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A Java Swing Panel that allows rotation, translation and zooming
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/*
* www.javagl.de - Viewer
*
* Copyright (c) 2013-2015 Marco Hutter - http://www.javagl.de
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
package de.javagl.viewer;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeMap;
import javax.swing.JPanel;
import de.javagl.geom.AffineTransforms;
import de.javagl.geom.Points;
import de.javagl.geom.Rectangles;
/**
* A panel that allows translating, rotating and zooming.
*
* Instances of classes implementing the {@link Painter} interface may be
* added to this viewer and perform painting operations. Their
* {@link Painter#paint(Graphics2D, AffineTransform, double, double) paint}
* method will receive the world-to-screen transform, as determined by the
* current translation, rotation and zoom of the viewer.
*
* The viewer supports multiple layers. The layer may be specified when a
* {@link Painter} is added using the {@link #addPainter(Painter, int)}
* method. The {@link Painter} instances will be called starting at the
* lowest layer. Inside one layer, the {@link Painter}s will be called in
* the order in which they have been added.
*
* A viewer has several methods that affect the translation, rotation and
* zoom factor:
*
*
* - {@link #translate(double, double)}
* - {@link #rotate(double, double, double)}
* - {@link #zoom(double, double, double, double)}
*
* These methods will usually not be called by clients or users of the
* viewer. Instead, they are called by a class that implements the
* {@link MouseControl} interface, and has been set using
* {@link #setMouseControl(MouseControl)}. These classes are responsible for
* making sure that these methods are called with valid parameters.
* Particularly, they should not be called with NaN or
* infinite values, and the zooming factors should not be 0.0. The viewer
* class itself does not perform any sanity checks on these arguments.
*/
public class Viewer extends JPanel
{
/**
* Serial UID
*/
private static final long serialVersionUID = -3252732941609348700L;
/**
* The map from each layer to the set of {@link Painter}s that will
* perform painting operations in the {@link #paintComponent(Graphics)}
* method.
*/
private final Map> painters;
/**
* The transformation of this viewer
*/
private final AffineTransform transform;
/**
* The inverse transform, computed on demand, and set to null
* when it is invalidated.
*/
private AffineTransform inverseTransform = null;
/**
* The area in world coordinates covered by this panel
*/
private final Rectangle2D worldArea;
/**
* A pending size for the world area. When
* {@link #setDisplayedWorldArea(Rectangle2D)} is called before
* this component is visible, the intended area has to be stored
* until the component becomes visible and the area update can
* actually be applied.
*/
private Rectangle2D pendingWorldArea = null;
/**
* The state of the {@link #maintainAspectRatio} flag when the
* {@link #pendingWorldArea} was set
*/
private boolean pendingWorldAreaMaintainAspectRatioState = false;
/**
* The last stored screen size
*/
private Dimension previousSize = null;
/**
* Whether the y-axis should be flipped to point from the
* bottom of the screen to the top
*/
private boolean flippedVertically = false;
/**
* A transform that will be concatenated with the world-to-screen
* transform, for example, to flip the y-axis vertically
*/
private AffineTransform basicWorldToScreenTransform = null;
/**
* Whether the contents should be resized when the screen
* is resized
*/
private boolean resizingContents = false;
/**
* This flag determines whether the aspect ratio should be maintained
* during resize operations (when resizingContents is true)
* or when {@link #setDisplayedWorldArea(Rectangle2D)} is called.
*/
private boolean maintainAspectRatio = true;
/**
* Whether the antialiasing rendering hint should be enabled
* by default
*/
private boolean antialiasing = true;
/**
* The {@link MouseControl} that is attached to this viewer
*/
private MouseControl mouseControl;
/**
* Creates a new Viewer.
