jQuery - 拖动 div css 背景

Question

我希望能够在 div 内按住鼠标并移动它的背景。在google上搜索了很多，没有找到我想要的。

这是目标（显示的地图是要拖动的对象）：http://pontografico.net/pvt/gamemap/

有什么建议吗？

干杯！

Answer 1

好的，让它工作；我想我已经解决了所有问题：

带有边界限制的最终 jQuery

$(document).ready(function(){
    var $bg = $('.bg-img'),
        elbounds = {
            w: parseInt($bg.width()),
            h: parseInt($bg.height())
        },
        bounds = {w: 2350 - elbounds.w, h: 1750 - elbounds.h},
        origin = {x: 0, y: 0},
        start = {x: 0, y: 0},
        movecontinue = false;

    function move (e){
        var inbounds = {x: false, y: false},
            offset = {
                x: start.x - (origin.x - e.clientX),
                y: start.y - (origin.y - e.clientY)
            };

        inbounds.x = offset.x < 0 && (offset.x * -1) < bounds.w;
        inbounds.y = offset.y < 0 && (offset.y * -1) < bounds.h;

        if (movecontinue && inbounds.x && inbounds.y) {
            start.x = offset.x;
            start.y = offset.y;

            $(this).css('background-position', start.x + 'px ' + start.y + 'px');
        }

        origin.x = e.clientX;
        origin.y = e.clientY;

        e.stopPropagation();
        return false;
    }

    function handle (e){
        movecontinue = false;
        $bg.unbind('mousemove', move);

        if (e.type == 'mousedown') {
            origin.x = e.clientX;
            origin.y = e.clientY;
            movecontinue = true;
            $bg.bind('mousemove', move);
        } else {
            $(document.body).focus();
        }

        e.stopPropagation();
        return false;
    }

    function reset (){
        start = {x: 0, y: 0};
        $(this).css('backgroundPosition', '0 0');
    }

    $bg.bind('mousedown mouseup mouseleave', handle);
    $bg.bind('dblclick', reset);
});

http://jsfiddle.net/userdude/q6r8f/4/

---

原答案

HTML

<div class="bg-img"></div>

CSS

div.bg-img {
    background-image: url(http://upload.wikimedia.org/wikipedia/commons/9/91/Flexopecten_ponticus_2008_G1.jpg);
    background-position: 0 0;
    background-repeat: no-repeat;
    background-color: blue;
    border: 1px solid #aaa;
    width: 250px;
    height: 250px;
    margin: 25px auto;
}

jQuery

$(document).ready(function(){
    var $bg = $('.bg-img'),
        origin = {x: 0, y: 0},
        start = {x: 0, y: 0},
        movecontinue = false;

    function move (e){
        var moveby = {
            x: origin.x - e.clientX,
            y: origin.y - e.clientY
        };

        if (movecontinue === true) {
            start.x = start.x - moveby.x;
            start.y = start.y - moveby.y;

            $(this).css('background-position', start.x + 'px ' + start.y + 'px');
        }

        origin.x = e.clientX;
        origin.y = e.clientY;

        e.stopPropagation();
        return false;
    }

    function handle (e){
        movecontinue = false;
        $bg.unbind('mousemove', move);

        if (e.type == 'mousedown') {
            origin.x = e.clientX;
            origin.y = e.clientY;
            movecontinue = true;
            $bg.bind('mousemove', move);
        } else {
            $(document.body).focus();
        }

        e.stopPropagation();
        return false;
    }

    function reset (){
        start = {x: 0, y: 0};
        $(this).css('backgroundPosition', '0 0');
    }

    $bg.bind('mousedown mouseup mouseleave', handle);
    $bg.bind('dblclick', reset);
});

http://jsfiddle.net/userdude/q6r8f/2/

Answer 2

来自 ui 可拖动演示：

拖动 DOM 元素很简单，无需重新发明轮子。

<style>
#draggable { width: 150px; height: 150px; padding: 0.5em; }
</style>
<script>
    $(function() {
        $( "#draggable" ).draggable();
    });
</script>



<div class="demo">

<div id="draggable" class="ui-widget-content">
    <p>Drag me around</p>
</div>

</div><!-- End demo -->



<div class="demo-description" style="display: none; ">
<p>Enable draggable functionality on any DOM element. Move the draggable object by clicking on it with the mouse and dragging it anywhere within the viewport.</p>
</div><!-- End demo-description -->

http://jqueryui.com/demos/draggable/

编辑： div 内的可拖动背景也是可能的。在这里看小提琴：http://jsfiddle.net/FyFZA/

Answer 3

这篇文章是我的问题的一个很好的起点。我结合了上面的答案和另一个与获取背景图像的原始尺寸有关的答案 (SO:How do I get background image size in jQuery?)

