forked from mirrors/gecko-dev
553 lines
16 KiB
C++
553 lines
16 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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// vim:cindent:ts=2:et:sw=2:
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "DottedCornerFinder.h"
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#include "mozilla/Move.h"
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#include "BorderCache.h"
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#include "BorderConsts.h"
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namespace mozilla {
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using namespace gfx;
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static inline Float
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Square(Float x)
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{
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return x * x;
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}
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static Point
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PointRotateCCW90(const Point& aP)
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{
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return Point(aP.y, -aP.x);
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}
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struct BestOverlap
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{
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Float overlap;
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size_t count;
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BestOverlap()
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: overlap(0.0f), count(0)
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{}
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BestOverlap(Float aOverlap, size_t aCount)
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: overlap(aOverlap), count(aCount)
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{}
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};
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static const size_t DottedCornerCacheSize = 256;
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nsDataHashtable<FourFloatsHashKey, BestOverlap> DottedCornerCache;
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DottedCornerFinder::DottedCornerFinder(const Bezier& aOuterBezier,
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const Bezier& aInnerBezier,
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mozilla::css::Corner aCorner,
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Float aBorderRadiusX,
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Float aBorderRadiusY,
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const Point& aC0, Float aR0,
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const Point& aCn, Float aRn,
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const Size& aCornerDim)
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: mOuterBezier(aOuterBezier),
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mInnerBezier(aInnerBezier),
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mCorner(aCorner),
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mNormalSign((aCorner == C_TL || aCorner == C_BR) ? -1.0f : 1.0f),
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mC0(aC0), mCn(aCn),
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mR0(aR0), mRn(aRn), mMaxR(std::max(aR0, aRn)),
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mCurveOrigin(mC0.x, mCn.y),
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mBestOverlap(0.0f),
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mHasZeroBorderWidth(false), mHasMore(true),
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mMaxCount(aCornerDim.width + aCornerDim.height),
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mType(OTHER),
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mI(0), mCount(0)
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{
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NS_ASSERTION(mR0 > 0.0f || mRn > 0.0f,
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"At least one side should have non-zero radius.");
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mInnerWidth = fabs(mInnerBezier.mPoints[0].x - mInnerBezier.mPoints[3].x);
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mInnerHeight = fabs(mInnerBezier.mPoints[0].y - mInnerBezier.mPoints[3].y);
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DetermineType(aBorderRadiusX, aBorderRadiusY);
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Reset();
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}
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static bool
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IsSingleCurve(Float aMinR, Float aMaxR,
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Float aMinBorderRadius, Float aMaxBorderRadius)
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{
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return aMinR > 0.0f &&
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aMinBorderRadius > aMaxR * 4.0f &&
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aMinBorderRadius / aMaxBorderRadius > 0.5f;
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}
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void
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DottedCornerFinder::DetermineType(Float aBorderRadiusX, Float aBorderRadiusY)
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{
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// Calculate parameters for the center curve before swap.
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Float centerCurveWidth = fabs(mC0.x - mCn.x);
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Float centerCurveHeight = fabs(mC0.y - mCn.y);
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Point cornerPoint(mCn.x, mC0.y);
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bool swapped = false;
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if (mR0 < mRn) {
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// Always draw from wider side to thinner side.
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Swap(mC0, mCn);
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Swap(mR0, mRn);
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Swap(mInnerBezier.mPoints[0], mInnerBezier.mPoints[3]);
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Swap(mInnerBezier.mPoints[1], mInnerBezier.mPoints[2]);
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Swap(mOuterBezier.mPoints[0], mOuterBezier.mPoints[3]);
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Swap(mOuterBezier.mPoints[1], mOuterBezier.mPoints[2]);
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mNormalSign = -mNormalSign;
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swapped = true;
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}
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// See the comment at mType declaration for each condition.