*
* The default settings are as follows:
*
* - {@link #isResizingContents()} is
false
* - {@link #isMaintainAspectRatio()} is
true
* - {@link #isAntialiasing()} is
true
*
* A default {@link MouseControls#createDefault(Viewer, boolean, boolean)
* MouseControl}, where rotation and non-uniform scaling are allowed,
* will be installed by calling {@link #setMouseControl(MouseControl)}
*/
public Viewer()
{
this.painters = new TreeMap>();
this.transform = new AffineTransform();
this.inverseTransform = new AffineTransform();
this.worldArea = new Rectangle2D.Double(0,0,1,1);
setMouseControl(
MouseControls.createDefault(this, true, true));
setBackground(Color.WHITE);
addComponentListener(new ComponentAdapter()
{
@Override
public void componentResized(ComponentEvent e)
{
handleResize();
repaint();
}
});
}
/**
* Set the given {@link MouseControl} as a MouseListener,
* MouseMotionListener and MouseWheelListener
* for this viewer. Any previously registered {@link MouseControl} will
* be removed.
*
* @param newMouseControl The {@link MouseControl} to set. This may be
* null to remove any {@link MouseControl}
*/
public final void setMouseControl(MouseControl newMouseControl)
{
if (mouseControl != null)
{
removeMouseListener(mouseControl);
removeMouseMotionListener(mouseControl);
removeMouseWheelListener(mouseControl);
}
this.mouseControl = newMouseControl;
if (mouseControl != null)
{
addMouseListener(mouseControl);
addMouseMotionListener(mouseControl);
addMouseWheelListener(mouseControl);
}
}
/**
* Set whether the y-axis should be flipped to point from the
* bottom of the screen to the top
*
* @param flippedVertically Whether the y-axis should be flipped
*/
public final void setFlippedVertically(boolean flippedVertically)
{
if (flippedVertically)
{
basicWorldToScreenTransform = getFlipVerticallyTransform();
}
else
{
basicWorldToScreenTransform = null;
}
this.flippedVertically = flippedVertically;
repaint();
}
/**
* Set whether the y-axis is flipped to point from the bottom of the
* screen to the top
*
* @return Whether the y-axis is be flipped
*/
public final boolean isFlippedVertically()
{
return flippedVertically;
}
/**
* Set whether the contents should be resized when the screen
* is resized. When this is set to true, then resizing
* this panel will adjust the scale factors accordingly, so that
* the world area that is displayed remains the same while resizing.
*
* Note that this usually only makes sense when the aspect ratio is not
* maintained - that is, when {@link #setMaintainAspectRatio(boolean)}
* was set to false.
*
* @param resizingContents The resizing behavior
*/
public final void setResizingContents(boolean resizingContents)
{
this.resizingContents = resizingContents;
}
/**
* Returns whether this viewer is configured so that the contents
* should be resized when the screen is resized. See
* {@link #setResizingContents(boolean)}.
*
* @return The resizing behavior
*/
public final boolean isResizingContents()
{
return resizingContents;
}
/**
* Set whether the aspect ratio of the displayed world area is
* maintained during resize operations of this panel, or when
* {@link #setDisplayedWorldArea(Rectangle2D)} is called.
*
* Note that this should usually be set to false when
* {@link #setResizingContents(boolean)} is set to true.
*
* @param maintainAspectRatio Whether the aspect ratio is maintained
*/
public final void setMaintainAspectRatio(boolean maintainAspectRatio)
{
this.maintainAspectRatio = maintainAspectRatio;
}
/**
* Returns whether the aspect ratio is maintained during resize operations
* or when {@link #setDisplayedWorldArea(Rectangle2D)} is called
*
* @return Whether the aspect ratio is maintained during resize operations
*/
public final boolean isMaintainAspectRatio()
{
return maintainAspectRatio;
}
/**
* Set whether the antialiasing rendering hint should be enabled
* by default
*
* @param antialiasing Whether antialiasing should be enabled
*/
public final void setAntialiasing(boolean antialiasing)
{
this.antialiasing = antialiasing;
}
/**
* Return whether the antialiasing rendering hint is enabled
* by default
*
* @return Whether antialiasing is enabled
*/
public final boolean isAntialiasing()
{
return antialiasing;
}
/**
* Add the given {@link Painter}, which will perform painting
* operations in the {@link #paintComponent(Graphics)} method.
* The painter will be added at the default layer (0). If the
* given painter is null, then this call will have
* no effect and false will be returned.
