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# ignore-this-changeset --HG-- extra : amend_source : 4d301d3b0b8711c4692392aa76088ba7fd7d1022
433 lines
14 KiB
C++
433 lines
14 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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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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#ifndef mozilla_DottedCornerFinder_h_
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#define mozilla_DottedCornerFinder_h_
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#include "mozilla/gfx/2D.h"
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#include "mozilla/gfx/BezierUtils.h"
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#include "gfxRect.h"
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namespace mozilla {
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// Calculate C_i and r_i for each filled/unfilled circles in dotted corner.
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// Returns circle with C_{2j} and r_{2j} where 0 < 2j < n.
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//
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// ____-----------+
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// __---- ***** ###|
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// __---- ********* ####|
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// __--- ##### ***********#####|
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// _-- ######### *****+*****#####+ C_0
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// _- ########### *** C_1****#####|
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// / #####+##### ********* ####|
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// / . ### C_2 ### ***** ###|
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// | ######### ____-------+
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// | . #####____-----
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// | __----
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// | . /
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// | /
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// | ***** |
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// | ******* |
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// |*********|
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// |****+****|
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// | C_{n-1} |
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// | ******* |
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// | ***** |
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// | ##### |
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// | ####### |
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// |#########|
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// +----+----+
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// C_n
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class DottedCornerFinder {
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typedef mozilla::gfx::Bezier Bezier;
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typedef mozilla::gfx::Float Float;
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typedef mozilla::gfx::Point Point;
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typedef mozilla::gfx::Size Size;
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public:
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struct Result {
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// Center point of dot and its radius.
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Point C;
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Float r;
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Result(const Point& aC, Float aR) : C(aC), r(aR) { MOZ_ASSERT(aR >= 0); }
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};
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// aBorderRadiusX
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// aCornerDim.width
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// |<----------------->|
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// | | v
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// --+-------------___---+--
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// ^ | __-- | |
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// | | _- | | aR0
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// | | / aC0 +--
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// | | / | ^
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// | | | |
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// aBorderRadiusY | | | __--+
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// aCornerDim.height | || _-
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// | || /
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// | | /
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// | | |
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// | | |
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// | | |
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// | | |
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// v | aCn |
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// --+----+----+
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// | |
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// |<-->|
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// aRn
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//
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// aCornerDim and (aBorderRadiusX, aBorderRadiusY) can be different when
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// aBorderRadiusX is smaller than aRn*2 or
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// aBorderRadiusY is smaller than aR0*2.
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//
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// aCornerDim.width
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// |<----------------->|
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// | |
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// | aBorderRadiusX |
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// |<--------->| |
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// | | |
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// -------------------+-------__--+-------+--
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// ^ ^ | _- | ^
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// | | | / | |
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// | | | / | |
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// | aBorderRadiusY | | | | | aR0
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// | | || | |
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// | | | | |
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// aCornerDim.height | v | | v
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// | --+ aC0 +--
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// | | |
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// | | |
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// | | |
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// | | |
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// | | |
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// v | aCn |
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// -------------------+---------+---------+
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// | |
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// |<------->|
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// aRn
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DottedCornerFinder(const Bezier& aOuterBezier, const Bezier& aInnerBezier,
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mozilla::Corner aCorner, Float aBorderRadiusX,
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Float aBorderRadiusY, const Point& aC0, Float aR0,
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const Point& aCn, Float aRn, const Size& aCornerDim);
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bool HasMore(void) const;
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Result Next(void);
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private:
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static const size_t MAX_LOOP = 32;
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// Bezier control points for the outer curve, the inner curve, and a curve
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// that center points of circles are on (center curve).
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//
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// ___---+ outer curve
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// __-- |
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// _- |
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// / __---+ center curve
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// / __-- |
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// | / |
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// | / __--+ inner curve
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// | | _-
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// | | /
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// | | /
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// | | |
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// | | |
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// | | |
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// | | |
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// | | |
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// +----+----+
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Bezier mOuterBezier;
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Bezier mInnerBezier;
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Bezier mCenterBezier;
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mozilla::Corner mCorner;
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// Sign of the normal vector used in radius calculation, flipped depends on
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// corner and start and end radii.
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Float mNormalSign;
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// Center points and raii for start and end circles, mR0 >= mRn.
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// mMaxR = max(mR0, mRn)
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//
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// v
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// ___---+------
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// __-- #|# | mRn
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// _- ##|## |
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// / ##+## ---
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// / mCn ^
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// | #|#
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// | __--+
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// | _-
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// | /
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// | /
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// | |
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// | |
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// | ##### |
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// | ####### |
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// |#########|
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// +----+----+
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// |## mC0 ##|
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// | ####### |
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// | ##### |
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// | |
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// |<-->|
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//
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// mR0
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//
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Point mC0;
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Point mCn;
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Float mR0;
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Float mRn;
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Float mMaxR;
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// Parameters for the center curve with perfect circle and the inner curve.
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// The center curve doesn't necessarily share the origin with others.
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//
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// ___---+
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// __-- |
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// _- |
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// / __-+ |
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// / __-- |
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// | / |
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// | / __--+--
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// | | _- | ^
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// | | / | |
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// | | / | |
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// | | | | |
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// | | | | | mInnerHeight
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// | | | | |
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// | + | | |
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// | | | v
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// +---------+---------+
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// | | mInnerCurveOrigin
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// |<------->|
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// mInnerWidth
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//
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// ___---+
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// __--
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// _-
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// / __-+
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// / __-- |
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// | / |
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// | / __--+
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// | | _- |
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// | | / |
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// | | / |
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// | | | |
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// | | | |
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// | | | |
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// | +--- | ------+
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// | | | | mCenterCurveOrigin
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// + | + |
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// | |
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// | |
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// | |
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// | |
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// |<---------->|
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// mCenterCurveR
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//
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Point mCenterCurveOrigin;
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Float mCenterCurveR;
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Point mInnerCurveOrigin;
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Float mInnerWidth;
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Float mInnerHeight;
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Point mLastC;
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Float mLastR;
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Float mLastT;
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// Overlap between two circles.
