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简单的支持网页画框拖拽缩放功能的js插件

Sunxb / 2568人阅读

摘要:我就不提除此以外还需要实现的一些业务上的细节交互了,本篇文章只讲讲我实现的拖拽功能的原理。这里其实大家就可以看出来了,得益于面向对象的机制,我们可以很简单的实现一些画框拖拽功能。

引言

前不久,老大给我分配一个比较吊炸天的任务。要我实现:在一张图片上,可以用鼠标画框。除此以外,画出来的框,可以实现resize,也就是说可以通过鼠标操作缩放,也可以进行拖拽。我就不提除此以外还需要实现的一些业务上的细节交互了,本篇文章只讲讲我实现的拖拽功能的原理。

初始画框对象

由于也是上的需求,要求不止画一个框,有可能用户会画好多框,如果只是简单的检测鼠标事件定位一个个框,很容易导致缩放和拖拽功能的紊乱,因此,运用面向对象的思想,将拖拽和缩放的框变成一个对象,其所有其他鼠标事件的绑定都在这个对象上。

废话不多说,直接上源码,思路很简单。

function newBox(options) {
    this.container = $("
"); this.dragLeft = $("
"); this.dragTop = $("
"); this.dragRight = $("
"); this.dragBottom = $("
"); this.dragTopLeft = $("
"); this.dragTopRight = $("
"); this.dragBottomLeft = $("
"); this.dragBottomRight = $("
"); this.sureBtn = $("
"); this.cancelBtn = $("
"); this.enableEdit = true; this.init(); this.options = options; } newBox.prototype = { init: function() { this.container.append(this.dragLeft); this.container.append(this.dragTop); this.container.append(this.dragRight); this.container.append(this.dragBottom); this.container.append(this.dragTopLeft); this.container.append(this.dragTopRight); this.container.append(this.dragBottomLeft); this.container.append(this.dragBottomRight); this.container.append(this.sureBtn); this.container.append(this.cancelBtn); this.container.on({ "mousedown": this.containerMouseDown.bind(this), "click": this.enableEditFunc.bind(this) }); this.dragRight.on("mousedown", this.dragRightMouseDown.bind(this)); this.dragLeft.on("mousedown", this.dragLeftMouseDown.bind(this)); this.dragTop.on("mousedown", this.dragTopMouseDown.bind(this)); this.dragBottom.on("mousedown", this.dragBottomMouseDown.bind(this)); this.dragTopLeft.on("mousedown", this.dragTopLeftMouseDown.bind(this)); this.dragTopRight.on("mousedown", this.dragTopRightMouseDown.bind(this)); this.dragBottomRight.on("mousedown", this.dragBottomRightMouseDown.bind(this)); this.dragBottomLeft.on("mousedown", this.dragBottomLeftMouseDown.bind(this)); this.sureBtn.on("click", this.sureFunc.bind(this)); this.cancelBtn.on("click", this.cancelFunc.bind(this)); }, sureFunc: function() { this.disableEditFunc(); if(this.options.sureFunc) this.options.sureFunc(this.container); return false; }, cancelFunc: function() { this.container.remove(); if(this.options.cancelFunc) this.options.cancelFunc(this.container); }, enableEditFunc: function() { var sureBtn = this.sureBtn; // 设置正在编辑的框的zindex为最大 this.container.css("z-index","100000000") // 先保存未保存的 $(".new_rect .sureBtn").each(function() { if($(this)[0] == sureBtn[0]){ return; } $(this).is(":visible") && $(this).click() && $(this).mouseleave(); }) this.enableEdit = true; this.container.find(".new_react-dots, .dots").show(); this.sureBtn.show(); this.cancelBtn.show(); }, disableEditFunc: function() { var width=this.container.width(); var height=this.container.height(); var area=parseInt(width*height); this.container.css("z-index",100000000-area); this.enableEdit = false; this.container.find(".new_react-dots, .dots").hide(); this.sureBtn.hide(); this.cancelBtn.hide(); }, setPosition: function(position) { this.container.css(position) }, dragRightMouseDown: function(ev) { if(!this.enableEdit) return false; var rightElem = this.dragRight; var o_x = ev.pageX; var o_width = this.container.width(); var o_right = parseFloat(this.container.css("right")); if(rightElem.setCapture) { rightElem.setCapture(); } $(document).on("mousemove.dragRight", doDragRight.bind(this)); $(document).on("mouseup.dragRight", stopDragRight.bind(this)); return false; function doDragRight(e) { var right = o_right - e.pageX + o_x; if(right < 0) right = 0; if(right > o_width + o_right) right = o_width + o_right this.setPosition({ right: right }); return false; } function stopDragRight(e) { if(rightElem.releaseCapture) { rightElem.releaseCapture(); } $(document).off("mousemove.dragRight"); $(document).off("mouseup.dragRight"); return false; } }, dragLeftMouseDown: function(ev) { if(!this.enableEdit) return