*
* @param painter The {@link Painter} to add
* @return Whether the painter was not yet contained in this viewer
*/
public final boolean addPainter(Painter painter)
{
return addPainter(painter, 0);
}
/**
* Add the given {@link Painter}, which will perform painting
* operations in the {@link #paintComponent(Graphics)} method,
* on the specified layer. If the given painter is null,
* then this call will have no effect and false will be
* returned.
*
* @param painter The {@link Painter} to add
* @param layer The layer for the {@link Painter}
* @return Whether the painter was not yet contained in this viewer
*/
public final boolean addPainter(Painter painter, int layer)
{
if (painter == null)
{
return false;
}
Set set = painters.get(layer);
if (set == null)
{
set = new LinkedHashSet();
painters.put(layer, set);
}
boolean changed = set.add(painter);
if (changed)
{
repaint();
}
return changed;
}
/**
* Remove the given {@link Painter} from all layers that it is contained
* in
*
* @param painter The {@link Painter} to remove
* @return Whether the painter was contained in this viewer
*/
public final boolean removePainter(Painter painter)
{
boolean changed = false;
Set toRemove = new LinkedHashSet();
for (Entry> entry : painters.entrySet())
{
Set set = entry.getValue();
boolean wasContained = set.remove(painter);
if (wasContained)
{
changed = true;
if (set.isEmpty())
{
toRemove.add(entry.getKey());
}
}
}
if (!toRemove.isEmpty())
{
painters.keySet().removeAll(toRemove);
}
if (changed)
{
repaint();
}
return changed;
}
/**
* Remove the given {@link Painter} from the specified layer
*
* @param painter The {@link Painter} to remove
* @param layer The layer from which the painter should be removed
* @return Whether the painter was contained in this layer
*/
public final boolean removePainter(Painter painter, int layer)
{
Set set = painters.get(layer);
boolean wasContained = set.remove(painter);
if (wasContained)
{
if (set.isEmpty())
{
painters.remove(layer);
}
repaint();
return true;
}
return false;
}
@Override
protected void paintComponent(Graphics gr)
{
super.paintComponent(gr);
Graphics2D g = (Graphics2D)gr;
if (pendingWorldArea != null)
{
boolean b = isMaintainAspectRatio();
setMaintainAspectRatio(
pendingWorldAreaMaintainAspectRatioState);
setDisplayedWorldArea(pendingWorldArea);
pendingWorldArea = null;
setMaintainAspectRatio(b);
}
if (antialiasing)
{
g.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
}
else
{
g.setRenderingHint(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_OFF);
}
for (Entry> entry : painters.entrySet())
{
Set set = entry.getValue();
for (Painter painter : set)
{
AffineTransform w = getWorldToScreen();
painter.paint(g, w, getWidth(), getHeight());
}
}
}
/**
* Returns a copy of the current world-to-screen transform
*
* @return The world-to-screen transform
*/
public final AffineTransform getWorldToScreen()
{
AffineTransform at = new AffineTransform(transform);
if (basicWorldToScreenTransform != null)
{
at.concatenate(basicWorldToScreenTransform);
}
return at;
}
/**
* Returns an affine transform that flips the contents vertically
*
* @return The affine transform
*/
private static AffineTransform getFlipVerticallyTransform()
{
AffineTransform at = new AffineTransform();
at.concatenate(AffineTransform.getTranslateInstance(0, 1));
at.concatenate(AffineTransform.getScaleInstance(1, -1));
return at;
}
/**
* Returns a copy of the screen-to-world transform
*
* @return The screen-to-world transform
*/
public final AffineTransform getScreenToWorld()
{
return new AffineTransform(getInverseTransform());
}
/**
* Returns the inverse transform, creating it if necessary
*
* @return The inverse transform
*/
private final AffineTransform getInverseTransform()
{
if (inverseTransform == null)
{
try
{
inverseTransform = getWorldToScreen().createInverse();
}
catch (NoninvertibleTransformException e)
{
throw new IllegalArgumentException(
"Non-invertible transform", e);
}
}
return inverseTransform;
}
/**
* Transform the contents of this viewer with the given transform
*
* @param t The transform
* @throws NullPointerException if the given transform is null
* @throws IllegalArgumentException if the determinant of the given
* transform is 0.0, or NaN, or infinite
*/
public final void transform(AffineTransform t)
{
validate(t);
transform.concatenate(t);
inverseTransform = null;
repaint();
}
/**
* Reset this viewer to the identity transform
*/
public final void resetTransform()
{
transform.setToIdentity();
inverseTransform = null;
repaint();
}
/**
* Set the world-to-screen transform of this viewer to the given transform.
