Package com.cburch.gray

Source Code of com.cburch.gray.CounterPoker

/* Copyright (c) 2010, Carl Burch. License information is located in the
* com.cburch.logisim.Main source code and at www.cburch.com/logisim/. */

package com.cburch.gray;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;

import com.cburch.logisim.data.BitWidth;
import com.cburch.logisim.data.Bounds;
import com.cburch.logisim.data.Value;
import com.cburch.logisim.instance.InstancePainter;
import com.cburch.logisim.instance.InstancePoker;
import com.cburch.logisim.instance.InstanceState;
import com.cburch.logisim.instance.StdAttr;

/** When the user clicks a counter using the Poke Tool, a CounterPoker object
* is created, and that object will handle all user events. Note that
* CounterPoker is a class specific to GrayCounter, and that it must be a
* subclass of InstancePoker in the com.cburch.logisim.instance package. */
public class CounterPoker extends InstancePoker {
  public CounterPoker() { }

  /** Determines whether the location the mouse was pressed should result
   * in initiating a poke.
   */
  @Override
  public boolean init(InstanceState state, MouseEvent e) {
    return state.getInstance().getBounds().contains(e.getX(), e.getY());
      // Anywhere in the main rectangle initiates the poke. The user might
      // have clicked within a label, but that will be outside the bounds.
  }

  /** Draws an indicator that the caret is being selected. Here, we'll draw
   * a red rectangle around the value. */
  @Override
  public void paint(InstancePainter painter) {
    Bounds bds = painter.getBounds();
    BitWidth width = painter.getAttributeValue(StdAttr.WIDTH);
    int len = (width.getWidth() + 3) / 4;

    Graphics g = painter.getGraphics();
    g.setColor(Color.RED);
    int wid = 7 * len + 2; // width of caret rectangle
    int ht = 16; // height of caret rectangle
    g.drawRect(bds.getX() + (bds.getWidth() - wid) / 2,
        bds.getY() + (bds.getHeight() - ht) / 2, wid, ht);
    g.setColor(Color.BLACK);
  }

  /** Processes a key by just adding it onto the end of the current value. */
  @Override
  public void keyTyped(InstanceState state, KeyEvent e) {
    // convert it to a hex digit; if it isn't a hex digit, abort.
    int val = Character.digit(e.getKeyChar(), 16);
    BitWidth width = state.getAttributeValue(StdAttr.WIDTH);
    if (val < 0 || (val & width.getMask()) != val) return;

    // compute the next value
    CounterData cur = CounterData.get(state, width);
    int newVal = (cur.getValue().toIntValue() * 16 + val) & width.getMask();
    Value newValue = Value.createKnown(width, newVal);
    cur.setValue(newValue);
    state.fireInvalidated();
   
    // You might be tempted to propagate the value immediately here, using
    // state.setPort. However, the circuit may currently be propagating in
    // another thread, and invoking setPort directly could interfere with
    // that. Using fireInvalidated notifies the propagation thread to
    // invoke propagate on the counter at its next opportunity.
  }
}
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