Using HTML5 Canvas to create water ripple effects, clicking an image will trigger,
This article will introduce how to use JavaScript to achieve water ripple. The water wave effect is triggered when any image is clicked. The source code is provided for download. For more information, see
Today, we will continue to share examples of the effects of JavaScript implementation. This article will introduce the effects of water ripple using JavaScript. The watermark effect is triggered when any image is clicked. Sometimes, we can use Javascript to create an interesting solution.
Source code download
Step 1. HTML
As before, the first step is the HTML code:
The Code is as follows:
<! DOCTYPE html>
<Html>
<Head>
<Meta charset = UTF-8/>
<Title> Water drops effect </title>
<Link rel = "stylesheet" href = "css/main.css" type = "text/css"/>
<Script src = "js/vector2d. js" type = "text/javascript" charset = "UTF-8"> </script>
<Script src = "js/waterfall. js" type = "text/javascript" charset = "UTF-8"> </script>
</Head>
<Body>
<Div class = "example">
<H3> <a href = "#"> Water drops effect </a> <Canvas id = "water"> HTML5 compliant browser required </canvas>
<Div id = "switcher">
</Div>
<Div id = "fps"> </div>
</Div>
</Body>
</Html>
Step 2. CSS
Here is the CSS code used:
The Code is as follows:
Body {background: # eee; margin: 0; padding: 0}
. Example {background: # FFF; width: 600px; border: 1px #000 solid; margin: 20px auto; padding: 15px;-moz-border-radius: 3px; -webkit-border-radius: 3px}
# Water {
Width: 500px;
Height: 400px;
Display: block;
Margin: 0px auto;
Cursor: pointer;
}
# Switcher {
Text-align: center;
Overflow: hidden;
Margin: 15px;
}
# Switcher img {
Width: 160px;
Height: 120px;
}
Step 3. JS
The following is the main JavaScript code:
The Code is as follows:
Function drop (x, y, damping, shading, refraction, ctx, screenWidth, screenHeight ){
This. x = x;
This. y = y;
This. shading = shading;
This. refraction = refraction;
This. bufferSize = this. x * this. y;
This. damping = damping;
This. background = ctx. getImageData (0, 0, screenWidth, screenHeight). data;
This. imageData = ctx. getImageData (0, 0, screenWidth, screenHeight );
This. buffer1 = [];
This. buffer2 = [];
For (var I = 0; I <this. bufferSize; I ++ ){
This. buffer1.push (0 );
This. buffer2.push (0 );
}
This. update = function (){
For (var I = this. x + 1, x = 1; I <this. bufferSize-this. x; I ++, x ++ ){
If (x <this. x )){
This. buffer2 [I] = (this. buffer1 [I-1] + this. buffer1 [I + 1] + this. buffer1 [I-this. x] + this. buffer1 [I + this. x])/2)-this. buffer2 [I];
This. buffer2 [I] * = this. damping;
} Else x = 0;
}
Var temp = this. buffer1;
This. buffer1 = this. buffer2;
This. buffer2 = temp;
}
This. draw = function (ctx ){
Var imageDataArray = this. imageData. data;
For (var I = this. x + 1, index = (this. x + 1) * 4; I <this. bufferSize-(1 + this. x); I ++, index + = 4 ){
Var xOffset = ~~ (This. buffer1 [I-1]-this. buffer1 [I + 1]);
Var yOffset = ~~ (This. buffer1 [I-this. x]-this. buffer1 [I + this. x]);
Var shade = xOffset * this. shading;
Var texture = index + (xOffset * this. refraction + yOffset * this. refraction * this. x) * 4;
ImageDataArray [index] = this. background [texture] + shade;
ImageDataArray [index + 1] = this. background [texture + 1] + shade;
ImageDataArray [index + 2] = 50 + this. background [texture + 2] + shade;
}
Ctx. putImageData (this. imageData, 0, 0 );
}
}
Var fps = 0;
Var watereff = {
// Variables
TimeStep: 20,
Refractions: 2,
Shading: 3,
Damping: 0.99,
ScreenWidth: 500,
ScreenHeight: 400,
Pond: null,
TextureImg: null,
Interval: null,
BackgroundURL: 'Data _ images/underwater1.jpg ',
// Initialization
Init: function (){
Var canvas = document. getElementById ('water ');
If (canvas. getContext ){
// Fps countrt
Fps = 0;
SetInterval (function (){
Document. getElementById ('fps'). innerHTML = fps/2 + 'fps ';
Fps = 0;
},2000 );
Canvas. onmousedown = function (e ){
Var mouse = watereff. getMousePosition (e). sub (new vector2d (canvas. offsetLeft, canvas. offsetTop ));
Watereff. pond. buffer1 [mouse. y * watereff. pond. x + mouse. x] + = 200;
}
Canvas. onmouseup = function (e ){
Canvas. onmousemove = null;
}
Canvas. width = this. screenWidth;
Canvas. height = this. screenHeight;
This. textureImg = new Image (256,256 );
This. textureImg. src = this. backgroundURL;
Canvas. getContext ('2d '). drawImage (this. textureImg, 0, 0 );
This. pond = new drop (
This. screenWidth,
This. screenHeight,
This. damping,
This. shading,
This. refractions,
Canvas. getContext ('2d '),
This. screenWidth, this. screenHeight
);
If (this. interval! = Null ){
ClearInterval (this. interval );
}
This. interval = setInterval (watereff. run, this. timeStep );
}
},
// Change image func
ChangePicture: function (url ){
This. backgroundURL = url;
This. init ();
},
// Get mouse position func
GetMousePosition: function (e ){
If (! E ){
Var e = window. event;
}
If (e. pageX | e. pageY ){
Return new vector2d (e. pageX, e. pageY );
} Else if (e. clientX | e. clientY ){
Return new vector2d (e. clientX, e. clientY );
}
},
// Loop drawing
Run: function (){
Var ctx = document. getElementById ('water'). getContext ('2d ');
Watereff. pond. update ();
Watereff. pond. draw (ctx );
Fps ++;
}
}
Window. onload = function (){
Watereff. init ();
}
As you can see, the Vector2D function is used here, which is provided in vector2d. js. Another difficult method is to use pure mathematics. If you are interested, try it yourself.
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