Android实现用文字生成图片的示例代码

package com.luoye.fpic.util;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;

public class Utils {
  /**
   * 核心，文本转成图片
   * @param bitmap 原图片
   * @param text 文本
   * @param fontSize 文字大小
   * @return 转好的图片
   */
  public static Bitmap getTextBitmap(Bitmap bitmap, String text, int fontSize)
  {
    if(bitmap==null)
      throw new IllegalArgumentException("Bitmap cannot be null.");
    int picWidth=bitmap.getWidth();
    int picHeight=bitmap.getHeight();
    Bitmap back= Bitmap.createBitmap((bitmap.getWidth()%fontSize==0)?bitmap.getWidth():((bitmap.getWidth()/fontSize+1)*fontSize)
        ,(bitmap.getHeight()%fontSize==0)?bitmap.getHeight():((bitmap.getHeight()/fontSize+1)*fontSize)
        , Bitmap.Config.ARGB_8888);
    Canvas canvas=new Canvas(back);
    canvas.drawColor(0xfff);
    int idx=0;
    for(int y=0;y<picHeight;y+=fontSize)
    {
      for(int x=0;x<picWidth;x+=fontSize)
      {
        int[] colors=getPixels(bitmap,x,y,fontSize,fontSize );

        Paint paint=new Paint();
        paint.setAntiAlias(true);
        paint.setColor(getAverage(colors));
        paint.setTextSize(fontSize);
        Paint.FontMetrics fontMetrics =paint.getFontMetrics();
        float padding=(y==0)?(fontSize+fontMetrics.ascent):((fontSize+fontMetrics.ascent)*2);

        canvas.drawText(String.valueOf(text.charAt(idx++)),x,y-padding,paint);
        if(idx==text.length())
        {
          idx=0;
        }

      }
    }

    return back;
  }

  /**
   * 获取某一块的所有像素的颜色
   * @param bitmap
   * @param x
   * @param y
   * @param w
   * @param h
   * @return 颜色数组
   */
  private static int[] getPixels(Bitmap bitmap,int x,int y,int w,int h)
  {
    int[] colors=new int[w*h];
    int idx=0;
    for (int i=y;(i<h+y)&&(i<bitmap.getHeight());i++)
    {
      for (int j=x;(j<w+x)&&(j<bitmap.getWidth());j++)
      {
        int color=bitmap.getPixel(j,i);
        colors[idx++]=color;
      }
    }
    return colors;
  }

  /**
   * 求多个颜色的平均值
   * @param colors
   * @return 平均颜色
   */
  private static  int getAverage (int[] colors)
  {
    //int alpha=0;
    int red=0;
    int green=0;
    int blue=0;
    for(int color:colors)
    {
      red += ((color&0xff0000)>>16);
      green += ((color&0xff00)>>8);
      blue += (color&0x0000ff);
    }
    float len=colors.length;
    //alpha=Math.round(alpha/len);
    red=Math.round(red/len);
    green=Math.round(green/len);
    blue=Math.round(blue/len);

    return Color.argb(0xff,red,green,blue);
  }

  private static void log(String log)
  {
    System.out.println("-------->Utils:"+log);
  }
}