animator and cubic bezier easing classes added (for future animations) (issue #66)

flatlaf-core/src/main/java/com/formdev/flatlaf/util/Animator.java

@@ -0,0 +1,299 @@
+/*
+ * Copyright 2020 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.util;
+
+import java.util.ArrayList;
+import javax.swing.Timer;
+
+/**
+ * Simple animator based on ideas and concepts from "Filthy Rich Clients" book
+ * and "Timing Framework" library.
+ *
+ * @author Karl Tauber
+ */
+public class Animator
+{
+	private int duration;
+	private int resolution = 10;
+	private Interpolator interpolator;
+	private final ArrayList<TimingTarget> targets = new ArrayList<>();
+
+	private boolean running;
+	private boolean hasBegun;
+	private boolean timeToStop;
+	private long startTime;
+	private Timer timer;
+
+	/**
+	 * Creates an animation that runs duration milliseconds.
+	 * Use {@link #addTarget(TimingTarget)} to receive timing events
+	 * and {@link #start()} to start the animation.
+	 *
+	 * @param duration the duration of the animation in milliseconds
+	 */
+	public Animator( int duration ) {
+		this( duration, null );
+	}
+
+	/**
+	 * Creates an animation that runs duration milliseconds.
+	 * Use {@link #start()} to start the animation.
+	 *
+	 * @param duration the duration of the animation in milliseconds
+	 * @param target the target that receives timing events
+	 */
+	public Animator( int duration, TimingTarget target ) {
+		setDuration( duration );
+		addTarget( target );
+	}
+
+	/**
+	 * Returns the duration of the animation in milliseconds.
+	 */
+	public int getDuration() {
+		return duration;
+	}
+
+	/**
+	 * Sets the duration of the animation in milliseconds.
+	 *
+	 * @throws IllegalStateException if animation is running
+	 * @throws IllegalArgumentException if duration is <= zero
+	 */
+	public void setDuration( int duration ) {
+		throwExceptionIfRunning();
+		if( duration <= 0 )
+			throw new IllegalArgumentException();
+		this.duration = duration;
+	}
+
+	/**
+	 * Returns the resolution of the animation in milliseconds (default is 10).
+	 * Resolution is the amount of time between timing events.
+	 */
+	public int getResolution() {
+		return resolution;
+	}
+
+	/**
+	 * Sets the resolution of the animation in milliseconds.
+	 *
+	 * @throws IllegalStateException if animation is running
+	 * @throws IllegalArgumentException if resolution is <= zero
+	 */
+	public void setResolution( int resolution ) {
+		throwExceptionIfRunning();
+		if( resolution <= 0 )
+			throw new IllegalArgumentException();
+		this.resolution = resolution;
+	}
+
+	/**
+	 * Returns the interpolator for the animation.
+	 * Default is {@code null}, which means linear.
+	 */
+	public Interpolator getInterpolator() {
+		return interpolator;
+	}
+
+	/**
+	 * Sets the interpolator for the animation.
+	 *
+	 * @throws IllegalStateException if animation is running
+	 */
+	public void setInterpolator( Interpolator interpolator ) {
+		throwExceptionIfRunning();
+		this.interpolator = interpolator;
+	}
+
+	/**
+	 * Adds a target to the animation that receives timing events.
+	 *
+	 * @param target the target that receives timing events
+	 */
+	public void addTarget( TimingTarget target ) {
+		if( target == null )
+			return;
+
+		synchronized( targets ) {
+			if( !targets.contains( target ) )
+				targets.add( target );
+		}
+	}
+
+	/**
+	 * Removes a target from the animation.
+	 *
+	 * @param target the target that should be removed
+	 */
+	public void removeTarget( TimingTarget target ) {
+		synchronized( targets ) {
+			targets.remove( target );
+		}
+	}
+
+	/**
+	 * Starts the animation.
+	 *
+	 * @throws IllegalStateException if animation is running
+	 */
+	public void start() {
+		throwExceptionIfRunning();
+
+		running = true;
+		hasBegun = false;
+		timeToStop = false;
+		startTime = System.nanoTime() / 1000000;
+
+		timer = new Timer( resolution, e -> {
+			if( !hasBegun ) {
+				begin();
+				hasBegun = true;
+			}
+
+			timingEvent( getTimingFraction() );
+		} );
+		timer.setInitialDelay( 0 );
+		timer.start();
+	}
+
+	/**
+	 * Stops the animation before it normally ends.
