About algorithm render tachometer gauge on embedded catalog example and demo
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I read source code in file qtsvgdialgauge.cpp and qtsvgdialgauge.h and in method QtSvgDialGauge::paintEvent I don't understand code lines:
@void QtSvgDialGauge::setNeedleOrigin(qreal x, qreal y)
{
m_originX = qMin(static_cast<qreal>(1.0), qMax(static_cast<qreal>(0.0), x));
m_originY = qMin(static_cast<qreal>(1.0), qMax(static_cast<qreal>(0.0), y));
}@
what is needle origin ,....
@// Tachometer
QtSvgDialGauge *gauge = new QtSvgDialGauge(group);
gauge->setSkin("Tachometer");
gauge->setNeedleOrigin(0.486, 0.466);@
why is 0.486 and 0.466
please help me understand this. Thank in advance![edit : Please use code tags (@ before and after your code) , Eddy]
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@
void QtSvgDialGauge::setNeedleOrigin(qreal x, qreal y)
{
// make sure x is between 0 and 1
m_originX = qMin( // originX = the smaller value of
static_cast<qreal>(1.0), // 1 and
qMax( // the bigger value of
static_cast<qreal>(0.0), // 0 and
x)); // x// make sure y is between 0 and 1 m_originY = qMin(static_cast<qreal>(1.0), qMax(static_cast<qreal>(0.0), y));}@
[quote]
@// Tachometer
QtSvgDialGauge *gauge = new QtSvgDialGauge(group);
gauge->setSkin("Tachometer");
gauge->setNeedleOrigin(0.486, 0.466);
@why is 0.486 and 0.466
[/quote]
It probably looks best... -
I still don't understand why make sure y is between 0 and 1?
I think 0.486 and 0.466 not "it probably looks best..."
anyone can explain for me? -
[quote author="banlinhtienphong" date="1316958365"]I still don't understand why make sure y is between 0 and 1?[/quote] I assume the coordinates need to be defined within the square (0.0,0.0)-(1.0,1.0). If that's the case, they're making sure the needle origin is within sight.
[quote author="banlinhtienphong" date="1316958365"]
I think 0.486 and 0.466 not "it probably looks best..."
anyone can explain for me?[/quote]What don't you understand? Do you not understand why the needle origin is just a tad off-center (so not (0.5, 0.5))? Do you not understand what the needle origin is to begin with?It seems you're a non-native English speaker, and I understand that can make it harder to write, but please try to state what exactly you're having trouble with.