Tutorial by Examples: r

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...

Here is an example of an IntentService that pretends to load images in the background. All you need to do to implement an IntentService is to provide a constructor that calls the super(String) constructor, and you need to implement the onHandleIntent(Intent) method. public class ImageLoaderIntentSe...

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; ...

Open Script Editor. 2.12.4 With Mac OS X Leopard and earlier, and OS X Yosemite and later, Script Editor is located at /Applications/Utilities/Script Editor.app 2.12.4 Between Mac OS X Snow Leopard and OS X Mavericks inclusive, Script Editor is AppleScript Editor. /Applications/Utiliti...

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...

This attribute is ignored. It was not ported over from VB6. In VB6, it was used in combination with the VB_Exposed attribute to control accessibility of classes outside of the current project. VB_Exposed=True VB_Creatable=True Would result in a Public Class, that could be accessed from other ...

Creates a Global Default Instance of a class. The default instance is accessed via the name of the class. Declaration VERSION 1.0 CLASS BEGIN MultiUse = -1 'True END Attribute VB_Name = "Class1" Attribute VB_GlobalNameSpace = False Attribute VB_Creatable = False Attribute VB_Pr...

Adds a text description to a class or module member that becomes visible in the Object Explorer. Ideally, all public members of a public interface / API should have a description. Public Function GiveMeATwo() As Integer Attribute GiveMeATwo.VB_Description = "Returns a two!" ...

VB_VarUserMemId (for module-scope variables) and VB_UserMemId (for procedures) attributes are used in VBA mostly for two things. Specifying the default member of a class A List class that would encapsulate a Collection would want to have an Item property, so the client code can do this: For i = 1...

Transcrypt is a tool to precompile a fairly extensive subset of Python into compact, readable Javascript. It has the following characteristics: Allows for classical OO programming with multiple inheritance using pure Python syntax, parsed by CPython’s native parser Seamless integration with the ...

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=...

Canvas does not have CSS's inner-shadow. Canvas will shadow the outside of a filled shape. Canvas will shadow both inside and outside a stroked shape. But it's easy to create inner-shadows using compositing. Strokes with an inner-shadow To create strokes with an inner-shadow, use destinat...

let's generate a DataFrame first: df = pd.DataFrame(np.arange(10).reshape(5,2), columns=list('ab')) print(df) # Output: # a b # 0 0 1 # 1 2 3 # 2 4 5 # 3 6 7 # 4 8 9 drop rows with indexes: 0 and 4 using drop([...], inplace=True) method: df.drop([0,4], inplace=True) ...

INSERT INTO Invoices [ /* column names may go here */ ] VALUES (123, '1234abc', '2016-08-05 20:18:25.770', 321, 5, '2016-08-04'); Column names are required if the table you are inserting into contains a column with the IDENTITY attribute. INSERT INTO Invoices ([ID], [Num], [DateTime], [Tota...

To get the list of all backup operations performed on the current database instance: SELECT sdb.Name AS DatabaseName, COALESCE(CONVERT(VARCHAR(50), bus.backup_finish_date, 120),'-') AS LastBackUpDateTime FROM sys.sysdatabases sdb LEFT OUTER JOIN msdb.dbo.backupset bus ON bus.database_nam...

CREATE SEQUENCE [dbo].[CustomersSeq] AS INT START WITH 10001 INCREMENT BY 1 MINVALUE -1;

INSERT INTO [dbo].[Customers] ([CustomerName]) VALUES ('Jerry'), ('Gorge') SELECT * FROM [dbo].[Customers] Results CustomerIDCustomerName10001Jerry10002Gorge

DELETE FROM [dbo].[Customers] WHERE CustomerName = 'Gorge'; INSERT INTO [dbo].[Customers] ([CustomerName]) VALUES ('George') SELECT * FROM [dbo].[Customers] Results CustomerIDCustomerName10001Jerry10003George