*
* @param t The transform to set
* @throws NullPointerException if the given transform is null
* @throws IllegalArgumentException if the determinant of the given
* transform is 0.0, or NaN, or infinite
*/
public final void setTransform(AffineTransform t)
{
validate(t);
transform.setTransform(t);
inverseTransform = null;
repaint();
}
/**
* Zoom about the specified point (in screen coordinates) by the given
* factor.
*
* This method will try to limit the zooming factor of this viewer in
* order to prevent rendering errors: When the zooming factor already
* is very large, then this method may not allow zooming in any further
* (and similarly, for zooming out when the zooming factor already
* is very small). But due to the limited precision of double
* computations, this limitation of the zoom may not always be
* effective - for example, when the translation is very large.
*
* @param screenCenterX The x-coordinate of the zooming center,
* in screen coordinates
* @param screenCenterY The y-coordinate of the zooming center,
* in screen coordinates
* @param factorX The zooming factor for the x-axis
* @param factorY The zooming factor for the y-axis
*/
public final void zoom(double screenCenterX, double screenCenterY,
double factorX, double factorY)
{
if (zoomExceedsLimits(factorX, factorX))
{
return;
}
Point2D worldCenter = Points.inverseTransform(
transform, new Point2D.Double(screenCenterX, screenCenterY), null);
AffineTransform t = new AffineTransform();
t.translate(worldCenter.getX(), worldCenter.getY());
t.scale(factorX, factorY);
t.translate(-worldCenter.getX(), -worldCenter.getY());
transform(t);
repaint();
}
/**
* Returns whether a {@link #zoom} with the given factors will exceed
* the limits. This is the case when the zoom is already very large
* or very small, and the additional zoom factors will likely introduce
* rendering errors.
*
* @param factorX The zooming factor for the x-axis
* @param factorY The zooming factor for the y-axis
* @return Whether the zoom exceeds the limits
*/
private boolean zoomExceedsLimits(double factorX, double factorY)
{
final double maxScale = 1e8;
final double minScale = 1e-8;
double dx = AffineTransforms.computeDistanceX(transform, 1.0);
double dy = AffineTransforms.computeDistanceY(transform, 1.0);
if (dx > maxScale && factorX > 1.0)
{
return true;
}
if (dy > maxScale && factorY > 1.0)
{
return true;
}
if (dx < minScale && factorX < 1.0)
{
return true;
}
if (dy < minScale && factorY < 1.0)
{
return true;
}
return false;
}
/**
* Translate this viewer by the given delta, in screen
* coordinates
*
* @param screenDx The movement delta in x-direction, in screen coordinates
* @param screenDy The movement delta in y-direction, in screen coordinates
*/
public final void translate(double screenDx, double screenDy)
{
Point2D worldOld = Points.inverseTransform(
transform, new Point2D.Double(0, 0), null);
Point2D worldNew = Points.inverseTransform(
transform, new Point2D.Double(screenDx, screenDy), null);
double tdx = worldNew.getX() - worldOld.getX();
double tdy = worldNew.getY() - worldOld.getY();
AffineTransform t = new AffineTransform();
t.translate(tdx, tdy);
transform(t);
repaint();
}
/**
* Rotate about the specified point (in screen coordinates)
* by the given angle (in radians)
*
* @param screenCenterX The x-coordinate of the zooming center,
* in screen coordinates
* @param screenCenterY The y-coordinate of the zooming center,
* in screen coordinates
* @param angleRad The angle, in radians
*/
public final void rotate(
double screenCenterX, double screenCenterY, double angleRad)
{
transform.preConcatenate(
AffineTransform.getRotateInstance(
angleRad, screenCenterX, screenCenterY));
inverseTransform = null;
repaint();
}
/**
* Set the area (in world coordinates) that should be shown.
