The Tor Browser: comparison layout/base/DisplayListClipState.h

--1:000000000000
+:0e13d62c4af9
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+* This Source Code Form is subject to the terms of the Mozilla Public
+* License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef DISPLAYLISTCLIPSTATE_H_
+#define DISPLAYLISTCLIPSTATE_H_
+#include "DisplayItemClip.h"
+#include "mozilla/DebugOnly.h"
+class nsIFrame;
+class nsDisplayListBuilder;
+namespace mozilla {
+/**
+* All clip coordinates are in appunits relative to the reference frame
+* for the display item we're building.
+*/
+class DisplayListClipState {
+public:
+DisplayListClipState()
+: mClipContentDescendants(nullptr)
+, mClipContainingBlockDescendants(nullptr)
+, mCurrentCombinedClip(nullptr)
+{}
+/**
+* Returns intersection of mClipContainingBlockDescendants and
+* mClipContentDescendants, allocated on aBuilder's arena.
+*/
+const DisplayItemClip* GetCurrentCombinedClip(nsDisplayListBuilder* aBuilder);
+const DisplayItemClip* GetClipForContainingBlockDescendants() const
+{
+return mClipContainingBlockDescendants;
+}
+const DisplayItemClip* GetClipForContentDescendants() const
+{
+return mClipContentDescendants;
+}
+class AutoSaveRestore;
+friend class AutoSaveRestore;
+class AutoClipContainingBlockDescendantsToContentBox;
+friend class AutoClipContainingBlockDescendantsToContentBox;
+class AutoClipMultiple;
+friend class AutoClipMultiple;
+enum {
+ASSUME_DRAWING_RESTRICTED_TO_CONTENT_RECT = 0x01
+};
+private:
+void SetClipForContainingBlockDescendants(const DisplayItemClip* aClip)
+{
+mClipContainingBlockDescendants = aClip;
+mCurrentCombinedClip = nullptr;
+}
+void Clear()
+{
+mClipContentDescendants = nullptr;
+mClipContainingBlockDescendants = nullptr;
+mCurrentCombinedClip = nullptr;
+}
+/**
+* Intersects the given clip rect (with optional aRadii) with the current
+* mClipContainingBlockDescendants and sets mClipContainingBlockDescendants to
+* the result, stored in aClipOnStack.
+*/
+void ClipContainingBlockDescendants(const nsRect& aRect,
+const nscoord* aRadii,
+DisplayItemClip& aClipOnStack);
+void ClipContentDescendants(const nsRect& aRect,
+const nscoord* aRadii,
+DisplayItemClip& aClipOnStack);
+/**
+* Clips containing-block descendants to the frame's content-box,
+* taking border-radius into account.
+* If aFlags contains ASSUME_DRAWING_RESTRICTED_TO_CONTENT_RECT then
+* we assume display items will not draw outside the content rect, so
+* clipping is only required if there is a border-radius. This is an
+* optimization to reduce the amount of clipping required.
+*/
+void ClipContainingBlockDescendantsToContentBox(nsDisplayListBuilder* aBuilder,
+nsIFrame* aFrame,
+DisplayItemClip& aClipOnStack,
+uint32_t aFlags);
+/**
+* All content descendants (i.e. following placeholder frames to their
+* out-of-flows if necessary) should be clipped by mClipContentDescendants.
+* Null if no clipping applies.
+*/
+const DisplayItemClip* mClipContentDescendants;
+/**
+* All containing-block descendants (i.e. frame descendants), including
+* display items for the current frame, should be clipped by
+* mClipContainingBlockDescendants.
+* Null if no clipping applies.
+*/
+const DisplayItemClip* mClipContainingBlockDescendants;
+/**
+* The intersection of mClipContentDescendants and
+* mClipContainingBlockDescendants.
+* Allocated in the nsDisplayListBuilder arena. Null if none has been
+* allocated or both mClipContentDescendants and mClipContainingBlockDescendants
+* are null.
+*/
+const DisplayItemClip* mCurrentCombinedClip;
+};
+/**
+* A class to automatically save and restore the current clip state. Also
+* offers methods for modifying the clip state. Only one modification is allowed
+* to be in scope at a time using one of these objects; multiple modifications
