cslide.java

经典java手机游戏J2me（Rpj游戏）

import javax.microedition.lcdui.Graphics;
import com.nokia.mid.ui.DirectGraphics;
import com.nokia.mid.ui.DirectUtils;
/*
 * 渐变类
 * 构造函数与设置渐变填充区域函数要一块设置
 */
public class CSlide
{
    private DirectGraphics    m_directGraphics;    //NOKIA 开发包带的画笔，带有填充透明色功能
    private int               m_slideState = 0;    //渐变效果：  0--没有渐变　1--渐入(由暗变亮)  2--渐出(由亮变暗)　3--变暗后转换场景
    private int               m_alpha = 0;         //ALPHA 值，用于渐变效果
    private int               m_slideAreaX[];    //渐变填充区域
    private int               m_slideAreaY[];
    
    //------------------------------------
    // 构造函数
    //------------------------------------
    public CSlide(Graphics offG)
    {
        m_directGraphics = DirectUtils.getDirectGraphics(offG);
    }
    
    //------------------------------------
    // 渲染渐变效果
    // 参数说明：
    //     color：向这种颜色渐变
    //     slideSpeed：渐变的速度
    //------------------------------------
    public void slideScene(int color, int slideSpeed)
    {
        switch (m_slideState)
        {
            case 1: //渐入(由暗变亮)，alpha 255 --> 0
                if (m_alpha > 0)
                    m_alpha -= slideSpeed;
                else
                {
                    m_alpha = 0;
                    m_slideState = 0;   //渐变动画结束
                }
                m_directGraphics.fillPolygon(m_slideAreaX, 0, m_slideAreaY, 0, 4, color + m_alpha * 0x10000000); //alpha = 0 时是透明
                break;
            case 2: //渐出(由亮变暗)，alpha 0 --> 255
                if (m_alpha < 255)
                    m_alpha += slideSpeed;
                else
                {
                    m_alpha = 255;
                    m_slideState = 3;   //变暗后进入 3 状态，即将判断应该切换至哪个场景
                }
                m_directGraphics.fillPolygon(m_slideAreaX, 0, m_slideAreaY, 0, 4, color + m_alpha * 0x10000000); //alpha = 255 时是不透明
                break;
        }
    }
    
    //------------------------------------
    // 设置 ALPHA 值
    //------------------------------------
    public void setAlpha(int alpha)
    {
        m_alpha = alpha;
    }
    
    //------------------------------------
    // 设置渐变状态
    //------------------------------------
    public void setSlideState(int slideState)
    {
        m_slideState = slideState;
    }
    
    //------------------------------------
    // 得到渐变状态
    //------------------------------------
    public int  getSlideState()
    {
        return m_slideState;
    }
    
    //------------------------------------
    // 设置渐变填充区域
    //------------------------------------
    public void setSlideArea(int xPoints[], int yPoints[])
    {
        m_slideAreaX = xPoints;
        m_slideAreaY = yPoints;
    }
    
}