figuras - html5 canvas drawing
Dibuja en HTML5 Canvas usando un mouse (9)
Quiero dibujar en un Lienzo HTML usando un mouse (ej: dibujar una firma, dibujar un nombre, ...)
Por favor, ayúdame, ¿cómo puedo hacer? Por favor, dame un código fuente. Gracias
Alco mira esto:
Ejemplo:
https://github.com/williammalone/Simple-HTML5-Drawing-App
Documentación:
http://www.williammalone.com/articles/create-html5-canvas-javascript-drawing-app/
Este documento incluye los siguientes códigos:
HTML:
<canvas id="canvas" width="490" height="220"></canvas>
JS:
context = document.getElementById(''canvas'').getContext("2d");
$(''#canvas'').mousedown(function(e){
var mouseX = e.pageX - this.offsetLeft;
var mouseY = e.pageY - this.offsetTop;
paint = true;
addClick(e.pageX - this.offsetLeft, e.pageY - this.offsetTop);
redraw();
});
$(''#canvas'').mouseup(function(e){
paint = false;
});
$(''#canvas'').mouseleave(function(e){
paint = false;
});
var clickX = new Array();
var clickY = new Array();
var clickDrag = new Array();
var paint;
function addClick(x, y, dragging)
{
clickX.push(x);
clickY.push(y);
clickDrag.push(dragging);
}
//Also redraw
function redraw(){
context.clearRect(0, 0, context.canvas.width, context.canvas.height); // Clears the canvas
context.strokeStyle = "#df4b26";
context.lineJoin = "round";
context.lineWidth = 5;
for(var i=0; i < clickX.length; i++) {
context.beginPath();
if(clickDrag[i] && i){
context.moveTo(clickX[i-1], clickY[i-1]);
}else{
context.moveTo(clickX[i]-1, clickY[i]);
}
context.lineTo(clickX[i], clickY[i]);
context.closePath();
context.stroke();
}
}
Y otro ejemplo impresionante
http://perfectionkills.com/exploring-canvas-drawing-techniques/
Aquí está mi lienzo de trabajo muy simple dibujar y borrar.
https://jsfiddle.net/richardcwc/d2gxjdva/
//Canvas
var canvas = document.getElementById(''canvas'');
var ctx = canvas.getContext(''2d'');
//Variables
var canvasx = $(canvas).offset().left;
var canvasy = $(canvas).offset().top;
var last_mousex = last_mousey = 0;
var mousex = mousey = 0;
var mousedown = false;
var tooltype = ''draw'';
//Mousedown
$(canvas).on(''mousedown'', function(e) {
last_mousex = mousex = parseInt(e.clientX-canvasx);
last_mousey = mousey = parseInt(e.clientY-canvasy);
mousedown = true;
});
//Mouseup
$(canvas).on(''mouseup'', function(e) {
mousedown = false;
});
//Mousemove
$(canvas).on(''mousemove'', function(e) {
mousex = parseInt(e.clientX-canvasx);
mousey = parseInt(e.clientY-canvasy);
if(mousedown) {
ctx.beginPath();
if(tooltype==''draw'') {
ctx.globalCompositeOperation = ''source-over'';
ctx.strokeStyle = ''black'';
ctx.lineWidth = 3;
} else {
ctx.globalCompositeOperation = ''destination-out'';
ctx.lineWidth = 10;
}
ctx.moveTo(last_mousex,last_mousey);
ctx.lineTo(mousex,mousey);
ctx.lineJoin = ctx.lineCap = ''round'';
ctx.stroke();
}
last_mousex = mousex;
last_mousey = mousey;
//Output
$(''#output'').html(''current: ''+mousex+'', ''+mousey+''<br/>last: ''+last_mousex+'', ''+last_mousey+''<br/>mousedown: ''+mousedown);
});
//Use draw|erase
use_tool = function(tool) {
tooltype = tool; //update
}
canvas {
cursor: crosshair;
border: 1px solid #000000;
}
<canvas id="canvas" width="800" height="500"></canvas>
<input type="button" value="draw" onclick="use_tool(''draw'');" />
<input type="button" value="erase" onclick="use_tool(''erase'');" />
<div id="output"></div>
Aquí hay una muestra de trabajo.
