minicolorchooser.java

这是手机下载网络图像源码 共初学者参考

/*
 * @(#)MiniColorChooser.java	1.2 03/01/22
 *
 * Copyright (c) 2000-2003 Sun Microsystems, Inc. All rights reserved. 
 * PROPRIETARY/CONFIDENTIAL
 * Use is subject to license terms
 */

package example.chooser;

import javax.microedition.lcdui.*;

/**
 * A Color chooser.  This screen can be used to display and
 * choose colors.  The current color is always available
 * via the getColor methods.  It can be  set with setColor.
 */
public class MiniColorChooser extends Canvas {
    /** current color */
    int rgbColor;
    /** current index */
    int ndx = 0;
    
    /**
     * Create a new MiniColorChooser for a single color.
     */
    public MiniColorChooser() {
	setColor(0xffff00);
    }

    /**
     * Sets the current color to the specified RGB values. All subsequent
     * rendering operations will use this specified color. The RGB value
     * passed in is interpreted with the least significant eight bits
     * giving the blue component, the next eight more significant bits
     * giving the green component, and the next eight more significant
     * bits giving the red component. That is to say, the color component
     * is specified like 0x00RRGGBB.
     * @param RGB The color being set.
     */
    public void setColor(int RGB) {
	rgbColor = RGB & 0x00ffffff;
    }

    /**
     * Gets the current color.
     * @return an integer in form 0x00RRGGBB
     * @see #setColor
     */
    public int getColor() {
        return rgbColor;
    }

    /** Border width */
    static final int BORDER = 2;
    /** Color bar height */
    static final int BAR_H = 14;

    /**
     * Paint the canvas with the current color and controls to change it.
     * @param g the graphics context to draw to the screen.
     */
    protected void paint(Graphics g) {

	int w = getWidth();
	int h = getHeight();

	int sample_w = w - 1;
	int sample_h = h - (BAR_H + BORDER) * 3;
	int sample_y = BORDER;

	int b_y = sample_y + sample_h + BORDER*2;
	int g_y = b_y + BAR_H;
	int r_y = g_y + BAR_H;
	

	// Fill the background
	g.setColor(0x000000);
	g.fillRect(0, 0, w, h);

	// Fill in the color sample
	g.setColor(rgbColor);
	g.fillRect(BORDER, sample_y, sample_w, sample_h);

	// Draw the colorbars
	int blue = (rgbColor >> 0) & 0xff;
	g.setColor(0, 0, 255);
	g.fillRect(20, b_y, blue / 4, 10);

	int green = (rgbColor >> 8) & 0xff;
	g.setColor(0, 255, 0);
	g.fillRect(20, g_y, green / 4, 10);

	int red = (rgbColor >> 16) & 0xff;
	g.setColor(255, 0, 0);
	g.fillRect(20, r_y, red / 4, 10);

	g.setColor(255, 255, 255);
	g.drawString(Integer.toString(blue), 
		     18, b_y-3,  Graphics.RIGHT|Graphics.TOP);
	g.drawString(Integer.toString(green), 
		     18, g_y-3,  Graphics.RIGHT|Graphics.TOP);
	g.drawString(Integer.toString(red), 
		     18, r_y-3,  Graphics.RIGHT|Graphics.TOP);

	if (ndx >= 0) {
	    int y = b_y + ndx * BAR_H;
	    g.drawRect(20, y, 63, 10);
	}

    }

    /**
     * Handle repeat as in pressed.
     * @param key was pressed
     */
    public void keyRepeated(int key) {
	keyPressed(key);
    }

    /**
     * Left and Right are used to change which color bar to change
     * Up and Down are used to increase/decrease the value of that bar.
     * @param key was pressed
     */
    protected void keyPressed(int key) {
	int action = getGameAction(key);
	int dir = 0;
	switch (action) {
	case RIGHT: dir += 1; break;
	case LEFT: dir -= 1; break;
	case UP: ndx -= 1; break;
	case DOWN: ndx += 1; break;
	default:
	    return;		// nothing we recognize, exit
	}
	
	// Limit selection to r,g,b and palette 
	if (ndx < 0)
	    ndx = 0;
	if (ndx > 2)
	    ndx = 2;
	if (ndx >= 0) {
	    int v = (rgbColor >> (ndx*8)) & 0xff;
	    v += dir * 0x20;
	    if (v < 0)
		v = 0;
	    if (v > 255)
		v = 255;
	    int mask = 0xff << (ndx*8);
	    rgbColor = (rgbColor & ~mask) | v << (ndx*8);
	}
	repaint();
    }
}