使用 CSS transform scale() 放大元素而不裁剪，保持滚动
Using CSS transform scale() to zoom into an element without cropping, maintaining scrolling
实例：https://jsfiddle.net/b8vLg0ny/
可以使用 CSS scale 和 translate 函数来放大元素。
以 2x2 网格中的 4 个框为例。
HTML:
<div id="container">
<div id="zoom-container">
<div class="box red">A</div>
<div class="box blue">B</div>
<div class="box green">C</div>
<div class="box black">D</div>
</div>
</div>
CSS:
* { margin: 0; }
body, html { height: 100%; }
#container {
height: 100%;
width: 50%;
margin: 0 auto;
}
#zoom-container {
height: 100%;
width: 100%;
transition: all 0.2s ease-in-out;
}
.box {
float: left;
width: 50%;
height: 50%;
color: white;
text-align: center;
display: block;
}
.red { background: red; }
.blue { background: blue; }
.green { background: green; }
.black { background: black; }
JavaScript:
window.zoomedIn = false;
$(".box").click(function(event) {
var el = this;
var zoomContainer = $("#zoom-container");
if (window.zoomedIn) {
console.log("resetting zoom");
zoomContainer.css("transform", "");
$("#container").css("overflow", "auto");
window.zoomedIn = false;
} else {
console.log("applying zoom");
var top = el.offsetTop;
var left = el.offsetLeft - 0.25*zoomContainer[0].clientWidth;
var translateY = 0.5*zoomContainer[0].clientHeight - top;
var translateX = 0.5*zoomContainer[0].clientWidth - left;
$("#container").css("overflow", "scroll");
zoomContainer.css("transform", "translate(" + 2 * translateX + "px, " + 2 * translateY + "px) scale(2)");
window.zoomedIn = true;
}
});
通过控制 translateX 和 translateY 的值，您可以更改缩放的工作方式。
初始渲染视图如下所示：
单击 A 框将适当地放大您：
（请注意，最后单击 D 只是通过缩小显示重置。）
问题是：缩放到框 D 会缩放缩放容器，这样滚动到顶部和左侧将不起作用，因为内容会溢出。缩放到框 B（左半部分被裁剪）和 C（上半部分被裁剪）时也会发生同样的情况。只有A才不会溢出容器外
在与缩放相关的类似情况下（参见 CSS3 Transform Scale and Container with Overflow），一种可能的解决方案是指定 transform-origin: top left（或 0 0）。由于缩放相对于左上角的工作方式，滚动功能得以保留。但这似乎在这里不起作用，因为这意味着您不再将内容重新定位以集中在单击的框（A、B、C 或 D）上。
另一种可能的解决方案是在缩放容器中添加一个 margin-left 和一个 margin-top，这样可以添加足够的 space 来弥补溢出的内容。但同样：翻译值不再排列。
所以：有没有办法同时放大给定元素，和滚动溢出，这样内容就不会裁剪了吗？
Update：通过动画化 scrollTop 和 scrollLeft 有一个粗略的几乎解决方案，类似于 (see the jsfiddle example)，但并不完全一个正确的解决方案，因为它首先缩放到左上角，而不是预期的目标。我开始怀疑这实际上是不可能的，因为这可能等同于要求 scrollLeft 为负数。
更新
我一直卡在不显示滚动条上，所以我需要调查那部分，所以代码被注释掉了，我使用延迟将点击的框移到视图中。
这是我用来玩的my fiddle demo，想弄清楚如何解决滚动条问题。
旁注：在@AVAVT 的评论中，我想 link 到 ，因为这可能对其他人有帮助，我觉得这很有趣在某些情况下可以选择。
(function(zoomed) {
$(".box").click(function(event) {
var el = this, elp = el.parentElement;
if (zoomed) {
zoomed = false;
$("#zoom-container").css({'transform': ''});
} else {
zoomed = true;
/* this zooms correct but show 1 or none scroll for B,C,D so need to figure out why
var tro = (Math.abs(elp.offsetTop - el.offsetTop) > 0) ? 'bottom' : 'top';
tro += (Math.abs(elp.offsetLeft - el.offsetLeft) > 0) ? ' right' : ' left';
$("#zoom-container").css({'transform-origin': tro, 'transform': 'scale(2)'});
*/
$("#zoom-container").css({'transform-origin': '0 0', 'transform': 'scale(2)'});
/* delay needed before scroll into view */
setTimeout(function() {
el.scrollIntoView();
},250);
}
});
})();
* { margin: 0; }
body, html { height: 100%; }
#container {
height: 100%;
width: 50%;
overflow: auto;
margin: 0 auto;
}
#zoom-container {
height: 100%;
width: 100%;
transition: all 0.2s ease-in-out;
}
.box {
float: left;
width: 50%;
height: 50%;
color: white;
text-align: center;
display: block;
}
.red {
background: red;
}
.blue {
background: blue;
}
.green {
background: green;
}
.black {
background: black;
}
