resize 向左向右問題

resize html

nick12345 2021-11-12 18:23:19 ‧ 909 瀏覽

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例如我定了WIDTH是500PX，我只能向500PX以下的縮小，不能拉大，請問怎樣用RESIZE把他拉大。

(function() {
        "use strict";

        // horizontal direction
        (function resizableX() {
            const resizer = document.querySelector(".resizer-x");
            resizer.addEventListener("mousedown", onmousedown);
            resizer.addEventListener("touchstart", ontouchstart);

            // for mobile
            function ontouchstart(e) {
                e.preventDefault();
                resizer.addEventListener("touchmove", ontouchmove);
                resizer.addEventListener("touchend", ontouchend);
            }

            function ontouchmove(e) {
                e.preventDefault();
                const clientX = e.touches[0].clientX;
                const deltaX = clientX - (resizer._clientX || clientX);
                resizer._clientX = clientX;
                const l = resizer.previousElementSibling;
                const r = resizer.nextElementSibling;
                // LEFT
                if (deltaX < 0) {
                    const w = Math.round(parseInt(getComputedStyle(l).width) + deltaX);
                    l.style.flex = `0 ${w < 10 ? 0 : w}px`;
                    r.style.flex = "1 0";
                }
                // RIGHT
                if (deltaX > 0) {
                    const w = Math.round(parseInt(getComputedStyle(r).width) - deltaX);
                    r.style.flex = `0 ${w < 10 ? 0 : w}px`;
                    l.style.flex = "1 0";
                }
            }

            function ontouchend(e) {
                e.preventDefault();
                resizer.removeEventListener("touchmove", ontouchmove);
                resizer.removeEventListener("touchend", ontouchend);
                delete e._clientX;
            }

            // for desktop
            function onmousedown(e) {
                e.preventDefault();
                document.addEventListener("mousemove", onmousemove);
                document.addEventListener("mouseup", onmouseup);
            }

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1 個回答

Felix

iT邦研究生 2 級 ‧ 2021-11-13 01:55:18

不建議使用觸控裝置來調整元素的寬高。

如果不需要縱向調整，將 y 和 height 刪除即可。

<div class="box">
    <span class="resizer"></span>
</div>

.box {
    width: 300px;
    height: 200px;
    position: relative;
    background-color: cyan;
}

.box .resizer {
    width: 10px;
    height: 10px;
    position: absolute;
    right: 0;
    bottom: 0;
    background-color: blue;
    cursor: se-resize;
}

const doc = document.querySelector('html');
const resizer = document.querySelector('.resizer');
const cursor = {
    x: 0,
    y: 0,
    width: 0,
    height: 0,
    target: null,
    dragging: false
};

doc.addEventListener('mousedown', grab);
doc.addEventListener('mousemove', drag);
doc.addEventListener('mouseup', release);

function grab(e) {
    if (e.button !== 0 || e.target !== resizer) return;

    const target = cursor.target = resizer.closest('.box');
    const cStyle = window.getComputedStyle(target);

    cursor.x = e.clientX;
    cursor.y = e.clientY;
    cursor.width = Number(cStyle.width.slice(0, -2));
    cursor.height = Number(cStyle.height.slice(0, -2));
    cursor.dragging = true;
}

function drag(e) {
    if (!cursor.dragging) return;

    cursor.target.style.width = `${cursor.width + e.clientX - cursor.x}px`;
    cursor.target.style.height = `${cursor.height + e.clientY - cursor.y}px`;
}

function release(e) {
    cursor.dragging = !cursor.dragging ? true : false;
}