html5实现的简单进度条效果

2024-09-05 12:18:55

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一个html5实现的简单进度条效果，带数字显示百分比，基于Canvas技术，不但生成了进度条，也生成了进度条的动画效果，需要 loadingbar的可研究下，部分功能需要JavaScript实现，希望大家喜欢。

<!DOCTYPE html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>html5实现的简单进度条效果 - www.vevb.com</title><script type="text/javascript">        var i = 0;        var res = 0;        var context = null;        var total_width = 300;        var total_height = 34;        var initial_x = 20;        var initial_y = 20;        var radius = total_height/2;        window.onload = function() {            var elem = document.getElementById('myCanvas');            if (!elem || !elem.getContext) {                return;            }            context = elem.getContext('2d');            if (!context) {                return;            }            context.font = "16px Verdana";            var progress_lingrad = context.createLinearGradient(0,initial_y+total_height,0,0);            progress_lingrad.addColorStop(0, '#4DA4F3');            progress_lingrad.addColorStop(0.4, '#ADD9FF');            progress_lingrad.addColorStop(1, '#9ED1FF');            context.fillStyle = progress_lingrad;            res = setInterval(draw, 30);        }        function draw() {            i+=1;            context.clearRect(initial_x-5,initial_y-5,total_width+15,total_height+15);            progressLayerRect(context, initial_x, initial_y, total_width, total_height, radius);            progressBarRect(context, initial_x, initial_y, i, total_height, radius, total_width);            progressText(context, initial_x, initial_y, i, total_height, radius, total_width );            if (i>=total_width) {                clearInterval(res);            }        }        function roundRect(ctx, x, y, width, height, radius) {            ctx.beginPath();            ctx.moveTo(x + radius, y);            ctx.lineTo(x + width - radius, y);            ctx.arc(x+width-radius, y+radius, radius, -Math.PI/2, Math.PI/2, false);            ctx.lineTo(x + radius, y + height);            ctx.arc(x+radius, y+radius, radius, Math.PI/2, 3*Math.PI/2, false);            ctx.closePath();            ctx.fill();        }        function roundInsetRect(ctx, x, y, width, height, radius) {            ctx.beginPath();            ctx.moveTo(1000, 1000);            ctx.lineTo(1000, -1000);            ctx.lineTo(-1000, -1000);            ctx.lineTo(-1000, 1000);            ctx.lineTo(1000, 1000);            ctx.moveTo(x + radius, y);            ctx.lineTo(x + width - radius, y);            ctx.arc(x+width-radius, y+radius, radius, -Math.PI/2, Math.PI/2, false);            ctx.lineTo(x + radius, y + height);            ctx.arc(x+radius, y+radius, radius, Math.PI/2, 3*Math.PI/2, false);            ctx.closePath();            ctx.fill();        }        function progressLayerRect(ctx, x, y, width, height, radius) {            ctx.save();            ctx.shadowOffsetX = 2;            ctx.shadowOffsetY = 2;            ctx.shadowBlur = 5;            ctx.shadowColor = '#666';            ctx.fillStyle = 'rgba(189,189,189,1)';            roundRect(ctx, x, y, width, height, radius);            ctx.shadowColor = 'rgba(0,0,0,0)'            // http://www.codefans.net            var lingrad = ctx.createLinearGradient(0,y+height,0,0);            lingrad.addColorStop(0, 'rgba(255,255,255, 0.1)');            lingrad.addColorStop(0.4, 'rgba(255,255,255, 0.7)');            lingrad.addColorStop(1, 'rgba(255,255,255,0.4)');            ctx.fillStyle = lingrad;            roundRect(ctx, x, y, width, height, radius);            ctx.fillStyle = 'white';            ctx.restore();        }        function progressBarRect(ctx, x, y, width, height, radius, max) {            var offset = 0;            ctx.beginPath();            if (width<radius) {                offset = radius - Math.sqrt(Math.pow(radius,2)-Math.pow((radius-width),2));                ctx.moveTo(x + width, y+offset);                ctx.lineTo(x + width, y+height-offset);                ctx.arc(x + radius, y + radius, radius, Math.PI - Math.acos((radius - width) / radius), Math.PI + Math.acos((radius - width) / radius), false);            }            else if (width+radius>max) {                offset = radius - Math.sqrt(Math.pow(radius,2)-Math.pow((radius - (max-width)),2));                ctx.moveTo(x + radius, y);                ctx.lineTo(x + width, y);                ctx.arc(x+max-radius, y + radius, radius, -Math.PI/2, -Math.acos((radius - (max-width)) / radius), false);                ctx.lineTo(x + width, y+height-offset);                ctx.arc(x+max-radius, y + radius, radius, Math.acos((radius - (max-width)) / radius), Math.PI/2, false);                ctx.lineTo(x + radius, y + height);                ctx.arc(x+radius, y+radius, radius, Math.PI/2, 3*Math.PI/2, false);            }            else {                ctx.moveTo(x + radius, y);                ctx.lineTo(x + width, y);                ctx.lineTo(x + width, y + height);                ctx.lineTo(x + radius, y + height);                ctx.arc(x+radius, y+radius, radius, Math.PI/2, 3*Math.PI/2, false);            }            ctx.closePath();            ctx.fill();            if (width<max-1) {                ctx.save();                ctx.shadowOffsetX = 1;                ctx.shadowBlur = 1;                ctx.shadowColor = '#666';                if (width+radius>max)                  offset = offset+1;                ctx.fillRect(x+width,y+offset,1,total_height-offset*2);                ctx.restore();            }        }        function progressText(ctx, x, y, width, height, radius, max) {            ctx.save();            ctx.fillStyle = 'white';            var text = Math.floor(width/max*100)+"%";            var text_width = ctx.measureText(text).width;            var text_x = x+width-text_width-radius/2;            if (width<=radius+text_width) {                text_x = x+radius/2;            }            ctx.fillText(text, text_x, y+22);            ctx.restore();        }</script></head><body><p><canvas id="myCanvas" width="500" height="150">您的浏览器不支持canvas.</canvas></p></body></html>

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