How to use html5 canvas to make graffiti drawing board
This article is about how to use html5 canvas to make graffiti drawing boards. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.
Empty the drawing board
Line width: 1
three
five
seven
nine
eleven
Color: black
Blue
Red
Green
Yellow
Gray
HTML code
We need a canvas element for painting and some drop-down boxes for the selection operation:
JAVASCRIPT
Our graffiti artboard js script has three main functions:
InitThis (): this method is used to initialize the required mouse events.
Draw (): this method draws a line each time the left mouse button is pressed.
ClearArea (): this method is used to empty all lines on the artboard.
Var mousePressed = false
Var lastX, lastY
Var ctx
Function InitThis () {
Ctx = document.getElementById ('myCanvas'). GetContext ("2d")
$('# myCanvas') .mousedown (function (e) {
MousePressed = true
Draw (e.pageX-$(this). Offset (). Left, e.pageY-$(this). Offset (). Top, false)
})
$('# myCanvas') .mousemove (function (e) {
If (mousePressed) {
Draw (e.pageX-$(this). Offset (). Left, e.pageY-$(this). Offset (). Top, true)
}
})
$('# myCanvas') .mouseup (function (e) {
MousePressed = false
})
$('# myCanvas') .mouseleave (function (e) {
MousePressed = false
})
}
Function Draw (x, y, isDown) {
If (isDown) {
Ctx.beginPath ()
Ctx.strokeStyle = $('# selColor') .val ()
Ctx.lineWidth = $('# selWidth') .val ()
Ctx.lineJoin = "round"
Ctx.moveTo (lastX, lastY)
Ctx.lineTo (x, y)
Ctx.closePath ()
Ctx.stroke ()
}
LastX = x; lastY = y
}
Function clearArea () {
/ / Use the identity matrix while clearing the canvas
Ctx.setTransform (1,0,0,1,0,0)
Ctx.clearRect (0,0, ctx.canvas.width, ctx.canvas.height)
}
Thank you for reading! This is the end of the article on "how to use html5 canvas to make graffiti drawing boards". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, you can share it out for more people to see!