在我的特定设置中，我使用了background-size:cover，因此我必须确定背景图像的高度/宽度比率，并将其与容器的高度/宽度比率进行比较。这意味着每个图像只允许在一维上滑动。

这里有两个你可能不需要的额外内容。我为当前正在操作的元素添加了一个边框，只是为了让它易于查看，完成后将其删除。我还用偏移值更新了输入，因此我可以将它们发送到服务器。

我的 cmets 往往非常冗长，所以有点冗长，但我希望它对某人有所帮助。

<script>
$(document).ready(function(){

    function reset (){
        start = {x: 0, y: 0};
        $(this).css('backgroundPosition', '0 0');
    }

    $(".bg-img").bind('dblclick', reset);

    //my jquery
$(".bg-img").on('mousedown mouseup', function(e){

    //declare some vars
    var start = {x: 0, y: 0};
    var move = {x: 0, y: 0};
    var id = $(this).attr('id');

    //pointer coordinates on mousedown
    var origin = {x: 0, y: 0};

    //container dimensions
    var container = {w: $(this).width(), h: $(this).height()};

    //container ratio
    var containerRatio = container.h / container.w;

    //background image dimensions, note: this gets dimensions of unscaled image
    var img = new Image;
    img.src = $(this).css('background-image').replace(/url\(|\)$/ig, "");
    var background = {w: img.width, h: img.height};

    //background ratio
    var backgroundRatio = background.h / background.w;

    //max x and y position, aka boundary
    var min = {x: 0, y: 0};
    var max = {x: 0, y: 0};

    //move x
    if(backgroundRatio < containerRatio){
        min.y = 0;
        min.x = -((container.h * (1/backgroundRatio)) - container.w);
    }

    //move y
    else if (backgroundRatio > containerRatio){
        min.x = 0;
        min.y = -((container.w * backgroundRatio) - container.h);
    }

    //ratios are equal, don't move anything
    else{
        min.x = 0;
        min.y = 0;
    }

    //activate
    if(e.type == 'mousedown'){

        //add border so it's easier to visualize
        $(this).css('border', '1px solid #000000');

        //get current position of mouse pointer
        origin.x = e.clientX;
        origin.y = e.clientY;

        //get current background image starting position
        var temp = $(this).css('background-position').split(" ");
        start.x = parseInt(temp[0]);
        start.y = parseInt(temp[1]);

        //mouse is dragged while mousedown
        $(this).mousemove(function(e){

            //move position
            move.x = start.x + (e.clientX - origin.x);
            move.y = start.y + (e.clientY - origin.y);

            //if it's in the bounds, move it
            if(move.x <= max.x && move.x >= min.x && move.y <= max.y && move.y >= min.y){

                console.log('both');

                //alter css
                $(this).css('background-position', move.x + 'px ' + move.y + 'px');

                //update input
                $("#" + id).val('x:' + move.x + ', y:' + move.y);
            }

            //in x bound,
            else if(move.x <= max.x && move.x >= min.x){

                console.log('x');

                //below min.y
                if(move.y < min.y){
                    $(this).css('background-position', move.x + 'px ' + min.y + 'px');

                    //update input
                    $("#" + id).val('x:' + move.x + ', y:' + min.y);
                }
                //above max.y
                else if(move.y > max.y){
                    $(this).css('background-position', move.x + 'px ' + max.y + 'px');

                    //update input
                    $("#" + id).val('x:' + move.x + ', y:' + max.y);
                }
            }

            //in y bound
            else if(move.y <= max.y && move.y >= min.y){

                console.log('y');

                //below min.x
                if(move.x < min.x){
                    $(this).css('background-position', min.x + 'px ' + move.y + 'px');

                    //update input
                    $("#" + id).val('x:' + min.x + ', y:' + move.y);            
                }

                //above max.x
                else if(move.x > max.x){
                    $(this).css('background-position', max.x + 'px ' + move.y + 'px');

                    //update input
                    $("#" + id).val('x:' + max.x + ', y:' + move.y);
                }
            }

            //out of both bounds
            else{
                console.log('problem');
            }
        });
    }

    //deactivate
    else{

        //remove border
        $(this).css('border', 'none');

        //remove mousemove
        $(this).off('mousemove');
        $(document.body).focus();
    }
});
});
</script>

Answer 4

我知道这是一篇旧帖子，但如果您使用 jQueryUI，另一种解决方案是在背景之上创建一个透明元素，然后使用拖动回调来更新原始节点的 backgroundPosition。这是一个例子：

/* node is the element containing the background image */
/* width/height variables are just there if your background image is a different width/height then the container */
var transparent = $('<div></div>');
transparent.css({
    position: 'absolute',
    zIndex: 10,
    left: node.offset().left,
    top: this.node.offset().top,
    width: width || node.width(),
    height: height || node.height(),
    backgroundColor: '#fff',
    opacity: 0.2
});

$('body').append(transparent);

options.config.drag = function(event, ui) {
    node.css({ backgroundPosition: (ui.position.left - ui.originalPosition.left) + 'px ' + (ui.position.top - ui.originalPosition.top) + 'px' });
};

$(transparent).draggable(options.config);

我特意留下了带有不透明度的白色背景颜色，以便您在测试时可以看到元素。