layout/base/DisplayListClipState.cpp

   1 /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "DisplayListClipState.h"
   7
   8 #include "nsDisplayList.h"
   9
  10 namespace mozilla {
  11
  12 const DisplayItemClip*
  13 DisplayListClipState::GetCurrentCombinedClip(nsDisplayListBuilder* aBuilder)
  14 {
  15   if (mCurrentCombinedClip) {
  16     return mCurrentCombinedClip;
  17   }
  18   if (!mClipContentDescendants && !mClipContainingBlockDescendants) {
  19     return nullptr;
  20   }
  21   if (mClipContentDescendants) {
  22     if (mClipContainingBlockDescendants) {
  23       DisplayItemClip intersection = *mClipContentDescendants;
  24       intersection.IntersectWith(*mClipContainingBlockDescendants);
  25       mCurrentCombinedClip = aBuilder->AllocateDisplayItemClip(intersection);
  26     } else {
  27       mCurrentCombinedClip =
  28         aBuilder->AllocateDisplayItemClip(*mClipContentDescendants);
  29     }
  30   } else {
  31     mCurrentCombinedClip =
  32       aBuilder->AllocateDisplayItemClip(*mClipContainingBlockDescendants);
  33   }
  34   return mCurrentCombinedClip;
  35 }
  36
  37 void
  38 DisplayListClipState::ClipContainingBlockDescendants(const nsRect& aRect,
  39                                                      const nscoord* aRadii,
  40                                                      DisplayItemClip& aClipOnStack)
  41 {
  42   if (aRadii) {
  43     aClipOnStack.SetTo(aRect, aRadii);
  44   } else {
  45     aClipOnStack.SetTo(aRect);
  46   }
  47   if (mClipContainingBlockDescendants) {
  48     aClipOnStack.IntersectWith(*mClipContainingBlockDescendants);
  49   }
  50   mClipContainingBlockDescendants = &aClipOnStack;
  51   mCurrentCombinedClip = nullptr;
  52 }
  53
  54 void
  55 DisplayListClipState::ClipContentDescendants(const nsRect& aRect,
  56                                              const nscoord* aRadii,
  57                                              DisplayItemClip& aClipOnStack)
  58 {
  59   if (aRadii) {
  60     aClipOnStack.SetTo(aRect, aRadii);
  61   } else {
  62     aClipOnStack.SetTo(aRect);
  63   }
  64   if (mClipContentDescendants) {
  65     aClipOnStack.IntersectWith(*mClipContentDescendants);
  66   }
  67   mClipContentDescendants = &aClipOnStack;
  68   mCurrentCombinedClip = nullptr;
  69 }
  70
  71 void
  72 DisplayListClipState::ClipContentDescendants(const nsRect& aRect,
  73                                              const nsRect& aRoundedRect,
  74                                              const nscoord* aRadii,
  75                                              DisplayItemClip& aClipOnStack)
  76 {
  77   if (aRadii) {
  78     aClipOnStack.SetTo(aRect, aRoundedRect, aRadii);
  79   } else {
  80     nsRect intersect = aRect.Intersect(aRoundedRect);
  81     aClipOnStack.SetTo(intersect);
  82   }
  83   if (mClipContentDescendants) {
  84     aClipOnStack.IntersectWith(*mClipContentDescendants);
  85   }
  86   mClipContentDescendants = &aClipOnStack;
  87   mCurrentCombinedClip = nullptr;
  88 }
  89
  90 void
  91 DisplayListClipState::ClipContainingBlockDescendantsToContentBox(nsDisplayListBuilder* aBuilder,
  92                                                                  nsIFrame* aFrame,
  93                                                                  DisplayItemClip& aClipOnStack,
  94                                                                  uint32_t aFlags)
  95 {
  96   nscoord radii[8];
  97   bool hasBorderRadius = aFrame->GetContentBoxBorderRadii(radii);
  98   if (!hasBorderRadius && (aFlags & ASSUME_DRAWING_RESTRICTED_TO_CONTENT_RECT)) {
  99     return;
 100   }
 101
 102   nsRect clipRect = aFrame->GetContentRectRelativeToSelf() +
 103     aBuilder->ToReferenceFrame(aFrame);
 104   // If we have a border-radius, we have to clip our content to that
 105   // radius.
 106   ClipContainingBlockDescendants(clipRect, hasBorderRadius ? radii : nullptr,
 107                                  aClipOnStack);
 108 }
 109
 110 DisplayListClipState::AutoSaveRestore::AutoSaveRestore(nsDisplayListBuilder* aBuilder)
 111   : mState(aBuilder->ClipState())
 112   , mSavedState(aBuilder->ClipState())
 113   , mClipUsed(false)
 114   , mRestored(false)
 115 {}
 116
 117 }