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<div id="container">
<div id="zoom-container">
<div class="box red">A</div>
<div class="box blue">B</div>
<div class="box green">C</div>
<div class="box black">D</div>
</div>
</div>
我正在回答我自己的问题，因为我相当有信心这实际上不可能满足给定的要求。至少不是没有一些会导致视觉问题的 hackery，例如，在将 transform-origin 切换到 0, 0 之后通过动画 scrollTop 来跳跃滚动（通过将所有内容带回容器来消除裁剪）。
我希望有人能证明我是错的，但这似乎等同于要求 scrollLeft = -10，MDN will tell you is not possible。 ("If set to a value less than 0 [...], scrollLeft is set to 0.")
但是，如果可以接受 将 UI 从滚动更改为缩放和 dragging/panning，那么它是可以实现的：https://jsfiddle.net/jegn4x0f/5/
这是与我原来的问题上下文相同的解决方案：
HTML:
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<button id="zoom-out">Zoom out</button>
<div id="container">
<div id="inner-container">
<div id="zoom-container">
<div class="box red">A</div>
<div class="box blue">B</div>
<div class="box green">C</div>
<div class="box black">D</div>
</div>
</div>
</div>
JavaScript:
//
// credit for the approach goes to
//
//
//
// and the corresponding example:
//
// https://jsfiddle.net/j8kLz6wm/1/
//
// in a real-world setting, you
// wouldn't keep this information
// on window. this is just for
// the demonstration.
window.zoomedIn = false;
// stores the initial translate values after clicking on a box
window.translateY = null;
window.translateX = null;
// stores the incremental translate values based on
// applying the initial translate values + delta
window.lastTranslateY = null;
window.lastTranslateX = null;
// cursor position relative to the container, at
// the time the drag started
window.dragStartX = null;
window.dragStartY = null;
var handleDragStart = function(element, xCursor, yCursor) {
window.dragStartX = xCursor - element.offsetLeft;
window.dragStartY = yCursor - element.offsetTop;
// disable transition animations, since we're starting a drag
$("#zoom-container").css("transition", "none");
};
var handleDragEnd = function() {
window.dragStartX = null;
window.dragStartY = null;
// remove the individual element's styling for transitions
// which brings back the stylesheet's default of animating.
$("#zoom-container").css("transition", "");
// keep track of the translate values we arrived at
window.translateY = window.lastTranslateY;
window.translateX = window.lastTranslateX;
};
var handleDragMove = function(xCursor, yCursor) {
var deltaX = xCursor - window.dragStartX;
var deltaY = yCursor - window.dragStartY;
var translateY = window.translateY + (deltaY / 2);
// the subtracted value here is to keep the letter in the center
var translateX = window.translateX + (deltaX / 2) - (0.25 * $("#inner-container")[0].clientWidth);
// fudge factor, probably because of percentage
// width/height problems. couldn't really trace down
// the underlying cause. hopefully the general approach
// is clear, though.
translateY -= 9;
translateX -= 4;
var innerContainer = $("#inner-container")[0];
// cap all values to prevent infinity scrolling off the page
if (translateY > 0.5 * innerContainer.clientHeight) {
translateY = 0.5 * innerContainer.clientHeight;
}
if (translateX > 0.5 * innerContainer.clientWidth) {
translateX = 0.5 * innerContainer.clientWidth;
}
if (translateY < -0.5 * innerContainer.clientHeight) {
translateY = -0.5 * innerContainer.clientHeight;
}
if (translateX < -0.5 * innerContainer.clientWidth) {
translateX = -0.5 * innerContainer.clientWidth;
}
// update the zoom container's translate values
// based on the original + delta, capped to the
// container's width and height.