*
* This will adjust the scaling and translation so that at least the
* specified rectangle is visible (even when the view is rotated).
*
* If this viewer is {@link #isMaintainAspectRatio() maintaining
* the aspect ratio}, then the smallest area with the current
* aspect ratio will be visible that entirely contains the specified
* rectangle.
*
* @param x The x-coordinate
* @param y The y-coordinate
* @param w The width
* @param h The height
*/
public final void setDisplayedWorldArea(
double x, double y, double w, double h)
{
setDisplayedWorldArea(new Rectangle2D.Double(x, y, w, h));
}
/**
* Set the area (in world coordinates) that should be shown.
*
* This will adjust the scaling and translation so that at least the
* given rectangle is visible (even when the view is rotated).
*
* If this viewer is {@link #isMaintainAspectRatio() maintaining
* the aspect ratio}, then the smallest area with the current
* aspect ratio will be visible that entirely contains the given
* rectangle.
*
* @param newWorldArea The world area
*/
public final void setDisplayedWorldArea(Rectangle2D newWorldArea)
{
if (getWidth() <= 0 || getHeight() <= 0)
{
pendingWorldArea = new Rectangle2D.Double();
pendingWorldArea.setRect(newWorldArea);
pendingWorldAreaMaintainAspectRatioState =
maintainAspectRatio;
return;
}
pendingWorldArea = null;
worldArea.setRect(newWorldArea);
Rectangle2D worldAreaInScreen = Rectangles.computeBounds(
getWorldToScreen(), worldArea, null);
double scaleX = getWidth() / worldAreaInScreen.getWidth();
double scaleY = getHeight() / worldAreaInScreen.getHeight();
double dx = -worldAreaInScreen.getX();
double dy = -worldAreaInScreen.getY();
if (maintainAspectRatio)
{
scaleX = Math.min(scaleX, scaleY);
scaleY = scaleX;
}
transform.preConcatenate(
AffineTransform.getTranslateInstance(dx, dy));
transform.preConcatenate(
AffineTransform.getScaleInstance(scaleX, scaleY));
transform.preConcatenate(
AffineTransform.getTranslateInstance(-dx * scaleX, -dy * scaleY));
inverseTransform = null;
Rectangle2D newWorldAreaInScreen = Rectangles.computeBounds(
getWorldToScreen(), worldArea, null);
double newDx = -newWorldAreaInScreen.getX();
double newDy = -newWorldAreaInScreen.getY();
translate(newDx, newDy);
repaint();
}
/**
* Update the scaling factor when this component was resized
*/
private void handleResize()
{
if (getWidth() <= 0 || getHeight() <= 0)
{
return;
}
if (pendingWorldArea != null)
{
boolean b = isMaintainAspectRatio();
setMaintainAspectRatio(
pendingWorldAreaMaintainAspectRatioState);
setDisplayedWorldArea(pendingWorldArea);
pendingWorldArea = null;
setMaintainAspectRatio(b);
pendingWorldArea = null;
}
if (resizingContents)
{
if (previousSize == null)
{
previousSize = getSize();
}
double scaleX = (double)getWidth() / previousSize.width;
double scaleY = (double)getHeight() / previousSize.height;
if (maintainAspectRatio)
{
scaleX = Math.min(scaleX, scaleY);
scaleY = scaleX;
}
transform.preConcatenate(
AffineTransform.getScaleInstance(scaleX, scaleY));
inverseTransform = null;
}
previousSize = getSize();
}
/**
* Make sure that the given determinant is non-null and has a
* valid (and non-zero) determinant
*
* @param at The affine transform
* @throws NullPointerException If the given transform is null
* @throws IllegalArgumentException If the determinant of the given
* transform is 0.0, or NaN, or infinite
*/
private static void validate(AffineTransform at)
{
double determinant = at.getDeterminant();
if (determinant == 0.0 ||
Double.isNaN(determinant) ||
Double.isInfinite(determinant))
{
throw new IllegalArgumentException("Determinant is "+determinant);
}
}
}