_origin;
bool needs_scroll_adjustment_in_x;
bool needs_scroll_adjustment_in_y;
};
// See blink::StickyPositionScrollingConstraints for documentation on this data.
struct StickyPositionNodeData {
// Must be a valid index into the scroll tree.
int32 scroll_ancestor;
// Additional fields derived from StickyPositionScrollingConstraints.
bool is_anchored_left;
bool is_anchored_right;
bool is_anchored_top;
bool is_anchored_bottom;
float left_offset;
float right_offset;
float top_offset;
float bottom_offset;
gfx.mojom.RectF constraint_box_rect;
gfx.mojom.RectF scroll_container_relative_sticky_box_rect;
gfx.mojom.RectF scroll_container_relative_containing_block_rect;
int32 nearest_node_shifting_sticky_box;
int32 nearest_node_shifting_containing_block;
gfx.mojom.Vector2dF total_sticky_box_sticky_offset;
gfx.mojom.Vector2dF total_containing_block_sticky_offset;
};
// Updates to a transform tree, not including the nodes themselves. These
// correspond to data members of cc::TransformTree.
struct TransformTreeUpdate {
float page_scale_factor;
float device_scale_factor;
float device_transform_scale_factor;
array<int32> nodes_affected_by_outer_viewport_bounds_delta;
array<StickyPositionNodeData> sticky_position_data;
array<AnchorPositionScrollData> anchor_position_scroll_data;
};
// Details about a new or updated node within a transform property tree.
struct TransformNode {
// The ID of this node. Must be in the range [0, N) for a transform tree with
// N nodes.
int32 id;
// The ID of the parent node. Must be in the range [0, N) for a transform tree
// with N nodes, or -1 if this is the root node.
int32 parent_id;
// The ID of the nearest ancestor node in the tree which corresponds to the
// root of a visible frame. Must be in the range [0, N) for a transform tree
// with N nodes, or -1 if no ancestor is desginated as a frame root by the
// client. May be the same as `id`.
int32 parent_frame_id;
// The stable ElementId of the client-side object to which this transform node
// applies.
cc.mojom.ElementId? element_id;
// Actual transformation parameters for this node. See cc::TransformNode.
gfx.mojom.Transform local;
gfx.mojom.Point3F origin;
gfx.mojom.Vector2dF post_translation;
gfx.mojom.PointF scroll_offset;
gfx.mojom.Vector2dF snap_amount;
// Optional index into the tree's sticky position constraint data.
uint32? sticky_position_constraint_id;
// Optional index into the tree's anchor position scroll data.
uint32? anchor_position_scroll_data_id;
// Arbitrary rendering context ID for sorting. This affects draw order within
// the layer tree relative to other nodes with sorting context IDs. Does not
// need to be validated.
int32 sorting_context_id;
// Flags reflecting client-side changes to transform state. These all
// correspond to equivalent flags on cc::TransformNode.
bool needs_local_transform_update;
bool has_potential_animation;
bool is_currently_animating;
bool flattens_inherited_transform;
bool scrolls;
bool should_undo_overscroll;
bool should_be_snapped;
bool moved_by_outer_viewport_bounds_delta_y;
bool in_subtree_of_page_scale_layer;
bool transform_changed;
bool delegates_to_parent_for_backface;
bool will_change_transform;
// The stable ElementId of the client-side object (e.g. document, in Blink)
// corresponding to this node, if this node corresponds to the root of a
// visible frame.
cc.mojom.ElementId? visible_frame_element_id;
};
// Details about a new or updated node within a clip property tree.
struct ClipNode {
// The ID of this node. Must be in the range [0, N) for a clip tree with N
// nodes.
int32 id;
// The ID of the parent node. Must be in the range [0, N) for a clip tree with
// N nodes, or -1 if this is the root node.
int32 parent_id;
// The ID of this clip node's corresponding transform node within the
// transform tree. Must be in the range [0, N) for a transform tree with N
// nodes.
int32 transform_id;
// The clip rectangle for this node, in the space of the corresponding
// transform node.
gfx.mojom.RectF clip;
// The ID of this node's pixel-moving filter in the effect tree, or -1.
int32 pixel_moving_filter_id;
};
// Details about a new or updated node within an effect property tree.
struct EffectNode {
// The ID of this node. Must be in the range [0, N) for an effect tree with N
// nodes.
int32 id;
// The ID of the parent node. Must be in the range [0, N) for an effect tree
// with N nodes, or -1 if this is the root node.
int32 parent_id;
// The ID of this effect node's corresponding transform node within the
// transform tree. Must be in the range [0, N) for a transform tree with N
// nodes.
int32 transform_id;
// The ID of this effect node's corresponding clip node within the clip tree.
// Must be in the range [0, N) for a clip tree with N nodes.
int32 clip_id;
// The stable ElementId of the client-side object to which this effect node
// applies.
cc.mojom.ElementId? element_id;
// The opacity of drawn layers associated with this effect node.
float opacity;
// TODO(rockot): Replace this with a RenderSurfaceReason enumeration. In
// practice the specific reason is only useful for metrics, and for now all we
// need is to know whether or not the reason is kNone.
bool has_render_surface;
// Scale applied to the contents of the render surface. Ignored if this node
// doesn't induce a render surface.
gfx.mojom.Vector2dF surface_contents_scale;
// This is an SkBlendMode, which has no mojom definition yet. Must be manually
// validated to be no greater than SkBlendMode::kLastMode.
uint32 blend_mode;
// The index of the ancestor EffectNode which induces a render surface. Must
// be a valid index in the same effect tree.
int32 target_id;
};
// Details about a new or updated node within a scroll property tree.
struct ScrollNode {
// The ID of this node. Must be in the range [0, N) for a scroll tree with N
// nodes.
int32 id;
// The ID of the parent node. Must be in the range [0, N) for a scroll tree
// with N nodes, or -1 if this is the root node.
int32 parent_id;
// The ID of this scroll node's corresponding transform node within the
// transform tree. Must be in the range [0, N) for a transform tree with N
// nodes.
int32 transform_id;
// The bounds of the scrollable container in which the scroll node's content
// resides. This does not include non-overlay scrollbar footprint.
gfx.mojom.Size container_bounds;
// The size of the content scrolled within the node's scrollable container.
gfx.mojom.Size bounds;
// The stable ElementId of the scrollable client-side object to which this
// scroll node applies.
cc.mojom.ElementId? element_id;
// Flags specifying the behavior of scrolls on this node.
bool max_scroll_offset_affected_by_page_scale;
bool scrolls_inner_viewport;
bool scrolls_outer_viewport;
bool prevent_viewport_scrolling_from_inner;
bool user_scrollable_horizontal;
bool user_scrollable_vertical;
bool is_composited;
};
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