$("#zoom-container").css("transform", "translate(" + (2*translateX) + "px, " + (2*translateY) + "px) scale(2)");
// keep track of the updated values for the next
// touchmove event.
window.lastTranslateX = translateX;
window.lastTranslateY = translateY;
};
// Drag start -- touch version
$("#container").on("touchstart", function(event) {
if (!window.zoomedIn) {
return true;
}
var xCursor = event.originalEvent.changedTouches[0].clientX;
var yCursor = event.originalEvent.changedTouches[0].clientY;
handleDragStart(this, xCursor, yCursor);
});
// Drag start -- mouse version
$("#container").on("mousedown", function(event) {
if (!window.zoomedIn) {
return true;
}
var xCursor = event.clientX;
var yCursor = event.clientY;
handleDragStart(this, xCursor, yCursor);
});
// Drag end -- touch version
$("#inner-container").on("touchend", function(event) {
if (!window.zoomedIn) {
return true;
}
handleDragEnd();
});
// Drag end -- mouse version
$("#inner-container").on("mouseup", function(event) {
if (!window.zoomedIn) {
return true;
}
handleDragEnd();
});
// Drag move -- touch version
$("#inner-container").on("touchmove", function(event) {
// prevent pull-to-refresh. could be smarter by checking
// if the page's scroll y-offset is 0, and even smarter
// by checking if we're pulling down, not up.
event.preventDefault();
if (!window.zoomedIn) {
return true;
}
var xCursor = event.originalEvent.changedTouches[0].clientX;
var yCursor = event.originalEvent.changedTouches[0].clientY;
handleDragMove(xCursor, yCursor);
});
// Drag move -- click version
$("#inner-container").on("mousemove", function(event) {
// prevent pull-to-refresh. could be smarter by checking
// if the page's scroll y-offset is 0, and even smarter
// by checking if we're pulling down, not up.
event.preventDefault();
// if we aren't dragging from anywhere, don't move
if (!window.zoomedIn || !window.dragStartX) {
return true;
}
var xCursor = event.clientX;
var yCursor = event.clientY;
handleDragMove(xCursor, yCursor);
});
var zoomInTo = function(element) {
console.log("applying zoom");
var top = element.offsetTop;
// the subtracted value here is to keep the letter in the center
var left = element.offsetLeft - (0.25 * $("#inner-container")[0].clientWidth);
var translateY = 0.5 * $("#zoom-container")[0].clientHeight - top;
var translateX = 0.5 * $("#zoom-container")[0].clientWidth - left;
$("#container").css("overflow", "scroll");
$("#zoom-container").css("transform", "translate(" + (2*translateX) + "px, " + (2*translateY) + "px) scale(2)");
window.translateY = translateY;
window.translateX = translateX;
window.zoomedIn = true;
}
var zoomOut = function() {
console.log("resetting zoom");
window.zoomedIn = false;
$("#zoom-container").css("transform", "");
$("#zoom-container").css("transition", "");
window.dragStartX = null;
window.dragStartY = null;
window.dragMoveJustHappened = null;
window.translateY = window.lastTranslateY;
window.translateX = window.lastTranslateX;
window.lastTranslateX = null;
window.lastTranslateY = null;
}
$(".box").click(function(event) {
var element = this;
var zoomContainer = $("#zoom-container");
if (!window.zoomedIn) {
zoomInTo(element);
}
});
$("#zoom-out").click(function(event) {
zoomOut();
});
CSS:
* {
margin: 0;
}
body,
html {
height: 100%;
}
#container {
height: 100%;
width: 50%;
margin: 0 auto;
}
#inner-container {
width: 100%;
height: 100%;
}
#zoom-container {
height: 100%;
width: 100%;
transition: transform 0.2s ease-in-out;
}
.box {
float: left;
width: 50%;
height: 50%;
color: white;
text-align: center;
display: block;
}
.red {
background: red;
}
.blue {
background: blue;
}
.green {
background: green;
}
.black {
background: black;
}
我从另一个问题 (), where the width and height are being changed. That doesn't quite apply in my case, because I need to zoom into a specific element on the page (with a lot boxes than in a 2x2 grid). The solution from that question (https://jsfiddle.net/j8kLz6wm/1/) shows the basic approach in pure JavaScript. If you have jQuery available, you can probably just use jquery.panzoom.
