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原文地址: J2ME下实现滚动文字效果

J2ME下实现滚动文字也很简单,就是基于剪裁区的应用

看一下效果:



来看一下代码:

[code:1]private int tipStringPos = SCREEN_WIDTH; //当前字符串左边的位置
private int tipStringSpeed = 2; //字符串移动速度
private static final int TIPSTR_LEFT = 5 - 5; //左边消失绘制坐标
private static final int TIPSTR_RIGHT = 123 + 5; //右边出现绘制坐标

private static final int FONT_HEIGHT = 11; //字体高度 font.getHeight() 不准确

/**
* @param Graphics g - 画刷
* @param String str - 所画字符串
* @param int height - 字符串高度
* @param int rectX - 剪裁区顶点X坐标
* @param int rectY - 剪裁区顶点Y坐标
* @param int rectWidth - 剪裁区宽度
* @param int rectHeight - 剪裁区高度
*/

private void drawTipString(Graphics g, String str, int height,
int rectX, int rectY, int rectWidth, int rectHeight) {
int strWidth = g.getFont().stringWidth(str);
int strHeight = FONT_HEIGHT;

tipStringPos -= tipStringSpeed;
if (tipStringPos + strWidth < TIPSTR_LEFT) {
tipStringPos = TIPSTR_RIGHT;
}

//裁减区
int oldClipX = g.getClipX();
int oldClipY = g.getClipY();
int oldClipWidth = g.getClipWidth();
int oldClipHeight = g.getClipHeight();

g.setClip(rectX, rectY, rectWidth, rectHeight);

g.drawString(str, tipStringPos, height - strHeight / 2,
Graphics.LEFT | Graphics.TOP);
g.setClip(oldClipX, oldClipY, oldClipWidth, oldClipHeight);
}
[/code:1]

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