chromium/src/third_party/blink/public/mojom/frame/viewport_intersection_state.mojom

// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module blink.mojom;

import "ui/gfx/geometry/mojom/geometry.mojom";
import "ui/gfx/mojom/transform.mojom";

// These values are used to implement a browser intervention: if a cross-
// origin iframe has moved more than 30 screen pixels (manhattan distance)
// within its embedding page's viewport within the last 500 milliseconds, most
// input events targeting the iframe will be quietly discarded.
const uint32 kMaxChildFrameScreenRectMovement = 30;
const uint32 kMinScreenRectStableTimeMs = 500;

// Indicates whether a child frame is occluded or visually altered (e.g., with
// CSS opacity or transform) by content or styles in the parent frame.
enum FrameOcclusionState {
  // No occlusion determination was made.
  kUnknown = 0,
  // The frame *may* be occluded or visually altered.
  kPossiblyOccluded = 1,
  // The frame is definitely not occluded or visually altered.
  kGuaranteedNotOccluded = 2,
};

// Communicates information about the position and visibility of a child frame
// within the viewport of the top-level main frame.
struct ViewportIntersectionState {
  // Portion of the child frame which is within the main frame's scrolling
  gfx.mojom.Rect viewport_intersection;

  // Same as viewport_intersection, but without applying the main frame's
  // document-level overflow clip.
  gfx.mojom.Rect main_frame_intersection;

  // Area of the child frame that needs to be rastered, in physical pixels.
  gfx.mojom.Rect compositor_visible_rect;

  // Occlusion state, as described above.
  FrameOcclusionState occlusion_state = FrameOcclusionState.kUnknown;

  // Main frame's size.
  gfx.mojom.Size main_frame_viewport_size;

  // Main frame's scrolling offset.
  gfx.mojom.Point main_frame_scroll_offset;

  // Child frame's transform to the coordinate system of the main frame.
  gfx.mojom.Transform main_frame_transform;
};