Implement scrollbar thumb scaling

Affects: #14
Affects: #13

com.io7m.jsycamore.api/src/main/java/com/io7m/jsycamore/api/components/SyComponentReadableType.java

@@ -26,6 +26,7 @@
 import com.io7m.jsycamore.api.visibility.SyVisibleReadableType;
 import com.io7m.jsycamore.api.windows.SyWindowReadableType;
 import com.io7m.jtensors.core.parameterized.vectors.PVector2I;
+import com.io7m.jtensors.core.parameterized.vectors.PVectors2I;
 
 import java.util.Objects;
 import java.util.Optional;
@@ -184,4 +185,27 @@ default PVector2I<SySpaceViewportType> viewportPositionOf(
       windowPosition.y() + y
     );
   }
+
+  /**
+   * Determine the parent-relative position of the given viewport position
+   * for component. The method will fail if this component is not attached to
+   * a window.
+   *
+   * @param position The source position
+   *
+   * @return The viewport position
+   */
+
+  default PVector2I<SySpaceParentRelativeType> relativePositionOf(
+    final PVector2I<SySpaceViewportType> position)
+  {
+    Objects.requireNonNull(position, "position");
+
+    final var base =
+      this.viewportPositionOf(PVectors2I.zero());
+    final var delta =
+      PVectors2I.subtract(position, base);
+
+    return PVector2I.of(delta.x(), delta.y());
+  }
 }

com.io7m.jsycamore.api/src/main/java/com/io7m/jsycamore/api/components/SyScrollBarHorizontalType.java

@@ -72,36 +72,4 @@ public interface SyScrollBarHorizontalType
    */
 
   void removeOnThumbDragListener();
-
-  /**
-   * Set the scroll position in the range {@code [0, 1]}.
-   *
-   * @param position The position
-   */
-
-  void setScrollPosition(double position);
-
-  /**
-   * Set the scroll position snapping value in the range {@code [0, 1]}. The
-   * given fraction is used to determine how many divisions will be used within
-   * the scrolling space. For example, a value of {@code 1.0 / 4.0} will yield
-   * four possible snapped position values.
-   *
-   * @param fraction The fraction
-   */
-
-  void setScrollPositionSnapping(double fraction);
-
-  /**
-   * Scrollbars are typically used to scroll a visible portion of some larger
-   * structure. Some implementations might want to scale the scrollbar thumb
-   * based on the portion of the visible space that is visible. A value of
-   * {@code 0.0} means that an infinitely small piece of the larger structure
-   * is visible. A value of {@code 1.0} means that the entirety of the larger
-   * structure is visible.
-   *
-   * @param amount The amount shown
-   */
-
-  void setScrollAmountShown(double amount);
 }

com.io7m.jsycamore.api/src/main/java/com/io7m/jsycamore/api/components/SyScrollBarPresencePolicy.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright © 2023 Mark Raynsford <code@io7m.com> https://www.io7m.com
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+
+package com.io7m.jsycamore.api.components;
+
+/**
+ * The presence policy for scrollbars.
+ */
+
+public enum SyScrollBarPresencePolicy
+{
+  /**
+   * The scrollbar should always be present and enabled.
+   */
+
+  ALWAYS_ENABLED,
+
+  /**
+   * The scrollbar is disabled if the entire range is shown.
+   *
+   * @see SyScrollBarType#setScrollAmountShown(double)
+   */
+
+  DISABLED_IF_ENTIRE_RANGE_SHOWN
+}

com.io7m.jsycamore.api/src/main/java/com/io7m/jsycamore/api/components/SyScrollBarReadableType.java

@@ -16,6 +16,8 @@
 
 package com.io7m.jsycamore.api.components;
 
+import com.io7m.jattribute.core.AttributeReadableType;
+
 /**
  * Read-only access to scrollbars.
  */
@@ -30,7 +32,6 @@ public interface SyScrollBarReadableType
   SyComponentReadableType thumb();
 
   /**
-   *
    * @return The scrollbar track
    */
 
@@ -47,4 +48,10 @@ public interface SyScrollBarReadableType
    */
 
   double scrollPositionSnapping();
+
+  /**
+   * @return The scrollbar presence policy
+   */
+
+  AttributeReadableType<SyScrollBarPresencePolicy> presencePolicy();
 }

com.io7m.jsycamore.api/src/main/java/com/io7m/jsycamore/api/components/SyScrollBarType.java

