HTML5 canvas – Custom brush #2 (Bubble brush) for your paing program

HTML5 canvas – Custom brush #2 (Bubble brush) for your paing program

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HTML5 canvas - Custom brush #2 (Bubble brush)

HTML5 canvas – Custom brush #2 (Bubble brush) for your paing program

In our previous tutorial we made BezierCurveBrush. Today I have decided to create new brush for same script. This brush will use ‘arc’ function. In result we will have interesting effect, just check out it!

Here are our demo and downloadable package:

Live Demo
download in package

Ok, download the source files and lets start coding !


Step 1. HTML

This is markup of our result page. Here it is.

index.html

<!DOCTYPE html>
<html lang="en" >
    <head>
        <meta charset="utf-8" />
        <title>HTML5 canvas - Custom brush #2 (Bubble brush) for your paing program | Script Tutorials</title>
        <link href="css/main.css" rel="stylesheet" type="text/css" />
        <script src="http://code.jquery.com/jquery-latest.min.js"></script>
        <script src="js/script.js"></script>
    </head>
    <body>
        <header>
            <h2>HTML5 canvas - Custom brush #2</h2>
            <a href="http://www.script-tutorials.com/html5-canvas-custom-brush2/" class="stuts">Back to original tutorial on <span>Script Tutorials</span></a>
        </header>
        <div class="container">
            <div class="column1">
                <canvas id="color" width="500" height="128"></canvas>
            </div>
            <div class="column2">
                <div>Preview:</div>
                <div id="preview"></div>
                <div id="pick"></div>
            </div>
            <div style="clear:both;"></div>
        </div>
        <canvas id="panel" width="1000" height="600"></canvas>
    </body>
</html>

Step 2. CSS

Here are all stylesheets

css/main.css

/* page layout styles */
*{
    margin:0;
    padding:0;
}
body {
    background-color:#eee;
    color:#fff;
    font:14px/1.3 Arial,sans-serif;
}
header {
    background-color:#212121;
    box-shadow: 0 -1px 2px #111111;
    display:block;
    height:70px;
    position:relative;
    width:100%;
    z-index:100;
}
header h2{
    font-size:22px;
    font-weight:normal;
    left:50%;
    margin-left:-400px;
    padding:22px 0;
    position:absolute;
    width:540px;
}
header a.stuts,a.stuts:visited{
    border:none;
    text-decoration:none;
    color:#fcfcfc;
    font-size:14px;
    left:50%;
    line-height:31px;
    margin:23px 0 0 110px;
    position:absolute;
    top:0;
}
header .stuts span {
    font-size:22px;
    font-weight:bold;
    margin-left:5px;
}
.container {
    color: #000;
    margin: 20px auto;
    overflow: hidden;
    position: relative;
    width: 800px;
}

/* custom styles */
.column1 {
    float:left;
    width:500px;
}
.column2 {
    float:left;
    padding-left:20px;
    width:170px;
}
#panel {
    border:1px #000 solid;
    box-shadow:4px 6px 6px #444444;
    cursor:crosshair;
    display:block;
    margin:0 auto;
    height:600px;
    width:1000px;
}
#color {
    border:1px #000 solid;
    box-shadow:0px 4px 6px #444444;
    cursor:crosshair;
}
.column2 > div {
    margin-bottom:10px;
}
#preview, #pick {
    background-color:rgb(0, 195, 135);
    border:1px #000 solid;
    box-shadow:2px 3px 3px #444444;
    height:40px;
    width:80px;

    border-radius:3px;
    -moz-border-radius:3px;
    -webkit-border-radius:3px;
}

Step 3. JS

js/script.js

var canvas;
var canvasColor;
var ctx;
var ctxColor;
var bMouseDown = false;
var selColorR = 0;
var selColorG = 195;
var selColorB = 135;

var BubbleBrush = {
    // inner variables
    iPrevX : 0,
    iPrevY : 0,

    // initialization function
    init: function () {
        ctx.globalCompositeOperation = 'source-over'; //'lighter' is nice too
        ctx.lineWidth = 1;
        ctx.strokeStyle = 'rgba(0, 0, 0, 0.2)';
        ctx.lineWidth = 2;
    },

    startCurve: function (x, y) {
        this.iPrevX = x;
        this.iPrevY = y;
        ctx.fillStyle = 'rgba(' + selColorR + ', ' + selColorG + ', ' + selColorB + ', 0.9)';
    },

    draw: function (x, y) {
        var iXAbs = Math.abs(x - this.iPrevX);
        var iYAbs = Math.abs(y - this.iPrevY);
        iXAbs = (iXAbs > 30) ? 30 : iXAbs;
        iYAbs = (iYAbs > 30) ? 30 : iYAbs;

        if (iXAbs > 10 || iYAbs > 10) {
            ctx.beginPath();
            ctx.arc(this.iPrevX, this.iPrevY, (iXAbs + iYAbs) * 0.5, 0, Math.PI*2, false);
            ctx.fill();
            ctx.stroke();
            this.iPrevX = x;
            this.iPrevY = y;
        }
    }
};

