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// Copyright (C) 2008 Lukas Lalinsky
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#include <cmath>
#include <QMouseEvent>
#include <QScrollBar>
#include <QTimer>
#include <QDebug>
#include "diagramview.h"
#include "diagramdocument.h"
using namespace std;
DiagramView::DiagramView(QWidget *parent)
: QGraphicsView(parent),
m_handScrolling(false),
m_autoScrollCount(0),
m_autoScrollMargin(16)
{
setAlignment(Qt::AlignLeft | Qt::AlignTop);
setRenderHint(QPainter::Antialiasing);
setDragMode(QGraphicsView::RubberBandDrag);
setRubberBandSelectionMode(Qt::ContainsItemBoundingRect);
m_autoScrollTimer = new QTimer(this);
connect(m_autoScrollTimer, SIGNAL(timeout()), SLOT(doAutoScroll()));
}
DiagramDocument *
DiagramView::document() const
{
return static_cast<DiagramDocument *>(scene());
}
void
DiagramView::setScene(QGraphicsScene *scene)
{
QGraphicsView::setScene(scene);
updateSceneRect2(scene->sceneRect());
connect(scene, SIGNAL(sceneRectChanged(const QRectF &)), SLOT(updateSceneRect2(const QRectF &)));
}
void
DiagramView::updateSceneRect2(const QRectF &rect)
{
QRectF sceneRect = rect.united(QRectF(QPointF(0, 0), QPointF(100, 100)));
setSceneRect(sceneRect);
}
void
DiagramView::mousePressEvent(QMouseEvent *event)
{
if (event->button() == Qt::MidButton) {
m_handScrolling = true;
m_handScrollingOrigin = QPoint(event->pos());
m_handScrollingValueX = horizontalScrollBar()->value();
m_handScrollingValueY = verticalScrollBar()->value();
m_savedCursor = viewport()->cursor();
viewport()->setCursor(Qt::ClosedHandCursor);
event->accept();
return;
}
QGraphicsView::mousePressEvent(event);
}
void
DiagramView::mouseMoveEvent(QMouseEvent *event)
{
if (m_handScrolling) {
QPoint delta = event->pos() - m_handScrollingOrigin;
horizontalScrollBar()->setValue(m_handScrollingValueX - delta.x());
verticalScrollBar()->setValue(m_handScrollingValueY - delta.y());
event->accept();
return;
}
QGraphicsView::mouseMoveEvent(event);
if (event->buttons() && !isAutoScrolling() && shouldAutoScroll(event->pos())) {
startAutoScroll();
}
}
void
DiagramView::mouseReleaseEvent(QMouseEvent *event)
{
if (m_handScrolling) {
m_handScrolling = false;
viewport()->setCursor(m_savedCursor);
event->accept();
return;
}
QGraphicsView::mouseReleaseEvent(event);
}
void
DiagramView::drawBackground(QPainter *painter, const QRectF &rect)
{
DiagramDocument *doc = document();
if (doc && doc->isGridVisible()) {
drawGrid(painter, rect);
}
}
void
DiagramView::drawGrid(QPainter *painter, const QRectF &rect)
{
const int pointBufferSize = 5000;
static QPoint pointBuffer[pointBufferSize];
DiagramDocument *doc = document();
int gridSize = doc->gridSize();
int x0 = gridSize * floor(rect.left() / gridSize);
int y0 = gridSize * floor(rect.top() / gridSize);
int x1 = gridSize * ceil(rect.right() / gridSize);
int y1 = gridSize * ceil(rect.bottom() / gridSize);
painter->save();
QPen pen;
pen.setColor(doc->gridColor());
pen.setWidth(0);
painter->setPen(pen);
painter->setRenderHint(QPainter::Antialiasing, false);
int pointsUsed = 0;
for (int x = x0; x < x1; x += gridSize) {
for (int y = y0; y < y1; y += gridSize) {
pointBuffer[pointsUsed].setX(x);
pointBuffer[pointsUsed].setY(y);
pointsUsed++;
if (pointsUsed == pointBufferSize) {
painter->drawPoints(pointBuffer, pointsUsed);
pointsUsed = 0;
}
}
}
if (pointsUsed > 0) {
painter->drawPoints(pointBuffer, pointsUsed);
pointsUsed = 0;
}
painter->restore();
}
static QRect
clipRect(QWidget *w)
{
if (!w->isVisible())
return QRect();
QRect r = w->rect();
int ox = 0;
int oy = 0;
while (w
&& w->isVisible()
&& !w->isWindow()
&& w->parentWidget()) {
ox -= w->x();
oy -= w->y();
w = w->parentWidget();
r &= QRect(ox, oy, w->width(), w->height());
}
return r;
}
void
DiagramView::startAutoScroll()
{
m_autoScrollTimer->start(50);
m_autoScrollCount = 0;
}
void
DiagramView::stopAutoScroll()
{
m_autoScrollTimer->stop();
m_autoScrollCount = 0;
}
bool
DiagramView::isAutoScrolling() const
{
return m_autoScrollTimer->isActive();
}
bool
DiagramView::shouldAutoScroll(const QPoint &pos) const
{
QRect area = clipRect(viewport());
return (pos.y() - area.top() < m_autoScrollMargin)
|| (area.bottom() - pos.y() < m_autoScrollMargin)
|| (pos.x() - area.left() < m_autoScrollMargin)
|| (area.right() - pos.x() < m_autoScrollMargin);
}
void
DiagramView::doAutoScroll()
{
int verticalStep = verticalScrollBar()->pageStep();
int horizontalStep = horizontalScrollBar()->pageStep();
if (m_autoScrollCount < qMax(verticalStep, horizontalStep))
++m_autoScrollCount;
int verticalValue = verticalScrollBar()->value();
int horizontalValue = horizontalScrollBar()->value();
QPoint pos = viewport()->mapFromGlobal(QCursor::pos());
QRect area = clipRect(viewport());
if (pos.y() - area.top() < m_autoScrollMargin)
verticalScrollBar()->setValue(verticalValue - m_autoScrollCount);
else if (area.bottom() - pos.y() < m_autoScrollMargin)
verticalScrollBar()->setValue(verticalValue + m_autoScrollCount);
if (pos.x() - area.left() < m_autoScrollMargin)
horizontalScrollBar()->setValue(horizontalValue - m_autoScrollCount);
else if (area.right() - pos.x() < m_autoScrollMargin)
horizontalScrollBar()->setValue(horizontalValue + m_autoScrollCount);
bool verticalUnchanged = (verticalValue == verticalScrollBar()->value());
bool horizontalUnchanged = (horizontalValue == horizontalScrollBar()->value());
if (verticalUnchanged && horizontalUnchanged) {
stopAutoScroll();
} else {
viewport()->update();
}
}
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