为什么不直接将 TransformOrigin 重新定位到 0 0 并在 动画之后使用适当的 scrollTop/scrollLeft ？
如果不需要动画，TransformOrigin可以一直保持0 0，只用滚动来显示框
为了使动画不那么跳跃，只对 transform 属性使用过渡，否则 transform-origin 也会得到动画。我已经用 4x4 元素编辑了示例，但我认为将框完全缩放到视图中是有意义的，这就是我更改缩放级别的原因。但是，如果您保持缩放级别 2 和网格大小 15x15，那么使用这种方法应该为变换计算真正精确的原点，然后还要计算正确的滚动。
无论如何，我不知道，如果你觉得这种方法有用。
堆栈片段
var zoomedIn = false;
var zoomContainer = $("#zoom-container");
$(".box").click(function(event) {
var el = this;
if (zoomedIn) {
zoomContainer.css({
transform: "scale(1)",
transformOrigin: "0 0"
});
zoomContainer.parent().scrollTop(0).scrollLeft(0);
zoomedIn = false;
return;
}
zoomedIn = true;
var $el = $(el);
animate($el);
zoomContainer.on('transitionend', function(){
zoomContainer.off('transitionend');
reposition($el);
})
});
var COLS = 4, ROWS = 4,
COLS_STEP = 100 / (COLS - 1), ROWS_STEP = 100 / (ROWS - 1),
ZOOM = 4;
function animate($box) {
var cell = getCell($box);
var col = cell.col * COLS_STEP + '%',
row = cell.row * ROWS_STEP + '%';
zoomContainer.parent().css('overflow', 'hidden');
zoomContainer.css({
transition: 'transform 0.2s ease-in-out',
transform: "scale(" + ZOOM + ")",
transformOrigin: col + " " + row
});
}
function reposition($box) {
zoomContainer.css({
transition: 'none',
transform: "scale(" + ZOOM + ")",
transformOrigin: '0 0'
});
zoomContainer.parent().css('overflow', 'auto');
$box.get(0).scrollIntoView();
}
function getCell ($box) {
var idx = $box.index();
var col = idx % COLS,
row = (idx / ROWS) | 0;
return { col: col, row: row };
}
* { margin: 0; }
body, html { height: 100%; }
#container {
height: 100%;
width: 50%;
margin: 0 auto;
overflow: hidden;
}
#zoom-container {
height: 100%;
width: 100%;
will-change: transform;
}
.box {
float: left;
width: 25%;
height: 25%;
color: white;
text-align: center;
}
.red { background: red; }
.blue { background: blue; }
.green { background: green; }
.black { background: black; }
.l { opacity: .3 }
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<div id="container">
<div id="zoom-container">
<div class="box red">A</div>
<div class="box blue">B</div>
<div class="box green">C</div>
<div class="box black">D</div>
<div class="box red l">E</div>
<div class="box blue l">F</div>
<div class="box green l">G</div>
<div class="box black l">H</div>
<div class="box red">I</div>
<div class="box blue">J</div>
<div class="box green">K</div>
<div class="box black">L</div>
<div class="box red l">M</div>
<div class="box blue l">N</div>
<div class="box green l">O</div>
<div class="box black l">P</div>
</div>
</div>
实例：https://jsfiddle.net/b8vLg0ny/
可以使用 CSS scale 和 translate 函数来放大元素。
以 2x2 网格中的 4 个框为例。
HTML:
<div id="container">
<div id="zoom-container">
<div class="box red">A</div>
<div class="box blue">B</div>
<div class="box green">C</div>
<div class="box black">D</div>
</div>
</div>
CSS:
* { margin: 0; }
body, html { height: 100%; }
#container {
height: 100%;
width: 50%;
margin: 0 auto;
}
#zoom-container {
height: 100%;
width: 100%;
transition: all 0.2s ease-in-out;
}
.box {
float: left;
width: 50%;
height: 50%;
color: white;
text-align: center;
display: block;
}
.red { background: red; }