$(function(){
    // creating canvas objects
    canvas = document.getElementById('panel');
    ctx = canvas.getContext('2d');

    canvasColor = document.getElementById('color');
    ctxColor = canvasColor.getContext('2d');

    drawGradients(ctxColor);

    BubbleBrush.init();

    $('#color').mousemove(function(e) { // mouse move handler
        var canvasOffset = $(canvasColor).offset();
        var canvasX = Math.floor(e.pageX - canvasOffset.left);
        var canvasY = Math.floor(e.pageY - canvasOffset.top);

        var imageData = ctxColor.getImageData(canvasX, canvasY, 1, 1);
        var pixel = imageData.data;

        var pixelColor = 'rgba('+pixel[0]+', '+pixel[1]+', '+pixel[2]+', '+pixel[3]+')';
        $('#preview').css('backgroundColor', pixelColor);
    });

    $('#color').click(function(e) { // mouse click handler
        var canvasOffset = $(canvasColor).offset();
        var canvasX = Math.floor(e.pageX - canvasOffset.left);
        var canvasY = Math.floor(e.pageY - canvasOffset.top);

        var imageData = ctxColor.getImageData(canvasX, canvasY, 1, 1);
        var pixel = imageData.data;

        var pixelColor = 'rgba('+pixel[0]+', '+pixel[1]+', '+pixel[2]+', '+pixel[3]+')';
        $('#pick').css('backgroundColor', pixelColor);

        selColorR = pixel[0];
        selColorG = pixel[1];
        selColorB = pixel[2];
    }); 

    $('#panel').mousedown(function(e) { // mouse down handler
        bMouseDown = true;
        var canvasOffset = $(canvas).offset();
        var canvasX = Math.floor(e.pageX - canvasOffset.left);
        var canvasY = Math.floor(e.pageY - canvasOffset.top);

        BubbleBrush.startCurve(canvasX, canvasY, false, false, false, false, false, false, canvasX, canvasY, 0, 0);
    });
    $('#panel').mouseup(function(e) { // mouse up handler
        bMouseDown = false;
    });
    $('#panel').mousemove(function(e) { // mouse move handler
        if (bMouseDown) {
            var canvasOffset = $(canvas).offset();
            var canvasX = Math.floor(e.pageX - canvasOffset.left);
            var canvasY = Math.floor(e.pageY - canvasOffset.top);

            BubbleBrush.draw(canvasX, canvasY, false, false, false, false, false, false, canvasX, canvasY, 0, 0);
        }
    });
});

function drawGradients() {
    var grad = ctxColor.createLinearGradient(20, 0, canvasColor.width - 20, 0);
    grad.addColorStop(0, 'red');
    grad.addColorStop(1 / 6, 'orange');
    grad.addColorStop(2 / 6, 'yellow');
    grad.addColorStop(3 / 6, 'green')
    grad.addColorStop(4 / 6, 'aqua');
    grad.addColorStop(5 / 6, 'blue');
    grad.addColorStop(1, 'purple');
    ctxColor.fillStyle=grad;
    ctxColor.fillRect(0, 0, canvasColor.width, canvasColor.height);
}

This is combination of two main elements – color picker and drawing board. Today – new brush – with bubble effect.


Live Demo
download in package

Conclusion

Hope that today’s lesson was interesting for you as usual. We made another one nice html5 sample. I will be glad to see your thanks and comments. Good luck!

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4 COMMENTS

  1. Could You explain why are You calling
    BubbleBrush.draw(canvasX, canvasY, false, false, false, false, false, false, canvasX, canvasY, 0, 0);
    instead of
    BubbleBrush.draw(canvasX, canvasY); ?

    • Hi Paul,
      Yes, you are right,
      Before, I tested with different variables, and, in final version I removed all unnecessary variables and, seems forgot to remove them here. Thanks for your notice.

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