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// It uses arc length on PERFECT, SINGLE_CURVE_AND_RADIUS, and SINGLE_CURVE,
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// and direct distance on OTHER.
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Float mBestOverlap;
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// If one of border-widths is 0, do not calculate overlap, and draw circles
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// until it reaches the other side or exceeds mMaxCount.
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bool mHasZeroBorderWidth;
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bool mHasMore;
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// The maximum number of filled/unfilled circles.
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size_t mMaxCount;
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enum {
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// radius.width
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// |<----------------->|
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// | |
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// --+-------------___---+----
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// ^ | __-- #|# ^
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// | | _- ##|## |
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// | | / ##+## | top-width
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// | | / ##|## |
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// | | | #|# v
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// | | | __--+----
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// radius.height | || _-
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// | || /
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// | | /
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// | | |
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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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// | ##### |
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// | |
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// |<------->|
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// left-width
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// * top-width == left-width
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// * radius.width == radius.height
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// * top-width < radius.width * 2
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//
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// All circles has same radii and are on single perfect circle's arc.
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// Overlap is known.
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//
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// Split the perfect circle's arc into 2n segments, each segment's length is
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// top-width * (1 - overlap). Place each circle's center point C_i on each
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// end of the segment, each circle's radius r_i is top-width / 2
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//
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// #####
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// #######
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// perfect #########
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// circle's ___---+####
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// arc ##### __-- ## C_0 ##
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// | #####_- ###|###
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// | ####+#### ##|##
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// | ##/C_i ## |
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// | |###### |
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// | | ##### |
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// +->| |
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// | |
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// ##|## |
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// ###|### |
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// ####|#### |
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// ####+-------------------+
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// ## C_n ##
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// #######
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// #####
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PERFECT,
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// * top-width == left-width
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// * 0.5 < radius.width / radius.height < 2.0
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// * top-width < min(radius.width, radius.height) * 2
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//
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// All circles has same radii and are on single elliptic arc.
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// Overlap is known.
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//
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// Split the elliptic arc into 2n segments, each segment's length is
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// top-width * (1 - overlap). Place each circle's center point C_i on each
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// end of the segment, each circle's radius r_i is top-width / 2
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//
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// #####
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// #######
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// ##### #########
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// ####### ____----+####
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// elliptic ######__--- ## C_0 ##
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// arc ##__+-### ###|###
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// | / # C_i # ##|##
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// +--> / ##### |
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// | |
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// ###|# |
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// ###|### |
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// ####|#### |
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// ####+------------------------+
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// ## C_n ##
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// #######
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// #####
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SINGLE_CURVE_AND_RADIUS,
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// * top-width != left-width
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// * 0 < min(top-width, left-width)
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// * 0.5 < radius.width / radius.height < 2.0
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// * max(top-width, left-width) < min(radius.width, radius.height) * 2
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//
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// All circles are on single elliptic arc.
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// Overlap is unknown.
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//
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// Place each circle's center point C_i on elliptic arc, each circle's
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// radius r_i is the distance between the center point and the inner curve.
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// The arc segment's length between C_i and C_{i-1} is
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// (r_i + r_{i-1}) * (1 - overlap).
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//
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// outer curve
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// /
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// /
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// / / center curve
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// / ####### /
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// /## /#
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// +# / #
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// /# / #
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// / # C_i / #
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// / # + # /
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// / # / \ # / inner curve
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// # / \ #/
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// # / r_i \+
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// #/ ##/
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// / ####### /
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// /
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SINGLE_CURVE,
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// Other cases.
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// Circles are not on single elliptic arc.
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// Overlap are unknown.
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//
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// Place tangent point innerTangent on the inner curve and find circle's
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// center point C_i and radius r_i where the circle is also tangent to the
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// outer curve.
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// Distance between C_i and C_{i-1} is (r_i + r_{i-1}) * (1 - overlap).
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//
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// outer curve
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// /
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// /
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// /
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// / #######
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// /## ##
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// +# #
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// /# \ #
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// / # \ #
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// / # + # /
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// / # C_i \ # / inner curve
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// # \ #/
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// # r_i \+
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// ## ##/ innerTangent
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// ####### /
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// /
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OTHER
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} mType;
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size_t mI;
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size_t mCount;
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// Determine mType from parameters.
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void DetermineType(Float aBorderRadiusX, Float aBorderRadiusY);
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// Reset calculation.
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void Reset(void);
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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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void FindPointAndRadius(Point& C, Float& r, const Point& innerTangent,
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const Point& normal, Float t);
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// Find next dot.
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Float FindNext(Float overlap);
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// Find mBestOverlap for parameters.
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void FindBestOverlap(Float aMinR, Float aMinBorderRadius,
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Float aMaxBorderRadius);
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// Fill corner with dots with given overlap, and return the number of dots
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// and last two dots's overlap.
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bool GetCountAndLastOverlap(Float aOverlap, size_t* aCount,
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Float* aActualOverlap);
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};
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} // namespace mozilla
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#endif /* mozilla_DottedCornerFinder_h_ */
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