# Length.h   [plain text]

/*
Copyright (C) 1999 Lars Knoll (knoll@kde.org)

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/

#ifndef Length_h
#define Length_h

#include <wtf/Assertions.h>
#include <wtf/MathExtras.h>

namespace WebCore {

class String;

const int undefinedLength = -1;
const int percentScaleFactor = 128;

enum LengthType { Auto, Relative, Percent, Fixed, Static, Intrinsic, MinIntrinsic };

struct Length {
Length()
: m_value(0)
{
}

Length(LengthType t)
: m_value(t)
{
}

Length(int v, LengthType t, bool q = false)
: m_value((v * 16) | (q << 3) | t) // FIXME: Doesn't work if the passed-in value is very large!
{
ASSERT(t != Percent);
}

Length(double v, LengthType t, bool q = false)
: m_value(static_cast<int>(v * percentScaleFactor) * 16 | (q << 3) | t)
{
ASSERT(t == Percent);
}

bool operator==(const Length& o) const { return m_value == o.m_value; }
bool operator!=(const Length& o) const { return m_value != o.m_value; }

int value() const {
ASSERT(type() != Percent);
return rawValue();
}

int rawValue() const { return (m_value & ~0xF) / 16; }

double percent() const
{
ASSERT(type() == Percent);
return static_cast<double>(rawValue()) / percentScaleFactor;
}

LengthType type() const { return static_cast<LengthType>(m_value & 7); }
bool quirk() const { return (m_value >> 3) & 1; }

void setValue(LengthType t, int value)
{
ASSERT(t != Percent);
setRawValue(t, value);
}

void setRawValue(LengthType t, int value) { m_value = value * 16 | (m_value & 0x8) | t; }

void setValue(int value)
{
ASSERT(!value || type() != Percent);
setRawValue(value);
}

void setRawValue(int value) { m_value = value * 16 | (m_value & 0xF); }

void setValue(LengthType t, double value)
{
ASSERT(t == Percent);
m_value = static_cast<int>(value * percentScaleFactor) * 16 | (m_value & 0x8) | t;
}

void setValue(double value)
{
ASSERT(type() == Percent);
m_value = static_cast<int>(value * percentScaleFactor) * 16 | (m_value & 0xF);
}

// note: works only for certain types, returns undefinedLength otherwise
int calcValue(int maxValue, bool roundPercentages = false) const
{
switch (type()) {
case Fixed:
return value();
case Percent:
if (roundPercentages)
return static_cast<int>(round(maxValue * percent() / 100.0));
return maxValue * rawValue() / (100 * percentScaleFactor);
case Auto:
return maxValue;
default:
return undefinedLength;
}
}

int calcMinValue(int maxValue, bool roundPercentages = false) const
{
switch (type()) {
case Fixed:
return value();
case Percent:
if (roundPercentages)
return static_cast<int>(round(maxValue * percent() / 100.0));
return maxValue * rawValue() / (100 * percentScaleFactor);
case Auto:
default:
return 0;
}
}

float calcFloatValue(int maxValue) const
{
switch (type()) {
case Fixed:
return static_cast<float>(value());
case Percent:
return static_cast<float>(maxValue * percent() / 100.0);
case Auto:
return static_cast<float>(maxValue);
default:
return static_cast<float>(undefinedLength);
}
}

bool isUndefined() const { return rawValue() == undefinedLength; }
bool isZero() const { return !(m_value & ~0xF); }
bool isPositive() const { return rawValue() > 0; }
bool isNegative() const { return rawValue() < 0; }

bool isAuto() const { return type() == Auto; }
bool isRelative() const { return type() == Relative; }
bool isPercent() const { return type() == Percent; }
bool isFixed() const { return type() == Fixed; }
bool isStatic() const { return type() == Static; }
bool isIntrinsicOrAuto() const { return type() == Auto || type() == MinIntrinsic || type() == Intrinsic; }

Length blend(const Length& from, double progress) const
{
// Blend two lengths to produce a new length that is in between them.  Used for animation.
if (!from.isZero() && !isZero() && from.type() != type())
return *this;

if (from.isZero() && isZero())
return *this;

LengthType resultType = type();
if (isZero())
resultType = from.type();

if (resultType == Percent) {
double fromPercent = from.isZero() ? 0. : from.percent();
double toPercent = isZero() ? 0. : percent();
return Length(fromPercent + (toPercent - fromPercent) * progress, Percent);
}

int fromValue = from.isZero() ? 0 : from.value();
int toValue = isZero() ? 0 : value();
return Length(int(fromValue + (toValue - fromValue) * progress), resultType);
}

private:
int m_value;
};

Length* newCoordsArray(const String&, int& len);
Length* newLengthArray(const String&, int& len);

} // namespace WebCore

#endif // Length_h