在图片上准确的绘制文字

package com.test.imgtest;


/**
 * @项目 SurfaceDemo  文件名 GLFont.java 
 * @GLFont
 */


/**
 * @author leolaurel
 * @version 1.0.0 2012-7-5
 */
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.graphics.Paint.FontMetrics;


public class GLFont {
    /*
     * 默认采用白色字体，宋体文字加粗
     */
public static Bitmap getImage(int width, int height ,String mString, int size) {
return getImage(width, height, mString, size, Color.RED, Typeface.create("宋体",Typeface.BOLD));
}

public static Bitmap getImage(int width, int height ,String mString,int size ,int color) {
return getImage(width, height, mString, size, color, Typeface.create("宋体",Typeface.BOLD));
}

public static Bitmap getImage(int width, int height ,String mString,int size ,int color, String familyName) {
return getImage(width, height, mString, size, color, Typeface.create(familyName,Typeface.BOLD));
}

public static Bitmap getImage(int width, int height ,String mString,int size, int color, Typeface font) {
int x = width;
int y = height;

Bitmap bmp = Bitmap.createBitmap(x, y, Bitmap.Config.ARGB_8888); 
//图象大小要根据文字大小算下,以和文本长度对应 
Canvas canvasTemp = new Canvas(bmp); 
canvasTemp.drawColor(Color.BLACK); 
Paint p = new Paint(); 
p.setColor(color);
p.setTypeface(font);
p.setAntiAlias(true);//去除锯齿
p.setFilterBitmap(true);//对位图进行滤波处理
p.setTextSize(scalaFonts(size));
float tX = (x - getFontlength(p, mString))/2;
float tY = (y - getFontHeight(p))/2+getFontLeading(p);
canvasTemp.drawText(mString,tX,tY,p); 


return bmp;
}


/**
* 根据屏幕系数比例获取文字大小
* @return
*/
private static float scalaFonts(int size) {
//暂未实现
return size;
}


/**
* @return 返回指定笔和指定字符串的长度
*/
public static float getFontlength(Paint paint, String str) {
return paint.measureText(str);
}
/**
* @return 返回指定笔的文字高度
*/
public static float getFontHeight(Paint paint)  {  
   FontMetrics fm = paint.getFontMetrics(); 
   return fm.descent - fm.ascent;  
} 
/**
* @return 返回指定笔离文字顶部的基准距离
*/
public static float getFontLeading(Paint paint)  {  
   FontMetrics fm = paint.getFontMetrics(); 
   return fm.leading- fm.ascent;  
} 

}