.blue { background: blue; }
.green { background: green; }
.black { background: black; }
JavaScript:
window.zoomedIn = false;
$(".box").click(function(event) {
var el = this;
var zoomContainer = $("#zoom-container");
if (window.zoomedIn) {
console.log("resetting zoom");
zoomContainer.css("transform", "");
$("#container").css("overflow", "auto");
window.zoomedIn = false;
} else {
console.log("applying zoom");
var top = el.offsetTop;
var left = el.offsetLeft - 0.25*zoomContainer[0].clientWidth;
var translateY = 0.5*zoomContainer[0].clientHeight - top;
var translateX = 0.5*zoomContainer[0].clientWidth - left;
$("#container").css("overflow", "scroll");
zoomContainer.css("transform", "translate(" + 2 * translateX + "px, " + 2 * translateY + "px) scale(2)");
window.zoomedIn = true;
}
});
通过控制 translateX 和 translateY 的值，您可以更改缩放的工作方式。
初始渲染视图如下所示：
单击 A 框将适当地放大您：
（请注意，最后单击 D 只是通过缩小显示重置。）
问题是：缩放到框 D 会缩放缩放容器，这样滚动到顶部和左侧将不起作用，因为内容会溢出。缩放到框 B（左半部分被裁剪）和 C（上半部分被裁剪）时也会发生同样的情况。只有A才不会溢出容器外
在与缩放相关的类似情况下（参见 CSS3 Transform Scale and Container with Overflow），一种可能的解决方案是指定 transform-origin: top left（或 0 0）。由于缩放相对于左上角的工作方式，滚动功能得以保留。但这似乎在这里不起作用，因为这意味着您不再将内容重新定位以集中在单击的框（A、B、C 或 D）上。
另一种可能的解决方案是在缩放容器中添加一个 margin-left 和一个 margin-top，这样可以添加足够的 space 来弥补溢出的内容。但同样：翻译值不再排列。
所以：有没有办法同时放大给定元素，和滚动溢出，这样内容就不会裁剪了吗？
Update：通过动画化 scrollTop 和 scrollLeft 有一个粗略的几乎解决方案，类似于 (see the jsfiddle example)，但并不完全一个正确的解决方案，因为它首先缩放到左上角，而不是预期的目标。我开始怀疑这实际上是不可能的，因为这可能等同于要求 scrollLeft 为负数。
更新
我一直卡在不显示滚动条上，所以我需要调查那部分，所以代码被注释掉了，我使用延迟将点击的框移到视图中。
这是我用来玩的my fiddle demo，想弄清楚如何解决滚动条问题。
旁注：在@AVAVT 的评论中，我想 link 到
(function(zoomed) {
$(".box").click(function(event) {
var el = this, elp = el.parentElement;
if (zoomed) {
zoomed = false;
$("#zoom-container").css({'transform': ''});
} else {
zoomed = true;
/* this zooms correct but show 1 or none scroll for B,C,D so need to figure out why
var tro = (Math.abs(elp.offsetTop - el.offsetTop) > 0) ? 'bottom' : 'top';
tro += (Math.abs(elp.offsetLeft - el.offsetLeft) > 0) ? ' right' : ' left';
$("#zoom-container").css({'transform-origin': tro, 'transform': 'scale(2)'});
*/
$("#zoom-container").css({'transform-origin': '0 0', 'transform': 'scale(2)'});
/* delay needed before scroll into view */
setTimeout(function() {
el.scrollIntoView();
},250);
}
});
})();
* { margin: 0; }
body, html { height: 100%; }
#container {
height: 100%;
width: 50%;
overflow: auto;
margin: 0 auto;
}
#zoom-container {
height: 100%;
width: 100%;
transition: all 0.2s ease-in-out;
}
.box {
float: left;
width: 50%;
height: 50%;
color: white;
text-align: center;
display: block;
}
.red {
background: red;
}
.blue {
background: blue;
}
.green {
background: green;
}
.black {
background: black;
}
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<div id="container">
<div id="zoom-container">
<div class="box red">A</div>
<div class="box blue">B</div>
<div class="box green">C</div>
<div class="box black">D</div>
</div>
</div>
我正在回答我自己的问题，因为我相当有信心这实际上不可能满足给定的要求。至少不是没有一些会导致视觉问题的 hackery，例如，在将 transform-origin 切换到 0, 0 之后通过动画 scrollTop 来跳跃滚动（通过将所有内容带回容器来消除裁剪）。