false; var leftElem = this.dragLeft; var o_x = ev.pageX; var o_width = this.container.width(); var o_left = parseFloat(this.container.css("left")); if(leftElem.setCapture) { leftElem.setCapture(); } $(document).on("mousemove.dragLeft", doDragLeft.bind(this)); $(document).on("mouseup.dragLeft", stopDragLeft.bind(this)); return false; function doDragLeft(e) { var left = o_left + e.pageX - o_x; if(left < 0) left = 0; if(left > o_width + o_left) left = o_width + o_left this.setPosition({ left: left }); return false; } function stopDragLeft(e) { if(leftElem.releaseCapture) { leftElem.releaseCapture(); } $(document).off("mousemove.dragLeft"); $(document).off("mouseup.dragLeft"); return false; } }, dragTopMouseDown: function(ev) { if(!this.enableEdit) return false; var topElem = this.dragTop; var o_y = ev.pageY; var o_height = this.container.height(); var o_top = parseFloat(this.container.css("top")); if(topElem.setCapture) { topElem.setCapture(); } $(document).on("mousemove.dragTop", doDragTop.bind(this)); $(document).on("mouseup.dragTop", stopDragTop.bind(this)); return false; function doDragTop(e) { var top = o_top + e.pageY - o_y; if(top < 0) top = 0; if(top > o_top + o_height) top = o_top + o_height this.setPosition({ top: top }); return false; } function stopDragTop(e) { if(topElem.releaseCapture) { topElem.releaseCapture(); } $(document).off("mousemove.dragTop"); $(document).off("mouseup.dragTop"); return false; } }, dragBottomMouseDown: function(ev) { if(!this.enableEdit) return false; var bottomElem = this.dragBottom; var o_y = ev.pageY; var o_height = this.container.height(); var o_bottom = parseFloat(this.container.css("bottom")); if(bottomElem.setCapture) { bottomElem.setCapture(); } $(document).on("mousemove.dragBottom", doDragBottom.bind(this)); $(document).on("mouseup.dragBottom", stopDragBottom.bind(this)); return false; function doDragBottom(e) { var bottom = o_bottom - e.pageY + o_y; if(bottom < 0) bottom = 0; if(bottom > o_bottom + o_height) bottom = o_bottom + o_height this.setPosition({ bottom: bottom }); return false; } function stopDragBottom(e) { if(bottomElem.releaseCapture) { bottomElem.releaseCapture(); } $(document).off("mousemove.dragBottom"); $(document).off("mouseup.dragBottom"); return false; } }, dragTopLeftMouseDown: function(ev) { if(!this.enableEdit) return false; var topLeftElem = this.dragTopLeft; var o_y = ev.pageY; var o_x = ev.pageX; var o_height = this.container.height(); var o_width = this.container.width(); var o_top = parseFloat(this.container.css("top")); var o_left = parseFloat(this.container.css("left")); if(topLeftElem.setCapture) { topLeftElem.setCapture(); } $(document).on("mousemove.dragTopLeft", doDragTopLeft.bind(this)); $(document).on("mouseup.dragTopLeft", stopDragTopLeft.bind(this)); return false; function doDragTopLeft(e) { var top = o_top + e.pageY - o_y; var left = o_left + e.pageX - o_x; if(top < 0) top = 0; if(top > o_top + o_height) top = o_top + o_height; if(left < 0) left = 0; if(left > o_width + o_left) left = o_width + o_left; this.setPosition({ top: top, left: left }); return false; } function stopDragTopLeft(e) { if(topLeftElem.releaseCapture) { topLeftElem.releaseCapture(); } $(document).off("mousemove.dragTopLeft"); $(document).off("mouseup.dragTopLeft"); return false; } }, dragTopRightMouseDown: function(ev) { if(!this.enableEdit) return false; var topRightElem = this.dragTopRight; var o_y = ev.pageY; var o_x = ev.pageX; var o_height = this.container.height(); var o_width = this.container.width(); var o_top = parseFloat(this.container.css("top")); var o_right = parseFloat(this.container.css("right")); if(topRightElem.setCapture) { topRightElem.setCapture(); } $(document).on("mousemove.dragTopRight", doDragTopRight.bind(this)); $(document).on("mouseup.dragTopRight", stopDragTopRight.bind(this)); return false; function doDragTopRight(e) { var top = o_top + e.pageY - o_y; var right = o_right - e.pageX + o_x; if(top < 0) top = 0; if(top > o_top + o_height) top = o_top + o_height; if(right < 0) right = 0; if(right > o_width + o_right) right = o_width + o_right; this.setPosition({ top: top, right: right }); return false; } function stopDragTopRight(e) { if(topRightElem.releaseCapture) { topRightElem.releaseCapture(); } $(document).off("mousemove.dragTopRight"); $(document).off("mouseup.dragTopRight"); return false; } }, dragBottomRightMouseDown: function(ev) { if(!this.enableEdit) return false; var bottomRightElem = this.dragBottomRight; var o_y = ev.pageY; var o_x = ev.pageX; var o_height = this.container.height(); var o_width = this.container.width(); var o_bottom = parseFloat(this.container.css("bottom")); var o_right = parseFloat(this.container.css("right")); if(bottomRightElem.setCapture) { bottomRightElem.setCapture(); } $(document).on("mousemove.dragBottomRight", doDragTopRight.bind(this)); $(document).on("mouseup.dragBottomRight", stopDragTopRight.bind(this)); return false; function doDragTopRight(e) { var bottom = o_bottom - e.pageY + o_y; var right = o_right - e.pageX + o_x; if(bottom < 0) bottom = 0; if(bottom > o_bottom + o_height) bottom = o_bottom + o_height; if(right < 0) right = 0; if(right > o_width + o_right) right = o_width + o_right; this.setPosition({ bottom: bottom, right: right }); return false; } function stopDragTopRight(e) { if(bottomRightElem.releaseCapture) { bottomRightElem.releaseCapture(); } $(document).off("mousemove.dragBottomRight"); $(document).off("mouseup.dragBottomRight"); return false; } }, dragBottomLeftMouseDown: function(ev) { if(!this.enableEdit) return false; var bottomLeftElem = this.dragBottomLeft; var o_y = ev.pageY; var o_x = ev.pageX; var o_height = this.container.height(); var o_width = this.container.width(); var o_bottom = parseFloat(this.container.css("bottom")); var o_left = parseFloat(this.container.css("left")); if(bottomLeftElem.setCapture) { bottomLeftElem.setCapture(); } $(document).on("mousemove.dragBottomLeft", doDragTopLeft.bind(this)); $(document).on("mouseup.dragBottomLeft", stopDragTopLeft.bind(this)); return false; function doDragTopLeft(e) { var bottom = o_bottom - e.pageY + o_y; var left = o_left + e.pageX - o_x; if(bottom < 0) bottom = 0; if(bottom > o_bottom + o_height) bottom = o_bottom + o_height; if(left < 0) left = 0; if(left > o_width + o_left) left = o_width + o_left; this.setPosition({ bottom: bottom, left: left }); return false; } function stopDragTopLeft(e) { if(bottomLeftElem.releaseCapture) { bottomLeftElem.releaseCapture(); } $(document).off("mousemove.dragBottomLeft"); $(document).off("mouseup.dragBottomLeft"); return false; } }, containerMouseDown: function(ev) { if(!this.enableEdit) return false; var o_x = ev.pageX; var o_y = ev.pageY; var containerWidth = this.container.width(); var containerHeight = this.container.height(); var o_top = parseFloat(this.container.css("top")); var o_left = parseFloat(this.container.css("left")); var o_right = parseFloat(this.container.css("right")); var o_bottom = parseFloat(this.container.css("bottom")); if(this.container.setCapture) { this.container.setCapture(); } $(document).on("mousemove.container", doDrag.bind(this)); $(document).on("mouseup.container", stopDrag.bind(this)); return false; function doDrag(e) { var disY = e.pageY - o_y; var disX = e.pageX - o_x; var top = o_top + disY; var left = o_left + disX; var right = o_right - disX; var bottom = o_bottom - disY; if(top < 0) { top = 0; bottom = o_bottom + o_top; } if(bottom < 0) { bottom = 0; top = o_top + o_bottom; } if(left < 0) { left = 0; right = o_right + o_left; } if(right < 0) { right = 0; left = o_right + o_left; } this.setPosition({top: top, bottom: bottom, left: left, right: right}); return false; } function stopDrag(ev) { if(this.container.releaseCapture) { this.container.releaseCapture(); } $(document).off("mousemove.container"); $(document).off("mouseup.container"); return false; } } }

