diff options
Diffstat (limited to 'src/qt3support/widgets/q3rangecontrol.cpp')
| -rw-r--r-- | src/qt3support/widgets/q3rangecontrol.cpp | 550 |
1 files changed, 550 insertions, 0 deletions
diff --git a/src/qt3support/widgets/q3rangecontrol.cpp b/src/qt3support/widgets/q3rangecontrol.cpp new file mode 100644 index 0000000..1373f28 --- /dev/null +++ b/src/qt3support/widgets/q3rangecontrol.cpp @@ -0,0 +1,550 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the Qt3Support module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "q3rangecontrol.h" +#ifndef QT_NO_RANGECONTROL +#include "qglobal.h" +#include <limits.h> + +QT_BEGIN_NAMESPACE + +/*! + \class Q3RangeControl + \brief The Q3RangeControl class provides an integer value within a range. + + \compat + + Although originally designed for the QScrollBar widget, the + Q3RangeControl can also be used in conjunction with other widgets + such as QSlider and QSpinBox. Here are the five main concepts in + the class: + + \list 1 + + \i \e{Current value} The bounded integer that + Q3RangeControl maintains. value() returns it, and several + functions, including setValue(), set it. + + \i \e{Minimum} The lowest value that value() can ever + return. Returned by minValue() and set by setRange() or one of the + constructors. + + \i \e{Maximum} The highest value that value() can ever + return. Returned by maxValue() and set by setRange() or one of the + constructors. + + \i \e{Line step} The smaller of two natural steps that + Q3RangeControl provides and typically corresponds to the user + pressing an arrow key. The line step is returned by lineStep() + and set using setSteps(). The functions addLine() and + subtractLine() respectively increment and decrement the current + value by lineStep(). + + \i \e{Page step} The larger of two natural steps that + Q3RangeControl provides and typically corresponds to the user + pressing PageUp or PageDown. The page step is returned by + pageStep() and set using setSteps(). The functions addPage() and + substractPage() respectively increment and decrement the current + value by pageStep(). + + \endlist + + Unity (1) may be viewed as a third step size. setValue() lets you + set the current value to any integer in the allowed range, not + just minValue() + \e n * lineStep() for integer values of \e n. + Some widgets may allow the user to set any value at all; others + may just provide multiples of lineStep() or pageStep(). + + Q3RangeControl provides three virtual functions that are well + suited for updating the on-screen representation of range controls + and emitting signals: valueChange(), rangeChange() and + stepChange(). + + Q3RangeControl also provides a function called bound() which lets + you force arbitrary integers to be within the allowed range of the + range control. + + We recommend that all widgets that inherit Q3RangeControl provide + at least a signal called valueChanged(); many widgets will want to + provide addStep(), addPage(), substractStep() and substractPage() + as slots. + + Note that you must use multiple inheritance if you plan to + implement a widget using Q3RangeControl because Q3RangeControl is + not derived from QWidget. +*/ + + +/*! + Constructs a range control with a minimum value of 0, maximum + value of 99, line step of 1, page step of 10 and initial value 0. +*/ + +Q3RangeControl::Q3RangeControl() +{ + minVal = 0; + maxVal = 99; + line = 1; + page = 10; + val = 0; + prevVal = -1; + d = 0; +} + +/*! + Constructs a range control whose value can never be smaller than + \a minValue or greater than \a maxValue, whose line step size is + \a lineStep and page step size is \a pageStep and whose value is + initially \a value (which is guaranteed to be in range using + bound()). +*/ + +Q3RangeControl::Q3RangeControl(int minValue, int maxValue, + int lineStep, int pageStep, + int value) +{ + minVal = minValue; + maxVal = maxValue; + line = QABS(lineStep); + page = QABS(pageStep); + prevVal = minVal - 1; + val = bound(value); + d = 0; +} + +/*! + Destroys the range control +*/ + +Q3RangeControl::~Q3RangeControl() +{ +} + + +/*! + \fn int Q3RangeControl::value() const + + Returns the current range control value. This is guaranteed to be + within the range [minValue(), maxValue()]. + + \sa setValue() prevValue() +*/ + +/*! + \fn int Q3RangeControl::prevValue() const + + Returns the previous value of the range control. "Previous value" + means the value before the last change occurred. Setting