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Float minR = std::min(mR0, mRn);
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Float minBorderRadius = std::min(aBorderRadiusX, aBorderRadiusY);
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Float maxBorderRadius = std::max(aBorderRadiusX, aBorderRadiusY);
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if (IsSingleCurve(minR, mMaxR, minBorderRadius, maxBorderRadius)) {
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if (mR0 == mRn) {
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Float borderLength;
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if (minBorderRadius == maxBorderRadius) {
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mType = PERFECT;
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borderLength = M_PI * centerCurveHeight / 2.0f;
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mCenterCurveR = centerCurveWidth;
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} else {
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mType = SINGLE_CURVE_AND_RADIUS;
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borderLength = GetQuarterEllipticArcLength(centerCurveWidth,
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centerCurveHeight);
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}
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Float diameter = mR0 * 2.0f;
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size_t count = round(borderLength / diameter);
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if (count % 2) {
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count++;
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}
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mCount = count / 2 - 1;
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if (mCount > 0) {
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mBestOverlap = 1.0f - borderLength / (diameter * count);
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}
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} else {
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mType = SINGLE_CURVE;
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}
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}
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if (mType == SINGLE_CURVE_AND_RADIUS || mType == SINGLE_CURVE) {
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Size cornerSize(centerCurveWidth, centerCurveHeight);
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GetBezierPointsForCorner(&mCenterBezier, mCorner,
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cornerPoint, cornerSize);
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if (swapped) {
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Swap(mCenterBezier.mPoints[0], mCenterBezier.mPoints[3]);
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Swap(mCenterBezier.mPoints[1], mCenterBezier.mPoints[2]);
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}
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}
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if (minR == 0.0f) {
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mHasZeroBorderWidth = true;
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}
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if ((mType == SINGLE_CURVE || mType == OTHER) && !mHasZeroBorderWidth) {
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FindBestOverlap(minR, minBorderRadius, maxBorderRadius);
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}
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}
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bool
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DottedCornerFinder::HasMore(void) const
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{
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if (mHasZeroBorderWidth) {
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return mI < mMaxCount && mHasMore;
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}
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return mI < mCount;
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}
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DottedCornerFinder::Result
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DottedCornerFinder::Next(void)
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{
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mI++;
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if (mType == PERFECT) {
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Float phi = mI * 4.0f * mR0 * (1 - mBestOverlap) / mCenterCurveR;
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if (mCorner == C_TL) {
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phi = -M_PI / 2.0f - phi;
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} else if (mCorner == C_TR) {
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phi = -M_PI / 2.0f + phi;
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} else if (mCorner == C_BR) {
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phi = M_PI / 2.0f - phi;
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} else {
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phi = M_PI / 2.0f + phi;
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}
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Point C(mCurveOrigin.x + mCenterCurveR * cos(phi),
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mCurveOrigin.y + mCenterCurveR * sin(phi));
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return DottedCornerFinder::Result(C, mR0);
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}
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// Find unfilled and filled circles.
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(void)FindNext(mBestOverlap);
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(void)FindNext(mBestOverlap);
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return Result(mLastC, mLastR);
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}
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void
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DottedCornerFinder::Reset(void)
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{
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mLastC = mC0;
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mLastR = mR0;
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mLastT = 0.0f;
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mHasMore = true;
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}
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void
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DottedCornerFinder::FindPointAndRadius(Point& C, Float& r,
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const Point& innerTangent,
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const Point& normal, Float t)
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{
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// Find radius for the given tangent point on the inner curve such that the
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// circle is also tangent to the outer curve.
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NS_ASSERTION(mType == OTHER, "Wrong mType");
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Float lower = 0.0f;
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Float upper = mMaxR;
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const Float DIST_MARGIN = 0.1f;
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for (size_t i = 0; i < MAX_LOOP; i++) {
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r = (upper + lower) / 2.0f;
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C = innerTangent + normal * r;
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Point Near = FindBezierNearestPoint(mOuterBezier, C, t);
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Float distSquare = (C - Near).LengthSquare();
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if (distSquare > Square(r + DIST_MARGIN)) {
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lower = r;
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} else if (distSquare < Square(r - DIST_MARGIN)) {
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upper = r;
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} else {
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break;
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}
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}
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}
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Float
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DottedCornerFinder::FindNext(Float overlap)
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{
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Float lower = mLastT;
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Float upper = 1.0f;
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Float t;
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Point C = mLastC;
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Float r = 0.0f;
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Float factor = (1.0f - overlap);
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Float circlesDist = 0.0f;
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Float expectedDist = 0.0f;
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const Float DIST_MARGIN = 0.1f;
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if (mType == SINGLE_CURVE_AND_RADIUS) {
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r = mR0;
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expectedDist = (r + mLastR) * factor;
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// Find C_i on the center curve.
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for (size_t i = 0; i < MAX_LOOP; i++) {
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t = (upper + lower) / 2.0f;
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C = GetBezierPoint(mCenterBezier, t);
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// Check overlap along arc.
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circlesDist = GetBezierLength(mCenterBezier, mLastT, t);
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if (circlesDist < expectedDist - DIST_MARGIN) {
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lower = t;
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} else if (circlesDist > expectedDist + DIST_MARGIN) {
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upper = t;
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} else {
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break;
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}
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}
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} else if (mType == SINGLE_CURVE) {
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// Find C_i on the center curve, and calculate r_i.
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for (size_t i = 0; i < MAX_LOOP; i++) {
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t = (upper + lower) / 2.0f;
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C = GetBezierPoint(mCenterBezier, t);
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Point Diff = GetBezierDifferential(mCenterBezier, t);
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Float DiffLength = Diff.Length();
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if (DiffLength == 0.0f) {
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// Basically this shouldn't happen.
