Swing/CaretColor の変更点

• 追加された行はこの色です。
• 削除された行はこの色です。
• Swing/CaretColor へ行く。
• Swing/CaretColor の差分を削除

---
category: swing
folder: CaretColor
title: JTextComponentのCaretの色を変更する
tags: [Caret, JTextComponent, JTextField, JTextArea, JTextPane]
author: aterai
pubdate: 2018-01-22T15:56:54+09:00
description: JTextFieldやJTextPaneなどのJTextComponentで、Caretの色を変更します。
image: https://drive.google.com/uc?id=1u7eaiGMgpBZefGTMjAxkHBsxf29Fu-ZfbQ
---
* Summary [#summary]
`JTextField`や`JTextPane`などの`JTextComponent`で、`Caret`の色を変更します。

#download(https://drive.google.com/uc?id=1u7eaiGMgpBZefGTMjAxkHBsxf29Fu-ZfbQ)

* Source Code Examples [#sourcecode]
#code(link){{
UIManager.put("TextArea.caretForeground", Color.ORANGE);
JTextArea area = new JTextArea("TextArea.caretForeground: ORANGE");

JTextField field = new JTextField("JTextField");
field.setCaretColor(Color.RED);
}}

* Description [#explanation]
* Description [#description]
- `JTextField`
-- `setCaretColor(...)`メソッドで`Caret`の色を変更
--- `null`を設定すると`JTextField`の文字色が`Caret`の色になる
-- `IME`で変換中の`Caret`は`setCaretColor(...)`での設定を無視して`JTextField`の文字色が`Caret`の色になる
- `JTextArea`
-- `UIManager.put("TextArea.caretForeground", Color.ORANGE)`で`Caret`の色を変更
-- `IME`で変換中の`Caret`は`setCaretColor(...)`での設定を無視して`JTextArea`の文字色が`Caret`の色になる
- `JTextPane`
-- `setCaretColor(null)`で`Caret`の色を`null`に設定
-- 上記のサンプルで`Caret`の色は一行目の途中(二行目の`111`の幅まで？)まで赤、それ以外は黒になる
-- `IME`で変換中の`Caret`は`setCaretColor(...)`での設定を無視して`Graphics#setXORMode(...)`で反転した色が`Caret`の色になる
--- 二行目では行の背景色の緑の反転色のピンク、文字色の赤の反転色の水色になる？(`JTextComponent.ComposedTextCaret`を参照)

#code{{
//
// Caret implementation for editing the composed text.
//
class ComposedTextCaret extends DefaultCaret implements Serializable {
  Color bg;

  //
  // Get the background color of the component
  //
  public void install(JTextComponent c) {
    super.install(c);

    Document doc = c.getDocument();
    if (doc instanceof StyledDocument) {
      StyledDocument sDoc = (StyledDocument)doc;
      Element elem = sDoc.getCharacterElement(c.composedTextStart.getOffset());
      AttributeSet attr = elem.getAttributes();
      bg = sDoc.getBackground(attr);
    }

    if (bg == null) {
      bg = c.getBackground();
    }
  }

  //
  // Draw caret in XOR mode.
  //
  public void paint(Graphics g) {
    if (isVisible()) {
      try {
        Rectangle r = component.modelToView(getDot());
        g.setXORMode(bg);
        g.drawLine(r.x, r.y, r.x, r.y + r.height - 1);
        g.setPaintMode();
      } catch (BadLocationException e) {
        // can't render I guess
        //System.err.println("Can't render cursor");
      }
    }
  }

  //
  // If some area other than the composed text is clicked by mouse,
  // issue endComposition() to force commit the composed text.
  //
  protected void positionCaret(MouseEvent me) {
    JTextComponent host = component;
    Point pt = new Point(me.getX(), me.getY());
    int offset = host.viewToModel(pt);
    int composedStartIndex = host.composedTextStart.getOffset();
    if ((offset < composedStartIndex) ||
        (offset > composedTextEnd.getOffset())) {
      try {
        // Issue endComposition
        Position newPos = host.getDocument().createPosition(offset);
        host.getInputContext().endComposition();

        // Post a caret positioning runnable to assure that the positioning
        // occurs *after* committing the composed text.
        EventQueue.invokeLater(new DoSetCaretPosition(host, newPos));
      } catch (BadLocationException ble) {
        System.err.println(ble);
      }
    } else {
      // Normal processing
      super.positionCaret(me);
    }
  }
}
}}

* Reference [#reference]
- [https://docs.oracle.com/javase/jp/8/docs/api/javax/swing/text/JTextComponent.html#setCaretColor-java.awt.Color- JTextComponent#setCaretColor(Color) (Java Platform SE 8)]

* Comment [#comment]
#comment
#comment