+	 * Invokes {@link TimingTarget#end()} on timing targets.
+	 */
+	public void stop() {
+		stop( false );
+	}
+
+	/**
+	 * Cancels the animation before it normally ends.
+	 * Does not invoke {@link TimingTarget#end()} on timing targets.
+	 */
+	public void cancel() {
+		stop( true );
+	}
+
+	private void stop( boolean cancel ) {
+		if( timer != null ) {
+			timer.stop();
+			timer = null;
+		}
+
+		if( !cancel )
+			end();
+
+		running = false;
+		timeToStop = false;
+	}
+
+	/**
+	 * Returns whether this animation is running.
+	 */
+	public boolean isRunning() {
+		return running;
+	}
+
+	private float getTimingFraction() {
+		long currentTime = System.nanoTime() / 1000000;
+		long elapsedTime = currentTime - startTime;
+		timeToStop = (elapsedTime >= duration);
+
+		float fraction = clampFraction( (float) elapsedTime / duration );
+		if( interpolator != null )
+			fraction = clampFraction( interpolator.interpolate( fraction ) );
+		return fraction;
+	}
+
+	private float clampFraction( float fraction ) {
+		if( fraction < 0 )
+			return 0;
+		if( fraction > 1 )
+			return 1;
+		return fraction;
+	}
+
+	private void timingEvent( float fraction ) {
+		synchronized( targets ) {
+			for( TimingTarget target : targets )
+				target.timingEvent( fraction );
+		}
+
+		if( timeToStop )
+			stop();
+	}
+
+	private void begin() {
+		synchronized( targets ) {
+			for( TimingTarget target : targets )
+				target.begin();
+		}
+	}
+
+	private void end() {
+		synchronized( targets ) {
+			for( TimingTarget target : targets )
+				target.end();
+		}
+	}
+
+	private void throwExceptionIfRunning() {
+		if( isRunning() )
+			throw new IllegalStateException();
+	}
+
+	//---- interface TimingTarget ---------------------------------------------
+
+	/**
+	 * Animation callbacks.
+	 */
+	@FunctionalInterface
+	public interface TimingTarget {
+		/**
+		 * Invoked multiple times while animation is running.
+		 *
+		 * @param fraction the percent (0 to 1) elapsed of the current animation cycle
+		 */
+		void timingEvent( float fraction );
+
+		/**
+		 * Invoked when the animation begins.
+		 */
+		default void begin() {}
+
+		/**
+		 * Invoked when the animation ends.
+		 */
+		default void end() {}
+	}
+
+	//---- interface Interpolator ---------------------------------------------
+
+	/**
+	 * Interpolator used by animation to change timing fraction. E.g. for easing.
+	 */
+	@FunctionalInterface
+	public interface Interpolator {
+		/**
+		 * Interpolate the given fraction and returns a new fraction.
+		 * Both fractions are in range [0, 1].
+		 *
+		 * @param fraction the percent (0 to 1) elapsed of the current animation cycle
+		 * @return new fraction in range [0, 1]
+		 */
+		float interpolate( float fraction );
+	}
+}

flatlaf-core/src/main/java/com/formdev/flatlaf/util/CubicBezierEasing.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2020 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.util;
+
+/**
+ * An interpolator for {@link Animator} that uses a cubic bezier curve.
+ *
+ * @author Karl Tauber
+ */
+public class CubicBezierEasing
+	implements Animator.Interpolator
+{
+	// common cubic-bezier easing functions (same as in CSS)
+	// https://developer.mozilla.org/en-US/docs/Web/CSS/easing-function
+	public static final CubicBezierEasing EASE = new CubicBezierEasing( 0.25f, 0.1f, 0.25f, 1f );
+	public static final CubicBezierEasing EASE_IN = new CubicBezierEasing( 0.42f, 0f, 1f, 1f );
+	public static final CubicBezierEasing EASE_IN_OUT = new CubicBezierEasing( 0.42f, 0f, 0.58f, 1f );
+	public static final CubicBezierEasing EASE_OUT = new CubicBezierEasing( 0f, 0f, 0.58f, 1f );
+
+	private final float x1;
+	private final float y1;
+	private final float x2;
+	private final float y2;
+
+	/**
+	 * Creates a cubic bezier easing interpolator with the given control points.
