很多購物網站現在都支持360實物全景圖像,可以360度任意選擇查看樣品,這樣對購買者來說是一個很好的消費體驗,網上有很多這樣的插件都是基于jQuery實現的有收費的也有免費的,其實很好用的一個叫3deye.js的插件。該插件支持桌面與移動終端iOS與Android, 它的demo程序:http://www.voidcanvas.com/demo/28823deye/
自己玩了玩這個Demo以后,照著它的思路,用HTML5 Canvas也實現了類似的功能。
所以先說一下它的360度全景圖的原理
1. 首先需要對實物拍照,間隔是每張照片旋轉15度,所以需要23張照片。
2.照片準備好了以后,盡量選擇JPG格式,裁剪到適當大小。
3.JavaScript中預加載所有照片,可以配合進度條顯示加載精度
4.創建/獲取Canvas對象,加上鼠標監聽事件,當鼠標左右移動時候,適度的繪制不同幀。大致的原理就是這樣,簡單吧!
實現代碼:
!DOCTYPE html html head meta charset=utf-8 title Full 360 degree View /title script var ctx = null; // global variable 2d context var frame = 1; // 23 var width = 0; var height = 0; var started = false; var images = new Array(); var startedX = -1; window.onload = function() { var canvas = document.getElementById( fullview_canvas canvas.width = 440;// window.innerWidth; canvas.height = 691;//window.innerHeight; width = canvas.width; height = canvas.height; var bar = document.getElementById( loadProgressBar for(var i=1; i i++) bar.value = i; if(i 10) images[i] = new Image(); images[i].src = 0 + i + .jpg else images[i] = new Image(); images[i].src = i + .jpg ctx = canvas.getContext( 2d // mouse event canvas.addEventListener( mousedown , doMouseDown, false); canvas.addEventListener( mousemove , doMouseMove, false); canvas.addEventListener( mouseup , doMouseUp, false); // loaded(); // frame = 1 frame = 1; images[frame].onload = function() { redraw(); bar.style.display = none function doMouseDown(event) { var x = event.pageX; var y = event.pageY; var canvas = event.target; var loc = getPointOnCanvas(canvas, x, y); console.log( mouse down at point( x: + loc.x + , y: + loc.y + ) startedX = loc.x; started = true; function doMouseMove(event) { var x = event.pageX; var y = event.pageY; var canvas = event.target; var loc = getPointOnCanvas(canvas, x, y); if (started) { var count = Math.floor(Math.abs((startedX - loc.x)/30)); var frameIndex = Math.floor((startedX - loc.x)/30); while(count 0) console.log( frameIndex = + frameIndex); count--; if(frameIndex 0) frameIndex--; frame++; } else if(frameIndex 0) frameIndex++; frame--; else if(frameIndex == 0) break; if(frame = 24) frame = 1; if(frame = 0) frame = 23; redraw(); function doMouseUp(event) { console.log( mouse up now if (started) { doMouseMove(event); startedX = -1; started = false; function getPointOnCanvas(canvas, x, y) { var bbox = canvas.getBoundingClientRect(); return { x: x - bbox.left * (canvas.width / bbox.width), y: y - bbox.top * (canvas.height / bbox.height) function loaded() { setTimeout( update, 1000/8); function redraw() // var imageObj = document.createElement( img // var imageObj = new Image(); var imageObj = images[frame]; ctx.clearRect(0, 0, width, height) ctx.drawImage(imageObj, 0, 0, width, height); function update() { redraw(); frame++; if (frame = 23) frame = 1; setTimeout( update, 1000/8); /script /head body progress id= loadProgressBar value= 0 max= 23 /progress canvas id= fullview_canvas /canvas button quot;loaded() Auto Play /button /body /html
Demo演示文件下載地址- fullview_jb51.rar
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以上就是HTML5 Canvas實現360度全景方法的詳細內容,其它編程語言
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