html5实现canvas阴影效果示例

2020-03-24 17:32:37

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在HTML5中实现Canvas阴影效果

复制代码代码如下:
!DOCTYPE html
html
head
meta http-equiv="X-UA-Compatible" content="chrome=IE8"
meta http-equiv="Content-type" content="text/html;charset=UTF-8"
title Canvas Clip Demo /title
link href="default.css" rel="stylesheet" /
script
var ctx = null; // global variable 2d context
var imageTexture = null;
window.onload = function() {
var canvas = document.getElementById("text_canvas");
console.log(canvas.parentNode.clientWidth);
canvas.width = canvas.parentNode.clientWidth;
canvas.height = canvas.parentNode.clientHeight;

if (!canvas.getContext) {
console.log("Canvas not supported. Please install a HTML5 compatible browser.");
return;
}
var context = canvas.getContext('2d');

// section one - shadow and blur
context.fill ;
context.fillRect(0, 0, canvas.width, canvas.height/4);
context.font = '60pt Calibri';

context.shadowColor = "white";
context.shadowOffsetX = 0;
context.shadowOffsetY = 0;
context.shadowBlur = 20;
context.fillText("Blur Canvas", 40, 80);
context.strokeStyle = "RGBA(0, 255, 0, 1)";
context.lineWidth = 2;
context.strokeText("Blur Canvas", 40, 80);

// section two - shadow font
var hh = canvas.height/4;
context.fill ;
context.fillRect(0, hh, canvas.width, canvas.height/4);
context.font = '60pt Calibri';

context.shadowColor = "RGBA(127,127,127,1)";
context.shadowOffsetX = 3;
context.shadowOffsetY = 3;
context.shadowBlur = 0;
context.fillStyle = "RGBA(0, 0, 0, 0.8)";
context.fillText("Blur Canvas", 40, 80+hh);

// section three - down shadow effect
var hh = canvas.height/4 + hh;
context.fill ;
context.fillRect(0, hh, canvas.width, canvas.height/4);
for(var i = 0; i i++)
{
context.shadowColor = "RGBA(255, 255, 255," + ((10-i)/10) + ")";
context.shadowOffsetX = i*2;
context.shadowOffsetY = i*2;
context.shadowBlur = i*2;
context.fillStyle = "RGBA(127, 127, 127, 1)";
context.fillText("Blur Canvas", 40, 80+hh);
}

// section four - fade effect
var hh = canvas.height/4 + hh;
context.fill ;
context.fillRect(0, hh, canvas.width, canvas.height/4);
for(var i = 0; i i++)
{
context.shadowColor = "RGBA(255, 255, 255," + ((10-i)/10) + ")";
context.shadowOffsetX = 0;
context.shadowOffsetY = -i*2;
context.shadowBlur = i*2;
context.fillStyle = "RGBA(127, 127, 127, 1)";
context.fillText("Blur Canvas", 40, 80+hh);
}
for(var i = 0; i i++)
{
context.shadowColor = "RGBA(255, 255, 255," + ((10-i)/10) + ")";
context.shadowOffsetX = 0;
context.shadowOffsetY = i*2;
context.shadowBlur = i*2;
context.fillStyle = "RGBA(127, 127, 127, 1)";
context.fillText("Blur Canvas", 40, 80+hh);
}
for(var i = 0; i i++)
{
context.shadowColor = "RGBA(255, 255, 255," + ((10-i)/10) + ")";
context.shadowOffsetX = i*2;
context.shadowOffsetY = 0;
context.shadowBlur = i*2;
context.fillStyle = "RGBA(127, 127, 127, 1)";
context.fillText("Blur Canvas", 40, 80+hh);
}
for(var i = 0; i i++)
{
context.shadowColor = "RGBA(255, 255, 255," + ((10-i)/10) + ")";
context.shadowOffsetX = -i*2;
context.shadowOffsetY = 0;
context.shadowBlur = i*2;
context.fillStyle = "RGBA(127, 127, 127, 1)";
context.fillText("Blur Canvas", 40, 80+hh);
}
}

/script
/head
body
h1 HTML5 Canvas /h1
pre Fill And Stroke Clip /pre
div id="my_painter"
canvas id="text_canvas" /canvas
/div
/body
/html
html教程

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