+	 * The start point of the cubic bezier curve is always 0,0 and the end point 1,1.
+	 *
+	 * @param x1 the x coordinate of the first control point in range [0, 1]
+	 * @param y1 the y coordinate of the first control point in range [0, 1]
+	 * @param x2 the x coordinate of the second control point in range [0, 1]
+	 * @param y2 the y coordinate of the second control point in range [0, 1]
+	 */
+	public CubicBezierEasing( float x1, float y1, float x2, float y2 ) {
+		if( x1 < 0 || x1 > 1 || y1 < 0 || y1 > 1 ||
+			x2 < 0 || x2 > 1 || y2 < 0 || y2 > 1 )
+		  throw new IllegalArgumentException( "control points must be in range [0, 1]");
+
+		this.x1 = x1;
+		this.y1 = y1;
+		this.x2 = x2;
+		this.y2 = y2;
+	}
+
+	@Override
+	public float interpolate( float fraction ) {
+		if( fraction <= 0 || fraction >= 1 )
+			return fraction;
+
+		// use binary search
+		float low = 0;
+		float high = 1;
+		while( true ) {
+			float mid = (low + high) / 2;
+			float estimate = cubicBezier( mid, x1, x2 );
+			if( Math.abs( fraction - estimate ) < 0.0005f )
+				return cubicBezier( mid, y1, y2 );
+			if( estimate < fraction )
+				low = mid;
+			else
+				high = mid;
+		}
+	}
+
+	/**
+	 * Computes the x or y point on a cubic bezier curve for a given t value.
+	 *
+	 * https://en.wikipedia.org/wiki/B%C3%A9zier_curve#Cubic_B%C3%A9zier_curves
+	 *
+	 * The general cubic bezier formula is:
+	 *   x = b0*x0 + b1*x1 + b2*x2 + b3*x3
+	 *   y = b0*y0 + b1*y1 + b2*y2 + b3*y3
+	 *
+	 * where:
+	 *   b0 = (1-t)^3
+	 *   b1 = 3 * t * (1-t)^2
+	 *   b2 = 3 * t^2 * (1-t)
+	 *   b3 = t^3
+	 *
+	 *  x0,y0 is always 0,0 and x3,y3 is 1,1, so we can simplify to:
+	 *   x = b1*x1 + b2*x2 + b3
+	 *   y = b1*x1 + b2*x2 + b3
+	 */
+	private static float cubicBezier( float t, float xy1, float xy2 ) {
+		float invT = (1 - t);
+		float b1 = 3 * t * (invT * invT);
+		float b2 = 3 * (t * t) * invT;
+		float b3 = t * t * t;
+		return (b1 * xy1) + (b2 * xy2) + b3;
+	}
+}

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatAnimatorTest.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2020 FormDev Software GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.formdev.flatlaf.testing;
+
+import java.awt.*;
+import javax.swing.*;
+import com.formdev.flatlaf.util.Animator;
+import com.formdev.flatlaf.util.CubicBezierEasing;
+import net.miginfocom.swing.*;
+
+/**
+ * @author Karl Tauber
+ */
+public class FlatAnimatorTest
+	extends FlatTestPanel
+{
+	private Animator linearAnimator;
+	private Animator easeInOutAnimator;
+
+	public static void main( String[] args ) {
+		SwingUtilities.invokeLater( () -> {
+			FlatTestFrame frame = FlatTestFrame.create( args, "FlatAnimatorTest" );
+			frame.showFrame( FlatAnimatorTest::new );
+		} );
+	}
+
+	FlatAnimatorTest() {
+		initComponents();
+	}
+
+	private void start() {
+		startLinear();
+		startEaseInOut();
+	}
+
+	private void startLinear() {
+		if( linearAnimator != null ) {
+			linearAnimator.stop();
+			linearAnimator.start();
+		} else {
+			linearAnimator = new Animator( 1000, t -> {
+				linearScrollBar.setValue( Math.round( t * linearScrollBar.getMaximum() ) );
+			} );
+			linearAnimator.start();
+		}
+	}
+
+	private void startEaseInOut() {
+		if( easeInOutAnimator != null ) {
+			easeInOutAnimator.stop();
+			easeInOutAnimator.start();
+		} else {
+			easeInOutAnimator = new Animator( 1000, t -> {
+				easeInOutScrollBar.setValue( Math.round( t * easeInOutScrollBar.getMaximum() ) );
+			} );
+			easeInOutAnimator.setInterpolator( CubicBezierEasing.EASE_IN_OUT );
