WorldWind Java谷歌地球般缩放
我已经为NASA Worldwind创建了一个输入处理程序，我正在尝试复制谷歌地球，就像放大一样 我正在尝试缩放鼠标光标，而不是屏幕中心（默认情况下是这样） 我已经让它有点工作了——除了它没有持续地向光标下的lat/long缩放外，它似乎漂移得太远了。我想做的是，在缩放期间，光标下保持相同的lat/long。因此，例如，如果您将光标悬停在特定的地标（如水体）上，当滚轮滚动时，它将停留在光标下方 我使用的代码主要基于以下内容： 这是我的输入处理程序：WorldWind Java谷歌地球般缩放,java,math,gis,google-earth,worldwind,Java,Math,Gis,Google Earth,Worldwind,我已经为NASA Worldwind创建了一个输入处理程序，我正在尝试复制谷歌地球，就像放大一样 我正在尝试缩放鼠标光标，而不是屏幕中心（默认情况下是这样） 我已经让它有点工作了——除了它没有持续地向光标下的lat/long缩放外，它似乎漂移得太远了。我想做的是，在缩放期间，光标下保持相同的lat/long。因此，例如，如果您将光标悬停在特定的地标（如水体）上，当滚轮滚动时，它将停留在光标下方 我使用的代码主要基于以下内容： 这是我的输入处理程序： import java.awt.event.M
import java.awt.event.MouseWheelEvent;
import gov.nasa.worldwind.awt.AbstractViewInputHandler;
import gov.nasa.worldwind.awt.ViewInputAttributes;
import gov.nasa.worldwind.geom.Position;
import gov.nasa.worldwind.geom.Vec4;
import gov.nasa.worldwind.view.orbit.BasicOrbitView;
import gov.nasa.worldwind.view.orbit.OrbitViewInputHandler;
public class ZoomToCursorViewInputHandler extends OrbitViewInputHandler {
protected class ZoomActionHandler extends VertTransMouseWheelActionListener {
@Override
public boolean inputActionPerformed(AbstractViewInputHandler inputHandler, MouseWheelEvent mouseWheelEvent,
ViewInputAttributes.ActionAttributes viewAction) {
double zoomInput = mouseWheelEvent.getWheelRotation();
Position position = getView().computePositionFromScreenPoint(mousePoint.x, mousePoint.y);
// Zoom toward the cursor if we're zooming in. Move straight out when zooming
// out.
if (zoomInput < 0 && position != null)
return this.zoomToPosition(position, zoomInput, viewAction);
else
return super.inputActionPerformed(inputHandler, mouseWheelEvent, viewAction);
}
protected boolean zoomToPosition(Position position, double zoomInput,
ViewInputAttributes.ActionAttributes viewAction) {
double zoomChange = zoomInput * getScaleValueZoom(viewAction);
BasicOrbitView view = (BasicOrbitView) getView();
System.out.println("================================");
System.out.println("Center Position: \t\t"+view.getCenterPosition());
System.out.println("Mouse is on Position: \t\t"+position);
Vec4 centerVector = view.getCenterPoint();
Vec4 cursorVector = view.getGlobe().computePointFromLocation(position);
Vec4 delta = cursorVector.subtract3(centerVector);
delta = delta.multiply3(-zoomChange);
centerVector = centerVector.add3(delta);
Position newPosition = view.getGlobe().computePositionFromPoint(centerVector);
System.out.println("New Center Position is: \t"+newPosition);
setCenterPosition(view, uiAnimControl, newPosition, viewAction);
onVerticalTranslate(zoomChange, viewAction);
return true;
}
}
public ZoomToCursorViewInputHandler() {
ViewInputAttributes.ActionAttributes actionAttrs = this.getAttributes()
.getActionMap(ViewInputAttributes.DEVICE_MOUSE_WHEEL)
.getActionAttributes(ViewInputAttributes.VIEW_VERTICAL_TRANSLATE);
actionAttrs.setMouseActionListener(new ZoomActionHandler());
}
}
import java.awt.event.mouseweelEvent；
import gov.nasa.worldwind.awt.AbstractViewInputHandler；
导入gov.nasa.worldwind.awt.viewInputAttribute；
import gov.nasa.worldwind.geom.Position；
import gov.nasa.worldwind.geom.Vec4；
导入gov.nasa.worldwind.view.orbit.BasicOrbitView；
导入gov.nasa.worldwind.view.orbit.OrbitViewInputHandler；
公共类ZoomToCursorViewInputHandler扩展了OrbitViewInputHandler{
受保护类ZoomActionHandler扩展VertTransMouseWheelActionListener{
@凌驾
执行公共布尔输入（AbstractViewInputHandler-inputHandler、MouseWheelEvent、MouseWheelEvent、，
ViewInputAttributes.ActionAttributes（viewAction）{
double zoomInput=mouseWheelEvent.getWheelRotation（）；
