收集了非常多bitmap相关的处理方法，差点儿所有应用在项目中，所以特记录下！
package com.tmacsky.utils;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.view.View;
import android.view.View.MeasureSpec;
public class ImageUtils {
//--->bitmap相关
//參考站点http://www.cnblogs.com/fighter/archive/2012/02/20/android-bitmap-drawable.html
// 见博客：http://blog.sina.com.cn/s/blog_afb547c60101j7qn.html
/**
* View转成bitmap
* @param view
* @return
*/
public static Bitmap convertViewToBitmap(View view) {
view.setDrawingCacheEnabled(true);
view.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
view.buildDrawingCache();
return view.getDrawingCache();
}
/**
* 缩放Drawable
* @param drawable
* @param w 缩放后须要的宽度
* @param h 缩放后须要的高度
* @return
*/
public static Drawable zoomDrawable(Drawable drawable, int w, int h) {
int width = drawable.getIntrinsicWidth();
int height = drawable.getIntrinsicHeight();
// drawable转换成bitmap
Bitmap oldbmp = drawableToBitmap(drawable);
// 创建操作图片用的Matrix对象
Matrix matrix = new Matrix();
// 计算缩放比例
float sx = ((float) w / width);
float sy = ((float) h / height);
// 设置缩放比例
matrix.postScale(sx, sy);
// 建立新的bitmap，其内容是对原bitmap的缩放后的图
Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height,
matrix, true);
return new BitmapDrawable(newbmp);
}
/**
* 缩放bitmap
* @param oldBitmap 输入bitmap
* @param newWidth
* @param newHeight
* @return
*/
public static Bitmap zoomBitmap(Bitmap oldBitmap, int newWidth, int newHeight) {
// 获得图片的宽高
int width = oldBitmap.getWidth();
int height = oldBitmap.getHeight();
// 计算缩放比例
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// 取得想要缩放的matrix參数
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
// 得到新的图片
Bitmap newbm = Bitmap.createBitmap(oldBitmap, 0, 0, width, height, matrix,
true);
return newbm;
}
/**
* 缩放网络图片 依赖于zoomBitmap
* @param img
* @param newWidth
* @param newHeight
* @return
*/
public static Bitmap zoomImg(String img, int newWidth, int newHeight) {
// 图片源
Bitmap bm = BitmapFactory.decodeFile(img);
if (null != bm) {
return zoomBitmap(bm, newWidth, newHeight);
}
return null;
}
/**
* 缩放网络图片 依赖于zoomBitmap
* @param context
* @param img
* @param newWidth
* @param newHeight
* @return
*/
public static Bitmap zoomImg(Context context, String img, int newWidth,
int newHeight) {
// 图片源
try {
Bitmap bm = BitmapFactory.decodeStream(context.getAssets()
.open(img));
if (null != bm) {
return zoomBitmap(bm, newWidth, newHeight);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
/**
* 推断bitmap是否存在
* @param bitmap
* @return
*/
public static boolean bitmapAvailable(Bitmap bitmap) {
return bitmap != null && bitmap.getWidth() > 0 && bitmap.getHeight() > 0;
}
/**
* drawable 转成bitmap
* @param drawable
* @return
*/
public static Bitmap drawableToBitmap(Drawable drawable) {
// 取 drawable 的长宽
int w = drawable.getIntrinsicWidth();
int h = drawable.getIntrinsicHeight();
// 取 drawable 的颜色格式
Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
: Bitmap.Config.RGB_565;
// 建立相应 bitmap
Bitmap bitmap = Bitmap.createBitmap(w, h, config);
// 建立相应 bitmap 的画布
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, w, h);
// 把 drawable 内容画到画布中
drawable.draw(canvas);
return bitmap;
}
/**
* Bitmap转换成Drawable
* @param context
* @param bitmap
* @return
*/
public static Drawable bitmapToDrawable(Context context,Bitmap bitmap){
//由于BtimapDrawable是Drawable的子类，终于直接使用bd对象就可以。
BitmapDrawable bd= new BitmapDrawable(context.getResources(), bitmap);
return bd;
}
/**
* 从资源中获取Bitmap
* @param context
* @param req R.drawable.icon(eg.)
* @return
*/
public Bitmap getBitmapFromResources(Context context,int req){
Resources res = context.getResources();
Bitmap bmp = BitmapFactory.decodeResource(res, req);
return bmp;
}
/**
* Byte[] -> Bitmap的转换
*/
public Bitmap Bytes2Bimap(byte[] b) {
if (b.length != 0) {
return BitmapFactory.decodeByteArray(b, 0, b.length);
} else {
return null;
}
}
/**
* Bitmap->Byte[]的转换
* @param bm
* @return
*/
public byte[] Bitmap2Bytes(Bitmap bm) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
return baos.toByteArray();
}
/**
* 获取圆角图片
* @param bitmap
* @param roundPx 圆角的弧度
* @return
*/
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) {
int w = bitmap.getWidth();
int h = bitmap.getHeight();
Bitmap output = Bitmap.createBitmap(w, h, Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, w, h);
final RectF rectF = new RectF(rect);
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
}