优化画布绘制以形成连续路径 [英] Optimize canvas drawing to make a continuous path
本文介绍了优化画布绘制以形成连续路径的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
这是一个用红色填充画布'网格方块的脚本。
我正在寻找如何优化我的脚本以连续填充方块的提示,而不是像这里一样砍掉:
我试图分离并合并一些函数,但无法找到解决方案。
这是
<!doctype html>
< html>
< head>
< link rel =stylesheettype =text / cssmedia =allhref =css / reset.css/> < ;! - reset css - >
< script type =text / javascriptsrc =http://code.jquery.com/jquery.min.js>< / script>
< style>
body {background-color:ivory; }
canvas {border:1px solid red;}
< / style>
< script>
$(function(){
var canvas = document.getElementById(canvas);
var context = canvas.getContext(2d);
var canvasOffset = $(#canvas)。offset();
var offsetX = canvasOffset.left;
var offsetY = canvasOffset.top;
var wt = canvas.width;
var ht = canvas.height;
var down = false;
var lastX = -20;
var lastY = -20;
var points = [];
var draw = function(e){};
draw。 started = false;
var count;
函数interpolateLine(startX,startY,endX,endY){
var lastForX;
var lastForY;
//
for(var pct = 0; pct< = 1; pct + = 0.06){
var dx = endX-startX;
var dy = endY-startY;
var X = startX + dx * pct;
var Y = startY + dy * pct;
if(!(X == lastForX&& Y = = lastForY)){
draw.ColorCell(X,Y);
}
lastForX = X;
lastForY = Y;
}
}
draw.ColorCell = function(x,y){
var rw = x - 1;
var rh = y - 1;
rw = rw - rw%5 + 0.5;
rh = rh - rh%5 + 0.5;
context.fillStyle =red;
context.fillRect(rw,rh,5,5);
};
draw.single = function(e){
var mouseX = parseInt(e.clientX-offsetX);
var mouseY = parseInt(e.clientY-offsetY);
draw.ColorCell(mouseX,mouseY);
};
// mousemove
draw.move = function(e){
if(!down){return;}
//获取当前鼠标位置
var mouseX = parseInt(e.clientX-offsetX);
var mouseY = parseInt(e.clientY-offsetY);
//如果我们没有离开这个XY,那么如果(mouseX == lastX&& mouseY == lastY){return;},请不要再处理
//当运行下面的for循环时,
//多次迭代将找不到新的网格单元
//所以lastForX / lastForY会让我们跳过重复的XY
var lastForX = lastX;
var lastForY = lastY;
//从最后一个鼠标移动位置
//沿着一条线走到当前的mousemove位置。
//然后为我们在walk
上传递的任何单元格着色(var pct = 0; pct< = 1; pct + = 0.06){
var dx = mouseX-lastX;
var dy = mouseY-lastY;
var X = parseInt(lastX + dx * pct);
var Y = parseInt(lastY + dy * pct);
if(!(X == lastForX&& Y == lastForY)){
draw.ColorCell(X,Y);
}
lastForX = X;
lastForY = Y;
}
//将此鼠标位置设置为下一个mousemove的起始位置
lastX = mouseX;
lastY = mouseY;
};
// mousedown
draw.start = function(e){
e.preventDefault();
lastX = parseInt(e.clientX-offsetX);
lastY = parseInt(e.clientY-offsetY);
down = true;
};
// mouseup
draw.stop = function(e){
e.preventDefault();
down = false;
};
function grid(){
context.strokeStyle =#f0f0f0;
var h = 2.5;
var p = 2.5;
context.strokeRect(0.5,0.5,5,5);
for(i = 0; i< wt; i + = p){
p * = 2;
context.drawImage(canvas,p,0);
}
for(i = 0; i< ht; i + = h){
h * = 2;
context.drawImage(canvas,0,h);
}
}
canvas.addEventListener('mouseup',draw.stop,false);
canvas.addEventListener('mouseout',draw.stop,false);
canvas.addEventListener('mousedown',draw.start,false);
canvas.addEventListener('click',draw.single,false);
canvas.addEventListener('mousemove',draw.move,false);
grid();
}); // end $(function(){});