Position Position=getView（）.computePositionFromScreenPoint（mousePoint.x，mousePoint.y）；
//如果放大，则向光标缩放。放大时直接向外移动
//出去。
if（zoomInput<0&&position！=null）
返回此.zoomToPosition（位置、zoomInput、viewAction）；
其他的
返回super.inputActionPerformed（inputHandler、mouseWheelEvent、viewAction）；
}
受保护的布尔zoomToPosition（位置，双zoomInput，
ViewInputAttributes.ActionAttributes（viewAction）{
双zoomChange=zoomInput*getScaleValueZoom（viewAction）；
BasicCorbitView视图=（BasicCorbitView）getView（）；
System.out.println（“=======================================================”）；
System.out.println（“中心位置：\t\t”+view.getCenterPosition（））；
System.out.println（“鼠标位于位置：\t\t”+位置）；
Vec4 centerVector=view.getCenterPoint（）；
Vec4 cursorVector=view.getGlobe（）.computePointFromLocation（位置）；
Vec4 delta=游标向量。减去3（中心向量）；
增量=增量倍数3（-zoomChange）；
centerVector=centerVector.add3（增量）；
Position newPosition=view.getGlobe（）.computePositionFromPoint（中心向量）；
System.out.println（“新中心位置为：\t”+新位置）；
setCenterPosition（视图、uiAnimControl、newPosition、viewAction）；
onVerticalTranslate（zoomChange、viewAction）；
返回true；
}
}
公共ZoomToCursorViewInputHandler（）{
ViewInputAttributes.ActionAttributes ActionAttributes=this.getAttributes（）
.getActionMap（ViewInputAttribute.DEVICE\u鼠标\u滚轮）
.getActionAttributes（ViewInputAttribute.VIEW\u VERTICAL\u TRANSLATE）；
setMouseActionListener（新的ZoomActionHandler（））；
}
}
<Property name="gov.nasa.worldwind.avkey.ViewInputHandlerClassName"
value="gov.nasa.worldwindx.examples.ZoomToCursorViewInputHandler"/>
经过对这个问题的思考，我相信没有封闭形式的解析解。你只需要考虑很多事情：地球的形状，当你移动中心时“眼睛”是如何移动的。所以我认为你能做的最好的技巧就是跟随主要的“缩放”动画，并在每个动画步骤后做一些小的调整。由于动画步骤很小，计算误差也应该较小，并且累积的误差应该较小，因为在下一步中，您将考虑所有以前的误差。因此，我在代码中的想法大致如下：创建一个
FixZoomPositionAnimatorstatic class FixZoomPositionAnimator extends BasicAnimator
{
static final String VIEW_ANIM_KEY = "FixZoomPositionAnimator";
static final double EPS = 0.005;
private final java.awt.Point mouseControlPoint;
private final Position mouseGeoLocation;
private final Vec4 mouseGeoPoint;
private final BasicOrbitView orbitView;
private final Animator zoomAnimator;
private int lastDxSign = 0;
private int lastDySign = 0;
int stepNumber = 0;
int stepsNoAdjustments = 0;
FixZoomPositionAnimator(BasicOrbitView orbitView, Animator zoomAnimator, java.awt.Point mouseControlPoint, Position mouseGeoLocation)
{
this.orbitView = orbitView;
this.zoomAnimator = zoomAnimator;
this.mouseControlPoint = mouseControlPoint;
this.mouseGeoLocation = mouseGeoLocation;
mouseGeoPoint = orbitView.getGlobe().computePointFromLocation(mouseGeoLocation);
}
public Point getMouseControlPoint()
{
return mouseControlPoint;
}
public Position getMouseGeoLocation()
{
return mouseGeoLocation;
}
private static int sign(double d)
{
if (Math.abs(d) < EPS)
return 0;
else if (d > 0)
return 1;
else
return -1;
}
double calcAccelerationK(double dSign, double lastDSign)
{
// as we are following zoom trying to catch up - accelerate adjustment
// but slow down if we overshot the target last time
if (!zoomAnimator.hasNext())
return 1.0;
else if (dSign != lastDSign)
return 0.5;
else
{
// reduce acceleration over time
if (stepNumber < 10)
return 5;
else if (stepNumber < 20)
return 3;
else
return 2;
}
}
static boolean isBetween(double checkedValue, double target1, double target2)
{
return ((target1 < checkedValue) && (checkedValue < target2))
|| ((target1 > checkedValue) && (checkedValue > target2));
}
static boolean isValid(Position position)
{
return isBetween(position.longitude.degrees, -180, 180)
&& isBetween(position.latitude.degrees, -90, 90);
}
@Override
public void next()
{
// super.next(); // do not call super to avoid NullPointerException!
