It's possible to clear complex shaped regions by changing the globalCompositeOperation property.
// All pixels being drawn will be transparent
ctx.globalCompositeOperation = 'destination-out';
// Clear a triangular section
ctx.globalAlpha = 1; // ensure alpha is 1
ctx.fillStyle = '#000'; /...
RxSwift provides not only the ways to control your data, but to represent user actions in a reactive way also.
RxCocoa contains everything you need. It wraps most of the UI components' properties into Observables, but not really. There are some upgraded Observables called ControlEvents (which repre...
While Runnable provides a means to wrap code to be executed in a different thread, it has a limitation in that it cannot return a result from the execution. The only way to get some return value from the execution of a Runnable is to assign the result to a variable accessible in a scope outside of t...
To make a jar, you need one or more class files. This should have a main method if it is to be run by a double click.
For this example, we will use:
import javax.swing.*;
import java.awt.Container;
public class HelloWorld {
public static void main(String[] args) {
JFrame f = ne...
A floating point type. Its range includes that of float. When combined with long, denotes the long double floating point type, whose range includes that of double.
double area(double radius) {
const double pi = 3.141592653589793;
return pi*radius*radius;
}
A specifier that can be applied to the declaration of a non-static, non-reference data member of a class. A mutable member of a class is not const even when the object is const.
class C {
int x;
mutable int times_accessed;
public:
C(): x(0), times_accessed(0) {
}
int get...
In R, data objects are manipulated using named data structures. The names of the objects might be called "variables" although that term does not have a specific meaning in the official R documentation. R names are case sensitive and may contain alphanumeric characters(a-z,A-z,0-9), the dot...
5.6
PHP 5.6 introduced variable-length argument lists (a.k.a. varargs, variadic arguments), using the ... token before the argument name to indicate that the parameter is variadic, i.e. it is an array including all supplied parameters from that one onward.
function variadic_func($nonVariadic, ...$...
You can define the signing configuration to sign the apk in the build.gradle file.
You can define:
storeFile : the keystore file
storePassword: the keystore password
keyAlias: a key alias name
keyPassword: A key alias password
You have to define the signingConfigs block to create a signin...
You can define the signing configuration in an external file as a signing.properties in the root directory of your project.
For example you can define these keys (you can use your favorite names):
STORE_FILE=myStoreFileLocation
STORE_PASSWORD=myStorePassword
KEY_ALIAS=myKeyAlias
KEY_PASSWOR...
You can store the signing information setting environment variables.
These values can be accessed with System.getenv("<VAR-NAME>")
In your build.gradle you can define:
signingConfigs {
release {
storeFile file(System.getenv("KEYSTORE"))
storePasswo...
Inserting elements is simple:
> let m = Map.singleton "Alex" 31
fromList [("Alex",31)]
> Map.insert "Bob" 99 m
fromList [("Alex",31),("Bob",99)]
The Data.Map module in the containers package provides a Map structure that has both strict and lazy implementations.
When using Data.Map, one usually imports it qualified to avoid clashes with functions already defined in Prelude:
import qualified Data.Map as Map
So we'd then prepend Map funct...
Unlike a parallel for-loop (parfor), which takes the iterations of a loop and distributes them among multiple threads, a single program, multiple data (spmd) statement takes a series of commands and distributes them to all the threads, so that each thread performs the command and stores the results....
To remove all elements from a Map, use the .clear() method:
map.clear();
Example:
const map = new Map([[1, 2], [3, 4]]);
console.log(map.size); // 2
map.clear();
console.log(map.size); // 0
console.log(map.get(1)); // undefined
To remove an element from a map use the .delete() method.
map.delete(key);
Example:
const map = new Map([[1, 2], [3, 4]]);
console.log(map.get(3)); // 4
map.delete(3);
console.log(map.get(3)); // undefined
This method returns true if the element existed and has been removed, otherwise fal...
Use .get(key) to get value by key and .set(key, value) to assign a value to a key.
If the element with the specified key doesn't exist in the map, .get() returns undefined.
.set() method returns the map object, so you can chain .set() calls.
const map = new Map();
console.log(map.get(1)); // und...
