使用ui.position.left设置jQuery Resizable/Draggable边界时的宽度异常问题

Hey there! I totally get your frustration—having the resize keep expanding even after you stop dragging is super annoying. Let's break down why this might be happening and how to fix it without relying on the containment property.

Why This Happens #

When you use ui.position.left to constrain resizing, you're tying the element's position directly to its width adjustment. The problem is that during the resize event, changes to the width can indirectly alter the element's position (or vice versa), creating a loop where the resize logic keeps triggering even after you release the mouse. Since your boundaries are other elements in the container, the containment property (which works with static containers) isn't helpful here.

Step-by-Step Solution #

Here's a reliable approach to manually enforce boundaries against other elements:

• Capture Boundary Context on Resize Start
  Before any resizing happens, grab the positions and sizes of the elements that act as your boundaries. This gives you fixed reference points to check against during the resize.
• Real-Time Size Validation During Resize
  On every resize tick, calculate if the element is about to cross a boundary. If it is, clamp the size to stay within the allowed space—this prevents the endless expansion.
• Clean Up Temporary Data on Resize Stop
  Remove any stored values once the resize is done to avoid conflicts with future interactions.

Example Code #

Let's say you have a resizable element #my-resizable and a right-side boundary element #right-boundary. Here's how to implement the fix:

$("#my-resizable").resizable({
  start: function(event, ui) {
    // Store initial state and boundary position
    $(this).data({
      originalWidth: ui.size.width,
      maxAllowedRight: $("#right-boundary").position().left
    });
  },
  resize: function(event, ui) {
    const maxRight = $(this).data("maxAllowedRight");
    const currentElementRight = ui.position.left + ui.size.width;

    // Check if we're hitting the right boundary
    if (currentElementRight > maxRight) {
      // Clamp the width to stay within the boundary
      const validWidth = maxRight - ui.position.left;
      ui.size.width = validWidth;
      // Sync the element's actual width to avoid loop triggers
      $(this).width(validWidth);
    }
  },
  stop: function(event, ui) {
    // Clear temporary data
    $(this).removeData("originalWidth maxAllowedRight");
  }
});

Key Notes #

• If you have boundaries on multiple sides (left, top, bottom), repeat the same logic for each direction—calculate the minimum allowed position/size and clamp accordingly.
• Make sure the boundary elements' positions are calculated correctly relative to the resizable element's parent (use .position() for relative positioning, .offset() for absolute if needed).
• Avoid overcomplicating the resize logic—keep the boundary checks simple to prevent performance issues during dragging.

This approach should stop the endless width expansion because you're explicitly limiting the size to stay within the space defined by your other container elements, without relying on the containment property.

内容的提问来源于stack exchange，提问作者RON2015