Android Bitmap More information (3)

Package Com.testbitmapscale;
Import Java.io.File;
Import Java.io.FileInputStream;
Import Java.io.FileOutputStream;
Import java.io.IOException;
Import Java.io.InputStream;
Import Java.util.Iterator;
Import com.testbitmapscale.r.drawable;
Import android.app.Activity;
Import Android.graphics.Bitmap;
Import Android.graphics.Bitmap.Config;
Import Android.graphics.BitmapFactory;
Import Android.graphics.Canvas;
Import Android.graphics.Matrix;
Import Android.graphics.Paint;
Import Android.graphics.PorterDuff.Mode;
Import Android.graphics.PorterDuffXfermode;
Import Android.graphics.Rect;
Import Android.graphics.RectF;
Import android.graphics.drawable.BitmapDrawable;
Import android.graphics.drawable.Drawable;
Import Android.media.ThumbnailUtils;
Import Android.os.Bundle;
Import android.os.Environment;
Import Android.view.View;
Import Android.widget.ImageView;
Method:
1 Creating rounded corners bitmap pictures
2 Generating Bitmap scale graphs
3 compressed picture width and kb
Attention:
The above code, it is best to comment out the rest of the code when testing one of the methods
public class Mainactivity extends Activity {
Private ImageView ImageView;
Private Bitmap CopyRawBitmap1;
Private Bitmap copyRawBitmap2;
Private Bitmap copyRawBitmap3;
@Override
public void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);
Setcontentview (R.layout.main);
ImageView = (ImageView) Findviewbyid (R.id.imageview);
The first way: get a picture from a resource file
Bitmap Rawbitmap = Bitmapfactory.decoderesource (Getresources (), R.drawable.haha);
Copyrawbitmap1=rawbitmap;
Copyrawbitmap2=rawbitmap;
Copyrawbitmap3=rawbitmap;
Second way: Get the picture from the SD card (Method 1)
String sdcarepath=environment.getexternalstoragedirectory (). toString ();
String filepath=sdcarepath+ "/" + "haha.jpg";
Bitmap RawBitmap1 = bitmapfactory.decodefile (FilePath, NULL);
Second way: Get the picture from the SD card (Method 2)
InputStream Inputstream=getbitmapinputstreamfromsdcard ("haha.jpg");
Bitmap rawBitmap2 = Bitmapfactory.decodestream (InputStream);

———— > Below is a rounded corner that will set the picture
Bitmap Roundcornerbitmap=this.toroundcorner (Rawbitmap, 40);
Imageview.setimagebitmap (ROUNDCORNERBITMAP);
———— > above to set the rounded corners of the picture

———— > below to compress the height and size of the picture kb
Get picture of original high width
int rawheight = Rawbitmap.getheight ();
int rawwidth = Rawbitmap.getwidth ();
Set the new height width of the picture
int newheight = 500;
int newwidth = 500;
Calculate scaling factor
float Heightscale = ((float) newheight)/rawheight;
float Widthscale = ((float) newwidth)/rawwidth;
New Build Matrix
Matrix matrix = new Matrix ();
Matrix.postscale (Heightscale, Widthscale);
Set the rotation angle of the picture
Matrix.postrotate (-30);
Set the tilt of a picture
Matrix.postskew (0.1f, 0.1f);
Compress the picture size
The width and height of the image and the size of the KB will change after compression
Bitmap Newbitmap = Bitmap.createbitmap (rawbitmap, 0, 0, rawwidth,rawwidth, Matrix, True);
Convert Bitmap to Drawable
drawable newbitmapdrawable = new bitmapdrawable (NEWBITMAP);
Imageview.setimagedrawable (newbitmapdrawable);
Then save the bitmap to the SDcard for easy comparison of the original picture
This.compressandsavebitmaptosdcard (Newbitmap, "xx100.jpg", 80);
Problem:
Original size of 625x690 90.2kB
If you set the picture 500x500 the size is 171kB after compression. That is, the KB becomes larger after compression.
The reasons are: Compress (Bitmap.CompressFormat.JPEG, quality, fileoutputstream);
The second parameter, quality, is set to a bit larger (for example, 100).
Commonly used is 80, just set 100 is too big to cause.
———— > above to compress image height and size kb


———— > below to compress the KB of the picture, the width and height are unchanged
This.compressandsavebitmaptosdcard (CopyRawBitmap1, "0011fa.jpg", 80);
———— > above to compress the KB of the picture, the width and height are unchanged

———— > Below is a thumbnail method for getting an SD card picture 1
String sdcarepath1=environment.getexternalstoragedirectory (). toString ();
String filepath1=sdcarepath1+ "/" + "haha.jpg";
Bitmap Bitmapthumbnail1=this.getbitmapthumbnail (FILEPATH1);
Imageview.setimagebitmap (BITMAPTHUMBNAIL1);
———— > above to get an SD card thumbnail image Method 1

———— > Below is a thumbnail method for getting an SD card picture 2
String sdcarepath2=environment.getexternalstoragedirectory (). toString ();
String filepath2=sdcarepath2+ "/" + "haha.jpg";
Bitmap Tempbitmap=bitmapfactory.decodefile (filePath2);
Bitmap Bitmapthumbnail2=thumbnailutils.extractthumbnail (tempbitmap, 100, 100);
Imageview.setimagebitmap (BITMAPTHUMBNAIL2);
———— > above to get an SD card thumbnail image Method 2

}
Read the picture under the SD card
Private InputStream Getbitmapinputstreamfromsdcard (String fileName) {
if (Environment.getexternalstoragestate (). Equals (environment.media_mounted)) {
String sdcarepath=environment.getexternalstoragedirectory (). toString ();
String Filepath=sdcarepath+file.separator+filename;
File File=new file (FilePath);
try {
FileInputStream fileinputstream=new fileinputstream (file);
return fileinputstream;
} catch (Exception e) {
E.printstacktrace ();
}

