javascript - 带有 json 数据的香蕉精灵 js 动画(正向/反向和淡入淡出)
问题描述
我正在开发一个自定义滚动动画框架。我可以通过一团 json 数据来控制序列。
这里的代码使用了一些订阅者——尽管正向/反向动画已经到位——淡入/淡出效果不佳——淡入出现故障。
使用 json - 我想提供块的骨架(类名、高度、宽度、背景),然后是与滚动值相关的每个开始/结束帧的动作。
我如何修改代码——修复褪色。
所以在这个例子中。
-- 如果滚动在 100-400 范围之间 - 滚动被指示向右移动。
-- 如果卷轴超过 400 - 摧毁方块。
所以动画要向前移动,但我想在相反的方向反转动画 - 所以时间线可以向前,向后移动 - 取决于滚动的速度 - 所以可以产生慢动作或加速效果抓住
--- 这是第一代代码 https://jsfiddle.net/d4053upt/1/
let data = [{
"structure": {
"name": "square",
"height": 30,
"width": 30,
"x": 0,
"y": 0,
"background": 'url("https://i.pinimg.com/originals/74/f3/5d/74f35d5885e8eb858e6af6b5a7844379.jpg")'
},
"frames": [{
"animation": "move",
"start": 0,
"stop": 300,
"startPositionX": 0,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 0,
}, {
"animation": "move",
"start": 301,
"stop": 600,
"startPositionX": 90,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 80,
}, {
"animation": "move",
"start": 601,
"stop": 900,
"startPositionX": 90,
"startPositionY": 80,
"endPositionX": 0,
"endPositionY": 0,
}, {
"animation": "show",
"start": 601,
"stop": 9999,
"positionX": 0,
"positionY": 0,
}],
},
{
"structure": {
"name": "pear",
"height": 30,
"width": 30,
"x": 90,
"y": 80,
"background": 'url("https://i.pinimg.com/originals/74/f3/5d/74f35d5885e8eb858e6af6b5a7844379.jpg")'
},
"frames": [{
"animation": "move",
"start": 0,
"stop": 300,
"startPositionX": 90,
"startPositionY": 80,
"endPositionX": 0,
"endPositionY": 80,
}, {
"animation": "move",
"start": 301,
"stop": 600,
"startPositionX": 0,
"startPositionY": 80,
"endPositionX": 0,
"endPositionY": 0,
}, {
"animation": "move",
"start": 601,
"stop": 900,
"startPositionX": 0,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 80,
}, {
"animation": "show",
"start": 601,
"stop": 9999,
"positionX": 90,
"positionY": 80,
}],
}
]
let animations = {
setup: function($container) {
this.$container = $container;
this.viewportWidth = $container.width();
this.viewportHeight = $container.height();
},
createBlock: function(blockSpec) {
let $block = $('<div>');
$block.addClass(blockSpec.name);
$block.addClass("animatedblock");
$block.css("height", blockSpec.height);
$block.css("width", blockSpec.width);
$block.css("background", blockSpec.background);
$block.css("background-size", "cover");
this.$container.append($block);
this.setPosition($block, blockSpec.x, blockSpec.y)
return $block;
},
setPosition($block, x, y) {
$block.css({
left: x / 100 * this.viewportWidth,
top: y / 100 * this.viewportHeight,
});
},
moveBlock($block, frame, scrollProgress) {
let blockPositionX = frame.startPositionX + scrollProgress * (frame.endPositionX - frame.startPositionX);
let blockPositionY = frame.startPositionY + scrollProgress * (frame.endPositionY - frame.startPositionY);
this.setPosition($block, blockPositionX, blockPositionY);
},
showBlock: function($block, frame) {
$block.show()
this.setPosition($block, frame.positionX, frame.positionY);
},
hideBlock: function($block) {
$block.hide()
},
}
class ScrollObserver {
constructor() {
let $window = $(window);
this.STOP_DISPATCH = 'STOP_DISPATCH';
this.subscribers = [];
$window.scroll(event => this.dispatch($window.scrollTop()));
}
subscribe(subscriberFn) {
this.subscribers.push(subscriberFn);
}
dispatch(scrollPosition) {
for (let subscriberFn of this.subscribers) {
if (subscriberFn(scrollPosition) == this.STOP_DISPATCH) break;
}
}
}
jQuery(function($) {
animations.setup($('.container'));
$(window).resize(event => animations.setup($('.container')));