< / script>
< / head>
< body>
< canvas id =canvaswidth = 501 height = 301>< / canvas>
< / body>
< / html>
This is a script for filling canvas' grid squares with red color. I'm looking for tips how to optimize my script to fill squares continuously, without chopping like here:
I tried to separate and merge some functions, but can't find a solution. Here's the updated jsFiddle and my code:
HTML:
<canvas id="plan" width="501px" height="301px"></canvas>
JavaScript (updated):
var canvas = document.getElementById('plan');
var context = canvas.getContext('2d'),
wt = canvas.width,
ht = canvas.height;
var down = false;
var draw = function (e) {};
window.onload = grid();
var oldPos = {
mX: 0,
mY: 0
};
var dPos = {
mX: 0,
mY: 0
};
var curPos = {
mX: 0,
mY: 0
};
draw.to = function (X, Y) {
oldPos = getMousePos(canvas, e); //update position
var mposX = X,
mposY = Y;
mposX = mposX - mposX % 5;
mposY = mposY - mposY % 5;
context.fillStyle = "red";
context.fillRect(mposX + 0.5, mposY + 0.5, 5, 5);
};
draw.single = function (e) {
oldPos = getMousePos(canvas, e);
var mpos = getMousePos(canvas, e);
mpos.mX = mpos.mX - mpos.mX % 5;
mpos.mY = mpos.mY - mpos.mY % 5;
context.fillStyle = "red";
context.fillRect(mpos.mX + 0.5, mpos.mY + 0.5, 5, 5);
};
draw.move = function (e) {
if (down) {
curPos = getMousePos(canvas, e);
dPos.mX = Math.abs(curPos.mX - oldPos.mX); // distance between old & new (delta X)
dPos.mY = Math.abs(curPos.mY - oldPos.mY); // delta Y
if (dPos.mX >= 5 || dPos.mY >= 5) { // if the distance is bigger than 5px hz OR 5px vertical
lightIntermediateSquares(oldPos.mX, oldPos.mY, curPos.mX, curPos.mY); // ^ connect them
} else {
draw.single(e); // simple
}
}
};
draw.start = function (e) {
e.preventDefault();
down = true;
draw.single(e);
};
draw.stop = function (e) {
down = false;
};
function lightIntermediateSquares(startX, startY, endX, endY) {
for (var pct = 0; pct <= 1; pct += 0.03) {
var dx = endX - startX;
var dy = endY - startY;
var X = startX + dx * pct;
var Y = startY + dy * pct;
draw.to(X, Y); // is it okay?
}
}
function grid() {
context.strokeStyle = "#f0f0f0";
var h = 2.5,
p = 2.5;
context.strokeRect(0.5, 0.5, 5, 5);
for (i = 0; i < wt; i += p) {
p *= 2;
context.drawImage(canvas, p, 0);
}
for (i = 0; i < ht; i += h) {
h *= 2;
context.drawImage(canvas, 0, h);
}
}
function getMousePos(canvas, e) {
var rect = canvas.getBoundingClientRect();
return {
mX: e.clientX - rect.left - 1,
mY: e.clientY - rect.top - 1
};
}
canvas.addEventListener('mouseup', draw.stop, false);
canvas.addEventListener('mousedown', draw.start, false);
canvas.addEventListener('mousemove', draw.move, false);
canvas.addEventListener('mouseout', draw.stop, false);
解决方案
Here's how to light the missing squares
Calculate a line between the previous mousemove and the current mousemove position.
Then walk that line using interpolation and color any grid squares that the line crosses.
// walk along a line from the last mousemove position
// to the current mousemove position.
