HTML5 Canvas 破碎重组的视频特效的示例代码前端canvas动画如何转成mp4视频的方法canvas像素点操作之视频绿幕抠图video结合canvas实现视频在线截图功能canvas绘制视频封面的方法详解基于canvas的视频遮罩插件canvas与html5实现视频截图功能示例Canvas获取视频第一帧缩略图的实现

 var video; var copy; var copycanvas; var draw; var TILE_WIDTH = 32; var TILE_HEIGHT = 24; var TILE_CENTER_WIDTH = 16; var TILE_CENTER_HEIGHT = 12; var SOURCERECT = {x:0, y:0, width:0, height:0}; var PAINTRECT = {x:0, y:0, width:1000, height:600}; function init(){ video = document.getElementById('sourcevid'); copycanvas = document.getElementById('sourcecopy'); copy = copycanvas.getContext('2d'); var outputcanvas = document.getElementById('output'); draw = outputcanvas.getContext('2d'); setInterval("processFrame()", 33); } function createTiles(){ var offsetX = TILE_CENTER_WIDTH+(PAINTRECT.width-SOURCERECT.width)/2; var offsetY = TILE_CENTER_HEIGHT+(PAINTRECT.height-SOURCERECT.height)/2; var y=0; while(y < SOURCERECT.height){ var x=0; while(x < SOURCERECT.width){ var tile = new Tile(); tile.videoX = x; tile.videoY = y; tile.originX = offsetX+x; tile.originY = offsetY+y; tile.currentX = tile.originX; tile.currentY = tile.originY; tiles.push(tile); x+=TILE_WIDTH; } y+=TILE_HEIGHT; } } var RAD = Math.PI/180; var randomJump = false; var tiles = []; var debug = false; function processFrame(){ if(!isNaN(video.duration)){ if(SOURCERECT.width == 0){ SOURCERECT = {x:0,y:0,width:video.videoWidth,height:video.videoHeight}; createTiles(); } //this is to keep my sanity while developing if(randomJump){ randomJump = false; video.currentTime = Math.random()*video.duration; } //loop if(video.currentTime == video.duration){ video.currentTime = 0; } } var debugStr = ""; //copy tiles copy.drawImage(video, 0, 0); draw.clearRect(PAINTRECT.x, PAINTRECT.y,PAINTRECT.width,PAINTRECT.height); for(var i=0; i 0.0001){ //expand tile.moveX *= tile.force; tile.moveY *= tile.force; tile.moveRotation *= tile.force; tile.currentX += tile.moveX; tile.currentY += tile.moveY; tile.rotation += tile.moveRotation; tile.rotation %= 360; tile.force *= 0.9; if(tile.currentX <= 0 || tile.currentX >= PAINTRECT.width){ tile.moveX *= -1; } if(tile.currentY <= 0 || tile.currentY >= PAINTRECT.height){ tile.moveY *= -1; } }else if(tile.rotation != 0 || tile.currentX != tile.originX || tile.currentY != tile.originY){ //contract var diffx = (tile.originX-tile.currentX)*0.2; var diffy = (tile.originY-tile.currentY)*0.2; var diffRot = (0-tile.rotation)*0.2; if(Math.abs(diffx) < 0.5){ tile.currentX = tile.originX; }else{ tile.currentX += diffx; } if(Math.abs(diffy) < 0.5){ tile.currentY = tile.originY; }else{ tile.currentY += diffy; } if(Math.abs(diffRot) < 0.5){ tile.rotation = 0; }else{ tile.rotation += diffRot; } }else{ tile.force = 0; } draw.save(); draw.translate(tile.currentX, tile.currentY); draw.rotate(tile.rotation*RAD); draw.drawImage(copycanvas, tile.videoX, tile.videoY, TILE_WIDTH, TILE_HEIGHT, -TILE_CENTER_WIDTH, -TILE_CENTER_HEIGHT, TILE_WIDTH, TILE_HEIGHT); draw.restore(); } if(debug){ debug = false; document.getElementById('trace').innerHTML = debugStr; } } function explode(x, y){ for(var i=0; i tile.force){ tile.force = force; var radians = Math.atan2(ydiff, xdiff); tile.moveX = Math.cos(radians); tile.moveY = Math.sin(radians); tile.moveRotation = 0.5-Math.random(); } } tiles.sort(zindexSort); processFrame(); } function zindexSort(a, b){ return (a.force-b.force); } function dropBomb(evt, obj){ var posx = 0; var posy = 0; var e = evt || window.event; if (e.pageX || e.pageY){ posx = e.pageX; posy = e.pageY; }else if (e.clientX || e.clientY) { posx = e.clientX + document.body.scrollLeft + document.documentElement.scrollLeft; posy = e.clientY + document.body.scrollTop + document.documentElement.scrollTop; } var canvasX = posx-obj.offsetLeft; var canvasY = posy-obj.offsetTop; explode(canvasX, canvasY); } function Tile(){ this.originX = 0; this.originY = 0; this.currentX = 0; this.currentY = 0; this.rotation = 0; this.force = 0; this.z = 0; this.moveX= 0; this.moveY= 0; this.moveRotation = 0; this.videoX = 0; this.videoY = 0; } /* getPixel return pixel object {r,g,b,a} */ function getPixel(imageData, x, y){ var data = imageData.data; var pos = (x + y * imageData.width) * 4; return {r:data[pos], g:data[pos+1], b:data[pos+2], a:data[pos+3]} } /* setPixel set pixel object {r,g,b,a} */ function setPixel(imageData, x, y, pixel){ var data = imageData.data; var pos = (x + y * imageData.width) * 4; data[pos] = pixel.r; data[pos+1] = pixel.g; data[pos+2] = pixel.b; data[pos+3] = pixel.a; } /* copyPixel faster then using getPixel/setPixel combo */ function copyPixel(sImageData, sx, sy, dImageData, dx, dy){ var spos = (sx + sy * sImageData.width) * 4; var dpos = (dx + dy * dImageData.width) * 4; dImageData.data[dpos] = sImageData.data[spos]; //R dImageData.data[dpos+1] = sImageData.data[spos+1]; //G dImageData.data[dpos+2] = sImageData.data[spos+2]; //B dImageData.data[dpos+3] = sImageData.data[spos+3]; //A }