我已将以下内容用于背景模糊过渡效果： http ://tympanus.net/codrops/2011/11/18/fullscreen-image-blur-effect-with-html5/
该示例可以在以下位置找到： http ://tympanus.net/Development/FullscreenImageBlurEffect/index3.html 下面的脚本使用“StackBlur”将模糊效果添加到画布。
$(function() {
var BlurBGImage = (function() {
var $bxWrapper = $('#bx-wrapper'),
// loading status to show while preloading images
$bxLoading = $bxWrapper.find('div.bx-loading'),
// container for the bg images and respective canvas
$bxContainer = $bxWrapper.find('div.bx-container'),
// the bg images we are gonna use
$bxImgs = $bxContainer.children('img'),
// total number of bg images
bxImgsCount = $bxImgs.length,
// current image's index
current = 0,
// variation to show the image:
// (1) - blurs the current one, fades out and shows the next image
// (2) - blurs the current one, fades out, shows the next one (but initially blurred)
// speed is the speed of the animation
// blur Factor is the factor used in the StackBlur script
animOptions = { speed : 700, variation : 2, blurFactor : 10 },
// control if currently animating
isAnim = false,
// check if canvas is supported
supportCanvas = Modernizr.canvas,
// slideshow
slideshow_interval = 6000,
slideshow_time,
// init function
init = function() {
// preload all images and respective canvas
var loaded = 0;
$bxImgs.each( function(i) {
var $bximg = $(this);
// save the position of the image in data-pos
$('<img data-pos="' + $bximg.index() + '"/>').load(function() {
var $img = $(this),
// size of image to be fullscreen and centered
dim = getImageDim( $img.attr('src') ),
pos = $img.data( 'pos' );
// add the canvas to the DOM
$.when( createCanvas( pos, dim ) ).done( function() {
++loaded;
// all images and canvas loaded
if( loaded === bxImgsCount ) {
// apply style for bg image and canvas
centerImageCanvas();
// hide loading status
$bxLoading.hide();
// initialize events
initEvents();
// start slideshow
startSlideshow();
}
});
}).attr( 'src', $bximg.attr('src') );
});
},
startSlideshow = function() {
slideshow_time = setTimeout( function() {
if( !isAnim ) {
var pos = current;
( pos < bxImgsCount - 1 ) ? ++pos : pos = 0;
isAnim = true;
// show the bg image
showImage( pos );
startSlideshow();
}
}, slideshow_interval );
},
// creates the blurred canvas image
createCanvas = function( pos, dim ) {
return $.Deferred( function(dfd) {
// if canvas not supported return
if( !supportCanvas ) {
dfd.resolve();
return false;
}
// create the canvas element:
// size and position will be the same like the fullscreen image
var $img = $bxImgs.eq( pos ),
imgW = dim.width,
imgH = dim.height,
imgL = dim.left,
imgT = dim.top,
canvas = document.createElement('canvas');
canvas.className = 'bx-canvas';
canvas.width = imgW;
canvas.height = imgH;
canvas.style.width = imgW + 'px';
canvas.style.height = imgH + 'px';
canvas.style.left = imgL + 'px';
canvas.style.top = imgT + 'px';
canvas.style.visibility = 'hidden';
// save position of canvas to know which image this is linked to
canvas.setAttribute('data-pos', pos);
// append the canvas to the same container where the images are
$bxContainer.append( canvas );
// blur it using the StackBlur script
stackBlurImage( $img.get(0), dim, canvas, animOptions.blurFactor, false, dfd.resolve );
}).promise();
},
// gets the image size and position in order to make it fullscreen and centered.
getImageDim = function( img ) {
var $img = new Image();
$img.src = img;
var $win = $( window ),
w_w = $win.width(),
w_h = $win.height(),
r_w = w_h / w_w,
i_w = $img.width,
i_h = $img.height,
r_i = i_h / i_w,
new_w, new_h, new_left, new_top;
if( r_w > r_i ) {
new_h = w_h;
new_w = w_h / r_i;
}
else {
new_h = w_w * r_i;
new_w = w_w;
}
return {
width : new_w,
height : new_h,
left : ( w_w - new_w ) / 2,
top : ( w_h - new_h ) / 2
};
},
// initialize the events
initEvents = function() {
$( window ).on('resize.BlurBGImage', function( event ) {
// apply style for bg image and canvas
centerImageCanvas();
return false;
});
},
// apply style for bg image and canvas
centerImageCanvas = function() {
$bxImgs.each( function(i) {
var $bximg = $(this),
dim = getImageDim( $bximg.attr('src') ),
$currCanvas = $bxContainer.children('canvas[data-pos=' + $bximg.index() + ']'),
styleCSS = {
width : dim.width,
height : dim.height,
left : dim.left,
top : dim.top
};
$bximg.css( styleCSS );
if( supportCanvas )
$currCanvas.css( styleCSS );
if( i === current )
$bximg.show();
});
},
// shows the image at position "pos"
showImage = function( pos ) {
// current image
var $bxImage = $bxImgs.eq( current );
// current canvas
$bxCanvas = $bxContainer.children('canvas[data-pos=' + $bxImage.index() + ']'),
// next image to show
$bxNextImage = $bxImgs.eq( pos ),
// next canvas to show
$bxNextCanvas = $bxContainer.children('canvas[data-pos='+$bxNextImage.index()+']');
// if canvas is supported
if( supportCanvas ) {
$bxCanvas.css( 'z-index', 100 ).css('visibility','visible');
$.when( $bxImage.fadeOut( animOptions.speed ) ).done( function() {
switch( animOptions.variation ) {
case 1 :
$.when( $bxNextImage.fadeIn( animOptions.speed ) ).done( function() {
$bxCanvas.css( 'z-index', 1 ).css('visibility','hidden');
current = pos;
$bxNextCanvas.css('visibility','hidden');
isAnim = false;
});
break;
case 2 :
$bxNextCanvas.css('visibility','visible');
$.when( $bxCanvas.fadeOut( animOptions.speed * 1.5 ) ).done( function() {
$(this).css({
'z-index' : 1,
'visibility' : 'hidden'
}).show();
$.when( $bxNextImage.fadeIn( animOptions.speed ) ).done( function() {
current = pos;
$bxNextCanvas.css('visibility','hidden');
isAnim = false;
});
});
break;
};
});
}
// if canvas is not shown just work with the bg images
else {
$.when( $bxNextImage.css( 'z-index', 102 ).fadeIn( animOptions.speed ) ).done( function() {
current = pos;
$bxImage.hide();
$(this).css( 'z-index', 101 );
isAnim = false;
});
}
};
return {
init : init
};
})();
// call the init function
BlurBGImage.init();
});
问题是，当我调整浏览器窗口的大小时，过渡会中断并且不再产生预期的效果。
据我所知，问题似乎与画布的大小有关。谁能给我一个如何解决它的想法？
非常感谢。