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This article introduces the relevant knowledge of "how to draw lines with canvas in HTML5". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

It's just a container for drawing graphics, with height and width properties in addition to id, class, style, and so on. There are three main steps to draw on the > element:

1. Gets the DOM object corresponding to the element, which is a Canvas object

two。 Call the getContext () method of the Canvas object to get a CanvasRenderingContext2D object

3. Call the CanvasRenderingContext2D object to draw.

Line Properti

In addition to the lineWidth attribute used above, the line has the following properties:

The lineCap property sets or returns the style of the line cap at the end of the line. You can take the following values:

"butt" adds a straight edge to each end of the line (default)

"round" adds a round cap to each end of the line

"square" adds a square cap to each end of the line.

The lineJoin property sets or returns the type of corner created when two lines meet. You can take the following values:

"miter" creates sharp corners (default)

"bevel" creates a bevel

"round" creates a fillet.

The miterLimit property sets or returns the maximum miter length (default is 10). Miter length refers to the distance between the inner and outer corners where two lines meet. MiterLimit is valid only if the lineJoin property is "miter".

JavaScript Code copies content to the clipboard

Var canvas = document.getElementById ("canvas")

Var context = canvas.getContext ("2d")

/ / Test lineCap properties

/ / set the baseline for easy observation

Context.moveTo (10 and 10)

Context.lineTo (10200)

Context.moveTo (2005,10)

Context.lineTo (200200)

Context.lineWidth= "1"

Context.stroke ()

/ / butt

Context.beginPath ()

Context.moveTo (10 and 50)

Context.lineTo (200550)

Context.lineCap= "butt"

Context.lineWidth= "10"

Context.stroke ()

/ / round

Context.beginPath ()

Context.moveTo (10100)

Context.lineTo (200100)

Context.lineCap= "round"

Context.lineWidth= "10"

Context.stroke ()

/ / square

Context.beginPath ()

Context.moveTo (10150)

Context.lineTo (200150)

Context.lineCap= "square"

Context.lineWidth= "10"

Context.stroke ()

/ / Test linJoin properties

/ / miter

Context.beginPath ()

Context.moveTo (300, 050)

Context.lineTo (450100)

Context.lineTo (300150)

Context.lineJoin= "miter"

Context.lineWidth= "10"

Context.stroke ()

/ / round

Context.beginPath ()

Context.moveTo (400 and 50)

Context.lineTo (550100)

Context.lineTo (400150)

Context.lineJoin= "round"

Context.lineWidth= "10"

Context.stroke ()

/ / square

Context.beginPath ()

Context.moveTo (5005.50)

Context.lineTo (650100)

Context.lineTo (500150)

Context.lineJoin= "bevel"

Context.lineWidth= "10"

Context.stroke ()

/ / Test miterLimit properties

Context.beginPath ()

Context.moveTo (700,050)

Context.lineTo (850100)

Context.lineTo (700150)

Context.lineJoin= "miter"

Context.miterLimit= "2"

Context.lineWidth= "10"

Context.strokeStyle= "# 2913EC"

Context.stroke ()

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