Android: Merge Bitmap and androidcanvas using Canvas

Android: Merge Bitmap and androidcanvas using Canvas

• Key Points

canvas.drawBitmap(bitmap, srcRect, dstRect, null);

Draw the srcRect area of bitmap to the dstRect area of the canvas.

• Demo

Main. xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/rl_root"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="@android:color/background_dark"    android:orientation="horizontal" >    <ImageView        android:id="@+id/iv_bmp1"        android:layout_width="80dp"        android:layout_height="100dp"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true"        android:layout_alignParentTop="true"        android:layout_marginLeft="20dp"        android:layout_marginStart="20dp"        android:layout_marginTop="20dp"        android:contentDescription="@null"        android:src="@drawable/baby" />    <ImageView        android:id="@+id/iv_bmp2"        android:layout_width="80dp"        android:layout_height="100dp"        android:layout_alignParentEnd="true"        android:layout_alignParentRight="true"        android:layout_alignParentTop="true"        android:layout_marginEnd="20dp"        android:layout_marginRight="20dp"        android:layout_marginTop="20dp"        android:contentDescription="@null"        android:src="@drawable/baby2" />    <Button        android:id="@+id/btn_merge"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_below="@id/iv_bmp1"        android:layout_centerHorizontal="true"        android:layout_marginTop="20dp"        android:text="Merge" />    <ImageView        android:id="@+id/iv_bmp_merge"        android:layout_width="160dp"        android:layout_height="100dp"        android:layout_below="@id/btn_merge"        android:layout_centerHorizontal="true"        android:layout_marginTop="20dp"        android:contentDescription="@null" /></RelativeLayout>

The purpose is to merge the images on ivbmp 1 and ivbmp 2 and display them on iv_bmp _merger.

• MainActivity. java

Package net. mobctrl. mergebitmap; import android. app. activity; import android. graphics. bitmap; import android. graphics. canvas; import android. graphics. rect; import android. graphics. drawable. bitmapDrawable; import android. OS. bundle; import android. OS. handler; import android. OS. handler. callback; import android. OS. message; import android. view. view; import android. view. view. onClickListener; import android. widget. button; import android. widget. imageView;/*** @ author Zheng Haibo * @ web http://www.mobctrl.net ***/public class MainActivity extends Activity {private ImageView ivbmp 1; private ImageView ivbmp 2; private ImageView ivbmp merge; private Button mergeBtn; @ Override protected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. main); initUi ();} private void initUi () {ivbmp 1 = (ImageView) findViewById (R. id. iv_bmp 1); ivbmp 2 = (ImageView) findViewById (R. id. iv_bmp 2); ivbmp merge = (ImageView) findViewById (R. id. iv_bmp _merge); mergeBtn = (Button) findViewById (R. id. btn_merge); mergeBtn. setOnClickListener (new OnClickListener () {@ Override public void onClick (View v) {showMergeBitmap () ;}});} private Handler handler = new Handler (new Callback () {@ Override public boolean handleMessage (Message msg) {Bitmap bitmap = (Bitmap) msg. obj; ivbmp merge. setImageBitmap (bitmap); return false ;}});/*** display the merged graph */protected void showMergeBitmap () {new Thread (new Runnable () {@ Override public void run () {Bitmap bitmap = mergeBitmap (); Message messge = handler. obtainMessage (); messge. obj = bitmap; handler. sendMessage (messge );}}). start ();}/** merge Bitmap Using Canvas */private Bitmap mergeBitmap () {// obtain Bitmap image Bitmap BMP 1 = (BitmapDrawable) ivbmp 1.getdrawable () on ImageView ()). getBitmap (); Bitmap BMP 2 = (BitmapDrawable) ivbmp 2.getdrawable ()). getBitmap (); // create an empty background bitmap // generate the canvas image Bitmap resultBitmap = Bitmap. createBitmap (ivbmp merge. getWidth (), ivbmp merge. getHeight (), Bitmap. config. RGB_565); Canvas canvas = new Canvas (resultBitmap); // use a blank image to generate a canvas. // draw BMP 1 on the Canvas. Rect srcRect = new Rect (0, 0, 0, BMP 1.getwidth (), BMP 1.getheight (); // truncate the Rect dstRect = new Rect (0, 0, ivbmp merge. getWidth ()/2, ivbmp merge. getHeight (); // position of BMP 1 in the target canvas. drawBitmap (BMP 1, srcRect, dstRect, null); // draw BMP 2 on the canvas srcRect = new Rect (0, 0, BMP 2.getwidth (), BMP 2.getheight ()); // intercept dstRect = new Rect (ivbmp merge. getWidth ()/2, 0, ivbmp merge. getWidth (), ivbmp merge. getHeight (); // position of BMP 2 in the target canvas. drawBitmap (BMP 2, srcRect, dstRect, null); // combines BMP 1 and BMP 2 to display return resultBitmap ;}}

• Running Effect
  
  Click merge.