+* require nested objects. The interface is written this way to prevent
+* dangling pointers to DisplayItemClips.
+*/
+class DisplayListClipState::AutoSaveRestore {
+public:
+AutoSaveRestore(nsDisplayListBuilder* aBuilder);
+void Restore()
+{
+mState = mSavedState;
+mRestored = true;
+}
+~AutoSaveRestore()
+{
+mState = mSavedState;
+}
+void Clear()
+{
+NS_ASSERTION(!mRestored, "Already restored!");
+mState.Clear();
+mClipUsed = false;
+}
+/**
+* Intersects the given clip rect (with optional aRadii) with the current
+* mClipContainingBlockDescendants and sets mClipContainingBlockDescendants to
+* the result, stored in aClipOnStack.
+*/
+void ClipContainingBlockDescendants(const nsRect& aRect,
+const nscoord* aRadii = nullptr)
+{
+NS_ASSERTION(!mRestored, "Already restored!");
+NS_ASSERTION(!mClipUsed, "mClip already used");
+mClipUsed = true;
+mState.ClipContainingBlockDescendants(aRect, aRadii, mClip);
+}
+void ClipContentDescendants(const nsRect& aRect,
+const nscoord* aRadii = nullptr)
+{
+NS_ASSERTION(!mRestored, "Already restored!");
+NS_ASSERTION(!mClipUsed, "mClip already used");
+mClipUsed = true;
+mState.ClipContentDescendants(aRect, aRadii, mClip);
+}
+/**
+* Clips containing-block descendants to the frame's content-box,
+* taking border-radius into account.
+* If aFlags contains ASSUME_DRAWING_RESTRICTED_TO_CONTENT_RECT then
+* we assume display items will not draw outside the content rect, so
+* clipping is only required if there is a border-radius. This is an
+* optimization to reduce the amount of clipping required.
+*/
+void ClipContainingBlockDescendantsToContentBox(nsDisplayListBuilder* aBuilder,
+nsIFrame* aFrame,
+uint32_t aFlags = 0)
+{
+NS_ASSERTION(!mRestored, "Already restored!");
+NS_ASSERTION(!mClipUsed, "mClip already used");
+mClipUsed = true;
+mState.ClipContainingBlockDescendantsToContentBox(aBuilder, aFrame, mClip, aFlags);
+}
+protected:
+DisplayListClipState& mState;
+DisplayListClipState mSavedState;
+DisplayItemClip mClip;
+DebugOnly<bool> mClipUsed;
+DebugOnly<bool> mRestored;
+};
+class DisplayListClipState::AutoClipContainingBlockDescendantsToContentBox : public AutoSaveRestore {
+public:
+AutoClipContainingBlockDescendantsToContentBox(nsDisplayListBuilder* aBuilder,
+nsIFrame* aFrame,
+uint32_t aFlags = 0)
+: AutoSaveRestore(aBuilder)
+{
+mClipUsed = true;
+mState.ClipContainingBlockDescendantsToContentBox(aBuilder, aFrame, mClip, aFlags);
+}
+};
+/**
+* Do not use this outside of nsFrame::BuildDisplayListForChild, use
+* multiple AutoSaveRestores instead. We provide this class just to ensure
+* BuildDisplayListForChild is as efficient as possible.
+*/
+class DisplayListClipState::AutoClipMultiple : public AutoSaveRestore {
+public:
+AutoClipMultiple(nsDisplayListBuilder* aBuilder)
+: AutoSaveRestore(aBuilder)
+, mExtraClipUsed(false)
+{}
+/**
+* *aClip must survive longer than this object. Be careful!!!
+*/
+void SetClipForContainingBlockDescendants(const DisplayItemClip* aClip)
+{
+mState.SetClipForContainingBlockDescendants(aClip);
+}
+/**
+* Intersects the given clip rect (with optional aRadii) with the current
+* mClipContainingBlockDescendants and sets mClipContainingBlockDescendants to
+* the result, stored in aClipOnStack.
+*/
+void ClipContainingBlockDescendantsExtra(const nsRect& aRect,
+const nscoord* aRadii)
+{
+NS_ASSERTION(!mRestored, "Already restored!");
+NS_ASSERTION(!mExtraClipUsed, "mExtraClip already used");
+mExtraClipUsed = true;
+mState.ClipContainingBlockDescendants(aRect, aRadii, mExtraClip);
+}
+protected:
+DisplayItemClip mExtraClip;
+DebugOnly<bool> mExtraClipUsed;
+};
+}
+#endif /* DISPLAYLISTCLIPSTATE_H_ */

The Tor Browser / file comparison

comparison: layout/base/DisplayListClipState.h

layout/base/DisplayListClipState.h