a new + range may affect the value, too, because the value is forced to be + inside the specified range. When the range control is initially + created, this is the same as value(). + + prevValue() can be outside the current legal range if a call to + setRange() causes the current value to change. For example, if the + range was [0, 1000] and the current value is 500, setRange(0, 400) + makes value() return 400 and prevValue() return 500. + + \sa value() setRange() +*/ + +/*! + Sets the range control's value to \a value and forces it to be + within the legal range. + + Calls the virtual valueChange() function if the new value is + different from the previous value. The old value can still be + retrieved using prevValue(). + + \sa value() +*/ + +void Q3RangeControl::setValue(int value) +{ + directSetValue(value); + if (prevVal != val) + valueChange(); +} + +/*! + Sets the range control \a value directly without calling + valueChange(). + + Forces the new \a value to be within the legal range. + + You will rarely have to call this function. However, if you want + to change the range control's value inside the overloaded method + valueChange(), setValue() would call the function valueChange() + again. To avoid this recursion you must use directSetValue() + instead. + + \sa setValue() +*/ + +void Q3RangeControl::directSetValue(int value) +{ + prevVal = val; + val = bound(value); +} + +/*! + Equivalent to \c{setValue(value() + pageStep())}. + + If the value is changed, then valueChange() is called. + + \sa subtractPage() addLine() setValue() +*/ + +void Q3RangeControl::addPage() +{ + setValue(value() + pageStep()); +} + +/*! + Equivalent to \c{setValue(value() - pageStep())}. + + If the value is changed, then valueChange() is called. + + \sa addPage() subtractLine() setValue() +*/ + +void Q3RangeControl::subtractPage() +{ + setValue(value() - pageStep()); +} + +/*! + Equivalent to \c{setValue(value() + lineStep())}. + + If the value is changed, then valueChange() is called. + + \sa subtractLine() addPage() setValue() +*/ + +void Q3RangeControl::addLine() +{ + setValue(value() + lineStep()); +} + +/*! + Equivalent to \c{setValue(value() - lineStep())}. + + If the value is changed, then valueChange() is called. + + \sa addLine() subtractPage() setValue() +*/ + +void Q3RangeControl::subtractLine() +{ + setValue(value() - lineStep()); +} + + +/*! + \fn int Q3RangeControl::minValue() const + + Returns the minimum value of the range. + + \sa setMinValue() setRange() maxValue() +*/ + +/*! + \fn int Q3RangeControl::maxValue() const + + Returns the maximum value of the range. + + \sa setMaxValue() setRange() minValue() +*/ + +/*! + Sets the minimum value of the range to \a minVal. + + If necessary, the maxValue() is adjusted so that the range remains + valid. + + \sa minValue() setMaxValue() +*/ +void Q3RangeControl::setMinValue(int minVal) +{ + int maxVal = maxValue(); + if (maxVal < minVal) + maxVal = minVal; + setRange(minVal, maxVal); +} + +/*! + Sets the minimum value of the range to \a maxVal. + + If necessary, the minValue() is adjusted so that the range remains + valid. + + \sa maxValue() setMinValue() +*/ +void Q3RangeControl::setMaxValue(int maxVal) +{ + int minVal = minValue(); + if (minVal > maxVal) + minVal = maxVal; + setRange(minVal, maxVal); +} + +/*! + Sets the range control's minimum value to \a minValue and its + maximum value to \a maxValue. + + Calls the virtual rangeChange() function if one or both of the new + minimum and maximum values are different from the previous + setting. Calls the virtual valueChange() function if the current + value is adjusted because it was outside the new range. + + If \a maxValue is smaller than \a minValue, \a minValue becomes + the only legal value. + + \sa minValue() maxValue() +*/ + +void Q3RangeControl::setRange(int minValue, int maxValue) +{ + if (minValue > maxValue) { + qWarning("Q3RangeControl::setRange: minValue %d > maxValue %d", + minValue, maxValue); + maxValue = minValue; + } + if (minValue == minVal && maxValue == maxVal) + return; + minVal = minValue; + maxVal = maxValue; + int tmp = bound(val); + rangeChange(); + if (tmp != val) { + prevVal = val; + val = tmp; + valueChange(); + } +} + + +/*! + \fn int Q3RangeControl::lineStep() const + + Returns the line step. + + \sa setSteps() pageStep() +*/ + +/*! + \fn int Q3RangeControl::pageStep() const + + Returns the page step. + + \sa setSteps() lineStep() +*/ + +/*! + Sets the range's