我希望有人能证明我是错的，但这似乎等同于要求 scrollLeft = -10，MDN will tell you is not possible。 ("If set to a value less than 0 [...], scrollLeft is set to 0.")
但是，如果可以接受 将 UI 从滚动更改为缩放和 dragging/panning，那么它是可以实现的：https://jsfiddle.net/jegn4x0f/5/
这是与我原来的问题上下文相同的解决方案：
HTML:
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<button id="zoom-out">Zoom out</button>
<div id="container">
<div id="inner-container">
<div id="zoom-container">
<div class="box red">A</div>
<div class="box blue">B</div>
<div class="box green">C</div>
<div class="box black">D</div>
</div>
</div>
</div>
JavaScript:
//
// credit for the approach goes to
//
//
//
// and the corresponding example:
//
// https://jsfiddle.net/j8kLz6wm/1/
//
// in a real-world setting, you
// wouldn't keep this information
// on window. this is just for
// the demonstration.
window.zoomedIn = false;
// stores the initial translate values after clicking on a box
window.translateY = null;
window.translateX = null;
// stores the incremental translate values based on
// applying the initial translate values + delta
window.lastTranslateY = null;
window.lastTranslateX = null;
// cursor position relative to the container, at
// the time the drag started
window.dragStartX = null;
window.dragStartY = null;
var handleDragStart = function(element, xCursor, yCursor) {
window.dragStartX = xCursor - element.offsetLeft;
window.dragStartY = yCursor - element.offsetTop;
// disable transition animations, since we're starting a drag
$("#zoom-container").css("transition", "none");
};
var handleDragEnd = function() {
window.dragStartX = null;
window.dragStartY = null;
// remove the individual element's styling for transitions
// which brings back the stylesheet's default of animating.
$("#zoom-container").css("transition", "");
// keep track of the translate values we arrived at
window.translateY = window.lastTranslateY;
window.translateX = window.lastTranslateX;
};
var handleDragMove = function(xCursor, yCursor) {
var deltaX = xCursor - window.dragStartX;
var deltaY = yCursor - window.dragStartY;
var translateY = window.translateY + (deltaY / 2);
// the subtracted value here is to keep the letter in the center
var translateX = window.translateX + (deltaX / 2) - (0.25 * $("#inner-container")[0].clientWidth);
// fudge factor, probably because of percentage
// width/height problems. couldn't really trace down
// the underlying cause. hopefully the general approach
// is clear, though.
translateY -= 9;
translateX -= 4;
var innerContainer = $("#inner-container")[0];
// cap all values to prevent infinity scrolling off the page
if (translateY > 0.5 * innerContainer.clientHeight) {
translateY = 0.5 * innerContainer.clientHeight;
}
if (translateX > 0.5 * innerContainer.clientWidth) {
translateX = 0.5 * innerContainer.clientWidth;
}
if (translateY < -0.5 * innerContainer.clientHeight) {
translateY = -0.5 * innerContainer.clientHeight;
}
if (translateX < -0.5 * innerContainer.clientWidth) {
translateX = -0.5 * innerContainer.clientWidth;
}
// update the zoom container's translate values
// based on the original + delta, capped to the
// container's width and height.
