Javascript 网格线开关HMTL5画布
我想用开关(开/关)绘制网格线x和y,但是HTML5画布正在渲染之前绘制的线,即使在ctx.clearRect之后,我只想用相同的按钮打开和关闭这些线。这是我的小提琴Javascript 网格线开关HMTL5画布,javascript,html,canvas,Javascript,Html,Canvas,我想用开关(开/关)绘制网格线x和y,但是HTML5画布正在渲染之前绘制的线,即使在ctx.clearRect之后,我只想用相同的按钮打开和关闭这些线。这是我的小提琴 var canvas=document.getElementById('canvas'), ctx=canvas.getContext('2d'); var gridline_x=false,gridline_y=false; var grid_x=函数(){ 网格线_x=(网格线_x)?false:true; 网格线(); }
var canvas=document.getElementById('canvas'),
ctx=canvas.getContext('2d');
var gridline_x=false,gridline_y=false;
var grid_x=函数(){
网格线_x=(网格线_x)?false:true;
网格线();
};
var grid_y=函数(){
gridline_y=(gridline_y)?false:true;
网格线();
};
var GridLines=函数(){
var ctx=canvas.getContext('2d');
clearRect(0,0,canvas.width,canvas.height);
log('Grid X:'+gridline_X+'Grid Y:'+gridline_Y));
ctx.save();
如果(网格线_y)
对于(变量i=1;i
在您的ctx.save
之后,第二次单击时不会删除这些行
beginPath
告诉浏览器您已经完成了以前的路径图形,并且正在开始新的图形
如果没有beginPath
,所有以前的图形都将被重新绘制——即使在clearRect
var canvas = document.getElementById('canvas'),
ctx = canvas.getContext('2d');
var gridline_x = false,gridline_y = false;
var grid_x = function(){
gridline_x = (gridline_x)?false:true;
GridLines();
};
var grid_y = function(){
gridline_y = (gridline_y)?false:true;
GridLines();
};
var GridLines = function(){
var ctx = canvas.getContext('2d');
ctx.clearRect(0,0,canvas.width,canvas.height);
console.log('Grid X: '+gridline_x + ' Grid Y: '+gridline_y);
ctx.save();
if(gridline_y)
for(var i = 1; i < canvas.width; i += 50) {
ctx.moveTo( i, 0 );
ctx.lineTo( i, canvas.height);
}
if(gridline_x)
for(var i = 1; i < canvas.height ; i += 50) {
ctx.moveTo( 0, i );
ctx.lineTo( canvas.width, i);
}
ctx.strokeStyle = 'hsla(0, 0%, 40%, .5)';
ctx.stroke();
ctx.restore();
//ctx.restore();
};