nextWithTilt(); // works OK on tilted Earth
// nextOld(); // IMHO better looking but stops working is user tilts the Earth
}
private void nextOld()
{
stepNumber++;
Vec4 curProjection = orbitView.project(mouseGeoPoint);
Rectangle viewport = orbitView.getViewport();
// for Y sign is inverted
double dX = (mouseControlPoint.x - curProjection.x);
double dY = (mouseControlPoint.y + curProjection.y - viewport.getHeight());
if (Math.abs(dX) > EPS || Math.abs(dY) > EPS)
{
double dCX = (mouseControlPoint.x - viewport.getCenterX());
double dCY = (mouseControlPoint.y + viewport.getCenterY() - viewport.getHeight());
final double stepPx = 10;
// As the Earth is curved and we are not guaranteed to have a frontal view on it
// latitude an longitude lines are not really parallel to X or Y. But we assume that
// locally they are parallel enough both around the mousePoint and around the center.
// So we use reference points near center to calculate how we want to move the center.
Vec4 controlPointRight = new Vec4(viewport.getCenterX() + stepPx, viewport.getCenterY());
Vec4 geoPointRight = orbitView.unProject(controlPointRight);
Position positionRight = (geoPointRight != null) ? orbitView.getGlobe().computePositionFromPoint(geoPointRight) : null;
Vec4 controlPointUp = new Vec4(viewport.getCenterX(), viewport.getCenterY() - stepPx);
Vec4 geoPointUp = orbitView.unProject(controlPointUp);
Position positionUp = (geoPointUp != null) ? orbitView.getGlobe().computePositionFromPoint(geoPointUp) : null;
Position centerPosition = orbitView.getCenterPosition();
double newCenterLongDeg;
if (Math.abs(dCX) <= 1.0) // same X => same longitude
{
newCenterLongDeg = mouseGeoLocation.longitude.degrees;
}
else if (positionRight == null) // if controlPointRight is outside of the globe - don't try to fix this coordinate
{
newCenterLongDeg = centerPosition.longitude.degrees;
}
else
{
double scaleX = -dX / stepPx;
// apply acceleration if possible
int dXSign = sign(dX);
double accScaleX = scaleX * calcAccelerationK(dXSign, lastDxSign);
lastDxSign = dXSign;
newCenterLongDeg = centerPosition.longitude.degrees * (1 - accScaleX) + positionRight.longitude.degrees * accScaleX;
// if we overshot - use non-accelerated mode
if (!isBetween(newCenterLongDeg, centerPosition.longitude.degrees, mouseGeoLocation.longitude.degrees)
|| !isBetween(newCenterLongDeg, -180, 180))
{
newCenterLongDeg = centerPosition.longitude.degrees * (1 - scaleX) + positionRight.longitude.degrees * scaleX;
}
}
double newCenterLatDeg;
if (Math.abs(dCY) <= 1.0) // same Y => same latitude
{
newCenterLatDeg = mouseGeoLocation.latitude.degrees;
}
else if (positionUp == null) // if controlPointUp is outside of the globe - don't try to fix this coordinate
{
newCenterLatDeg = centerPosition.latitude.degrees;
}
else
{
double scaleY = -dY / stepPx;
// apply acceleration if possible
int dYSign = sign(dY);
double accScaleY = scaleY * calcAccelerationK(dYSign, lastDySign);
lastDySign = dYSign;
newCenterLatDeg = centerPosition.latitude.degrees * (1 - accScaleY) + positionUp.latitude.degrees * accScaleY;
// if we overshot - use non-accelerated mode
if (!isBetween(newCenterLatDeg, centerPosition.latitude.degrees, mouseGeoLocation.latitude.degrees)
|| !isBetween(newCenterLatDeg, -90, 90))
{
newCenterLatDeg = centerPosition.latitude.degrees * (1 - scaleY) + positionUp.latitude.degrees * scaleY;
}
}
Position newCenterPosition = Position.fromDegrees(newCenterLatDeg, newCenterLongDeg);
orbitView.setCenterPosition(newCenterPosition);
}
if (!zoomAnimator.hasNext())
stop();
}