@@ -16,12 +16,47 @@
 
 package com.io7m.jsycamore.api.components;
 
+import com.io7m.jattribute.core.AttributeType;
+
 /**
  * Write access to scrollbars.
  */
 
 public interface SyScrollBarType
   extends SyScrollBarReadableType, SyComponentType
 {
+  @Override
+  AttributeType<SyScrollBarPresencePolicy> presencePolicy();
+
+  /**
+   * Set the scroll position in the range {@code [0, 1]}.
+   *
+   * @param position The position
+   */
+
+  void setScrollPosition(double position);
+
+  /**
+   * Set the scroll position snapping value in the range {@code [0, 1]}. The
+   * given fraction is used to determine how many divisions will be used within
+   * the scrolling space. For example, a value of {@code 1.0 / 4.0} will yield
+   * four possible snapped position values.
+   *
+   * @param fraction The fraction
+   */
+
+  void setScrollPositionSnapping(double fraction);
+
+  /**
+   * Scrollbars are typically used to scroll a visible portion of some larger
+   * structure. Some implementations might want to scale the scrollbar thumb
+   * based on the portion of the visible space that is visible. A value of
+   * {@code 0.0} means that an infinitely small piece of the larger structure
+   * is visible. A value of {@code 1.0} means that the entirety of the larger
+   * structure is visible.
+   *
+   * @param amount The amount shown
+   */
 
+  void setScrollAmountShown(double amount);
 }

com.io7m.jsycamore.components.standard/pom.xml

@@ -24,6 +24,10 @@
       <version>${project.version}</version>
     </dependency>
 
+    <dependency>
+      <groupId>com.io7m.jinterp</groupId>
+      <artifactId>com.io7m.jinterp.core</artifactId>
+    </dependency>
     <dependency>
       <groupId>com.io7m.jaffirm</groupId>
       <artifactId>com.io7m.jaffirm.core</artifactId>

com.io7m.jsycamore.components.standard/src/main/java/com/io7m/jsycamore/components/standard/SyMenuBar.java

@@ -236,21 +236,24 @@ public PAreaSizeI<SySpaceParentRelativeType> layout(
     protected SyEventConsumed onEvent(
       final SyEventType event)
     {
-      if (event instanceof SyMouseEventOnPressed) {
-        this.menuBar.menuChangeSelection(this);
-        return EVENT_CONSUMED;
-      }
-
-      if (event instanceof SyMouseEventOnOver) {
-        if (this.menuBar.menuAnySelected()) {
-          if (!this.menuBar.menuIsSelected(this)) {
-            this.menuBar.menuChangeSelection(this);
-            return EVENT_CONSUMED;
+      return switch (event) {
+        case final SyMouseEventOnPressed e -> {
+          this.menuBar.menuChangeSelection(this);
+          yield EVENT_CONSUMED;
+        }
+        case final SyMouseEventOnOver e -> {
+          if (this.menuBar.menuAnySelected()) {
+            if (!this.menuBar.menuIsSelected(this)) {
+              this.menuBar.menuChangeSelection(this);
+              yield EVENT_CONSUMED;
+            }
           }
+          yield EVENT_NOT_CONSUMED;
         }
-      }
-
-      return EVENT_NOT_CONSUMED;
+        default -> {
+          yield EVENT_NOT_CONSUMED;
+        }
+      };
     }
 
     @Override

com.io7m.jsycamore.components.standard/src/main/java/com/io7m/jsycamore/components/standard/SyScrollBarsHorizontal.java

@@ -19,7 +19,7 @@
 
 import com.io7m.jsycamore.api.components.SyScrollBarHorizontalType;
 import com.io7m.jsycamore.api.themes.SyThemeClassNameType;
-import com.io7m.jsycamore.components.standard.internal.scrollbars.SyScrollBarHorizontalBasic;
+import com.io7m.jsycamore.components.standard.internal.scrollbars.SyScrollBarH;
 
 import java.util.List;
 
@@ -45,7 +45,7 @@ private SyScrollBarsHorizontal()
   public static SyScrollBarHorizontalType create(
     final List<SyThemeClassNameType> themeClassesExtra)
   {
-    return new SyScrollBarHorizontalBasic(themeClassesExtra);
+    return new SyScrollBarH(themeClassesExtra);
   }
 
