Bitmap用法总结由刀豆文库小编整理，希望给你工作、学习、生活带来方便，猜你可能喜欢“asif的用法总结”。
Bitmap用法总结
1、Drawable → Bitmap
public static Bitmap drawableToBitmap(Drawable drawable){
Bitmap bitmap = Bitmap
.createBitmap（drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight(),drawable.getOpacity()!= PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(bitmap);
// canvas.setBitmap(bitmap);
drawable.setBounds(0, 0, drawable.getIntrinsicWidth(),drawable.getIntrinsicHeight());
drawable.draw(canvas);
return bitmap;
}
2、从资源中获取Bitmap
Resources res=getResources();
Bitmap bmp=BitmapFactory.decodeResource(res, R.drawable.pic);
3、Bitmap → byte[]
private byte[] Bitmap2Bytes(Bitmap bm){
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compre(Bitmap.CompreFormat.PNG, 100, baos);
return baos.toByteArray();
}
4、byte[] → Bitmap
private Bitmap Bytes2Bimap(byte[] b){
if(b.length!=0){
return BitmapFactory.decodeByteArray(b, 0, b.length);
}
else {
return null;
}
}
5、保存bitmap
static boolean saveBitmap2file(Bitmap bmp,String filename){
CompreFormat format= Bitmap.CompreFormat.JPEG;
int quality = 100;
OutputStream stream = null;
try {
stream = new FileOutputStream(“/sdcard/” + filename);
} catch(FileNotFoundException e){
// TODO Auto-generated catch block
Generated by Foxit PDF Creator © Foxit Software7、bitmap的用法小结
BitmapFactory.Options option = new BitmapFactory.Options();
option.inSampleSize = 2;//将图片设为原来宽高的1/2，防止内存溢出
Bitmap bm = BitmapFactory.decodeFile(“”,option);//文件流
URL url = new URL(“”);
InputStream is = url.openStream();
Bitmap bm = BitmapFactory.decodeStream(is);
android:scaleType：
android:scaleType是控制图片如何resized/moved来匹对ImageView的size。ImageView.ScaleType /
android:scaleType值的意义区别：
CENTER /center 按图片的原来size居中显示，当图片长/宽超过View的长/宽，则截取图片的居中部分
显示
CENTER_CROP / centerCrop 按比例扩大图片的size居中显示，使得图片长(宽)等于或大于View的长
(宽)
CENTER_INSIDE / centerInside 将图片的内容完整居中显示，通过按比例缩小或原来的size使得图片
长/宽等于或小于View的长/宽
Generated by Foxit PDF Creator © Foxit Software
http:// For evaluation only.FIT_CENTER / fitCenter 把图片按比例扩大/缩小到View的宽度，居中显示
FIT_END / fitEnd 把图片按比例扩大/缩小到View的宽度，显示在View的下部分位置 FIT_START / fitStart 把图片按比例扩大/缩小到View的宽度，显示在View的上部分位置 FIT_XY / fitXY 把图片 不按比例 扩大/缩小到View的大小显示
MATRIX / matrix 用矩阵来绘制，动态缩小放大图片来显示。
//放大缩小图片
public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){
int width = bitmap.getWidth();
int height = bitmap.getHeight();
Matrix matrix = new Matrix();
float scaleWidht =((float)w / width);
float scaleHeight =((float)h / height);
matrix.postScale(scaleWidht, scaleHeight);
Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
return newbmp;
}
//将Drawable转化为Bitmap
public static Bitmap drawableToBitmap(Drawable drawable){
int width = drawable.getIntrinsicWidth();
int height = drawable.getIntrinsicHeight();
Bitmap bitmap = Bitmap.createBitmap(width, height,drawable.getOpacity()!= PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888 : Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0,0,width,height);
drawable.draw(canvas);
return bitmap;
Generated by Foxit PDF Creator © Foxit Software
http:// For evaluation only.}
//获得圆角图片的方法
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){ Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());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;
}
//获得带倒影的图片方法
public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap){ final int reflectionGap = 4;
int width = bitmap.getWidth();
int height = bitmap.getHeight();
Matrix matrix = new Matrix();
matrix.preScale(1,-1);
Bitmap reflectionImage = Bitmap.createBitmap(bitmap,0, height/2, width, height/2, matrix, false);
Bitmap bitmapWithReflection = Bitmap.createBitmap(width,(height + height/2), Config.ARGB_8888);
Canvas canvas = new Canvas(bitmapWithReflection);
canvas.drawBitmap(bitmap, 0, 0, null);
Paint deafalutPaint = new Paint();
Generated by Foxit PDF Creator © Foxit Software
http:// For evaluation only.canvas.drawRect(0, height,width,height + reflectionGap,deafalutPaint);
canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);Paint paint = new Paint();
LinearGradient shader = new LinearGradient(0,bitmap.getHeight(), 0, bitmapWithReflection.getHeight()
+ reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);
paint.setShader(shader);
// Set the Transfer mode to be porter duff and destination in
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
// Draw a rectangle using the paint with our linear gradient
canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()+ reflectionGap, paint);
return bitmapWithReflection;
} }