$("#zoom-container").css("transform", "translate(" + (2*translateX) + "px, " + (2*translateY) + "px) scale(2)");
// keep track of the updated values for the next
// touchmove event.
window.lastTranslateX = translateX;
window.lastTranslateY = translateY;
};
// Drag start -- touch version
$("#container").on("touchstart", function(event) {
if (!window.zoomedIn) {
return true;
}
var xCursor = event.originalEvent.changedTouches[0].clientX;
var yCursor = event.originalEvent.changedTouches[0].clientY;
handleDragStart(this, xCursor, yCursor);
});
// Drag start -- mouse version
$("#container").on("mousedown", function(event) {
if (!window.zoomedIn) {
return true;
}
var xCursor = event.clientX;
var yCursor = event.clientY;
handleDragStart(this, xCursor, yCursor);
});
// Drag end -- touch version
$("#inner-container").on("touchend", function(event) {
if (!window.zoomedIn) {
return true;
}
handleDragEnd();
});
// Drag end -- mouse version
$("#inner-container").on("mouseup", function(event) {
if (!window.zoomedIn) {
return true;
}
handleDragEnd();
});
// Drag move -- touch version
$("#inner-container").on("touchmove", function(event) {
// prevent pull-to-refresh. could be smarter by checking
// if the page's scroll y-offset is 0, and even smarter
// by checking if we're pulling down, not up.
event.preventDefault();
if (!window.zoomedIn) {
return true;
}
var xCursor = event.originalEvent.changedTouches[0].clientX;
var yCursor = event.originalEvent.changedTouches[0].clientY;
handleDragMove(xCursor, yCursor);
});
// Drag move -- click version
$("#inner-container").on("mousemove", function(event) {
// prevent pull-to-refresh. could be smarter by checking
// if the page's scroll y-offset is 0, and even smarter
// by checking if we're pulling down, not up.
event.preventDefault();
// if we aren't dragging from anywhere, don't move
if (!window.zoomedIn || !window.dragStartX) {
return true;
}
var xCursor = event.clientX;
var yCursor = event.clientY;
handleDragMove(xCursor, yCursor);
});
var zoomInTo = function(element) {
console.log("applying zoom");
var top = element.offsetTop;
// the subtracted value here is to keep the letter in the center
var left = element.offsetLeft - (0.25 * $("#inner-container")[0].clientWidth);
var translateY = 0.5 * $("#zoom-container")[0].clientHeight - top;
var translateX = 0.5 * $("#zoom-container")[0].clientWidth - left;
$("#container").css("overflow", "scroll");
$("#zoom-container").css("transform", "translate(" + (2*translateX) + "px, " + (2*translateY) + "px) scale(2)");
window.translateY = translateY;
window.translateX = translateX;
window.zoomedIn = true;
}
var zoomOut = function() {
console.log("resetting zoom");
window.zoomedIn = false;
$("#zoom-container").css("transform", "");
$("#zoom-container").css("transition", "");
window.dragStartX = null;
window.dragStartY = null;
window.dragMoveJustHappened = null;
window.translateY = window.lastTranslateY;
window.translateX = window.lastTranslateX;
window.lastTranslateX = null;
window.lastTranslateY = null;
}
$(".box").click(function(event) {
var element = this;
var zoomContainer = $("#zoom-container");
if (!window.zoomedIn) {
zoomInTo(element);
}
});
$("#zoom-out").click(function(event) {
zoomOut();
});
CSS:
* {
margin: 0;
}
body,
html {
height: 100%;
}
#container {
height: 100%;
width: 50%;
margin: 0 auto;
}
#inner-container {
width: 100%;
height: 100%;
}
#zoom-container {
height: 100%;
width: 100%;
transition: transform 0.2s ease-in-out;
}
.box {
float: left;
width: 50%;
height: 50%;
color: white;
text-align: center;
display: block;
}
.red {
background: red;
}
.blue {
background: blue;
}
.green {
background: green;
}
.black {
background: black;
}
我从另一个问题 (width and height are being changed. That doesn't quite apply in my case, because I need to zoom into a specific element on the page (with a lot boxes than in a 2x2 grid). The solution from that question (https://jsfiddle.net/j8kLz6wm/1/) shows the basic approach in pure JavaScript. If you have jQuery available, you can probably just use jquery.panzoom.