<html>
<script type="text/javascript">
var canvas, ctx, flag = false,
prevX = 0,
currX = 0,
prevY = 0,
currY = 0,
dot_flag = false;
var x = "black",
y = 2;
function init() {
canvas = document.getElementById(''can'');
ctx = canvas.getContext("2d");
w = canvas.width;
h = canvas.height;
canvas.addEventListener("mousemove", function (e) {
findxy(''move'', e)
}, false);
canvas.addEventListener("mousedown", function (e) {
findxy(''down'', e)
}, false);
canvas.addEventListener("mouseup", function (e) {
findxy(''up'', e)
}, false);
canvas.addEventListener("mouseout", function (e) {
findxy(''out'', e)
}, false);
}
function color(obj) {
switch (obj.id) {
case "green":
x = "green";
break;
case "blue":
x = "blue";
break;
case "red":
x = "red";
break;
case "yellow":
x = "yellow";
break;
case "orange":
x = "orange";
break;
case "black":
x = "black";
break;
case "white":
x = "white";
break;
}
if (x == "white") y = 14;
else y = 2;
}
function draw() {
ctx.beginPath();
ctx.moveTo(prevX, prevY);
ctx.lineTo(currX, currY);
ctx.strokeStyle = x;
ctx.lineWidth = y;
ctx.stroke();
ctx.closePath();
}
function erase() {
var m = confirm("Want to clear");
if (m) {
ctx.clearRect(0, 0, w, h);
document.getElementById("canvasimg").style.display = "none";
}
}
function save() {
document.getElementById("canvasimg").style.border = "2px solid";
var dataURL = canvas.toDataURL();
document.getElementById("canvasimg").src = dataURL;
document.getElementById("canvasimg").style.display = "inline";
}
function findxy(res, e) {
if (res == ''down'') {
prevX = currX;
prevY = currY;
currX = e.clientX - canvas.offsetLeft;
currY = e.clientY - canvas.offsetTop;
flag = true;
dot_flag = true;
if (dot_flag) {
ctx.beginPath();
ctx.fillStyle = x;
ctx.fillRect(currX, currY, 2, 2);
ctx.closePath();
dot_flag = false;
}
}
if (res == ''up'' || res == "out") {
flag = false;
}
if (res == ''move'') {
if (flag) {
prevX = currX;
prevY = currY;
currX = e.clientX - canvas.offsetLeft;
currY = e.clientY - canvas.offsetTop;
draw();
}
}
}
</script>
<body onload="init()">
<canvas id="can" width="400" height="400" style="position:absolute;top:10%;left:10%;border:2px solid;"></canvas>
<div style="position:absolute;top:12%;left:43%;">Choose Color</div>
<div style="position:absolute;top:15%;left:45%;width:10px;height:10px;background:green;" id="green" onclick="color(this)"></div>
<div style="position:absolute;top:15%;left:46%;width:10px;height:10px;background:blue;" id="blue" onclick="color(this)"></div>
<div style="position:absolute;top:15%;left:47%;width:10px;height:10px;background:red;" id="red" onclick="color(this)"></div>
<div style="position:absolute;top:17%;left:45%;width:10px;height:10px;background:yellow;" id="yellow" onclick="color(this)"></div>
<div style="position:absolute;top:17%;left:46%;width:10px;height:10px;background:orange;" id="orange" onclick="color(this)"></div>
<div style="position:absolute;top:17%;left:47%;width:10px;height:10px;background:black;" id="black" onclick="color(this)"></div>
<div style="position:absolute;top:20%;left:43%;">Eraser</div>
<div style="position:absolute;top:22%;left:45%;width:15px;height:15px;background:white;border:2px solid;" id="white" onclick="color(this)"></div>
<img id="canvasimg" style="position:absolute;top:10%;left:52%;" style="display:none;">
<input type="button" value="save" id="btn" size="30" onclick="save()" style="position:absolute;top:55%;left:10%;">
<input type="button" value="clear" id="clr" size="23" onclick="erase()" style="position:absolute;top:55%;left:15%;">
</body>
</html>
Avíseme si tiene problemas para implementar esto. Utiliza processing.js y tiene características para cambiar colores y hacer que el punto de dibujo sea más grande y más pequeño.
<html>
<head>
<!--script librarires-->
<script type="text/javascript" src="processing.js"></script>
<script type="text/javascript" src="init.js"></script>
<!--styles -->
<style type="text/css" src="stylesheet.css">
</style>
</head>
<body>
<!--toolbox -->
<div id="draggable toolbox"></div>
<script type="application/processing">
// new script
int prevx, prevy;
int newx, newy;
boolean cliked;
color c1 = #000000;
int largeur=2;
int ps = 20;
int px = 50;
int py = 50;
void setup() {
size(500,500);
frameRate(25);
background(50);
prevx = mouseX;
prevy = mouseY;
cliked = false;
}
void draw() {
//couleur
noStroke(0);
fill(#FFFFFF);//blanc
rect(px, py, ps, ps);
fill(#000000);
rect(px, py+(ps), ps, ps);
fill(#FF0000);
rect(px, py+(ps*2), ps, ps);
fill(#00FF00);
rect(px, py+(ps*3), ps, ps);
fill(#FFFF00);
rect(px, py+(ps*4), ps, ps);
fill(#0000FF);
rect(px, py+(ps*5), ps, ps);
//largeur
fill(#FFFFFF);
rect(px, py+(ps*7), ps, ps);
fill(#FFFFFF);
rect(px, py+(ps*8), ps, ps);
stroke(#000000);
line(px+2, py+(ps*7)+(ps/2), px+(ps-2), py+(ps*7)+(ps/2));
line(px+(ps/2), py+(ps*7)+1, px+(ps/2), py+(ps*8)-1);
line(px+2, py+(ps*8)+(ps/2), px+(ps-2), py+(ps*8)+(ps/2));
if(cliked==false){
prevx = mouseX;
prevy = mouseY;
}
if(mousePressed) {
cliked = true;
newx = mouseX;
newy = mouseY;
strokeWeight(largeur);
stroke(c1);
line(prevx, prevy, newx, newy);
prevx = newx;
prevy = newy;
}else{
cliked= false;
}
}
void mouseClicked() {
if (mouseX>=px && mouseX<=(px+ps)){
//couleur
if (mouseY>=py && mouseY<=py+(ps*6)){
c1 = get(mouseX, mouseY);
}
//largeur
if (mouseY>=py+(ps*7) && mouseY<=py+(ps*8)){
largeur += 2;
}
if (mouseY>=py+(ps*8) && mouseY<=py+(ps*9)){
if (largeur>2){
largeur -= 2;
}
}
}
}
</script><canvas></canvas>
</body>
</html>
Busqué en Google esto ("programa de pintura de lienzo html5"). Parece lo que necesitas.