for (let obj of data) {
let scrollObserver = new ScrollObserver();
let blockSpec = obj.structure;
let $block = animations.createBlock(blockSpec);
for (let frame of obj.frames) {
scrollObserver.subscribe(scrollPosition => {
if (scrollPosition >= frame.start && scrollPosition <= frame.stop) {
let scrollProgress = (scrollPosition - frame.start) / (frame.stop - frame.start);
switch (frame.animation) {
case 'move':
animations.moveBlock($block, frame, scrollProgress);
break;
case 'show':
animations.showBlock($block, frame);
}
return scrollObserver.STOP_DISPATCH;
}
});
}
}
});
body {
height: 1500px;
}
.container {
background: grey;
position: fixed;
top: 0;
left: 0;
height: 100vh;
width: 100vw;
box-sizing: content-box;
}
.animatedblock {
position: absolute;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="container"></div>
-- 这是当前淡入淡出故障的第二代代码 https://jsfiddle.net/26jkLnup/1/
let data = [{
"structure": {
"name": "square",
"height": 30,
"width": 30,
"x": 0,
"y": 0,
"background": 'url("https://i.pinimg.com/originals/74/f3/5d/74f35d5885e8eb858e6af6b5a7844379.jpg")'
},
"frames": [{
"animation": "fadein",
"start": 0,
"stop": 300,
"startPositionX": 0,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 0,
}, {
"animation": "move",
"start": 301,
"stop": 600,
"startPositionX": 90,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 80,
}, {
"animation": "fadeout",
"start": 601,
"stop": 900,
"positionX": 0,
"positionY": 0,
}],
}/*,
{
"structure": {
"name": "pear",
"height": 30,
"width": 30,
"x": 90,
"y": 80,
"background": 'url("https://image.flaticon.com/icons/svg/272/272135.svg")'
},
"frames": [{
"animation": "move",
"start": 0,
"stop": 300,
"startPositionX": 90,
"startPositionY": 80,
"endPositionX": 0,
"endPositionY": 80,
}, {
"animation": "move",
"start": 301,
"stop": 600,
"startPositionX": 0,
"startPositionY": 80,
"endPositionX": 0,
"endPositionY": 0,
}, {
"animation": "move",
"start": 601,
"stop": 900,
"startPositionX": 0,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 80,
}, {
"animation": "show",
"start": 601,
"stop": 9999,
"positionX": 90,
"positionY": 80,
}],
}*/
]
let animations = {
setup: function($container) {
this.$container = $container;
this.viewportWidth = $container.width();
this.viewportHeight = $container.height();
},
createBlock: function(blockSpec) {
let $block = $('<div>');
$block.addClass(blockSpec.name);
$block.addClass("animatedblock");
$block.css("height", blockSpec.height);
$block.css("width", blockSpec.width);
$block.css("background", blockSpec.background);
$block.css("background-size", "cover");
this.$container.append($block);
this.setPosition($block, blockSpec.x, blockSpec.y)
return $block;
},
setPosition($block, x, y) {
$block.css({
left: x / 100 * this.viewportWidth,
top: y / 100 * this.viewportHeight,
});
},
moveBlock($block, frame, scrollProgress) {
let blockPositionX = frame.startPositionX + scrollProgress * (frame.endPositionX - frame.startPositionX);
let blockPositionY = frame.startPositionY + scrollProgress * (frame.endPositionY - frame.startPositionY);
this.setPosition($block, blockPositionX, blockPositionY);
},
showBlock: function($block, frame) {
$block.show()
this.setPosition($block, frame.positionX, frame.positionY);
},
hideBlock: function($block) {
$block.hide()
},
fadeinBlock: function($block, frame, scrollProgress) {
//console.log("scrollProgress", scrollProgress)
$block.css({
opacity: 1 * scrollProgress
