Tutorial by Examples: g

Most Canvas drawings are either rectangular (rectangles, images, text-blocks) or circular (circles). Circles & rectangles have mathematical tests to check if the mouse is inside them. This makes testing circles and rectangles easy, quick and efficient. You can "hit-test" hundreds of c...

See this Example for a general explanation of dragging Shapes around the Canvas. This annotated example shows how to drag images around the Canvas // canvas related vars var canvas=document.createElement("canvas"); var ctx=canvas.getContext("2d"); canvas.width=378; canvas.h...

The exposition pipe operator, %$%, exposes the column names as R symbols within the left-hand side object to the right-hand side expression. This operator is handy when piping into functions that do not have a data argument (unlike, say, lm) and that don't take a data.frame and column names as arg...

Given the 3 points of a quadratic curve the following function returns the length. function quadraticBezierLength(x1,y1,x2,y2,x3,y3) var a, e, c, d, u, a1, e1, c1, d1, u1, v1x, v1y; v1x = x2 * 2; v1y = y2 * 2; d = x1 - v1x + x3; d1 = y1 - v1y + y3; e = v1x - 2 * x1; ...

Python's built-in crypto functionality is currently limited to hashing. Encryption requires a third-party module like pycrypto. For example, it provides the AES algorithm which is considered state of the art for symmetric encryption. The following code will encrypt a given message using a passphrase...

Consider the following Python2.x code. Save the file as example.py Python 2.x2.0 def greet(name): print "Hello, {0}!".format(name) print "What's your name?" name = raw_input() greet(name) In the above file, there are several incompatible lines. The raw_input() meth...

c++17 C++17 introduces int std::uncaught_exceptions() (to replace the limited bool std::uncaught_exception()) to know how many exceptions are currently uncaught. That allows for a class to determine if it is destroyed during a stack unwinding or not. #include <exception> #include <strin...

In VBA, this attribute is ignored. It was not ported over from VB6. In VB6, it creates a Default Global Instance of the class (a "shortcut") so that class members can be accessed without using the class name. For example, DateTime (as in DateTime.Now) is actually part of the VBA.Conversio...

This code adds outwardly increasing shadows to an image to create a "sticker" version of the image. Notes: In addition to being an ImageObject, the "img" argument can also be a Canvas element. This allows you to stickerize your own custom drawings. If you draw text on the Can...

Once shadowing is turned on, every new drawing to the canvas will be shadowed. Turn off further shadowing by setting context.shadowColor to a transparent color. // start shadowing context.shadowColor='black'; ... render some shadowed drawings ... // turn off shadowing. context.shadowColor=...

Warning! Apply shadows sparingly! Applying shadowing is expensive and is multiplicatively expensive if you apply shadowing inside an animation loop. Instead, cache a shadowed version of your image (or other drawing): At the start of your app, create a shadowed version of your image in a secon...

This function will take 2 datetime parameters, the DOB, and a date to check the age at CREATE FUNCTION [dbo].[Calc_Age] ( @DOB datetime , @calcDate datetime ) RETURNS int AS BEGIN declare @age int IF (@calcDate < @DOB ) RETURN -1 -- If a DOB is supplied a...

Will start with ## (##temp). Will be deleted only if user disconnects all connections. It behaves like a permanent table. CREATE TABLE ##NewGlobalTempTable( StudentID int, StudentName varchar(50), StudentAddress varchar(150)) Insert ...

Depending on the structure of your data, you can create variables that update dynamically. DECLARE @CurrentID int = (SELECT TOP 1 ID FROM Table ORDER BY CreateDate desc) DECLARE @Year int = 2014 DECLARE @CurrentID int = (SELECT ID FROM Table WHERE Year = @Year) In most cases, you will want...

Example of setting the isolation level: SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED; SELECT * FROM Products WHERE ProductId=1; SET TRANSACTION ISOLATION LEVEL REPEATABLE READ; --return to the default one READ UNCOMMITTED - means that a query in the current transaction can't access the...

First, in addition to the normal Fresco Gradle dependency, you have to add the OkHttp 3 dependency to your build.gradle: compile "com.facebook.fresco:imagepipeline-okhttp3:1.2.0" // Or a newer version. When you initialize Fresco (usually in your custom Application implementation), you ...

Create a custom BitmapImageViewTarget to load the image into: public class CircularBitmapImageViewTarget extends BitmapImageViewTarget { private Context context; private ImageView imageView; public CircularBitmapImageViewTarget(Context context, ImageView imageView) { ...

Note: This example requires a valid Admob account and valid Admob ad code. Build.gradle on app level Change to the latest version if existing: compile 'com.google.firebase:firebase-ads:10.2.1' Manifest Internet permission is required to access the ad data. Note that this permission does not h...

Strikethrough the entire text String sampleText = "This is a test strike"; textView.setPaintFlags(tv.getPaintFlags()| Paint.STRIKE_THRU_TEXT_FLAG); textView.setText(sampleText); Output: This is a test strike Strikethrough only parts of the text String sampleText = "This is a...

To achieve the simplest task in Entity Framework - to connect to an existing database ExampleDatabase on your local instance of MSSQL you have to implement two classes only. First is the entity class, that will be mapped to our database table dbo.People. class Person { public int...