这篇文章主要介绍了运用HTML5Canvas绘制暗影结果的办法,包含一个3D拉影+边沿依稀结果文字的编写例子,在暗影结果的应用上进一步深入,需要的伴侣可以参照 下 这篇文章主要介绍了运用HTML5 Canvas绘制暗影结果的办法,包含一个3D拉影+边沿依稀结果文字的编写例子,在暗影结果的应用上进一步深入,需要的伴侣可以参照 下

新建暗影结果需要操纵下列4个属性：

1.context.shadowColor：暗影色彩。
2.context.shadowOffsetX：暗影x轴位移。正值向右，负值向左。
3.context.shadowOffsetY：暗影y轴位移。正值向下，负值向上。
4.context.shadowBlur：暗影依稀滤镜。数据越大，扩散程度越大。
这四个属性只有设定了首先个和剩下三个中的任意一个就有暗影结果。不外平常状况下，四个属性都要设定。

例如，新建一个向右下方位移各5px的红色暗影，依稀2px，可以这样写。

context.shadowColor = "red";   
context.shadowOffsetX = 5;   
context.shadowOffsetY = 5;   
context.shadowBlur= 2;

需要注意的是，这里的暗影同其他属性设定同样，都是基于状态的设定。因而，要是只想为某一个对象利用暗影而不是全局暗影，需要鄙人次绘制前重置暗影的这四个属性。
运转效果：

程序代码：

     
     
     
     
     
     
     
    《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.fillStyle="black";     
            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.fillStyle="white";     
            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.fillStyle="black";     
            context.fillRect(0, hh, canvas.width, canvas.height/4);     
            for(var i = 0; i < 10; 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.fillStyle="green";     
            context.fillRect(0, hh, canvas.width, canvas.height/4);     
            for(var i = 0; i < 10; 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 < 10; 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 < 10; 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 < 10; 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》     
     
     
    
HTML5 Canvas Clip Demo - By Gloomy Fish
     
    
Fill And Stroke Clip
     
    
     
             
    
     
     

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