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A Java Swing Panel that allows rotation, translation and zooming
/*
* 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.painters;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.geom.AffineTransform;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.function.Predicate;
import de.javagl.geom.AffineTransforms;
import de.javagl.viewer.ObjectPainter;
/**
* Implementation of an {@link ObjectPainter} for strings that serve as
* labels, to be painted with a certain font and layout
*/
public final class LabelPainter implements ObjectPainter
{
/**
* Temporary affine transform, used internally
*/
private static final AffineTransform TEMP_AFFINE_TRANSFORM =
new AffineTransform();
/**
* A class describing the state of a label that is about to be
* painted. An instance of this class will be passed to the
* label painting condition predicate that may have been set
* with {@link #setLabelPaintingCondition(Predicate)}, to
* determine whether the label should be painted.
*/
public static class LabelPaintState
{
/**
* The label
*/
private String label;
/**
* The label bounds
*/
private final Rectangle2D labelBounds;
/**
* The affine transform that will be applied to the graphics
* before the label is painted
*/
private final AffineTransform labelTransform;
/**
* The affine transform that was passed to the painting method
* of the {@link LabelPainter}
*/
private final AffineTransform worldToScreenTransform;
/**
* Default constructor
*/
LabelPaintState()
{
label = "";
labelBounds = new Rectangle2D.Double();
labelTransform = new AffineTransform();
worldToScreenTransform = new AffineTransform();
}
/**
* Returns the label that is about to be painted
*
* @return The label
*/
public String getLabel()
{
return label;
}
/**
* Returns a reference to the bounds of the label that is about
* to be painted. These are the untransformed bounds, and thus,
* only depend on the font and contents of the label.
*
* @return The label bounds
*/
public Rectangle2D getLabelBounds()
{
return labelBounds;
}
/**
* Returns a reference to the affine transform that will be applied
* to the graphics context before the label is painted at the origin.
* If the calling {@link LabelPainter} is
* {@link LabelPainter#isTransformingLabels() transforming the labels},
* then this will include the world to screen transform.
*
* @return The affine transform
*/
public AffineTransform getLabelTransform()
{
return labelTransform;
}
/**
* Returns a reference to an affine transform that is equal to
* the transform that was passed to the painting method of
* the {@link LabelPainter}
*
* @return The affine transform
*/
public AffineTransform getWorldToScreenTransform()
{
return worldToScreenTransform;
}
/**
* Set the label
*
* @param label The label
*/
void setLabel(String label)
{
this.label = label;
}
/**
* Set the label bounds
*
* @param labelBounds The label bounds
*/
void setLabelBounds(Rectangle2D labelBounds)
{
this.labelBounds.setFrame(labelBounds);
}
/**
* Set the label transform.
*
* @param transform The label transform
*/
void setLabelTransform(AffineTransform transform)
{
this.labelTransform.setTransform(transform);
}
/**
* Set the world to screen transform
*
* @param transform The transform
*/
void setWorldToScreenTransform(AffineTransform transform)
{
this.worldToScreenTransform.setTransform(transform);
}
}
/**
* The anchor of the label
*/
private final Point2D labelAnchor;
/**
* The location of the label
*/
private final Point2D labelLocation;
/**
* The angle of the label
*/
private double angleRad;
/**
* The paint of the label
*/
private Paint paint;
/**
* The font of the label
*/
private Font font;
/**
* Whether labels are transformed with the graphics transform
*/
private boolean transformingLabels;
/**
* Describes the state of a label that is about to be painted.
*/
private final LabelPaintState labelPaintState;
/**
* The condition that says whether a label should be painted.
* If this is null, then the label will always
* be painted.
*/
private Predicate labelPaintingCondition;
/**
* Creates a new label painter.
*
* -
* The {@link #setLabelAnchor(double, double) label anchor} will be
* at (0.5, 0.5), causing the label to be centered at the desired
* location
*
* -
* The {@link #setLabelLocation(double, double) label location} will
* be at (0.0, 0.0)
*
* -
* The {@link #setAngle(double) angle} will be 0.0.
*
* -
* The painter will be {@link #setTransformingLabels(boolean)
* transforming} the labels
*
* -
* The {@link #setFont(Font) font}, {@link #setPaint(Paint) paint}
* and {@link #setLabelPaintingCondition(Predicate) label painting
* condition} will be
null, causing the label to always
* be painted, with the default font and paint of the graphics context
*
*
*
*/
public LabelPainter()
{
this.labelAnchor = new Point2D.Double(0.5, 0.5);
this.labelLocation = new Point2D.Double(0.0, 0.0);
this.angleRad = 0.0;
this.font = null;
this.paint = null;
this.transformingLabels = true;
this.labelPaintingCondition = null;
this.labelPaintState = new LabelPaintState();
}
/**
* Set the font that should be used for the label. If the given font
* is null, then the font of the graphics context will
* be used.
