Android Bitmap Usage Summary

Android Bitmap Usage Summary Normal 0 7.8 lb 0 2 false false MicrosoftInternetExplorer4

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. Get bitmap from the resources

Resources res=getresources ();

Bitmap Bmp=bitmapfactory.decoderesource (res, r.drawable.pic);

3, bitmap→byte[]

Private byte[] Bitmap2bytes (Bitmap BM) {

Bytearrayoutputstream BAOs = new Bytearrayoutputstream ();

Bm.compress (Bitmap.CompressFormat.PNG, 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. Save Bitmap

Static Boolean savebitmap2file (Bitmap bmp,string filename) {

Compressformat format= Bitmap.CompressFormat.JPEG;

int quality = 100;

OutputStream stream = null;

try {

stream = new FileOutputStream ("/sdcard/" + filename);

} catch (FileNotFoundException e) {

TODO auto-generated Catch block

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E.printstacktrace ();

}

return bmp.compress (format, quality, stream);

}

6, the picture according to their own requirements to zoom

Picture Source

Bitmap BM = Bitmapfactory.decodestream (Getresources ()

. Openrawresource (R.drawable.dog));

Get the picture's width high

int width = bm.getwidth ();

int height = bm.getheight ();

Set the desired size

int newwidth = 320;

int newheight = 480;

Calculating the zoom ratio

float ScaleWidth = ((float) newwidth)/width;

float ScaleHeight = ((float) newheight)/height;

Get the Matrix parameter you want to scale

Matrix matrix = new Matrix ();

Matrix.postscale (ScaleWidth, ScaleHeight);

Get a new picture

Bitmap NEWBM = bitmap.createbitmap (BM, 0, 0, width, height, matrix,

true);

Put it on the canvas.

Canvas.drawbitmap (NEWBM, 0, 0, paint);

Related knowledge Link: http://www.eoeandroid.com/thread-3162-1-1.html

7. Summary of usage of bitmap

bitmapfactory.options option = new Bitmapfactory.options ();

Option.insamplesize = 2; Set the image to 1/2 of its original width to prevent memory overflow

Bitmap BM = Bitmapfactory.decodefile ("", option);//File stream

URL url = new URL ("");

InputStream is = Url.openstream ();

Bitmap BM = Bitmapfactory.decodestream (IS);

Android:scaletype:

Android:scaletype is a size that controls how the picture resized/moved to the ImageView. Imageview.scaletype/

The meaning difference of Android:scaletype value:

Center/center is centered on the original size of the image, and when the picture is longer/wider than the length/width of the view, the center portion of the picture is captured

Show

Center_crop/centercrop proportionally enlarges the size of the image so that the image is long (wide) equal to or greater than the length of the view

Wide

Center_inside/centerinside Displays the contents of the picture in full, by scaling it down or the original size to make the picture

Length/width equal to or less than view length/width

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Fit_center/fitcenter enlarge/Shrink the picture to the width of the view, centered on the display

Fit_end/fitend Zoom in/out to the width of the view, displayed in the lower part of the view

Fit_start/fitstart enlarge/Shrink the image to the width of the view, displayed in the upper part of the view

Fit_xy/fitxy The picture is not scaled up/down to the view size display

The Matrix/matrix is drawn with a matrix and is displayed by zooming in and out of the image.

Zoom in and out of pictures

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;

}

Convert drawable to 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;

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}

Ways to get rounded pictures

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;

}

Get the image method with reflection

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 ();

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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 being 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;

}

Android Bitmap Usage Summary