chromium/src/third_party/blink/renderer/core/paint/paint_phase.h

/*
 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
 *           (C) 2000 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights
 * reserved.
 * Copyright (C) 2009 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_PAINT_PAINT_PHASE_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_PAINT_PAINT_PHASE_H_

namespace blink {

// The painting of a layer occurs in 5 phases, Each involves a recursive
// descent into the layer's layout objects in painting order:
//  1. Background phase: backgrounds and borders of all blocks are painted.
//     Inlines are not painted at all. Touch-action and wheel hit test rects are
//     also painted during this phase (see: paint/README.md#hit-test-painting).
//  2. ForcedColorsModeBackplate phase: a readability backplate is painted
//     behind all inline text, split by paragraph. This phase should only paint
//     content when in forced colors mode to ensure readability for text above
//     images.
//  3. Float phase: floating objects are painted above block backgrounds but
//     entirely below inline content that can overlap them.
//  4. Foreground phase: all inlines are fully painted. Atomic inline elements
//     will get all 4 non-backplate phases invoked on them during this phase,
//     as if they were stacking contexts (see
//     ObjectPainter::paintAllPhasesAtomically()).
//  5. Outline phase: outlines are painted over the foreground.

enum class PaintPhase {
  // Background phase
  //
  // Paint background of the current object and non-self-painting descendants.
  kBlockBackground,
  //
  // The following two values are added besides the normal
  // kBlockBackground to distinguish backgrounds for the object itself
  // and for descendants, because the two backgrounds are often painted with
  // different scroll offsets and clips.
  //
  // Paint background of the current object only.
  kSelfBlockBackgroundOnly,
  // Paint backgrounds of non-self-painting descendants only. The painter should
  // call each non-self-painting child's paint method by passing
  // paintInfo.forDescendants() which converts kDescendantBlockBackgroundsOnly
  // to kBlockBackground.
  kDescendantBlockBackgroundsOnly,

  // ForcedColorsModeBackplate phase - used to ensure readability in forced
  // colors mode.
  kForcedColorsModeBackplate,

  // Float phase
  kFloat,

  // Foreground phase
  kForeground,

  // Outline phase
  //
  // Paint outline for the current object and non-self-painting descendants.
  kOutline,
  //
  // Similar to the background phase, the following two values are added for
  // painting outlines of the object itself and for descendants.
  //
  // Paint outline for the current object only.
  kSelfOutlineOnly,
  // Paint outlines of non-self-painting descendants only. The painter should
  // call each non-self-painting child's paint method by passing
  // paintInfo.forDescendants() which converts kDescendantOutlinesOnly to
  // kOutline.
  kDescendantOutlinesOnly,

  // The below are auxiliary phases which are used to paint special effects.
  kOverlayOverflowControls,
  kSelectionDragImage,
  kTextClip,
  kMask,

  kMax = kMask,
  // These values must be kept in sync with DisplayItem::Type and
  // DisplayItem::typeAsDebugString().
};

inline bool ShouldPaintSelfBlockBackground(PaintPhase phase) {
  return phase == PaintPhase::kBlockBackground ||
         phase == PaintPhase::kSelfBlockBackgroundOnly;
}

inline bool ShouldPaintSelfOutline(PaintPhase phase) {
  return phase == PaintPhase::kOutline || phase == PaintPhase::kSelfOutlineOnly;
}

inline bool ShouldPaintDescendantBlockBackgrounds(PaintPhase phase) {
  return phase == PaintPhase::kBlockBackground ||
         phase == PaintPhase::kDescendantBlockBackgroundsOnly;
}

inline bool ShouldPaintDescendantOutlines(PaintPhase phase) {
  return phase == PaintPhase::kOutline ||
         phase == PaintPhase::kDescendantOutlinesOnly;
}

// Those flags are meant as global tree operations. This means
// that they should be constant for a paint phase.
enum GlobalPaintFlag {
  kGlobalPaintNormalPhase = 0,
  // Used when painting selection as part of a drag-image. This
  // flag disables a lot of the painting code and specifically
  // triggers a PaintPhaseSelection.
  kGlobalPaintSelectionDragImageOnly = 1 << 0,
  // Used when painting a drag-image or printing in order to
  // ignore the hardware layers and paint the whole tree
  // into the topmost layer.
  kGlobalPaintFlattenCompositingLayers = 1 << 1,
  // Used when printing or painting a preview to in order to add URL
  // metadata for links.
  kGlobalPaintAddUrlMetadata = 1 << 2
};

typedef unsigned GlobalPaintFlags;

}  // namespace blink

#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_PAINT_PAINT_PHASE_H_