line step to \a lineStep and page step to \a + pageStep. + + Calls the virtual stepChange() function if the new line step + or page step are different from the previous settings. + + \sa lineStep() pageStep() setRange() +*/ + +void Q3RangeControl::setSteps(int lineStep, int pageStep) +{ + if (lineStep != line || pageStep != page) { + line = QABS(lineStep); + page = QABS(pageStep); + stepChange(); + } +} + + +/*! + This virtual function is called whenever the range control value + changes. You can reimplement it if you want to be notified when + the value changes. The default implementation does nothing. + + Note that this method is called after the value has changed. The + previous value can be retrieved using prevValue(). + + \sa setValue(), addPage(), subtractPage(), addLine(), + subtractLine() rangeChange(), stepChange() +*/ + +void Q3RangeControl::valueChange() +{ +} + + +/*! + This virtual function is called whenever the range control's range + changes. You can reimplement it if you want to be notified when + the range changes. The default implementation does nothing. + + Note that this method is called after the range has changed. + + \sa setRange(), valueChange(), stepChange() +*/ + +void Q3RangeControl::rangeChange() +{ +} + + +/*! + This virtual function is called whenever the range control's + line or page step settings change. You can reimplement it if you + want to be notified when the step changes. The default + implementation does nothing. + + Note that this method is called after a step setting has changed. + + \sa setSteps(), rangeChange(), valueChange() +*/ + +void Q3RangeControl::stepChange() +{ +} + + +/*! + Forces the value \a v to be within the range from minValue() to + maxValue() inclusive, and returns the result. + + This function is provided so that you can easily force other + numbers than value() into the allowed range. You do not need to + call it in order to use Q3RangeControl itself. + + \sa setValue() value() minValue() maxValue() +*/ + +int Q3RangeControl::bound(int v) const +{ + if (v < minVal) + return minVal; + if (v > maxVal) + return maxVal; + return v; +} + + +/*! + Converts \a logical_val to a pixel position. minValue() maps to 0, + maxValue() maps to \a span and other values are distributed evenly + in-between. + + This function can handle the entire integer range without + overflow, providing \a span is \<= 4096. + + Calling this method is useful when actually drawing a range + control such as a QScrollBar on-screen. + + \sa valueFromPosition() +*/ + +int Q3RangeControl::positionFromValue(int logical_val, int span) const +{ + if (span <= 0 || logical_val < minValue() || maxValue() <= minValue()) + return 0; + if (logical_val > maxValue()) + return span; + + uint range = maxValue() - minValue(); + uint p = logical_val - minValue(); + + if (range > (uint)INT_MAX/4096) { + const int scale = 4096*2; + return ((p/scale) * span) / (range/scale); + // ### the above line is probably not 100% correct + // ### but fixing it isn't worth the extreme pain... + } else if (range > (uint)span) { + return (2*p*span + range) / (2*range); + } else { + uint div = span / range; + uint mod = span % range; + return p*div + (2*p*mod + range) / (2*range); + } + //equiv. to (p*span)/range + 0.5 + // no overflow because of this implicit assumption: + // span <= 4096 +} + + +/*! + Converts the pixel position \a pos to a value. 0 maps to + minValue(), \a span maps to maxValue() and other values are + distributed evenly in-between. + + This function can handle the entire integer range without + overflow. + + Calling this method is useful if you actually implemented a range + control widget such as QScrollBar and want to handle mouse press + events. This function then maps screen coordinates to the logical + values. + + \sa positionFromValue() +*/ + +int Q3RangeControl::valueFromPosition(int pos, int span) const +{ + if (span <= 0 || pos <= 0) + return minValue(); + if (pos >= span) + return maxValue(); + + uint range = maxValue() - minValue(); + + if ((uint)span > range) + return minValue() + (2*pos*range + span) / (2*span); + else { + uint div = range / span; + uint mod = range % span; + return minValue() + pos*div + (2*pos*mod + span) / (2*span); + } + // equiv. to minValue() + (pos*range)/span + 0.5 + // no overflow because of this implicit assumption: + // pos <= span < sqrt(INT_MAX+0.0625)+0.25 ~ sqrt(INT_MAX) +} + +QT_END_NAMESPACE + +#endif // QT_NO_RANGECONTROL |