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ChrriisChrriis
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Smooth scrolling implementation
1 parent c953ff8 commit c791cd0

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7 files changed

+629
-15
lines changed

7 files changed

+629
-15
lines changed

‎flatlaf-core/src/main/java/com/formdev/flatlaf/FlatLaf.java‎

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Original file line numberDiff line numberDiff line change
@@ -112,6 +112,7 @@ public abstract class FlatLaf
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private PopupFactory oldPopupFactory;
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private MnemonicHandler mnemonicHandler;
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private boolean subMenuUsabilityHelperInstalled;
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private boolean smoothScrollingHelperInstalled;
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private Consumer<UIDefaults> postInitialization;
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private List<Function<Object, Object>> uiDefaultsGetters;
@@ -271,6 +272,9 @@ public void initialize() {
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// install submenu usability helper
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subMenuUsabilityHelperInstalled = SubMenuUsabilityHelper.install();
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// install smooth scrolling helper
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smoothScrollingHelperInstalled = SmoothScrollingHelper.install();
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// listen to desktop property changes to update UI if system font or scaling changes
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if( SystemInfo.isWindows ) {
@@ -364,6 +368,12 @@ public void uninitialize() {
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subMenuUsabilityHelperInstalled = false;
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}
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// uninstall smooth scrolling helper
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if( smoothScrollingHelperInstalled ) {
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SmoothScrollingHelper.uninstall();
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smoothScrollingHelperInstalled = false;
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}
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// restore default link color
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new HTMLEditorKit().getStyleSheet().addRule( "a, address { color: blue; }" );
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postInitialization = null;

‎flatlaf-core/src/main/java/com/formdev/flatlaf/FlatSystemProperties.java‎

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@@ -132,6 +132,14 @@ public interface FlatSystemProperties
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*/
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String ANIMATION = "flatlaf.animation";
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/**
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* Specifies whether smooth scrolling is enabled.
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* <p>
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* <strong>Allowed Values</strong> {@code false} and {@code true}<br>
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* <strong>Default</strong> {@code true}
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*/
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String SMOOTH_SCROLLING = "flatlaf.smoothScrolling";
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/**
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* Specifies whether vertical text position is corrected when UI is scaled on HiDPI screens.
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* <p>