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// If differential is 0, we cannot calculate tangent circle,
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// skip this point.
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t = (t + upper) / 2.0f;
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continue;
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}
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Point normal = PointRotateCCW90(Diff / DiffLength) * (-mNormalSign);
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r = CalculateDistanceToEllipticArc(C, normal, mCurveOrigin,
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mInnerWidth, mInnerHeight);
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// Check overlap along arc.
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circlesDist = GetBezierLength(mCenterBezier, mLastT, t);
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expectedDist = (r + mLastR) * factor;
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if (circlesDist < expectedDist - DIST_MARGIN) {
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lower = t;
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} else if (circlesDist > expectedDist + DIST_MARGIN) {
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upper = t;
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} else {
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break;
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}
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}
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} else {
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Float distSquareMax = Square(mMaxR * 3.0f);
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Float circlesDistSquare = 0.0f;
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// Find C_i and r_i.
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for (size_t i = 0; i < MAX_LOOP; i++) {
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t = (upper + lower) / 2.0f;
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Point innerTangent = GetBezierPoint(mInnerBezier, t);
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if ((innerTangent - mLastC).LengthSquare() > distSquareMax) {
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// It's clear that this tangent point is too far, skip it.
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upper = t;
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continue;
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}
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Point Diff = GetBezierDifferential(mInnerBezier, t);
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Float DiffLength = Diff.Length();
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if (DiffLength == 0.0f) {
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// Basically this shouldn't happen.
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// If differential is 0, we cannot calculate tangent circle,
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// skip this point.
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t = (t + upper) / 2.0f;
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continue;
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}
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Point normal = PointRotateCCW90(Diff / DiffLength) * mNormalSign;
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FindPointAndRadius(C, r, innerTangent, normal, t);
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// Check overlap with direct distance.
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circlesDistSquare = (C - mLastC).LengthSquare();
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expectedDist = (r + mLastR) * factor;
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if (circlesDistSquare < Square(expectedDist - DIST_MARGIN)) {
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lower = t;
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} else if (circlesDistSquare > Square(expectedDist + DIST_MARGIN)) {
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upper = t;
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} else {
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break;
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}
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}
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circlesDist = sqrt(circlesDistSquare);
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}
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mLastT = t;
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mLastC = C;
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mLastR = r;
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if (mHasZeroBorderWidth) {
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const Float T_MARGIN = 0.001f;
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if (mLastT >= 1.0f - T_MARGIN ||
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(mLastC - mCn).LengthSquare() < Square(mLastR)) {
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mHasMore = false;
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}
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}
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if (expectedDist == 0.0f) {
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return 0.0f;
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}
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return 1.0f - circlesDist * factor / expectedDist;
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}
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void
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DottedCornerFinder::FindBestOverlap(Float aMinR, Float aMinBorderRadius,
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Float aMaxBorderRadius)
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{
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// If overlap is not calculateable, find it with binary search,
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// such that there exists i that C_i == C_n with the given overlap.
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FourFloats key(aMinR, mMaxR,
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aMinBorderRadius, aMaxBorderRadius);
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BestOverlap best;
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if (DottedCornerCache.Get(key, &best)) {
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mCount = best.count;
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mBestOverlap = best.overlap;
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return;
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}
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Float lower = 0.0f;
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Float upper = 0.5f;
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// Start from lower bound to find the minimum number of circles.
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Float overlap = 0.0f;
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mBestOverlap = overlap;
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size_t targetCount = 0;
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const Float OVERLAP_MARGIN = 0.1f;
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for (size_t j = 0; j < MAX_LOOP; j++) {
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Reset();
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size_t count;
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Float actualOverlap;
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if (!GetCountAndLastOverlap(overlap, &count, &actualOverlap)) {
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if (j == 0) {
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mCount = mMaxCount;
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break;
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}
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}
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if (j == 0) {
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if (count < 3 || (count == 3 && actualOverlap > 0.5f)) {
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// |count == 3 && actualOverlap > 0.5f| means there could be
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// a circle but it is too near from both ends.