*
* @param font The font
*/
public void setFont(Font font)
{
this.font = font;
}
/**
* Returns the font that is used for the label. This may be
* null if no font was set explicitly.
*
* @return The font
*/
public Font getFont()
{
return font;
}
/**
* Set the paint that should be used for the label. If the given paint
* is null, then the current paint of the graphics context
* will be used.
*
* @param paint The paint
*/
public void setPaint(Paint paint)
{
this.paint = paint;
}
/**
* Returns the paint that is used for the label. This may be
* null if no paint was set explicitly.
*
* @return The paint
*/
public Paint getPaint()
{
return paint;
}
/**
* Set the anchor position of the label. The anchor position describes
* a point relative to the bounding box of the label (so it is
* usually - but not necessarily - a point in [(0,0)...(1,1)]).
*
* This is the point that will be placed at the
* {@link #setLabelLocation(double, double) label location}. For example,
* in order to place the center of the label at a certain location,
* an anchor point of (0.5, 0.5) may be set.
*
* This is also the point that the label is rotated about, when a non-zero
* {@link #setAngle(double) rotation angle} is set.
*
*
* @param x The x-coordinate of the anchor position
* @param y The y-coordinate of the anchor position
*/
public void setLabelAnchor(double x, double y)
{
labelAnchor.setLocation(x, y);
}
/**
* Returns a new point that describes the current anchor position of
* the label. See {@link #setLabelAnchor(double, double)}.
*
* @return The new point storing the anchor position
*/
public Point2D getLabelAnchor()
{
return new Point2D.Double(labelAnchor.getX(), labelAnchor.getY());
}
/**
* Set the absolute location of the label. This is the location of the
* label, relative to the origin of the world coordinate system that
* this painter is painting to.
*
* @param x The x coordinate of the location
* @param y The y-coordinate of the location
*/
public void setLabelLocation(double x, double y)
{
labelLocation.setLocation(x, y);
}
/**
* Returns a new point that describes the location of the label.
* See {@link #setLabelLocation(double, double)}.
*
* @return The new point storing the location
*/
public Point2D getLabelLocation()
{
return new Point2D.Double(labelLocation.getX(), labelLocation.getY());
}
/**
* Set the angle (in radians) about that the label will be rotated
* around its {@link #setLabelAnchor(double, double) anchor point}.
*
* @param angleRad The rotation angle, in radians
*/
public void setAngle(double angleRad)
{
this.angleRad = angleRad;
}
/**
* Returns the angle (in radians) about that the label will be rotated
* around its {@link #setLabelAnchor(double, double) anchor point}.
*
* @return The rotation angle, in radians
*/
public double getAngle()
{
return angleRad;
}
/**
* Set whether this painter is transforming the labels using the
* worldToScreen transform that is passed to its
* {@link #paint(Graphics2D, AffineTransform, double, double, String) paint}
* method.
*
* If this is set to true, then the label strings will
* be transformed with the worldToScreen transform, like
* all other painted elements: When the view is scaled, then the
* text will be scaled. When the view is rotated, then the labels
* will be rotated.
*
* If this is set to false, then the labels will be
* fixed. This means that they will always be painted with the
* size that is defined via the {@link #setFont(Font) font}, and
* they will always be oriented horizontally (unless they are
* rotated by this painter itself, via the {@link #setAngle(double) angle}).
*
* @param transformingLabels Whether this painter is transforming the labels
*/
public void setTransformingLabels(boolean transformingLabels)
{
this.transformingLabels = transformingLabels;
}
/**
* Returns whether this painter is transforming the labels. See
* {@link #setTransformingLabels(boolean)}.
*
* @return Whether this painter is transforming the labels
*/
public boolean isTransformingLabels()
{
return transformingLabels;
}
/**
* Set the condition indicating whether a certain label should be
* painted.
*
* The given predicate will receive the {@link LabelPaintState}
* of each label that is about to be painted. It has to be assumed
* that the same {@link LabelPaintState} instance will be used
* for all these calls. So the predicate may not store and / or
* modify the {@link LabelPaintState}.
*
* If the given condition is null, then the
* labels will always be painted.