‎flatlaf-core/src/main/java/com/formdev/flatlaf/SmoothScrollingHelper.java‎

Lines changed: 209 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,209 @@
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/*
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* Christopher Deckers ([email protected])
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* http://www.nextencia.net
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*
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* See the file "readme.txt" for information on usage and redistribution of
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* this file, and for a DISCLAIMER OF ALL WARRANTIES.
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*/
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package com.formdev.flatlaf;
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import java.awt.AWTEvent;
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import java.awt.Component;
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import java.awt.Container;
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import java.awt.Rectangle;
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import java.awt.Toolkit;
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import java.awt.event.AWTEventListener;
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import java.awt.event.ComponentEvent;
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import java.awt.event.KeyEvent;
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import java.awt.event.MouseEvent;
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import java.util.Collections;
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import java.util.IdentityHashMap;
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import java.util.Set;
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import javax.swing.JComponent;
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import javax.swing.JScrollBar;
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import javax.swing.JScrollPane;
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import javax.swing.JViewport;
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import javax.swing.RepaintManager;
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import javax.swing.SwingUtilities;
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import com.formdev.flatlaf.util.Animator;
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/**
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* @author Christopher Deckers
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*/
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public class SmoothScrollingHelper implements AWTEventListener
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{
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private static SmoothScrollingHelper instance;
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static synchronized boolean install() {
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if( instance != null )
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return false;
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instance = new SmoothScrollingHelper();
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long eventMask = AWTEvent.MOUSE_EVENT_MASK | AWTEvent.MOUSE_MOTION_EVENT_MASK | AWTEvent.MOUSE_WHEEL_EVENT_MASK | AWTEvent.KEY_EVENT_MASK;
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Toolkit.getDefaultToolkit().addAWTEventListener(instance, eventMask);
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return true;
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}
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static synchronized void uninstall() {
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if( instance == null )
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return;
50+
Toolkit.getDefaultToolkit().removeAWTEventListener(instance);
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instance = null;
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}
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@Override
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public void eventDispatched( AWTEvent event ) {
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if( event instanceof ComponentEvent && ((ComponentEvent)event).getComponent() instanceof JScrollBar ) {
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// Do not disconnect blit scroll mode when e.g. dragging the scroll bar.
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return;
59+
}
60+
if( Animator.useAnimation() && FlatSystemProperties.getBoolean( FlatSystemProperties.SMOOTH_SCROLLING, true ) ) {
61+
boolean isHoldingScrollModeBlocked = false;
62+
switch(event.getID()) {
63+
case MouseEvent.MOUSE_MOVED:
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case MouseEvent.MOUSE_ENTERED:
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case MouseEvent.MOUSE_EXITED:
66+
if(isBlitScrollModeBlocked) {
67+
int modifiersEx = ((MouseEvent)event).getModifiersEx();
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if((modifiersEx & (MouseEvent.BUTTON1_DOWN_MASK | MouseEvent.BUTTON2_DOWN_MASK | MouseEvent.BUTTON3_DOWN_MASK)) == 0) {
69+
// If the scroll mode was blocked for dragging, let's release if we receive a non-drag-related event (i.e. drag is done).
70+
for( JViewport viewport: viewportSet ) {
71+
setBlitScrollModeBlocked( viewport, false );
72+
