ScrollColorProducer.java

/*
 * Copyright 2000-2016 JetBrains s.r.o.
 *
 * 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
 *
 * http://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.intellij.ui.components;

import com.intellij.ui.ColorUtil;
import com.intellij.ui.JBColor;
import com.intellij.util.NotNullProducer;
import com.intellij.util.ui.UIUtil;
import org.jetbrains.annotations.NotNull;

import java.awt.Color;
import java.awt.Component;
import java.awt.Container;
import javax.swing.JScrollPane;

import static com.intellij.ui.components.JBScrollPane.BRIGHTNESS_FROM_VIEW;

/**
 * @author Sergey.Malenkov
 */
final class ScrollColorProducer implements NotNullProducer<Color> {
  private final Component myComponent;
  private final Color myBrightColor;
  private final Color myDarkColor;
  private final boolean isBackground;
  // cached color values
  private volatile Color myOriginal;
  private volatile Color myModified;

  @SuppressWarnings("UseJBColor")
  private ScrollColorProducer(Component component, int bright, int dark, boolean background) {
    myComponent = component;
    myBrightColor = new Color(bright);
    myDarkColor = new Color(dark);
    isBackground = background;
  }

  @NotNull
  @Override
  public Color produce() {
    Container parent = myComponent.getParent();
    if (isBackground && parent instanceof JScrollPane && ScrollSettings.isBackgroundFromView()) {
      Color background = JBScrollPane.getViewBackground((JScrollPane)parent);
      if (background != null) {
        if (!background.equals(myOriginal)) {
          myModified = ColorUtil.shift(background, ColorUtil.isDark(background) ? 1.05 : 0.96);
          myOriginal = background;
        }
        return myModified;
      }
    }
    return isDark(myComponent) ? myDarkColor : myBrightColor;
  }

  static void setForeground(Component component) {
    component.setForeground(new JBColor(new ScrollColorProducer(component, 0xE6E6E6, 0x3C3F41, false)));
  }

  static void setBackground(Component component) {
    component.setBackground(new JBColor(new ScrollColorProducer(component, 0xF5F5F5, 0x3C3F41, true)));
  }

  static boolean isDark(Component c) {
    Container parent = c.getParent();
    if (parent instanceof JScrollPane) {
      JScrollPane pane = (JScrollPane)parent;
      Object property = pane.getClientProperty(BRIGHTNESS_FROM_VIEW);
      if (property instanceof Boolean && (Boolean)property) {
        Color color = JBScrollPane.getViewBackground(pane);
        if (color != null) return ColorUtil.isDark(color);
      }
    }
    return UIUtil.isUnderDarcula();
  }
}