}
return null;
}


Get the directory path feature for SDcard
Private String Getsdcardpath () {
String sdcardpath = null;
Determine if sdcard exists
Boolean issdcardexist = Environment.getexternalstoragestate (). Equals (Android.os.Environment.MEDIA_MOUNTED);
if (issdcardexist) {
Sdcardpath = Environment.getexternalstoragedirectory (). toString ();
}
return sdcardpath;
}
Compress and save pictures to SDcard
private void Compressandsavebitmaptosdcard (Bitmap rawbitmap,string filename,int quality) {
String Savefilepaht=this.getsdcardpath () +file.separator+filename;
File Savefile=new file (savefilepaht);
if (!savefile.exists ()) {
try {
Savefile.createnewfile ();
FileOutputStream fileoutputstream=new FileOutputStream (saveFile);
if (fileoutputstream!=null) {
Imagebitmap.compress (format, quality, stream);
Writes the compressed information of a bitmap to a specified output stream
The first parameter, format, is compressed
The second parameter quality the value of the image compression ratio, 0-100.0 means small size compression, 100 means high quality compression
The third parameter, stream, is the output stream
Rawbitmap.compress (Bitmap.CompressFormat.JPEG, quality, fileoutputstream);
}
Fileoutputstream.flush ();
Fileoutputstream.close ();
} catch (IOException e) {
E.printstacktrace ();

}
}
}

Get thumbnails of pictures
Private Bitmap Getbitmapthumbnail (String filePath) {
Bitmapfactory.options options=new bitmapfactory.options ();
True will not return the actual bitmap object, do not allocate memory space, but can get some decoding boundary information, such as picture size information
Options.injustdecodebounds=true;
Rawbitmap is null at this time
Bitmap Rawbitmap = Bitmapfactory.decodefile (FilePath, Options);
if (rawbitmap==null) {
System.out.println ("Rawbitmap is null at this time");
}
Insamplesize indicates that the thumbnail size is a fraction of the original image size, if the value is 3
The width and height of the thumbnails are 1/3 of the original image, and the image size is 1/9 of the original size.
Calculate samplesize
int samplesize=computesamplesize (options, 150, 200*200);
In order to read the picture, the options.injustdecodebounds must be set back to False
Options.injustdecodebounds = false;
Options.insamplesize = samplesize;
Original size of 625x690 90.2kB
Test call Computesamplesize (options, 100, 200*100);
Get samplesize=8
Get width and high 79 and 87
79*8=632 87*8=696
Bitmap thumbnailbitmap=bitmapfactory.decodefile (FilePath, Options);
Save to SD card for easy comparison
This.compressandsavebitmaptosdcard (Thumbnailbitmap, "15.jpg", 80);
return thumbnailbitmap;
}

Resources:
http://my.csdn.net/zljk000/code/detail/18212
First parameter: The options of the original bitmap
Second parameter: the smaller value of the wide high school that you want to generate the thumbnail for
Third parameter: total pixels of the indent graph you want to generate
public static int computesamplesize (bitmapfactory.options options,int minsidelength, int maxnumofpixels) {
int initialsize = computeinitialsamplesize (options, minsidelength,maxnumofpixels);
int roundedsize;
if (initialsize <= 8) {
Roundedsize = 1;
while (Roundedsize < initialsize) {
Roundedsize <<= 1;
}
} else {
Roundedsize = (initialsize + 7)/8 * 8;
}
return roundedsize;
}

private static int computeinitialsamplesize (bitmapfactory.options options,int minsidelength, int maxnumofpixels) {
The width of the original picture
Double w = options.outwidth;
The height of the original picture
Double h = options.outheight;
System.out.println ("========== w=" +w+ ", h=" +h);
int lowerbound = (Maxnumofpixels = =-1)? 1: (int) Math.ceil (Math
. sqrt (w * h/maxnumofpixels));
int upperbound = (Minsidelength = =-1)? : (int) Math.min (
Math.floor (W/minsidelength), Math.floor (h/minsidelength));
if (Upperbound < lowerbound) {
Return the larger one when there is no overlapping zone.
return lowerbound;
}
if ((Maxnumofpixels = =-1) && (minsidelength = =-1)) {
return 1;
} else if (minsidelength = =-1) {
return lowerbound;
} else {
return upperbound;
}
}

/**
* @param bitmap need to change the picture
* @param the radian of pixels fillet
* @return Fillet picture
*/
Resources:
http://blog.csdn.net/c8822882/article/details/6906768
Public Bitmap Toroundcorner (Bitmap Bitmap, int pixels) {
Bitmap Roundcornerbitmap = Bitmap.createbitmap (Bitmap.getwidth (), Bitmap.getheight (), config.argb_8888);
Canvas canvas = new canvas (ROUNDCORNERBITMAP);
int color = 0xff424242;//int color = 0xff424242;
Paint paint = new paint ();
Paint.setcolor (color);
Anti-aliasing
Paint.setantialias (TRUE);
Rect rect = new Rect (0, 0, bitmap.getwidth (), Bitmap.getheight ());
RECTF RECTF = new RECTF (rect);
float roundpx = pixels;
Equivalent to clear screen
Canvas.drawargb (0, 0, 0, 0);
A rectangle with rounded corners is drawn first.
Canvas.drawroundrect (RECTF, ROUNDPX, ROUNDPX, paint);
Paint.setxfermode (New Porterduffxfermode (mode.src_in));
and draw the original bitmap to the present bitmap!!!. Pay attention to this understanding
Canvas.drawbitmap (Bitmap, rect, rect, paint);
return roundcornerbitmap;
}

}

Android Bitmap More information (3)