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//
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// if actualOverlap == 0.0
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// 1 2 3
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// +-------+-------+-------+-------+
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// | ##### | ***** | ##### | ##### |
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// |#######|*******|#######|#######|
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// |###+###|***+***|###+###|###+###|
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// |# C_0 #|* C_1 *|# C_2 #|# C_n #|
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// | ##### | ***** | ##### | ##### |
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// +-------+-------+-------+-------+
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// |
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// V
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// +-------+---+-------+---+-------+
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// | ##### | | ##### | | ##### |
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// |#######| |#######| |#######|
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// |###+###| |###+###| |###+###| Find the best overlap to place
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// |# C_0 #| |# C_1 #| |# C_n #| C_1 at the middle of them
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// | ##### | | ##### | | ##### |
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// +-------+---+-------+---|-------+
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//
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// if actualOverlap == 0.5
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// 1 2 3
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// +-------+-------+-------+---+
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// | ##### | ***** | ##### |## |
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// |#######|*******|##### C_n #|
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// |###+###|***+***|###+###+###|
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// |# C_0 #|* C_1 *|# C_2 #|###|
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// | ##### | ***** | ##### |## |
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// +-------+-------+-------+---+
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// |
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// V
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// +-------+-+-------+-+-------+
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// | ##### | | ##### | | ##### |
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// |#######| |#######| |#######|
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// |###+###| |###+###| |###+###| Even if we place C_1 at the middle
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// |# C_0 #| |# C_1 #| |# C_n #| of them, it's too near from them
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// | ##### | | ##### | | ##### |
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// +-------+-+-------+-|-------+
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// |
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// V
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// +-------+-----------+-------+
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// | ##### | | ##### |
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// |#######| |#######|
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// |###+###| |###+###| Do not draw any circle
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// |# C_0 #| |# C_n #|
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// | ##### | | ##### |
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// +-------+-----------+-------+
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mCount = 0;
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break;
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}
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// targetCount should be 2n, as we're searching C_1 to C_n.
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//
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// targetCount = 4
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// mCount = 1
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// 1 2 3 4
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// +-------+-------+-------+-------+-------+
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// | ##### | ***** | ##### | ***** | ##### |
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// |#######|*******|#######|*******|#######|
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// |###+###|***+***|###+###|***+***|###+###|
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// |# C_0 #|* C_1 *|# C_2 #|* C_3 *|# C_n #|
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// | ##### | ***** | ##### | ***** | ##### |
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// +-------+-------+-------+-------+-------+
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// 1
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//
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// targetCount = 6
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// mCount = 2
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// 1 2 3 4 5 6
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// +-------+-------+-------+-------+-------+-------+-------+
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// | ##### | ***** | ##### | ***** | ##### | ***** | ##### |
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// |#######|*******|#######|*******|#######|*******|#######|
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// |###+###|***+***|###+###|***+***|###+###|***+***|###+###|
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// |# C_0 #|* C_1 *|# C_2 #|* C_3 *|# C_4 #|* C_5 *|# C_n #|
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// | ##### | ***** | ##### | ***** | ##### | ***** | ##### |
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// +-------+-------+-------+-------+-------+-------+-------+
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// 1 2
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if (count % 2) {
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targetCount = count + 1;
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} else {
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targetCount = count;
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}
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mCount = targetCount / 2 - 1;
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}
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if (count == targetCount) {
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mBestOverlap = overlap;
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|
|
if (fabs(actualOverlap - overlap) < OVERLAP_MARGIN) {
|
|
break;
|
|
}
|
|
|
|
// We started from upper bound, no need to update range when j == 0.
|
|
if (j > 0) {
|
|
if (actualOverlap > overlap) {
|
|
lower = overlap;
|
|
} else {
|
|
upper = overlap;
|
|
}
|
|
}
|
|
} else {
|
|
// |j == 0 && count != targetCount| means that |targetCount = count + 1|,
|
|
// and we started from upper bound, no need to update range when j == 0.
|
|
if (j > 0) {
|
|
if (count > targetCount) {
|
|
upper = overlap;
|
|
} else {
|
|
lower = overlap;
|
|
}
|
|
}
|
|
}
|
|
|
|
overlap = (upper + lower) / 2.0f;
|
|
}
|
|
|
|
if (DottedCornerCache.Count() > DottedCornerCacheSize) {
|
|
DottedCornerCache.Clear();
|
|
}
|
|
DottedCornerCache.Put(key, BestOverlap(mBestOverlap, mCount));
|
|
}
|
|
|
|
bool
|
|
DottedCornerFinder::GetCountAndLastOverlap(Float aOverlap,
|
|
size_t* aCount,
|
|
Float* aActualOverlap)
|
|
{
|
|
// Return the number of circles and the last circles' overlap for the
|
|
// given overlap.
|
|
|
|
Reset();
|
|
|
|
const Float T_MARGIN = 0.001f;
|
|
const Float DIST_MARGIN = 0.1f;
|
|
const Float DIST_MARGIN_SQUARE = Square(DIST_MARGIN);
|
|
for (size_t i = 0; i < mMaxCount; i++) {
|
|
Float actualOverlap = FindNext(aOverlap);
|
|
if (mLastT >= 1.0f - T_MARGIN ||
|
|
(mLastC - mCn).LengthSquare() < DIST_MARGIN_SQUARE) {
|
|
*aCount = i + 1;
|
|
*aActualOverlap = actualOverlap;
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
} // namespace mozilla
|