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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 MOZILLA_GFX_TILEDREGION_H_
#define MOZILLA_GFX_TILEDREGION_H_
#include <utility>
#include "mozilla/ArrayView.h"
#include "mozilla/gfx/Rect.h"
#include "nsRegion.h"
#include "pixman.h"
namespace mozilla {
namespace gfx {
// See TiledRegion.cpp for documentation on TiledRegionImpl.
class TiledRegionImpl {
public:
void Clear() { mRects.Clear(); }
bool AddRect(const pixman_box32_t& aRect);
bool Intersects(const pixman_box32_t& aRect) const;
bool Contains(const pixman_box32_t& aRect) const;
operator ArrayView<pixman_box32_t>() const {
return ArrayView<pixman_box32_t>(mRects);
}
private:
nsTArray<pixman_box32_t> mRects;
};
/**
* A auto-simplifying region type that supports one rectangle per tile.
* The virtual tile grid is anchored at (0, 0) and has quadratic tiles whose
* size is hard-coded as kTileSize in TiledRegion.cpp.
* A TiledRegion starts out empty. You can add rectangles or (regular) regions
* into it by calling Add(). Add() is a mutating union operation (similar to
* OrWith on nsRegion) that's *not* exact, because it will enlarge the region as
* necessary to satisfy the "one rectangle per tile" requirement.
* Tiled regions convert implicitly to the underlying regular region type.
* The only way to remove parts from a TiledRegion is by calling SetEmpty().
*/
template <typename RegionT>
class TiledRegion {
public:
typedef typename RegionT::RectType RectT;
TiledRegion() : mCoversBounds(false) {}
TiledRegion(const TiledRegion& aOther)
: mBounds(aOther.mBounds), mImpl(aOther.mImpl), mCoversBounds(false) {}
TiledRegion(TiledRegion&& aOther)
: mBounds(aOther.mBounds),
mImpl(std::move(aOther.mImpl)),
mCoversBounds(false) {}
RegionT GetRegion() const {
if (mBounds.IsEmpty()) {
return RegionT();
}
if (mCoversBounds) {
// Rect limit hit or allocation failed, treat as 1 rect.
return RegionT(mBounds);
}
return RegionT(mImpl);
}
TiledRegion& operator=(const TiledRegion& aOther) {
if (&aOther != this) {
mBounds = aOther.mBounds;
mImpl = aOther.mImpl;
mCoversBounds = aOther.mCoversBounds;
}
return *this;
}
void Add(const RectT& aRect) {
if (aRect.IsEmpty()) {
return;
}
Maybe<RectT> newBounds = mBounds.SafeUnion(aRect);
if (!newBounds) {
return;
}
mBounds = newBounds.value();
MOZ_ASSERT(!mBounds.Overflows());
if (mCoversBounds) {
return;
}
if (!mImpl.AddRect(RectToBox(aRect))) {
FallBackToBounds();
}
}
void Add(const RegionT& aRegion) {
Maybe<RectT> newBounds = mBounds.SafeUnion(aRegion.GetBounds());
if (!newBounds) {
return;
}
mBounds = newBounds.value();
MOZ_ASSERT(!mBounds.Overflows());
if (mCoversBounds) {
return;
}
for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
RectT r = iter.Get();
if (r.IsEmpty() || r.Overflows()) {
// This can happen if e.g. a negative-width rect was wrapped into a
// region. Treat it the same as we would if such a rect was passed to
// the Add(const RectT&) function.
continue;
}
if (!mImpl.AddRect(RectToBox(r))) {
FallBackToBounds();
return;
}
}
}
bool IsEmpty() const { return mBounds.IsEmpty(); }
void SetEmpty() {
mBounds.SetEmpty();
mImpl.Clear();
mCoversBounds = false;
}
RectT GetBounds() const { return mBounds; }
bool CoversBounds() const { return mCoversBounds; }
bool Intersects(const RectT& aRect) const {
if (aRect.IsEmpty()) {
return true;
}
if (aRect.Overflows() || !mBounds.Intersects(aRect)) {
return false;
}
if (mCoversBounds) {
return true;
}
return mImpl.Intersects(RectToBox(aRect));
}
bool Contains(const RectT& aRect) const {
if (aRect.IsEmpty()) {
return true;
}
if (aRect.Overflows() || !mBounds.Contains(aRect)) {
return false;
}
if (mCoversBounds) {
return true;
}
return mImpl.Contains(RectToBox(aRect));
}
private:
void FallBackToBounds() {
mCoversBounds = true;
mImpl.Clear();
}
static pixman_box32_t RectToBox(const RectT& aRect) {
MOZ_ASSERT(!aRect.IsEmpty());
MOZ_ASSERT(!aRect.Overflows());
return {aRect.X(), aRect.Y(), aRect.XMost(), aRect.YMost()};
}
RectT mBounds;
TiledRegionImpl mImpl;
// mCoversBounds is true if we bailed out due to a large number of tiles.
// mCoversBounds being true means that this TiledRegion is just a simple
// rectangle (our mBounds).
// Once set to true, the TiledRegion will stay in this state until SetEmpty
// is called.
bool mCoversBounds;
};
typedef TiledRegion<IntRegion> TiledIntRegion;
} // namespace gfx
} // namespace mozilla
#endif /* MOZILLA_GFX_TILEDREGION_H_ */
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