зеркало из https://github.com/mozilla/gecko-dev.git
279 строки
9.5 KiB
C++
279 строки
9.5 KiB
C++
/* -*- 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_DashedCornerFinder_h_
|
|
#define mozilla_DashedCornerFinder_h_
|
|
|
|
#include "mozilla/gfx/2D.h"
|
|
#include "mozilla/gfx/BezierUtils.h"
|
|
|
|
namespace mozilla {
|
|
|
|
// Calculate {OuterT_i, InnerT_i} for each 1 < i < n, that
|
|
// (OuterL_i + InnerL_i) / 2 == dashLength * (W_i + W_{i-1}) / 2
|
|
// where
|
|
// OuterP_i: OuterCurve(OuterT_i)
|
|
// InnerP_i: InnerCurve(OuterT_i)
|
|
// OuterL_i: Elliptic arc length between OuterP_i - OuterP_{i-1}
|
|
// InnerL_i: Elliptic arc length between InnerP_i - InnerP_{i-1}
|
|
// W_i = |OuterP_i - InnerP_i|
|
|
// 1.0 < dashLength < 3.0
|
|
//
|
|
// OuterP_1 OuterP_0
|
|
// _+__-----------+ OuterCurve
|
|
// OuterP_2 __---- | OuterL_1 |
|
|
// __+--- | |
|
|
// __--- | OuterL_2 | |
|
|
// OuterP_3 _-- | | W_1 | W_0
|
|
// _+ | | |
|
|
// / \ W_2 | | |
|
|
// / \ | | InnerL_1 |
|
|
// | \ | InnerL_2|____-------+ InnerCurve
|
|
// | \ |____----+ InnerP_0
|
|
// | . \ __---+ InnerP_1
|
|
// | \ / InnerP_2
|
|
// | . /+ InnerP_3
|
|
// | |
|
|
// | . |
|
|
// | |
|
|
// | |
|
|
// | |
|
|
// OuterP_{n-1} +--------+ InnerP_{n-1}
|
|
// | |
|
|
// | |
|
|
// | |
|
|
// | |
|
|
// | |
|
|
// OuterP_n +--------+ InnerP_n
|
|
//
|
|
// Returns region with [OuterCurve((OuterT_{2j} + OuterT_{2j-1}) / 2),
|
|
// OuterCurve((OuterT_{2j} + OuterT_{2j-1}) / 2),
|
|
// InnerCurve((OuterT_{2j} + OuterT_{2j+1}) / 2),
|
|
// InnerCurve((OuterT_{2j} + OuterT_{2j+1}) / 2)],
|
|
// to start and end with half segment.
|
|
//
|
|
// _+__----+------+ OuterCurve
|
|
// _+---- | |######|
|
|
// __+---#| | |######|
|
|
// _+---##|####| | |######|
|
|
// _-- |#####|#####| | |#####|
|
|
// _+ |#####|#####| | |#####|
|
|
// / \ |#####|####| | |#####|
|
|
// / \ |####|#####| | |#####|
|
|
// | \ |####|####| |____-+-----+ InnerCurve
|
|
// | \ |####|____+---+
|
|
// | . \ __+---+
|
|
// | \ /
|
|
// | . /+
|
|
// | |
|
|
// | . |
|
|
// | |
|
|
// | |
|
|
// | |
|
|
// +--------+
|
|
// | |
|
|
// | |
|
|
// +--------+
|
|
// |########|
|
|
// |########|
|
|
// +--------+
|
|
|
|
class DashedCornerFinder
|
|
{
|
|
typedef mozilla::gfx::Bezier Bezier;
|
|
typedef mozilla::gfx::Float Float;
|
|
typedef mozilla::gfx::Point Point;
|
|
typedef mozilla::gfx::Size Size;
|
|
|
|
public:
|
|
struct Result
|
|
{
|
|
// Control points for the outer curve and the inner curve.
