ImageSpan

自定义ImageSpan继承类，可以设置图片大小和位置

import android.content.Context;

import android.graphics.Bitmap;

import android.graphics.Canvas;

import android.graphics.Matrix;

import android.graphics.Paint;

import android.graphics.Paint.FontMetricsInt;

import android.graphics.PixelFormat;

import android.graphics.Rect;

import android.graphics.drawable.BitmapDrawable;

import android.graphics.drawable.Drawable;

import android.text.style.ImageSpan;

import com.xuehu365.xuehu.utils.LogHelp;

/**

 * Created by Administrator on 2016/10/20.

 */

public class MyImageSpan extends ImageSpan {

    public MyImageSpan(Context arg0, int arg1) {

        super(arg0, arg1);

    }

    public int getSize(Paint paint, CharSequence text, int start, int end,

                       Paint.FontMetricsInt fm) {

        Drawable d = getDrawable();

//        Drawable d2 = zoomDrawable(d, 50, 50);

        Rect rect = d.getBounds();

        if (fm != null) {

            FontMetricsInt fmPaint = paint.getFontMetricsInt();

            int fontHeight = fmPaint.bottom - fmPaint.top;

            int drHeight = rect.bottom - rect.top;

            int top = drHeight / 2 - fontHeight / 4;

            int bottom = drHeight / 2 + fontHeight / 4;

            fm.ascent = -bottom;

            fm.top = -bottom;

            fm.bottom = top;

            fm.descent = top;

        }

        return rect.right;

    }

    @Override

    public void draw(Canvas canvas, CharSequence text, int start, int end,

                     float x, int top, int y, int bottom, Paint paint) {

        Drawable b = getDrawable();

        canvas.save();

        int transY = 0;

        transY = ((bottom - top) - b.getBounds().bottom) / 2 + top;

        canvas.translate(x, transY);

        b.draw(canvas);

        canvas.restore();

    }

    public Drawable zoomDrawable(Drawable drawable, int w, int h) {

        int width = drawable.getIntrinsicWidth();

        int height = drawable.getIntrinsicHeight();

        Bitmap oldbmp = drawableToBitmap(drawable);// drawable转换成bitmap

        Matrix matrix = new Matrix();   // 创建操作图片用的Matrix对象

        float scaleWidth = ((float) w / width);   // 计算缩放比例

        LogHelp.i("move", "width:" + width + ";;w:" + w + ";;scaleWidth:" + scaleWidth);

        float scaleHeight = ((float) h / height);

        matrix.postScale(scaleWidth, scaleHeight);         // 设置缩放比例

        Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height, matrix, true);       // 建立新的bitmap，其内容是对原bitmap的缩放后的图

        return new BitmapDrawable(newbmp);       // 把bitmap转换成drawable并返回

    }

    public Bitmap drawableToBitmap(Drawable drawable)// drawable 转换成bitmap

    {

        int width = drawable.getIntrinsicWidth();   // 取drawable的长宽

        int height = drawable.getIntrinsicHeight();

        Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565;         // 取drawable的颜色格式

        Bitmap bitmap = Bitmap.createBitmap(width, height, config);     // 建立对应bitmap

        Canvas canvas = new Canvas(bitmap);         // 建立对应bitmap的画布

        drawable.setBounds(0, 0, width, height);

        drawable.draw(canvas);      // 把drawable内容画到画布中

        return bitmap;

    }

}