Created
January 10, 2013 12:19
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Algoritmo que recebe 2 cores hexadecimais e que desenha o gradiente entre as duas usando canvas do HTML5.
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| <html> | |
| <body> | |
| <fieldset> | |
| <input id="cor1" type="color" /> | |
| <input id="cor2" type="color" /> | |
| <button id="btn">Gradiente!</button> | |
| </fieldset> | |
| <canvas id="canvas"></canvas> | |
| <script> | |
| var in1 = document.getElementById("cor1"); | |
| var in2 = document.getElementById("cor2"); | |
| var btn = document.getElementById("btn"); | |
| var canvas = document.getElementById("canvas"); | |
| canvas.style.width = "500px"; | |
| canvas.style.height = "500px" | |
| var ctx = canvas.getContext('2d'); | |
| btn.onclick = function(event) { | |
| ctx.clearRect(0,0,canvas.width,canvas.height); | |
| var hex1 = in1.value; | |
| var hex2 = in2.value; | |
| var gradiente = Gradiente.fromHex(hex1, hex2); | |
| for(var i=0; i <= canvas.height; i++) { | |
| var porcentagem = i / canvas.height; | |
| var cor = gradiente.at(porcentagem); | |
| ctx.fillStyle = cor.hex(); | |
| ctx.fillRect(0, i , canvas.width, 1); | |
| } | |
| }; | |
| function Gradiente(cor1, cor2) { | |
| this.at = function(porc) { | |
| var red = transicao(cor1.red(), cor2.red(), porc); | |
| var green = transicao(cor1.green(), cor2.green(), porc); | |
| var blue = transicao(cor1.blue(), cor2.blue(), porc); | |
| return new Cor(red, green, blue); | |
| }; | |
| function transicao(n1, n2, porc) { | |
| return parseInt(n2 + (n1 - n2) * porc); | |
| } | |
| } | |
| Gradiente.fromHex = function(hex1, hex2) { | |
| return new Gradiente(Cor.fromHex(hex1), Cor.fromHex(hex2)); | |
| }; | |
| function Cor(red, green, blue) { | |
| this.red = function(){return red}; | |
| this.green = function(){return green}; | |
| this.blue = function(){return blue}; | |
| this.hex = function() { | |
| return "#" + toHex(red) + toHex(green) + toHex(blue); | |
| }; | |
| function toHex(n) { | |
| var hex = n.toString(16); | |
| if(hex.length === 1) { | |
| return "0" + hex; | |
| } | |
| return hex; | |
| } | |
| } | |
| Cor.fromHex = function(hex) { | |
| var match = hex.match(/[^\#]{2}/g); | |
| var red = parseInt(match[0],16); | |
| var green = parseInt(match[1],16); | |
| var blue = parseInt(match[2],16); | |
| return new Cor(red, green, blue); | |
| }; | |
| </script> | |
| </body> | |
| </html> |
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