我们可以在 JfreeChart 中将平移功能实现为鼠标拖动事件吗？现在，我按 CTRL 并拖动鼠标来平移图表。我想通过拖动鼠标来实现平移功能。这可能吗？
使用当前的 JFreeChart API 显然不可能更改修饰键，如here所述（但它正在管道中）。
但是，可以通过编程方式平移图表，因此您可以尝试以下操作：
MouseMotionListenerChartPanelmouseDragged()XYPlot.panDomainAxes()XYPlot.panRangeAxis()从
ChartPanel/**
* Temporary storage for the width and height of the chart
* drawing area during panning.
*/
private double panW, panH;
/** The last mouse position during panning. */
private Point panLast;
/**
* The mask for mouse events to trigger panning.
*
* @since 1.0.13
*/
private int panMask = InputEvent.CTRL_MASK;
...
/**
* Handles a 'mouse pressed' event.
* <P>
* This event is the popup trigger on Unix/Linux. For Windows, the popup
* trigger is the 'mouse released' event.
*
* @param e The mouse event.
*/
@Override
public void mousePressed(MouseEvent e) {
if (this.chart == null) {
return;
}
Plot plot = this.chart.getPlot();
int mods = e.getModifiers();
if ((mods & this.panMask) == this.panMask) {
// can we pan this plot?
if (plot instanceof Pannable) {
Pannable pannable = (Pannable) plot;
if (pannable.isDomainPannable() || pannable.isRangePannable()) {
Rectangle2D screenDataArea = getScreenDataArea(e.getX(),
e.getY());
if (screenDataArea != null && screenDataArea.contains(
e.getPoint())) {
this.panW = screenDataArea.getWidth();
this.panH = screenDataArea.getHeight();
this.panLast = e.getPoint();
setCursor(Cursor.getPredefinedCursor(
Cursor.MOVE_CURSOR));
}
}
// the actual panning occurs later in the mouseDragged()
// method
}
}
else if (this.zoomRectangle == null) {
...
}
}
...
/**
* Handles a 'mouse dragged' event.
*
* @param e the mouse event.
*/
@Override
public void mouseDragged(MouseEvent e) {
// if the popup menu has already been triggered, then ignore dragging...
if (this.popup != null && this.popup.isShowing()) {
return;
}
// handle panning if we have a start point
if (this.panLast != null) {
double dx = e.getX() - this.panLast.getX();
double dy = e.getY() - this.panLast.getY();
if (dx == 0.0 && dy == 0.0) {
return;
}
double wPercent = -dx / this.panW;
double hPercent = dy / this.panH;
boolean old = this.chart.getPlot().isNotify();
this.chart.getPlot().setNotify(false);
Pannable p = (Pannable) this.chart.getPlot();
if (p.getOrientation() == PlotOrientation.VERTICAL) {
p.panDomainAxes(wPercent, this.info.getPlotInfo(),
this.panLast);
p.panRangeAxes(hPercent, this.info.getPlotInfo(),
this.panLast);
}
else {
p.panDomainAxes(hPercent, this.info.getPlotInfo(),
this.panLast);
p.panRangeAxes(wPercent, this.info.getPlotInfo(),
this.panLast);
}
this.panLast = e.getPoint();
this.chart.getPlot().setNotify(old);
return;
}
...
}
...
/**
* Handles a 'mouse released' event. On Windows, we need to check if this
* is a popup trigger, but only if we haven't already been tracking a zoom
* rectangle.
*
* @param e information about the event.
*/
@Override
public void mouseReleased(MouseEvent e) {
// if we've been panning, we need to reset now that the mouse is
// released...
if (this.panLast != null) {
this.panLast = null;
setCursor(Cursor.getDefaultCursor());
}
...
}
编辑：注意到当前API的唯一问题是
panMaskField mask = ChartPanel.class.getDeclaredField("panMask");
mask.setAccessible(true);
mask.set(yourChartPanel, Integer.valueOf(0)); // The "0" mask is equivalent to no mask. You could also set a different modifier.
新版本仍然没有提供解决方案，所以我把对我来说完美无缺的东西，当你滚动时它也会自动缩放范围轴：
ChartPanel panel = new ChartPanel(chart);
panel.setMouseZoomable(false);
panel.setMouseWheelEnabled(true);
panel.setDomainZoomable(true);
panel.setRangeZoomable(false);
panel.setPreferredSize(new Dimension(1680, 1100));
panel.setZoomTriggerDistance(Integer.MAX_VALUE);
panel.setFillZoomRectangle(false);
panel.setZoomOutlinePaint(new Color(0f, 0f, 0f, 0f));
panel.setZoomAroundAnchor(true);
try {
Field mask = ChartPanel.class.getDeclaredField("panMask");
mask.setAccessible(true);
mask.set(panel, 0);
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
panel.addMouseWheelListener(arg0 -> panel.restoreAutoRangeBounds());
现在 JFreeChart 的行为就像任何其他专业图表软件一样。
这是我的解决方案。
问候 TA
ChartPanel cp = new ChartPanel(chart)
{
/**
* A hack to change the zoom and panning function.
* With this override we can pan around by dragging.
* If SHIFT is pressed we get the zoom rectangle.
* @param e
*/
@Override
public void mousePressed(MouseEvent e)
{
int mods = e.getModifiers();
int panMask = MouseEvent.BUTTON1_MASK;
if (mods == MouseEvent.BUTTON1_MASK+MouseEvent.SHIFT_MASK)
{
panMask = 255; //The pan test will match nothing and the zoom rectangle will be activated.
}
try
{
Field mask = ChartPanel.class.getDeclaredField("panMask");
mask.setAccessible(true);
mask.set(this, panMask);
}
catch (Exception ex)
{
ex.printStackTrace();
}
super.mousePressed(e);
}
};
受之前答案的启发，我制作了以下重写方法，在输入原始方法之前替换鼠标事件值（Jfreechart 版本 1.5.4）
ChartPanel panel = new ChartPanel(chart) {
// for MacOSX we can't use the CTRL key for mouse drags, see:
// http://developer.apple.com/qa/qa2004/qa1362.html
int panMask1 = System.getProperty("os.name").toLowerCase().startsWith("mac os x") ? InputEvent.ALT_MASK : InputEvent.CTRL_MASK;
@Override
public void mousePressed(MouseEvent e) {
int mods = e.getModifiers();
if ((mods & panMask1) == panMask1)
mods -= panMask1;
else
mods += panMask1;
MouseEvent e2 = new MouseEvent((Component) e.getSource(), e.getID(), e.getWhen(), mods, e.getX(),
e.getY(), e.getClickCount(), e.isPopupTrigger());
super.mousePressed(e2);
}
};