至此,一个支持缩放和拖拽功能的box对象已经创建好了,但是,还没有实现初始画框功能,其实画初始框的思路更加简单,就是记录mousedown的时候鼠标地的x,y坐标和mouseup时鼠标的x,y坐标,然后根据坐标值,设置新建的div的宽度和高度和定位就可以了。下面是源码,我直接把它做成了jquery插件。

$.fn.draw_drag_test = function(options) {
    var position = {}
    var elemWidth, elemHeight, o_x, o_y, d_x, d_y, rect, o_left, o_top;

    var mouseDown = function(e) {
      $(this).on({
        "mousemove": mouseMove,
        "mouseup": mouseUp
      })

      var elemLeft = $(this).offset().left,
          elemTop = $(this).offset().top;

      elemWidth = $(this).width();
      elemHeight = $(this).height();
      o_x = e.pageX;
      o_y = e.pageY;

      position.left = o_left = o_x - elemLeft;
      position.top = o_top = o_y - elemTop;

      rect = new newBox(options);
      rect.container.css("z-index","100000000");
      $(this).append(rect.container);

    }

    var mouseMove = function(e) {
      var m_x = e.pageX,
          m_y = e.pageY;

      d_x = m_x - o_x;
      d_y = m_y - o_y;

      position.right = elemWidth - position.left - d_x;
      position.bottom = elemHeight - position.top - d_y;

      if(d_x < 0) {
          position.right = elemWidth - o_left;
          position.left = o_left + d_x;
      }else {
          position.left = o_left;
      }

      if(d_y < 0) {
          position.bottom = elemHeight - o_top;
          position.top = o_top + d_y;
      }else {
          position.top = o_top;
      }

      rect.setPosition(position);
    }

    var mouseUp = function(e) {
      $(this).off("mouseup", mouseUp);
      $(this).off("mousemove", mouseMove);
      $(this).off("mousedown", mouseDown);
    }

    return this.each(function() {
      $(this).off("mousedown").on({
        "mousedown": mouseDown
      })
      return this;
    })

}

这里其实大家就可以看出来了,得益于面向对象的机制,我们可以很简单的实现一些画框拖拽功能。并且该方法还留了回调的接口,方便根据不同的业务需求进行一些交互操作。

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