Creo que otros ejemplos son demasiado complicados. Este es más simple y solo JS ...
// create canvas element and append it to document body
var canvas = document.createElement(''canvas'');
document.body.appendChild(canvas);
// some hotfixes... ( ≖_≖)
document.body.style.margin = 0;
canvas.style.position = ''fixed'';
// get canvas 2D context and set him correct size
var ctx = canvas.getContext(''2d'');
resize();
// last known position
var pos = { x: 0, y: 0 };
window.addEventListener(''resize'', resize);
document.addEventListener(''mousemove'', draw);
document.addEventListener(''mousedown'', setPosition);
document.addEventListener(''mouseenter'', setPosition);
// new position from mouse event
function setPosition(e) {
pos.x = e.clientX;
pos.y = e.clientY;
}
// resize canvas
function resize() {
ctx.canvas.width = window.innerWidth;
ctx.canvas.height = window.innerHeight;
}
function draw(e) {
// mouse left button must be pressed
if (e.buttons !== 1) return;
ctx.beginPath(); // begin
ctx.lineWidth = 5;
ctx.lineCap = ''round'';
ctx.strokeStyle = ''#c0392b'';
ctx.moveTo(pos.x, pos.y); // from
setPosition(e);
ctx.lineTo(pos.x, pos.y); // to
ctx.stroke(); // draw it!
}
Esta es la manera más directa de crear una aplicación de dibujo con lienzo:
- Adjunte un
mousedownmousemovemousedown,mousemoveymouseupal DOM demouseup - en
mousedown, obtenga las coordenadas del mouse y use el métodomoveTo()parabeginPath()el cursor de dibujo y el métodobeginPath()para comenzar una nueva ruta de dibujo. - en
mousemove, agrega continuamente un nuevo punto a la ruta conlineTo()y colorea el último segmento constroke(). - en
mouseup, establece una bandera para deshabilitar el dibujo.
A partir de ahí, puede agregar todo tipo de otras funciones, como darle al usuario la capacidad de elegir un grosor de línea, color, trazos de pincel e incluso capas.
Estaba buscando utilizar este método para las firmas, encontré una muestra en http://codetheory.in/ .
He agregado el siguiente código a jsfiddle
Html:
<div id="sketch">
<canvas id="paint"></canvas>
</div>
Javascript:
(function() {
var canvas = document.querySelector(''#paint'');
var ctx = canvas.getContext(''2d'');
var sketch = document.querySelector(''#sketch'');
var sketch_style = getComputedStyle(sketch);
canvas.width = parseInt(sketch_style.getPropertyValue(''width''));
canvas.height = parseInt(sketch_style.getPropertyValue(''height''));
var mouse = {x: 0, y: 0};
var last_mouse = {x: 0, y: 0};
/* Mouse Capturing Work */
canvas.addEventListener(''mousemove'', function(e) {
last_mouse.x = mouse.x;
last_mouse.y = mouse.y;
mouse.x = e.pageX - this.offsetLeft;
mouse.y = e.pageY - this.offsetTop;
}, false);
/* Drawing on Paint App */
ctx.lineWidth = 5;
ctx.lineJoin = ''round'';
ctx.lineCap = ''round'';
ctx.strokeStyle = ''blue'';
canvas.addEventListener(''mousedown'', function(e) {
canvas.addEventListener(''mousemove'', onPaint, false);
}, false);
canvas.addEventListener(''mouseup'', function() {
canvas.removeEventListener(''mousemove'', onPaint, false);
}, false);
var onPaint = function() {
ctx.beginPath();
ctx.moveTo(last_mouse.x, last_mouse.y);
ctx.lineTo(mouse.x, mouse.y);
ctx.closePath();
ctx.stroke();
};
}());
revisa esto http://jsfiddle.net/ArtBIT/kneDX/ . Esto debería dirigirlo en la dirección correcta