setInSmoothScrolling( viewport, false );
73+
}
74+
isBlitScrollModeBlocked = false;
75+
}
76+
}
77+
break;
78+
case MouseEvent.MOUSE_PRESSED:
79+
case MouseEvent.MOUSE_DRAGGED:
80+
isHoldingScrollModeBlocked = true;
81+
// Fall through
82+
case MouseEvent.MOUSE_RELEASED:
83+
case MouseEvent.MOUSE_CLICKED:
84+
case MouseEvent.MOUSE_WHEEL:
85+
case KeyEvent.KEY_PRESSED:
86+
case KeyEvent.KEY_RELEASED:
87+
case KeyEvent.KEY_TYPED:
88+
boolean isBlitScrollModeBlocked_ = isBlitScrollModeBlocked;
89+
if(!isBlitScrollModeBlocked_) {
90+
Component c = ((ComponentEvent)event).getComponent();
91+
for( JViewport viewport: viewportSet ) {
92+
Container scrollPane = viewport.getParent();
93+
if(scrollPane == c || scrollPane.isAncestorOf( c )) {
94+
setInSmoothScrolling( viewport, true );
95+
}
96+
setBlitScrollModeBlocked( viewport, true );
97+
}
98+
isBlitScrollModeBlocked = true;
99+
}
100+
if( !isHoldingScrollModeBlocked && ( !isBlitScrollModeBlocked_ || event.getID() == MouseEvent.MOUSE_RELEASED )) {
101+
SwingUtilities.invokeLater( () -> {
102+
for( JViewport viewport: viewportSet ) {
103+
setBlitScrollModeBlocked( viewport, false );
104+
setInSmoothScrolling( viewport, false );
105+
}
106+
isBlitScrollModeBlocked = false;
107+
} );
108+
}
109+
break;
110+
}
111+
}
112+
}
113+
114+
private boolean isBlitScrollModeBlocked;
115+
116+
public static synchronized void setBlitScrollModeBlocked( JViewport viewport, boolean isBlocked ) {
117+
if( instance == null )
118+
return;
119+
String clientPropertyName = "_flatlaf.originalScrollMode";
120+
if( isBlocked ) {
121+
int scrollMode = viewport.getScrollMode();
122+
if( scrollMode == JViewport.BLIT_SCROLL_MODE ) {
123+
viewport.putClientProperty( clientPropertyName , scrollMode );
124+
viewport.setScrollMode( JViewport.SIMPLE_SCROLL_MODE );
125+
}
126+
} else {
127+
Integer scrollMode = (Integer)viewport.getClientProperty( clientPropertyName );
128+
if( scrollMode != null ) {
129+
viewport.setScrollMode( scrollMode );
130+
viewport.putClientProperty( clientPropertyName , null );
131+
}
132+
}
133+
}
134+
135+
public static void setScrollBarValueWithOptionalRepaint(JViewport viewport, JScrollBar scrollbar, int value) {
136+
Container viewportParent = null;
137+
Rectangle dirtyRegion = null;
138+
viewportParent = viewport == null? null: viewport.getParent();
139+
dirtyRegion = viewportParent instanceof JComponent? RepaintManager.currentManager( viewport ).getDirtyRegion((JComponent)viewportParent ): null;
140+
int scrollMode = viewport.getScrollMode();
141+
if(scrollMode == JViewport.BLIT_SCROLL_MODE) {
142+
viewport.setScrollMode( JViewport.SIMPLE_SCROLL_MODE );
143+
}
144+
scrollbar.setValue( value );
145+
if(scrollMode == JViewport.BLIT_SCROLL_MODE) {
146+
viewport.setScrollMode( JViewport.BLIT_SCROLL_MODE );
147+
}
148+
if(dirtyRegion != null && dirtyRegion.width == 0 && dirtyRegion.height == 0) {
149+
// There was no dirty region. Let's restore that state for blit scroll mode to work.
150+
RepaintManager.currentManager( viewport ).markCompletelyClean( (JComponent)viewportParent );
151+
}
152+
}
153+
154+
public static synchronized boolean isInBlockedBlitScrollMode( JViewport viewport ) {
155+
if( instance == null )
156+
return false;
157+
String clientPropertyName = "_flatlaf.originalScrollMode";
158+
return viewport.getClientProperty( clientPropertyName ) != null && viewport.getScrollMode() == JViewport.SIMPLE_SCROLL_MODE;
159+
}
160+
161+
public static synchronized void allowBlitScrollModeTemporarily( JViewport viewport, boolean isAllowed ) {
162+
if( instance == null )
163+
return;
164+
// When mouse is dragged, blit scroll mode is deactivated so that drag timers that provoke more scrolling do not repaint at wrong position.
165+
// The FlatLaf animator re-activates the blit scroll mode just for its timed operation.
166+
String clientPropertyName = "_flatlaf.originalScrollMode";
167+
if(viewport.getClientProperty( clientPropertyName ) != null) {
168+
if(isAllowed) {
169+
viewport.setScrollMode( JViewport.BLIT_SCROLL_MODE );
170+
} else {
171+
viewport.setScrollMode( JViewport.SIMPLE_SCROLL_MODE );
172+
}
173+
}
174+
}
175+
176+
public static synchronized boolean isInSmoothScrolling( JViewport viewport ) {
177+
if( instance == null )
178+
return false;
179+
String clientPropertyName = "_flatlaf.inSmoothScrolling";
180+
return viewport != null && viewport.getClientProperty( clientPropertyName ) != null;
181+
}
182+
183+
private static synchronized void setInSmoothScrolling( JViewport viewport, boolean isInSmoothScrolling ) {
184+
if( instance == null )
185+
return;
186+
String clientPropertyName = "_flatlaf.inSmoothScrolling";
187+
viewport.putClientProperty( clientPropertyName , isInSmoothScrolling? Boolean.TRUE: null);
188+
}
189+
190+
private static Set<JViewport> viewportSet = Collections.newSetFromMap(new IdentityHashMap<JViewport, Boolean>());
191+
192+
public static synchronized void registerViewport( JViewport viewport ) {
193+
if( instance == null )
194+
return;
195+
if(viewport.getParent() instanceof JScrollPane) {
196+
viewportSet.add( viewport );
197+
}
198+
}
199+
200+
public static synchronized void unregisterViewport( JViewport viewport ) {
201+
if( instance == null )
202+
return;
203+
if( instance.isBlitScrollModeBlocked ) {
204+
instance.setBlitScrollModeBlocked( viewport, false );
205+
}
206+
viewportSet.remove( viewport );
207+
}
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209+
}

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