})
/*
$block.css({
opacity: frame.startPositionY / 100 * this.viewportHeight
})*/
},
fadeoutBlock: function($block, frame, scrollProgress) {
//console.log("scrollProgress22222",scrollProgress)
/*
$block.css({
opacity: frame.startPositionY / 100 * this.viewportHeight
})*/
$block.css({
opacity: 1 * (1-scrollProgress)
})
},
}
class ScrollObserver {
constructor() {
let $window = $(window);
this.STOP_DISPATCH = 'STOP_DISPATCH';
this.subscribers = [];
$window.scroll(event => this.dispatch($window.scrollTop()));
}
subscribe(subscriberFn) {
this.subscribers.push(subscriberFn);
}
dispatch(scrollPosition) {
for (let subscriberFn of this.subscribers) {
if (subscriberFn(scrollPosition) == this.STOP_DISPATCH) break;
}
}
}
jQuery(function($) {
animations.setup($('.animationcontainer'));
$(window).resize(event => animations.setup($('.animationcontainer')));
for (let obj of data) {
let scrollObserver = new ScrollObserver();
let blockSpec = obj.structure;
let $block = animations.createBlock(blockSpec);
for (let frame of obj.frames) {
scrollObserver.subscribe(scrollPosition => {
if (scrollPosition >= frame.start && scrollPosition <= frame.stop) {
let scrollProgress = (scrollPosition - frame.start) / (frame.stop - frame.start);
switch (frame.animation) {
case 'move':
animations.moveBlock($block, frame, scrollProgress);
break;
case 'show':
animations.showBlock($block, frame);
break;
case 'fadein':
animations.fadeinBlock($block, frame, scrollProgress);
break;
case 'fadeout':
animations.fadeoutBlock($block, frame, scrollProgress);
break;
}
return scrollObserver.STOP_DISPATCH;
}
});
}
}
});
body {
height: 1500px;
}
.animationcontainer {
background: grey;
border: 1px solid pink;
position: fixed;
top: 0;
left: 0;
height: 100vh;
width: 100vw;
box-sizing: content-box;
}
.animatedblock {
position: absolute;
}
@media only screen and (min-width: 600px) {
body {
background-color: lightblue;
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<body>
<div class="animationcontainer"></div>
<div class="animationcontainer"></div>
</body>
解决方案
恕我直言,存在一些概念性问题:您拥有移动对象fadein
的fadeout
动画。并不是说这是不可能的,而且我根据我对您想要实现的目标的理解做出了“修复”动画的更改,但这使得move
动画操作有点多余。就 API 而言,将动画中的所有内容编码到单个转换描述符中似乎更有意义,例如第一个是:
"frames": [{
"start": 0,
"stop": 300,
"startPositionX": 0,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 0,
"startOpacity": 0,
"endOpacity": 1
}]
我没有改变它,但为了在淡入时移动,我必须在两者之后应用 movefadein
和fadeout
。这使他们有效地fadeinandmove
和fadeoutandmove
。
我所做的另一个更改是设置的初始不透明度,否则,当不透明度达到 100% 时,您开始淡入。
这是您的代码段的一个分支:https ://jsfiddle.net/5hxg02d3/
祝你的框架好运!
编辑:正如您正确注意到的那样,快速来回移动会破坏序列。如果我慢慢拖动,而不是来回滚动,淡入淡出确实会达到零,所以我相信你指的是同样的效果。发生这种情况是由于我之前提出的 API 一致性问题。快速滚动移动允许动画从第 1 帧跳转到第 3 帧或 vv 从第 3 帧跳转到第 1 帧,甚至超出动画范围(低于 0 或高于 900),结果位置与您的预期不一致,因为没有调用更新。我根据我在这个小提琴中的最初建议更新了片段:https ://jsfiddle.net/twkq9jyf/1/并将用它更新下面的片段。我的初始片段在上面的小提琴中供您参考。
let data = [{
"structure": {
"name": "square",
"height": 30,
"width": 30,
"x":0,
"y":0,
"opacity": 0,
"background": 'url("https://i.pinimg.com/originals/74/f3/5d/74f35d5885e8eb858e6af6b5a7844379.jpg")'
},
"frames": [{
"start": 0,
"stop": 300,
"startPositionX": 0,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 0,
"startOpacity": 0,
"endOpacity": 1
}, {
"start": 301,
"stop": 600,
"startPositionX": 90,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 80,
"startOpacity": 1,
"endOpacity": 1
}, {
"start": 601,
"stop": 900,
"startPositionX": 90,
"startPositionY": 80,
"endPositionX": 90,
"endPositionY": 80,