private void nextWithTilt()
{
stepNumber++;
if (!zoomAnimator.hasNext() || (stepsNoAdjustments > 20))
{
System.out.println("Stop after " + stepNumber);
stop();
}
Vec4 curProjection = orbitView.project(mouseGeoPoint);
Rectangle viewport = orbitView.getViewport();
System.out.println("----------------------------------");
System.out.println("Mouse: mouseControlPoint = " + mouseControlPoint + "\t location = " + mouseGeoLocation + "\t viewSize = " + viewport);
System.out.println("Mouse: curProjection = " + curProjection);
double dX = (mouseControlPoint.x - curProjection.x);
double dY = (viewport.getHeight() - mouseControlPoint.y - curProjection.y); // Y is inverted
Vec4 dTgt = new Vec4(dX, dY);
// sometimes if you zoom close to the edge curProjection is calculated as somewhere
// way beyond where it is and it leads to overflow. This is a protection against it
if (Math.abs(dX) > viewport.width / 4 || Math.abs(dY) > viewport.height / 4)
{
Vec4 unproject = orbitView.unProject(new Vec4(mouseControlPoint.x, viewport.getHeight() - mouseControlPoint.y));
System.out.println("!!!End Mouse:"
+ " dX = " + dX + "\t" + " dY = " + dY
+ "\n" + "unprojectPt = " + unproject
+ "\n" + "unprojectPos = " + orbitView.getGlobe().computePositionFromPoint(unproject)
);
stepsNoAdjustments += 1;
return;
}
if (Math.abs(dX) <= EPS && Math.abs(dY) <= EPS)
{
stepsNoAdjustments += 1;
System.out.println("Mouse: No adjustment: " + " dX = " + dX + "\t" + " dY = " + dY);
return;
}
else
{
stepsNoAdjustments = 0;
}
// create reference points about 10px away from the center to the Up and to the Right
// and then map them to screen coordinates and geo coordinates
// Unfortunately unproject often generates points far from the Earth surface (and
// thus with significantly less difference in lat/long)
// So this longer but more fool-proof calculation is used
final double stepPx = 10;
Position centerPosition = orbitView.getCenterPosition();
Position eyePosition = orbitView.getEyePosition();
double pixelGeoSize = orbitView.computePixelSizeAtDistance(eyePosition.elevation - centerPosition.elevation);
Vec4 geoCenterPoint = orbitView.getCenterPoint();
Vec4 geoRightPoint = geoCenterPoint.add3(new Vec4(pixelGeoSize * stepPx, 0, 0));
Vec4 geoUpPoint = geoCenterPoint.add3(new Vec4(0, pixelGeoSize * stepPx, 0));
Position geoRightPosition = orbitView.getGlobe().computePositionFromPoint(geoRightPoint);
Position geoUpPosition = orbitView.getGlobe().computePositionFromPoint(geoUpPoint);
Vec4 controlCenter = orbitView.project(geoCenterPoint);
Vec4 controlRight = orbitView.project(geoRightPoint);
Vec4 controlUp = orbitView.project(geoUpPoint);
Vec4 controlRightDif = controlRight.subtract3(controlCenter);
controlRightDif = new Vec4(controlRightDif.x, controlRightDif.y); // ignore z for scale calculation
Vec4 controlUpDif = controlUp.subtract3(controlCenter);
controlUpDif = new Vec4(controlUpDif.x, controlUpDif.y); // ignore z for scale calculation
double scaleRight = -dTgt.dot3(controlRightDif) / controlRightDif.getLengthSquared3();
double scaleUp = -dTgt.dot3(controlUpDif) / controlUpDif.getLengthSquared3();
Position posRightDif = geoRightPosition.subtract(centerPosition);
Position posUpDif = geoUpPosition.subtract(centerPosition);
double totalLatDifDeg = posRightDif.latitude.degrees * scaleRight + posUpDif.latitude.degrees * scaleUp;
double totalLongDifDeg = posRightDif.longitude.degrees * scaleRight + posUpDif.longitude.degrees * scaleUp;
Position totalDif = Position.fromDegrees(totalLatDifDeg, totalLongDifDeg);
// don't copy elevation!