为什么不直接将 TransformOrigin 重新定位到 0 0 并在 动画之后使用适当的 scrollTop/scrollLeft ？
如果不需要动画，TransformOrigin可以一直保持0 0，只用滚动来显示框
为了使动画不那么跳跃，只对 transform 属性使用过渡，否则 transform-origin 也会得到动画。我已经用 4x4 元素编辑了示例，但我认为将框完全缩放到视图中是有意义的，这就是我更改缩放级别的原因。但是，如果您保持缩放级别 2 和网格大小 15x15，那么使用这种方法应该为变换计算真正精确的原点，然后还要计算正确的滚动。
无论如何，我不知道，如果你觉得这种方法有用。
堆栈片段
var zoomedIn = false;
var zoomContainer = $("#zoom-container");
$(".box").click(function(event) {
var el = this;
if (zoomedIn) {
zoomContainer.css({
transform: "scale(1)",
transformOrigin: "0 0"
});
zoomContainer.parent().scrollTop(0).scrollLeft(0);
zoomedIn = false;
return;
}
zoomedIn = true;
var $el = $(el);
animate($el);
zoomContainer.on('transitionend', function(){
zoomContainer.off('transitionend');
reposition($el);
})
});
var COLS = 4, ROWS = 4,
COLS_STEP = 100 / (COLS - 1), ROWS_STEP = 100 / (ROWS - 1),
ZOOM = 4;
function animate($box) {
var cell = getCell($box);
var col = cell.col * COLS_STEP + '%',
row = cell.row * ROWS_STEP + '%';
zoomContainer.parent().css('overflow', 'hidden');
zoomContainer.css({
transition: 'transform 0.2s ease-in-out',
transform: "scale(" + ZOOM + ")",
transformOrigin: col + " " + row
});
}
function reposition($box) {
zoomContainer.css({
transition: 'none',
transform: "scale(" + ZOOM + ")",
transformOrigin: '0 0'
});
zoomContainer.parent().css('overflow', 'auto');
$box.get(0).scrollIntoView();
}
function getCell ($box) {
var idx = $box.index();
var col = idx % COLS,
row = (idx / ROWS) | 0;
return { col: col, row: row };
}
* { margin: 0; }
body, html { height: 100%; }
#container {
height: 100%;
width: 50%;
margin: 0 auto;
overflow: hidden;
}
#zoom-container {
height: 100%;
width: 100%;
will-change: transform;
}
.box {
float: left;
width: 25%;
height: 25%;
color: white;
text-align: center;
}
.red { background: red; }
.blue { background: blue; }
.green { background: green; }
.black { background: black; }
.l { opacity: .3 }
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.2.2/jquery.min.js"></script>
<div id="container">
<div id="zoom-container">
<div class="box red">A</div>
<div class="box blue">B</div>
<div class="box green">C</div>
<div class="box black">D</div>
<div class="box red l">E</div>
<div class="box blue l">F</div>
<div class="box green l">G</div>
<div class="box black l">H</div>
<div class="box red">I</div>
<div class="box blue">J</div>
<div class="box green">K</div>
<div class="box black">L</div>
<div class="box red l">M</div>
<div class="box blue l">N</div>
<div class="box green l">O</div>
<div class="box black l">P</div>
</div>
</div>