   /**

com.io7m.jsycamore.components.standard/src/main/java/com/io7m/jsycamore/components/standard/internal/scrollbars/SyScrollBarHorizontalBasic.java → com.io7m.jsycamore.components.standard/src/main/java/com/io7m/jsycamore/components/standard/internal/scrollbars/SyScrollBarH.java

@@ -17,31 +17,37 @@
 
 package com.io7m.jsycamore.components.standard.internal.scrollbars;
 
+import com.io7m.jattribute.core.AttributeType;
 import com.io7m.jregions.core.parameterized.areas.PAreasI;
 import com.io7m.jregions.core.parameterized.sizes.PAreaSizeI;
 import com.io7m.jsycamore.api.components.SyButtonReadableType;
 import com.io7m.jsycamore.api.components.SyComponentReadableType;
 import com.io7m.jsycamore.api.components.SyConstraints;
 import com.io7m.jsycamore.api.components.SyScrollBarDrag;
 import com.io7m.jsycamore.api.components.SyScrollBarHorizontalType;
+import com.io7m.jsycamore.api.components.SyScrollBarPresencePolicy;
 import com.io7m.jsycamore.api.events.SyEventConsumed;
 import com.io7m.jsycamore.api.events.SyEventType;
 import com.io7m.jsycamore.api.layout.SyLayoutContextType;
 import com.io7m.jsycamore.api.spaces.SySpaceParentRelativeType;
 import com.io7m.jsycamore.api.themes.SyThemeClassNameType;
 import com.io7m.jsycamore.components.standard.SyComponentAbstract;
+import com.io7m.jsycamore.components.standard.SyComponentAttributes;
 import com.io7m.jtensors.core.parameterized.vectors.PVector2I;
 
 import java.util.List;
 import java.util.function.Consumer;
 
+import static com.io7m.jsycamore.api.active.SyActive.ACTIVE;
+import static com.io7m.jsycamore.api.active.SyActive.INACTIVE;
+import static com.io7m.jsycamore.api.components.SyScrollBarPresencePolicy.DISABLED_IF_ENTIRE_RANGE_SHOWN;
 import static com.io7m.jsycamore.api.events.SyEventConsumed.EVENT_NOT_CONSUMED;
 
 /**
  * A horizontal scrollbar.
  */
 
-public final class SyScrollBarHorizontalBasic
+public final class SyScrollBarH
   extends SyComponentAbstract
   implements SyScrollBarHorizontalType
 {
@@ -51,18 +57,22 @@ public final class SyScrollBarHorizontalBasic
   private final SyScrollBarHButtonLeft buttonLeft;
   private final SyScrollBarHButtonRight buttonRight;
   private final SyScrollBarHTrack track;
+  private final AttributeType<SyScrollBarPresencePolicy> presencePolicy;
 
   /**
    * A horizontal scrollbar.
    *
    * @param inThemeClassesExtra The extra theme classes, if any
    */
 
-  public SyScrollBarHorizontalBasic(
+  public SyScrollBarH(
     final List<SyThemeClassNameType> inThemeClassesExtra)
   {
     super(inThemeClassesExtra);
 
+    this.presencePolicy =
+      SyComponentAttributes.get().create(DISABLED_IF_ENTIRE_RANGE_SHOWN);
+
     this.buttonLeft =
       new SyScrollBarHButtonLeft();
     this.buttonRight =
@@ -265,6 +275,22 @@ public void setScrollAmountShown(
     final double amount)
   {
     this.track.setScrollAmountShown(amount);
+
+    switch (this.presencePolicy.get()) {
+      case ALWAYS_ENABLED -> {
+        final var active = ACTIVE;
+        this.buttonLeft.setActive(active);
+        this.buttonRight.setActive(active);
+        this.track.setActive(active);
+      }
+      case DISABLED_IF_ENTIRE_RANGE_SHOWN -> {
+        final var active =
+          this.track.scrollAmountShown() >= 1.0 ? INACTIVE : ACTIVE;
+        this.buttonLeft.setActive(active);
+        this.buttonRight.setActive(active);
+        this.track.setActive(active);
+      }
+    }
   }
 
   @Override
@@ -302,4 +328,10 @@ public double scrollPositionSnapping()
   {
     return this.track.scrollPositionSnapping();
   }
+
+  @Override
+  public AttributeType<SyScrollBarPresencePolicy> presencePolicy()
+  {
+    return this.presencePolicy;
+  }
 }