Position newCenterPosition = Position.fromDegrees(centerPosition.latitude.degrees + totalLatDifDeg,
centerPosition.longitude.degrees + totalLongDifDeg);
// if we overshot - try to slow down
if (!isValid(newCenterPosition))
{
newCenterPosition = Position.fromDegrees(centerPosition.latitude.degrees + totalLatDifDeg / 2,
centerPosition.longitude.degrees + totalLongDifDeg / 2);
if (!isValid(newCenterPosition))
{
System.out.println("Too much overshot: " + newCenterPosition);
stepsNoAdjustments += 1;
return;
}
}
System.out.println("Mouse:"
+ " dX = " + dX + "\t" + " dY = " + dY
+ "\n"
+ " centerPosition = " + centerPosition
+ "\n"
+ " geoUpPoint = " + geoUpPoint + "\t " + " geoUpPosition = " + geoUpPosition
+ "\n"
+ " geoRightPoint = " + geoRightPoint + "\t " + " geoRightPosition = " + geoRightPosition
+ "\n"
+ " posRightDif = " + posRightDif
+ "\t"
+ " posUpDif = " + posUpDif
+ "\n"
+ " scaleRight = " + scaleRight + "\t" + " scaleUp = " + scaleUp);
System.out.println("Mouse: oldCenterPosition = " + centerPosition);
System.out.println("Mouse: newCenterPosition = " + newCenterPosition);
orbitView.setCenterPosition(newCenterPosition);
}
}
尝试使用delta=delta.multiply3（zoomChange-1）；而不是delta=delta.multiply3（-zoomChange）；我试过了，但似乎不起作用。这是对try的唯一更改吗？try delta=delta.multiply3（（zoomChange-1）/zoomChange）；在你尝试这个之前还有一件事，想知道你在zoomChange中得到了什么价值？它是绝对的还是%的？i、 当我说缩放150%时。。。那你是1.5分还是150分？如果你得到的是abs，即1.5，那么这个新的变化应该会起作用。如果你得到的是150，那么你需要将它除以100得到abs值1.5。让我们来看看。如果向量数学是
delta=cursorVector-centerVectorcenterVector=cursorVector-deltacenterVector=centerVector+deltaFixZoomPositionA
public class ZoomToCursorViewInputHandler extends OrbitViewInputHandler
{
public ZoomToCursorViewInputHandler()
{
ViewInputAttributes.ActionAttributes actionAttrs = this.getAttributes()
.getActionMap(ViewInputAttributes.DEVICE_MOUSE_WHEEL)
.getActionAttributes(ViewInputAttributes.VIEW_VERTICAL_TRANSLATE);
actionAttrs.setMouseActionListener(new ZoomActionHandler());
}
protected class ZoomActionHandler extends VertTransMouseWheelActionListener
{
@Override
public boolean inputActionPerformed(AbstractViewInputHandler inputHandler, MouseWheelEvent mouseWheelEvent,
final ViewInputAttributes.ActionAttributes viewAction)
{
double zoomInput = mouseWheelEvent.getWheelRotation();
Position position = wwd.getCurrentPosition();
Point mouseControlPoint = mouseWheelEvent.getPoint();
// Zoom toward the cursor if we're zooming in. Move straight out when zooming
// out.
if (zoomInput < 0 && position != null)
{
boolean res = super.inputActionPerformed(inputHandler, mouseWheelEvent, viewAction);
BasicOrbitView view = (BasicOrbitView) getView();
OrbitViewMoveToZoomAnimator zoomAnimator = (OrbitViewMoveToZoomAnimator) uiAnimControl.get(VIEW_ANIM_ZOOM);
// for continuous scroll preserve the original target if mouse was not moved
FixZoomPositionAnimator old = (FixZoomPositionAnimator) uiAnimControl.get(FixZoomPositionAnimator.VIEW_ANIM_KEY);
if (old != null && old.getMouseControlPoint().equals(mouseControlPoint))
{
position = old.getMouseGeoLocation();
}
FixZoomPositionAnimator fixZoomPositionAnimator = new FixZoomPositionAnimator(view, zoomAnimator, mouseControlPoint, position);
fixZoomPositionAnimator.start();
uiAnimControl.put(FixZoomPositionAnimator.VIEW_ANIM_KEY, fixZoomPositionAnimator);
return res;
}
else
{
uiAnimControl.remove(FixZoomPositionAnimator.VIEW_ANIM_KEY); // when zoom direction changes we don't want to make position adjustments anymore
return super.inputActionPerformed(inputHandler, mouseWheelEvent, viewAction);
}
}
}
// here goes aforementioned FixZoomPositionAnimator
}