*
* @param labelPaintingCondition The label painting condition
*/
public void setLabelPaintingCondition(
Predicate labelPaintingCondition)
{
this.labelPaintingCondition = labelPaintingCondition;
}
@Override
public void paint(Graphics2D g, AffineTransform worldToScreen,
double w, double h, String label)
{
if (label == null)
{
return;
}
g.setFont(font);
g.setPaint(paint);
if (transformingLabels)
{
drawStringTransformed(g, worldToScreen, label);
}
else
{
drawStringFixed(g, worldToScreen, label);
}
}
/**
* Draw the given string into the given graphics, transformed with
* the given world-to-screen transform.
*
* @param g The Graphics used for painting
* @param worldToScreen The world-to-screen transform
* @param string The string to paint
*/
private void drawStringTransformed(Graphics2D g,
AffineTransform worldToScreen, String string)
{
Rectangle2D labelBounds =
StringBoundsUtils.computeStringBounds(string, g.getFont());
double absoluteLabelAnchorX =
computeAbsoluteX(labelBounds, labelAnchor);
double absoluteLabelAnchorY =
computeAbsoluteY(labelBounds, labelAnchor);
TEMP_AFFINE_TRANSFORM.setTransform(worldToScreen);
TEMP_AFFINE_TRANSFORM.translate(
labelLocation.getX(), labelLocation.getY());
TEMP_AFFINE_TRANSFORM.rotate(angleRad);
TEMP_AFFINE_TRANSFORM.translate(
-absoluteLabelAnchorX, -absoluteLabelAnchorY);
if (labelPaintingCondition != null)
{
labelPaintState.setLabel(string);
labelPaintState.setLabelBounds(labelBounds);
labelPaintState.setLabelTransform(TEMP_AFFINE_TRANSFORM);
labelPaintState.setWorldToScreenTransform(worldToScreen);
boolean shouldPaint = labelPaintingCondition.test(labelPaintState);
if (!shouldPaint)
{
return;
}
}
AffineTransform oldAt = g.getTransform();
g.transform(TEMP_AFFINE_TRANSFORM);
g.drawString(string, 0, 0);
g.setTransform(oldAt);
}
/**
* Draw the given string into the given graphics. This will draw
* the string without transforming it with the world-to-screen
* transform.
*
* @param g The Graphics used for painting
* @param worldToScreen The world-to-screen transform
* @param string The string to paint
*/
private void drawStringFixed(Graphics2D g,
AffineTransform worldToScreen, String string)
{
Rectangle2D labelBounds =
StringBoundsUtils.computeStringBounds(string, g.getFont());
double labelLocationScreenX =
AffineTransforms.computeX(worldToScreen, labelLocation);
double labelLocationScreenY =
AffineTransforms.computeY(worldToScreen, labelLocation);
double absoluteLabelAnchorX =
computeAbsoluteX(labelBounds, labelAnchor);
double absoluteLabelAnchorY =
computeAbsoluteY(labelBounds, labelAnchor);
TEMP_AFFINE_TRANSFORM.setToTranslation(
labelLocationScreenX, labelLocationScreenY);
TEMP_AFFINE_TRANSFORM.rotate(angleRad);
TEMP_AFFINE_TRANSFORM.translate(
-absoluteLabelAnchorX, -absoluteLabelAnchorY);
if (labelPaintingCondition != null)
{
labelPaintState.setLabel(string);
labelPaintState.setLabelBounds(labelBounds);
labelPaintState.setLabelTransform(TEMP_AFFINE_TRANSFORM);
labelPaintState.setWorldToScreenTransform(worldToScreen);
boolean shouldPaint = labelPaintingCondition.test(labelPaintState);
if (!shouldPaint)
{
return;
}
}
AffineTransform oldAT = g.getTransform();
g.transform(TEMP_AFFINE_TRANSFORM);
g.drawString(string, 0, 0);
g.setTransform(oldAT);
}
/**
* Compute the absolute x-coordinate of the point that defines relative
* coordinates in the given rectangle
*
* @param rectangle The rectangle
* @param relativePoint The relative point
* @return The x-coordinate
*/
private static double computeAbsoluteX(
Rectangle2D rectangle, Point2D relativePoint)
{
return rectangle.getX() + rectangle.getWidth() * relativePoint.getX();
}
/**
* Compute the absolute y-coordinate of the point that defines relative
* coordinates in the given rectangle
*
* @param rectangle The rectangle
* @param relativePoint The relative point
* @return The y-coordinate
*/
private static double computeAbsoluteY(
Rectangle2D rectangle, Point2D relativePoint)
{
return rectangle.getY() + rectangle.getHeight() * relativePoint.getY();
}
}