[置顶]很实用的android压缩图片的算法

分类：android 2013-11-06 14:31 534人阅读评论(2) 收藏举报 android 压缩图片这些天一直为android程序如何压缩图片烦恼，上网找了很多资料，整理了一下，经过测试，都是可用的， [java] view plain copy

/**
*压缩图片
*@parambitmap源图片
*@paramwidth想要的宽度
*@paramheight想要的高度
*@paramisAdjust是否自动调整尺寸,true图片就不会拉伸，false严格按照你的尺寸压缩
*@returnBitmap
*/
publicBitmapreduce(Bitmapbitmap,intwidth,intheight,booleanisAdjust){
//如果想要的宽度和高度都比源图片小，就不压缩了，直接返回原图
if(bitmap.getWidth()<width&&bitmap.getHeight()<height){returnbitmap;}
//根据想要的尺寸精确计算压缩比例,方法详解：publicBigDecimaldivide(BigDecimaldivisor,intscale,introundingMode);
//scale表示要保留的小数位,roundingMode表示如何处理多余的小数位，BigDecimal.ROUND_DOWN表示自动舍弃
floatsx=newBigDecimal(width).divide(newBigDecimal(bitmap.getWidth()),4,BigDecimal.ROUND_DOWN).floatValue();
floatsy=newBigDecimal(height).divide(newBigDecimal(bitmap.getHeight()),4,BigDecimal.ROUND_DOWN).floatValue();
if(isAdjust){//如果想自动调整比例，不至于图片会拉伸
sx=(sx<sy?sx:sy);sy=sx;//哪个比例小一点，就用哪个比例
}
Matrixmatrix=newMatrix();
matrix.postScale(sx,sy);//调用api中的方法进行压缩，就大功告成了
returnBitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,true);
}

旋转图片：

[java] view plain copy

/**
*旋转图片
*@parambitmap源图片
*@paramangle旋转角度(90为顺时针旋转,-90为逆时针旋转)
*@returnBitmap
*/
publicBitmaprotate(Bitmapbitmap,floatangle){
Matrixmatrix=newMatrix();
matrix.postRotate(angle);
returnBitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,true);
}

放大或缩小图片： [java] view plain copy

/**
*放大或缩小图片
*@parambitmap源图片
*@paramratio放大或缩小的倍数，大于1表示放大，小于1表示缩小
*@returnBitmap
*/
publicBitmapzoom(Bitmapbitmap,floatratio){
if(ratio<0f){returnbitmap;}
Matrixmatrix=newMatrix();
matrix.postScale(ratio,ratio);
returnBitmap.createBitmap(bitmap,0,0,bitmap.getWidth(),bitmap.getHeight(),matrix,true);
}

在图片上印字：

[java] view plain copy

/**
*在图片上印字
*@parambitmap源图片
*@paramtext印上去的字
*@paramparam字体参数分别为：颜色,大小,是否加粗,起点x,起点y;比如：{color:0xFF000000,size:30,bold:true,x:20,y:20}
*@returnBitmap
*/
publicBitmapprintWord(Bitmapbitmap,Stringtext,Map<String,Object>param){
if(ToolUtil.get().isBlank(text)||null==param){returnbitmap;}
BitmapnewBitmap=Bitmap.createBitmap(bitmap.getWidth(),bitmap.getHeight(),Config.ARGB_8888);
Canvascanvas=newCanvas(newBitmap);
canvas.drawBitmap(bitmap,0,0,null);canvas.save(Canvas.ALL_SAVE_FLAG);canvas.restore();
Paintpaint=newPaint();
paint.setColor(null!=param.get("color")?(Integer)param.get("color"):Color.BLACK);
paint.setTextSize(null!=param.get("size")?(Integer)param.get("size"):20);
paint.setFakeBoldText(null!=param.get("bold")?(Boolean)param.get("bold"):false);
canvas.drawText(text,null!=param.get("x")?(Integer)param.get("x"):0,null!=param.get("y")?(Integer)param.get("y"):0,paint);
canvas.save(Canvas.ALL_SAVE_FLAG);canvas.restore();
returnnewBitmap;
}

创建logo(给图片加水印), ： [java] view plain copy

/**
*创建logo(给图片加水印),
*@parambitmaps原图片和水印图片
*@paramleft左边起点坐标
*@paramtop顶部起点坐标t
*@returnBitmap
*/
publicBitmapcreateLogo(Bitmap[]bitmaps,intleft,inttop){
BitmapnewBitmap=Bitmap.createBitmap(bitmaps[0].getWidth(),bitmaps[0].getHeight(),Config.ARGB_8888);
Canvascanvas=newCanvas(newBitmap);
for(inti=0;i<bitmaps.length;i++){
if(i==0){
canvas.drawBitmap(bitmaps[0],0,0,null);
}else{
canvas.drawBitmap(bitmaps[i],left,top,null);
}
canvas.save(Canvas.ALL_SAVE_FLAG);canvas.restore();
}
returnnewBitmap;
}

产生一个4位随机数字的图片验证码：

[java] view plain copy

privateintwidth=140,height=40,codeLen=4;
privateStringcheckCode="";
privateRandomrandom=newRandom();
/**
*产生一个4位随机数字的图片验证码
*@returnBitmap
*/
publicBitmapcreateCode(){
checkCode="";
String[]chars={"0","1","2","3","4","5","6","7","8","9"};
for(inti=0;i<codeLen;i++){checkCode+=chars[random.nextInt(chars.length)];}
Bitmapbitmap=Bitmap.createBitmap(width,height,Config.ARGB_8888);
Canvascanvas=newCanvas(bitmap);canvas.drawColor(Color.WHITE);
Paintpaint=newPaint();paint.setTextSize(30);paint.setColor(Color.BLUE);
for(inti=0;i<checkCode.length();i++){
paint.setColor(randomColor(1));paint.setFakeBoldText(random.nextBoolean());
floatskewX=random.nextInt(11)/10;
paint.setTextSkewX(random.nextBoolean()?skewX:-skewX);
intx=width/codeLen*i+random.nextInt(10);
canvas.drawText(String.valueOf(checkCode.charAt(i)),x,28,paint);
}
for(inti=0;i<3;i++){drawLine(canvas,paint);}
for(inti=0;i<255;i++){drawPoints(canvas,paint);}
canvas.save(Canvas.ALL_SAVE_FLAG);canvas.restore();
returnbitmap;
}
/**
*获得一个随机的颜色
*@paramrate
*@return
*/
publicintrandomColor(intrate){
intred=random.nextInt(256)/rate,green=random.nextInt(256)/rate,blue=random.nextInt(256)/rate;
returnColor.rgb(red,green,blue);
}
/**
*画随机线条
*@paramcanvas
*@parampaint
*/
publicvoiddrawLine(Canvascanvas,Paintpaint){
intstartX=random.nextInt(width),startY=random.nextInt(height);
intstopX=random.nextInt(width),stopY=random.nextInt(height);
paint.setStrokeWidth(1);paint.setColor(randomColor(1));
canvas.drawLine(startX,startY,stopX,stopY,paint);
}
/**
*画随机干扰点
*@paramcanvas
*@parampaint
*/
publicvoiddrawPoints(Canvascanvas,Paintpaint){
intstopX=random.nextInt(width),stopY=random.nextInt(height);
paint.setStrokeWidth(1);
paint.setColor(randomColor(1));
canvas.drawPoint(stopX,stopY,paint);
}
/**
*返回真实验证码字符串
*@returnString
*/
publicStringgetCheckCode(){
returncheckCode;

很实用的android压缩图片的算法

[置顶]很实用的android压缩图片的算法

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