// Then color any cells we pass over on our walk
for(var pct=0;pct<=1;pct+=0.06){
var dx = mouseX-lastX;
var dy = mouseY-lastY;
var X = parseInt(lastX + dx*pct);
var Y = parseInt(lastY + dy*pct);
if( !(X==lastForX && Y==lastForY) ){
draw.ColorCell(X,Y);
}
Here is code and a Fiddle: http://jsfiddle.net/m1erickson/WvuHL/
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; }
canvas{border:1px solid red;}
</style>
<script>
$(function(){
var canvas=document.getElementById("canvas");
var context=canvas.getContext("2d");
var canvasOffset=$("#canvas").offset();
var offsetX=canvasOffset.left;
var offsetY=canvasOffset.top;
var wt = canvas.width;
var ht = canvas.height;
var down = false;
var lastX=-20;
var lastY=-20;
var points=[];
var draw = function (e) {};
draw.started = false;
var count;
function interpolateLine(startX,startY,endX,endY){
var lastForX;
var lastForY;
//
for(var pct=0;pct<=1;pct+=0.06){
var dx = endX-startX;
var dy = endY-startY;
var X = startX + dx*pct;
var Y = startY + dy*pct;
if( !(X==lastForX && Y==lastForY) ){
draw.ColorCell(X,Y);
}
lastForX=X;
lastForY=Y;
}
}
draw.ColorCell=function(x,y){
var rw = x - 1;
var rh = y - 1;
rw = rw - rw % 5 + 0.5;
rh = rh - rh % 5 + 0.5;
context.fillStyle = "red";
context.fillRect( rw, rh, 5, 5);
};
draw.single = function (e) {
var mouseX=parseInt(e.clientX-offsetX);
var mouseY=parseInt(e.clientY-offsetY);
draw.ColorCell(mouseX,mouseY);
};
// mousemove
draw.move = function (e) {
if(!down){return;}
// get the current mouse position
var mouseX=parseInt(e.clientX-offsetX);
var mouseY=parseInt(e.clientY-offsetY);
// if we haven't moved off this XY, then don't bother processing further
if(mouseX==lastX && mouseY==lastY){return;}
// When running the for-loop below,
// many iterations will not find a new grid-cell
// so lastForX/lastForY will let us skip duplicate XY
var lastForX=lastX;
var lastForY=lastY;
// walk along a line from the last mousemove position
// to the current mousemove position.
// Then color any cells we pass over on our walk
for(var pct=0;pct<=1;pct+=0.06){
var dx = mouseX-lastX;
var dy = mouseY-lastY;
var X = parseInt(lastX + dx*pct);
var Y = parseInt(lastY + dy*pct);
if( !(X==lastForX && Y==lastForY) ){
draw.ColorCell(X,Y);
}
lastForX=X;
lastForY=Y;
}
// set this mouse position as starting position for next mousemove
lastX=mouseX;
lastY=mouseY;
};
// mousedown
draw.start = function (e) {
e.preventDefault();
lastX=parseInt(e.clientX-offsetX);
lastY=parseInt(e.clientY-offsetY);
down = true;
};
// mouseup
draw.stop = function (e) {
e.preventDefault();
down = false;
};
function grid() {
context.strokeStyle = "#f0f0f0";
var h = 2.5;
var p = 2.5;
context.strokeRect(0.5, 0.5, 5, 5);
for (i = 0; i < wt; i += p) {
p *= 2;
context.drawImage(canvas, p, 0);
}
for (i = 0; i < ht; i += h) {
h *= 2;
context.drawImage(canvas, 0, h);
}
}
canvas.addEventListener('mouseup', draw.stop, false);
canvas.addEventListener('mouseout', draw.stop, false);
canvas.addEventListener('mousedown', draw.start, false);
canvas.addEventListener('click', draw.single, false);
canvas.addEventListener('mousemove', draw.move, false);
grid();
}); // end $(function(){});
</script>
</head>
<body>
<canvas id="canvas" width=501 height=301></canvas>
</body>
</html>
这篇关于优化画布绘制以形成连续路径的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文