To draw graphics, the android.graphics.Canvas is used in android that provides methods to draw oval, rectangle, picture, text, line, etc. Along with the canvas, the android.graphics.Paint class is used to draw the objects. The information about the color and style are included in the Paint class.
Example:
In the below example, we are using the Android Canvas, Color, and Paint classes to display the 2D graphics in android.
activity_main.xml:
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/textView" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:textSize="30dp" android:text="Image Effects" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Android Graphics" android:id="@+id/textView2" android:layout_below="@+id/textView" android:layout_centerHorizontal="true" android:textSize="35dp" android:textColor="#3aa8c1" /> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/imageView" android:layout_below="@+id/textView2" android:layout_centerHorizontal="true" android:src="@drawable/php"/> <Button style="@style/Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Gray" android:onClick="gray" android:id="@+id/button" android:layout_alignParentBottom="true" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_marginBottom="97dp" /> <Button style="@style/Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="dark" android:onClick="dark" android:id="@+id/button2" android:layout_alignBottom="@+id/button" android:layout_alignParentRight="true" android:layout_alignParentEnd="true" /> <Button style="@style/Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Bright" android:onClick="bright" android:id="@+id/button3" android:layout_alignTop="@+id/button2" android:layout_centerHorizontal="true" /> <Button style="@style/Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Red" android:onClick="gama" android:id="@+id/button4" android:layout_below="@+id/button3" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" /> <Button style="@style/Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Green" android:onClick="green" android:id="@+id/button5" android:layout_alignTop="@+id/button4" android:layout_alignLeft="@+id/button3" android:layout_alignStart="@+id/button3" /> <Button style="@style/Widget.AppCompat.Button.Colored" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="blue" android:onClick="blue" android:id="@+id/button6" android:layout_below="@+id/button2" android:layout_toRightOf="@+id/textView" android:layout_toEndOf="@+id/textView" /> </RelativeLayout> |
Activity class:(File: MainActivity.java)
package com.example.radioapp; import android.graphics.Bitmap; import android.graphics.Color; import android.graphics.drawable.BitmapDrawable; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.ImageView; public class MainActivity extends AppCompatActivity { Button b1, b2, b3; ImageView im; private Bitmap bmp; private Bitmap operation; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); b1 = (Button) findViewById(R.id.button); b2 = (Button) findViewById(R.id.button2); b3 = (Button) findViewById(R.id.button3); im = (ImageView) findViewById(R.id.imageView); BitmapDrawable abmp = (BitmapDrawable) im.getDrawable(); bmp = abmp.getBitmap(); } public void gray(View view) { operation = Bitmap.createBitmap(bmp.getWidth(),bmp.getHeight(), bmp.getConfig()); double red = 0.33; double green = 0.59; double blue = 0.11; for (int i = 0; i < bmp.getWidth(); i++) { for (int j = 0; j < bmp.getHeight(); j++) { int p = bmp.getPixel(i, j); int r = Color.red(p); int g = Color.green(p); int b = Color.blue(p); r = (int) red * r; g = (int) green * g; b = (int) blue * b; operation.setPixel(i, j, Color.argb(Color.alpha(p), r, g, b)); } } im.setImageBitmap(operation); } public void bright(View view){ operation= Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(),bmp.getConfig()); for(int i=0; i<bmp.getWidth(); i++){ for(int j=0; j<bmp.getHeight(); j++){ int p = bmp.getPixel(i, j); int r = Color.red(p); int g = Color.green(p); int b = Color.blue(p); int alpha = Color.alpha(p); r = 100 + r; g = 100 + g; b = 100 + b; alpha = 100 + alpha; operation.setPixel(i, j, Color.argb(alpha, r, g, b)); } } im.setImageBitmap(operation); } public void dark(View view){ operation= Bitmap.createBitmap(bmp.getWidth(),bmp.getHeight(),bmp.getConfig()); for(int i=0; i<bmp.getWidth(); i++){ for(int j=0; j<bmp.getHeight(); j++){ int p = bmp.getPixel(i, j); int r = Color.red(p); int g = Color.green(p); int b = Color.blue(p); int alpha = Color.alpha(p); r = r - 50; g = g - 50; b = b - 50; alpha = alpha -50; operation.setPixel(i, j, Color.argb(Color.alpha(p), r, g, b)); } } im.setImageBitmap(operation); } public void gama(View view) { operation = Bitmap.createBitmap(bmp.getWidth(),bmp.getHeight(),bmp.getConfig()); for(int i=0; i<bmp.getWidth(); i++){ for(int j=0; j<bmp.getHeight(); j++){ int p = bmp.getPixel(i, j); int r = Color.red(p); int g = Color.green(p); int b = Color.blue(p); int alpha = Color.alpha(p); r = r + 150; g = 0; b = 0; alpha = 0; operation.setPixel(i, j, Color.argb(Color.alpha(p), r, g, b)); } } im.setImageBitmap(operation); } public void green(View view){ operation = Bitmap.createBitmap(bmp.getWidth(),bmp.getHeight(), bmp.getConfig()); for(int i=0; i<bmp.getWidth(); i++){ for(int j=0; j<bmp.getHeight(); j++){ int p = bmp.getPixel(i, j); int r = Color.red(p); int g = Color.green(p); int b = Color.blue(p); int alpha = Color.alpha(p); r = 0; g = g+150; b = 0; alpha = 0; operation.setPixel(i, j, Color.argb(Color.alpha(p), r, g, b)); } } im.setImageBitmap(operation); } public void blue(View view){ operation = Bitmap.createBitmap(bmp.getWidth(),bmp.getHeight(), bmp.getConfig()); for(int i=0; i<bmp.getWidth(); i++){ for(int j=0; j<bmp.getHeight(); j++){ int p = bmp.getPixel(i, j); int r = Color.red(p); int g = Color.green(p); int b = Color.blue(p); int alpha = Color.alpha(p); r = 0; g = 0; b = b+150; alpha = 0; operation.setPixel(i, j, Color.argb(Color.alpha(p), r, g, b)); } } im.setImageBitmap(operation); } } |
AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.radioapp"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name=".MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest> |
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