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Diffstat (limited to 'layout/base/DottedCornerFinder.h')
| -rw-r--r-- | layout/base/DottedCornerFinder.h | 438 |
1 files changed, 438 insertions, 0 deletions
diff --git a/layout/base/DottedCornerFinder.h b/layout/base/DottedCornerFinder.h new file mode 100644 index 000000000..79eba5af8 --- /dev/null +++ b/layout/base/DottedCornerFinder.h @@ -0,0 +1,438 @@ +/* -*- Mode: C++; tab-width: 2; 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 mozilla_DottedCornerFinder_h_ +#define mozilla_DottedCornerFinder_h_ + +#include "mozilla/gfx/2D.h" +#include "mozilla/gfx/BezierUtils.h" +#include "gfxRect.h" + +namespace mozilla { + +// Calculate C_i and r_i for each filled/unfilled circles in dotted corner. +// Returns circle with C_{2j} and r_{2j} where 0 < 2j < n. +// +// ____-----------+ +// __---- ***** ###| +// __---- ********* ####| +// __--- ##### ***********#####| +// _-- ######### *****+*****#####+ C_0 +// _- ########### *** C_1****#####| +// / #####+##### ********* ####| +// / . ### C_2 ### ***** ###| +// | ######### ____-------+ +// | . #####____----- +// | __---- +// | . / +// | / +// | ***** | +// | ******* | +// |*********| +// |****+****| +// | C_{n-1} | +// | ******* | +// | ***** | +// | ##### | +// | ####### | +// |#########| +// +----+----+ +// C_n + +class DottedCornerFinder +{ + typedef mozilla::gfx::Bezier Bezier; + typedef mozilla::gfx::Float Float; + typedef mozilla::gfx::Point Point; + typedef mozilla::gfx::Size Size; + +public: + struct Result + { + // Center point of dot and its radius. + Point C; + Float r; + + Result(const Point& aC, Float aR) + : C(aC), r(aR) + { + MOZ_ASSERT(aR >= 0); + } + }; + + // aBorderRadiusX + // aCornerDim.width + // |<----------------->| + // | | v + // --+-------------___---+-- + // ^ | __-- | | + // | | _- | | aR0 + // | | / aC0 +-- + // | | / | ^ + // | | | | + // aBorderRadiusY | | | __--+ + // aCornerDim.height | || _- + // | || / + // | | / + // | | | + // | | | + // | | | + // | | | + // v | aCn | + // --+----+----+ + // | | + // |<-->| + // aRn + // + // aCornerDim and (aBorderRadiusX, aBorderRadiusY) can be different when + // aBorderRadiusX is smaller than aRn*2 or + // aBorderRadiusY is smaller than aR0*2. + // + // aCornerDim.width + // |<----------------->| + // | | + // | aBorderRadiusX | + // |<--------->| | + // | | | + // -------------------+-------__--+-------+-- + // ^ ^ | _- | ^ + // | | | / | | + // | | | / | | + // | aBorderRadiusY | | | | | aR0 + // | | || | | + // | | | | | + // aCornerDim.height | v | | v + // | --+ aC0 +-- + // | | | + // | | | + // | | | + // | | | + // | | | + // v | aCn | + // -------------------+---------+---------+ + // | | + // |<------->| + // aRn + DottedCornerFinder(const Bezier& aOuterBezier, const Bezier& aInnerBezier, + mozilla::css::Corner aCorner, + Float aBorderRadiusX, Float aBorderRadiusY, + const Point& aC0, Float aR0, const Point& aCn, Float aRn, + const Size& aCornerDim); + + bool HasMore(void) const; + Result Next(void); + +private: + static const size_t MAX_LOOP = 32; + + // Bezier control points for the outer curve, the inner curve, and a curve + // that center points of circles are on (center curve). + // + // ___---+ outer curve + // __-- | + // _- | + // / __---+ center curve + // / __-- | + // | / | + // | / __--+ inner curve + // | | _- + // | | / + // | | / + // | | | + // | | | + // | | | + // | | | + // | | | + // +----+----+ + Bezier mOuterBezier; + Bezier mInnerBezier; + Bezier mCenterBezier; + + mozilla::css::Corner mCorner; + + // Sign of the normal vector used in radius calculation, flipped depends on + // corner and start and end radii. + Float mNormalSign; + + // Center points and raii for start and end circles, mR0 >= mRn. + // mMaxR = max(mR0, mRn) + // + // v + // ___---+------ + // __-- #|# | mRn + // _- ##|## | + // / ##+## --- + // / mCn ^ + // | #|# + // | __--+ + // | _- + // | / + // | / + // | | + // | | + // | ##### | + // | ####### | + // |#########| + // +----+----+ + // |## mC0 ##| + // | ####### | + // | ##### | + // | | + // |<-->| + // + // mR0 + // + Point mC0; + Point mCn; + Float mR0; + Float mRn; + Float mMaxR; + + // Parameters for the center curve with perfect circle and the inner curve. + // The center curve doesn't necessarily share the origin with others. + // + // ___---+ + // __-- | + // _- | + // / __-+ | + // / __-- | + // | / | + // | / __--+-- + // | | _- | ^ + // | | / | | + // | | / | | + // | | | | | + // | | | | | mInnerHeight + // | | | | | + // | + | | | + // | | | v + // +---------+---------+ + // | | mInnerCurveOrigin + // |<------->| + // mInnerWidth + // + // ___---+ + // __-- + // _- + // / __-+ + // / __-- | + // | / | + // | / __--+ + // | | _- | + // | | / | + // | | / | + // | | | | + // | | | | + // | | | | + // | +--- | ------+ + // | | | | mCenterCurveOrigin + // + | + | + // | | + // | | + // | | + // | | + // |<---------->| + // mCenterCurveR + // + Point mCenterCurveOrigin; + Float mCenterCurveR; + Point mInnerCurveOrigin; + Float mInnerWidth; + Float mInnerHeight; + + Point mLastC; + Float mLastR; + Float mLastT; + + // Overlap between two circles. + // It uses arc length on PERFECT, SINGLE_CURVE_AND_RADIUS, and SINGLE_CURVE, + // and direct distance on OTHER. + Float mBestOverlap; + + // If one of border-widths is 0, do not calculate overlap, and draw circles + // until it reaches the other side or exceeds mMaxCount. + bool mHasZeroBorderWidth; + bool mHasMore; + + // The maximum number of filled/unfilled circles. + size_t mMaxCount; + + enum { + // radius.width + // |<----------------->| + // | | + // --+-------------___---+---- + // ^ | __-- #|# ^ + // | | _- ##|## | + // | | / ##+## | top-width + // | | / ##|## | + // | | | #|# v + // | | | __--+---- + // radius.height | || _- + // | || / + // | | / + // | | | + // | | | + // | | ##### | + // | | ####### | + // v |#########| + // --+----+----+ + // |#########| + // | ####### | + // | ##### | + // | | + // |<------->| + // left-width + + // * top-width == left-width + // * radius.width == radius.height + // * top-width < radius.width * 2 + // + // All circles has same radii and are on single perfect circle's arc. + // Overlap is known. + // + // Split the perfect circle's arc into 2n segments, each segment's length is + // top-width * (1 - overlap). Place each circle's center point C_i on each + // end of the segment, each circle's radius r_i is top-width / 2 + // + // ##### + // ####### + // perfect ######### + // circle's ___---+#### + // arc ##### __-- ## C_0 ## + // | #####_- ###|### + // | ####+#### ##|## + // | ##/C_i ## | + // | |###### | + // | | ##### | + // +->| | + // | | + // ##|## | + // ###|### | + // ####|#### | + // ####+-------------------+ + // ## C_n ## + // ####### + // ##### + PERFECT, + + // * top-width == left-width + // * 0.5 < radius.width / radius.height < 2.0 + // * top-width < min(radius.width, radius.height) * 2 + // + // All circles has same radii and are on single elliptic arc. + // Overlap is known. + // + // Split the elliptic arc into 2n segments, each segment's length is + // top-width * (1 - overlap). Place each circle's center point C_i on each + // end of the segment, each circle's radius r_i is top-width / 2 + // + // ##### + // ####### + // ##### ######### + // ####### ____----+#### + // elliptic ######__--- ## C_0 ## + // arc ##__+-### ###|### + // | / # C_i # ##|## + // +--> / ##### | + // | | + // ###|# | + // ###|### | + // ####|#### | + // ####+------------------------+ + // ## C_n ## + // ####### + // ##### + SINGLE_CURVE_AND_RADIUS, + + // * top-width != left-width + // * 0 < min(top-width, left-width) + // * 0.5 < radius.width / radius.height < 2.0 + // * max(top-width, left-width) < min(radius.width, radius.height) * 2 + // + // All circles are on single elliptic arc. + // Overlap is unknown. + // + // Place each circle's center point C_i on elliptic arc, each circle's + // radius r_i is the distance between the center point and the inner curve. + // The arc segment's length between C_i and C_{i-1} is + // (r_i + r_{i-1}) * (1 - overlap). + // + // outer curve + // / + // / + // / / center curve + // / ####### / + // /## /# + // +# / # + // /# / # + // / # C_i / # + // / # + # / + // / # / \ # / inner curve + // # / \ #/ + // # / r_i \+ + // #/ ##/ + // / ####### / + // / + SINGLE_CURVE, + + // Other cases. + // Circles are not on single elliptic arc. + // Overlap are unknown. + // + // Place tangent point innerTangent on the inner curve and find circle's + // center point C_i and radius r_i where the circle is also tangent to the + // outer curve. + // Distance between C_i and C_{i-1} is (r_i + r_{i-1}) * (1 - overlap). + // + // outer curve + // / + // / + // / + // / ####### + // /## ## + // +# # + // /# \ # + // / # \ # + // / # + # / + // / # C_i \ # / inner curve + // # \ #/ + // # r_i \+ + // ## ##/ innerTangent + // ####### / + // / + OTHER + } mType; + + size_t mI; + size_t mCount; + + // Determine mType from parameters. + void DetermineType(Float aBorderRadiusX, Float aBorderRadiusY); + + // Reset calculation. + void Reset(void); + + // Find radius for the given tangent point on the inner curve such that the + // circle is also tangent to the outer curve. + void FindPointAndRadius(Point& C, Float& r, const Point& innerTangent, + const Point& normal, Float t); + + // Find next dot. + Float FindNext(Float overlap); + + // Find mBestOverlap for parameters. + void FindBestOverlap(Float aMinR, + Float aMinBorderRadius, Float aMaxBorderRadius); + + // Fill corner with dots with given overlap, and return the number of dots + // and last two dots's overlap. + bool GetCountAndLastOverlap(Float aOverlap, + size_t* aCount, Float* aActualOverlap); +}; + +} // namespace mozilla + +#endif /* mozilla_DottedCornerFinder_h_ */ |