|
|
//
|
|
// outerSectionBezier
|
|
// |
|
|
// v _+ 3
|
|
// ___---#|
|
|
// 0 +---#######|
|
|
// |###########|
|
|
// |###########|
|
|
// |##########|
|
|
// |##########|
|
|
// |#########|
|
|
// |#####____+ 3
|
|
// 0 +----
|
|
// ^
|
|
// |
|
|
// innerSectionBezier
|
|
Bezier outerSectionBezier;
|
|
Bezier innerSectionBezier;
|
|
|
|
Result(const Bezier& aOuterSectionBezier,
|
|
const Bezier& aInnerSectionBezier)
|
|
: outerSectionBezier(aOuterSectionBezier),
|
|
innerSectionBezier(aInnerSectionBezier)
|
|
{}
|
|
};
|
|
|
|
// aCornerDim.width
|
|
// |<----------------->|
|
|
// | |
|
|
// --+-------------___---+--
|
|
// ^ | __-- | ^
|
|
// | | _- | |
|
|
// | | / | | aBorderWidthH
|
|
// | | / | |
|
|
// | | | | v
|
|
// | | | __--+--
|
|
// aCornerDim.height | || _-
|
|
// | || /
|
|
// | | /
|
|
// | | |
|
|
// | | |
|
|
// | | |
|
|
// | | |
|
|
// v | |
|
|
// --+---------+
|
|
// | |
|
|
// |<------->|
|
|
// aBorderWidthV
|
|
DashedCornerFinder(const Bezier& aOuterBezier, const Bezier& aInnerBezier,
|
|
Float aBorderWidthH, Float aBorderWidthV,
|
|
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 and the inner curve.
|
|
//
|
|
// ___---+ outer curve
|
|
// __-- |
|
|
// _- |
|
|
// / |
|
|
// / |
|
|
// | |
|
|
// | __--+ inner curve
|
|
// | _-
|
|
// | /
|
|
// | /
|
|
// | |
|
|
// | |
|
|
// | |
|
|
// | |
|
|
// | |
|
|
// +---------+
|
|
Bezier mOuterBezier;
|
|
Bezier mInnerBezier;
|
|
|
|
Point mLastOuterP;
|
|
Point mLastInnerP;
|
|
Float mLastOuterT;
|
|
Float mLastInnerT;
|
|
|
|
// Length for each segment, ratio of the border width at that point.
|
|
Float mBestDashLength;
|
|
|
|
// If one of border-widths is 0, do not calculate mBestDashLength, and draw
|
|
// segments until it reaches the other side or exceeds mMaxCount.
|
|
bool mHasZeroBorderWidth;
|
|
bool mHasMore;
|
|
|
|
// The maximum number of segments.
|
|
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
|
|
//
|
|
// Split the perfect circle's arc into 2n segments, each segment's length is
|
|
// top-width * dashLength. Then split the inner curve and the outer curve
|
|
// with same angles.
|
|
//
|
|
// radius.width
|
|
// |<---------------------->|
|
|
// | | v
|
|
// --+------------------------+--
|
|
// ^ | | | top-width / 2
|
|
// | | perfect | |
|
|
// | | circle's ___---+--
|
|
// | | arc __-+ | ^
|
|
// | | | _- | |
|
|
// radius.height | | | + | +--
|
|
// | | | / \ | |
|
|
// | | | | \ | |
|
|
// | | | | \ | |
|
|
// | | +->| \ | |
|
|
// | | +---__ \ | |
|
|
// | | | --__ \ | |
|
|
// | | | ---__ \ | |
|
|
// v | | --_\||
|
|
// --+----+----+--------------+
|
|
// | | |
|
|
// |<-->| |
|
|
// left-width / 2
|
|
PERFECT,
|
|
|
|
// Other cases.
|
|
//
|
|
// Split the outer curve and the inner curve into 2n segments, each segment
|
|
// satisfies following:
|
|
// (OuterL_i + InnerL_i) / 2 == dashLength * (W_i + W_{i-1}) / 2
|
|
OTHER
|
|
} mType;
|
|
|
|
size_t mI;
|
|
size_t mCount;
|
|
|
|
// Determine mType from parameters.
|
|
void DetermineType(Float aBorderWidthH, Float aBorderWidthV);
|
|
|
|
// Reset calculation.
|
|
void Reset(void);
|
|
|
|
// Find next segment.
|
|
Float FindNext(Float dashLength);
|
|
|
|
// Find mBestDashLength for parameters.
|
|
void FindBestDashLength(Float aMinBorderWidth, Float aMaxBorderWidth,
|
|
Float aMinBorderRadius, Float aMaxBorderRadius);
|
|
|
|
// Fill corner with dashes with given dash length, and return the number of
|
|
// segments and last segment's dash length.
|
|
bool GetCountAndLastDashLength(Float aDashLength,
|
|
size_t* aCount, Float* aActualDashLength);
|
|
};
|
|
|
|
} // namespace mozilla
|
|
|
|
#endif /* mozilla_DashedCornerFinder_h_ */
|