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Zoom about mouse cursor

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This commit is contained in:
Matt Keeter 2014-03-24 19:32:12 -04:00
parent 9283aa4752
commit 54206d3f9c
1 changed files with 13 additions and 1 deletions
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14
src/canvas.cpp
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@ -161,7 +161,6 @@ void Canvas::mouseMoveEvent(QMouseEvent* event)
}
else if (event->buttons() & Qt::RightButton)
{
qDebug() << d;
center = transform_matrix().inverted() *
view_matrix().inverted() *
QVector3D(-d.x() / (0.5*width()),
@ -173,6 +172,14 @@ void Canvas::mouseMoveEvent(QMouseEvent* event)
void Canvas::wheelEvent(QWheelEvent *event)
{
// Find GL position before the zoom operation
// (to zoom about mouse cursor)
auto p = event->pos();
QVector3D v(1 - p.x() / (0.5*width()),
p.y() / (0.5*height()) - 1, 0);
QVector3D a = transform_matrix().inverted() *
view_matrix().inverted() * v;
if (event->delta() < 0)
{
for (int i=0; i > event->delta(); --i)
@ -183,5 +190,10 @@ void Canvas::wheelEvent(QWheelEvent *event)
for (int i=0; i < event->delta(); ++i)
zoom /= 1.001;
}
// Then find the cursor's GL position post-zoom and adjust center.
QVector3D b = transform_matrix().inverted() *
view_matrix().inverted() * v;
center += b - a;
update();
}