framedtext.java

书籍"Java_面向事件编程"的附带光盘代码

import objectdraw.*;
import java.awt.*;

// A FramedText object displays a specified text message on a
// background framed by a distinct border.
public class FramedText extends FramedDisplay {
    
    private Text message;            // The message displayed
    private Location frameCenter;    // Where message belongs
    
    // Create a FramedText object displaying the text 'contents'
    // at the position and with the dimensions specified.
    public FramedText( String contents, double x, double y,
                       double width, double height,
                       DrawingCanvas canvas ) {
        
        // construct the frame
        super( x, y, width, height, canvas );
        
        // Construct and appropriately position the message
        frameCenter = new Location( x + width/2, y + height/2 );
        message = new Text ( contents, x, y, canvas );
        message.setColor( Color.white );
        positionContents();
    }
    
    // Position the message to center it in the frame
    private void positionContents() {
        message.moveTo( frameCenter );
        message.move( -message.getWidth()/2, -message.getHeight()/2 );
    }        
    
    // Change the font size used
    public void setTextSize( int size ) {
        message.setFontSize( size );
        positionContents();
    }
    
}