+			easeInOutAnimator.start();
+		}
+	}
+
+	private void initComponents() {
+		// JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
+		JLabel label1 = new JLabel();
+		linearScrollBar = new JScrollBar();
+		JLabel label2 = new JLabel();
+		easeInOutScrollBar = new JScrollBar();
+		startButton = new JButton();
+
+		//======== this ========
+		setLayout(new MigLayout(
+			"ltr,insets dialog,hidemode 3",
+			// columns
+			"[fill]" +
+			"[grow,fill]",
+			// rows
+			"[]" +
+			"[]" +
+			"[]"));
+
+		//---- label1 ----
+		label1.setText("Linear:");
+		add(label1, "cell 0 0");
+
+		//---- linearScrollBar ----
+		linearScrollBar.setOrientation(Adjustable.HORIZONTAL);
+		linearScrollBar.setBlockIncrement(1);
+		add(linearScrollBar, "cell 1 0");
+
+		//---- label2 ----
+		label2.setText("Ease in out:");
+		add(label2, "cell 0 1");
+
+		//---- easeInOutScrollBar ----
+		easeInOutScrollBar.setOrientation(Adjustable.HORIZONTAL);
+		easeInOutScrollBar.setBlockIncrement(1);
+		add(easeInOutScrollBar, "cell 1 1");
+
+		//---- startButton ----
+		startButton.setText("Start");
+		startButton.addActionListener(e -> start());
+		add(startButton, "cell 0 2");
+		// JFormDesigner - End of component initialization  //GEN-END:initComponents
+	}
+
+	// JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
+	private JScrollBar linearScrollBar;
+	private JScrollBar easeInOutScrollBar;
+	private JButton startButton;
+	// JFormDesigner - End of variables declaration  //GEN-END:variables
+}

flatlaf-testing/src/main/java/com/formdev/flatlaf/testing/FlatAnimatorTest.jfd

@@ -0,0 +1,62 @@
+JFDML JFormDesigner: "7.0.2.0.298" Java: "14.0.2" encoding: "UTF-8"
+
+new FormModel {
+	contentType: "form/swing"
+	root: new FormRoot {
+		auxiliary() {
+			"JavaCodeGenerator.defaultVariableLocal": true
+		}
+		add( new FormContainer( "com.formdev.flatlaf.testing.FlatTestPanel", new FormLayoutManager( class net.miginfocom.swing.MigLayout ) {
+			"$layoutConstraints": "ltr,insets dialog,hidemode 3"
+			"$columnConstraints": "[fill][grow,fill]"
+			"$rowConstraints": "[][][]"
+		} ) {
+			name: "this"
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "label1"
+				"text": "Linear:"
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 0 0"
+			} )
+			add( new FormComponent( "javax.swing.JScrollBar" ) {
+				name: "linearScrollBar"
+				"orientation": 0
+				"blockIncrement": 1
+				auxiliary() {
+					"JavaCodeGenerator.variableLocal": false
+				}
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 0"
+			} )
+			add( new FormComponent( "javax.swing.JLabel" ) {
+				name: "label2"
+				"text": "Ease in out:"
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 0 1"
+			} )
+			add( new FormComponent( "javax.swing.JScrollBar" ) {
+				name: "easeInOutScrollBar"
+				"orientation": 0
+				"blockIncrement": 1
+				auxiliary() {
+					"JavaCodeGenerator.variableLocal": false
+				}
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 1 1"
+			} )
+			add( new FormComponent( "javax.swing.JButton" ) {
+				name: "startButton"
+				"text": "Start"
+				auxiliary() {
+					"JavaCodeGenerator.variableLocal": false
+				}
+				addEvent( new FormEvent( "java.awt.event.ActionListener", "actionPerformed", "start", false ) )
+			}, new FormLayoutConstraints( class net.miginfocom.layout.CC ) {
+				"value": "cell 0 2"
+			} )
+		}, new FormLayoutConstraints( null ) {
+			"location": new java.awt.Point( 0, 0 )
+			"size": new java.awt.Dimension( 415, 350 )
+		} )
+	}
+}