"startOpacity": 1,
"endOpacity": 0
}],
}
]
let animations = {
setup: function($container) {
this.$container = $container;
this.viewportWidth = $container.width();
this.viewportHeight = $container.height();
},
createBlock: function(blockSpec) {
let $block = $('<div>');
$block.addClass(blockSpec.name);
$block.addClass("animatedblock");
$block.css("height", blockSpec.height);
$block.css("width", blockSpec.width);
$block.css("background", blockSpec.background);
$block.css("background-size", "cover");
$block.css("opacity", blockSpec.opacity);
this.$container.append($block);
return $block;
},
setPosition($block, x, y) {
$block.css({
left: x / 100 * this.viewportWidth,
top: y / 100 * this.viewportHeight,
});
},
updatePosition: function($block, frame, scrollProgress) {
let blockPositionX = frame.startPositionX + scrollProgress * (frame.endPositionX - frame.startPositionX);
let blockPositionY = frame.startPositionY + scrollProgress * (frame.endPositionY - frame.startPositionY);
this.setPosition($block, blockPositionX, blockPositionY);
},
updateOpacity: function($block, frame, scrollProgress) {
$block.css({
opacity: frame.startOpacity + scrollProgress * (frame.endOpacity - frame.startOpacity)
})
},
}
class ScrollObserver {
constructor() {
let $window = $(window);
this.STOP_DISPATCH = 'STOP_DISPATCH';
this.subscribers = [];
$window.scroll(event => this.dispatch($window.scrollTop()));
}
subscribe(subscriberFn) {
this.subscribers.push(subscriberFn);
}
dispatch(scrollPosition) {
for (let subscriberFn of this.subscribers) {
if (subscriberFn(scrollPosition) == this.STOP_DISPATCH) break;
}
}
}
jQuery(function($) {
animations.setup($('.animationcontainer'));
$(window).resize(event => animations.setup($('.animationcontainer')));
for (let obj of data) {
let scrollObserver = new ScrollObserver();
let blockSpec = obj.structure;
let $block = animations.createBlock(blockSpec);
for (let frame of obj.frames) {
scrollObserver.subscribe(scrollPosition => {
if ( (scrollPosition >= frame.start || frame.start == 0) &&
(scrollPosition <= frame.stop || frame.stop == 900) ) {
let scrollProgress = (scrollPosition - frame.start) / (frame.stop - frame.start);
animations.updatePosition($block, frame, scrollProgress);
animations.updateOpacity($block, frame, scrollProgress);
return scrollObserver.STOP_DISPATCH;
}
});
}
}
});
body {
height: 1500px;
}
.animationcontainer {
background: grey;
border: 1px solid pink;
position: fixed;
top: 0;
left: 0;
height: 100vh;
width: 100vw;
box-sizing: content-box;
}
.animatedblock {
position: absolute;
}
@media only screen and (min-width: 600px) {
body {
background-color: lightblue;
}
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<body>
<div class="animationcontainer"></div>
<div class="animationcontainer"></div>
</body>
MORE:在当前滚动位置的滚动动作上触发订阅者,找到与该位置匹配的第一帧,计算scrollProgress(找到的帧内的0..1参数)并触发位置和不透明度的更新。除了我修复的问题之外,这种方法不能保证数据的正确性(可能有多个帧覆盖相同的滚动位置,并且后续帧的帧结尾可能与下一个帧的开头不相等)。为了解决这个问题,您可以考虑使用 startPosition 和 stopPosition 来存储关键帧,而不是存储具有如下描述的关键帧:
"frames": [{
"key": 0,
"x": 0,
"y": 90,
"opacity": 0
},
{
"key": 300,
"x": 90,
"y": 0,
"opacity": 1
}, ...]
而不是框架
"frames": [{
"start": 0,
"stop": 300,
"startPositionX": 0,
"startPositionY": 0,
"endPositionX": 90,
"endPositionY": 0,
"startOpacity": 0,
"endOpacity": 1
}, ... ]
确保后续帧具有匹配的开始和结束状态(关键帧)。的数量keyframes
将等于您的数量frames+1
。我建议尝试自己实现这一点,因为这是一个简单的练习,有助于提高你的理解。
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