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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
#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::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::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_ */