css平行四邊形與菱形變換-html教學-PHP中文網

*以下技巧皆源自於Lea Verou所著《CSS Secrets》

平行四邊形

　　平行四邊形的構造可以基於矩形透過skew()的變形屬性進行斜向拉升得到（skew所用的座標系，縱向是X軸，橫向是Y軸，與常見的座標系相反）。

<span style="color: #0000ff"><!</span><span style="color: #ff00ff">DOCTYPE html</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">html </span><span style="color: #ff0000">lang</span><span style="color: #0000ff">="en"</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">meta </span><span style="color: #ff0000">charset</span><span style="color: #0000ff">="UTF-8"</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>Title<span style="color: #0000ff"></</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">style</span><span style="color: #0000ff">></span><span style="background-color: #f5f5f5; color: #800000">
        .location</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
            position</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> relative</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            top</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 150px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            left</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 150px</span><span style="background-color: #f5f5f5; color: #000000">;</span>
        <span style="background-color: #f5f5f5; color: #000000">}</span><span style="background-color: #f5f5f5; color: #800000">
         .button</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
             color</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> white</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             background-color</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> #51bfff</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             width</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 120px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             height</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 50px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             line-height</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 50px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             text-align</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> center</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             transform</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> skewX(-45deg)</span><span style="background-color: #f5f5f5; color: #000000">;</span>
         <span style="background-color: #f5f5f5; color: #000000">}</span>
    <span style="color: #0000ff"></</span><span style="color: #800000">style</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">div </span><span style="color: #ff0000">class</span><span style="color: #0000ff">="location button"</span><span style="color: #0000ff">></span>click<span style="color: #0000ff"></</span><span style="color: #800000">div</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">html</span><span style="color: #0000ff">></span>

登入後複製

　　但是內容傾斜可能不是我們所需要的效果，一種常規的解決方案就是在內層嵌套一個div，然後加上一個反方向的拉升transform: skewX(45deg);但是有代碼潔癖的人表示接受不能。

　　另一個想法是將所有樣式應用到偽元素上。然後再對偽元素進行變形。

<span style="color: #0000ff"><!</span><span style="color: #ff00ff">DOCTYPE html</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">html </span><span style="color: #ff0000">lang</span><span style="color: #0000ff">="en"</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">meta </span><span style="color: #ff0000">charset</span><span style="color: #0000ff">="UTF-8"</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>Title<span style="color: #0000ff"></</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">style</span><span style="color: #0000ff">></span><span style="background-color: #f5f5f5; color: #800000">
        .location</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
            position</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> relative</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            top</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 150px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            left</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 150px</span><span style="background-color: #f5f5f5; color: #000000">;</span>
        <span style="background-color: #f5f5f5; color: #000000">}</span><span style="background-color: #f5f5f5; color: #800000">
         .button</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
             width</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 120px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             height</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 50px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             line-height</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 50px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             text-align</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> center</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             color</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> white</span><span style="background-color: #f5f5f5; color: #000000">;</span>
         <span style="background-color: #f5f5f5; color: #000000">}</span><span style="background-color: #f5f5f5; color: #800000">
        .button:before</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
            content</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> ''</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            position</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> absolute</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            top</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 0</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000"> right</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 0</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000"> bottom</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 0</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000"> left</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 0</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            background-color</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> #51bfff</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            transform</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> skewX(-45deg)</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            z-index</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> -1</span><span style="background-color: #f5f5f5; color: #000000">;</span>
        <span style="background-color: #f5f5f5; color: #000000">}</span>
    <span style="color: #0000ff"></</span><span style="color: #800000">style</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">div </span><span style="color: #ff0000">class</span><span style="color: #0000ff">="location button"</span><span style="color: #0000ff">></span>click<span style="color: #0000ff"></</span><span style="color: #800000">div</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">html</span><span style="color: #0000ff">></span>

登入後複製

　　這樣不但解決了內容傾斜的問題，而且html結構還是和之前一樣乾淨。不過要注意偽元素生成的圖案是重疊在內容之上的，一旦為它設定背景，就會遮住內容，所以要加上z-index: -1。

菱形圖片

　　如果是在正方形的基礎之上，菱形就是正方形圖案旋轉45度的圖形。我們很容易想到將外層div旋轉45度再將內層img反向旋轉45度。得到如下的圖案。

<span style="color: #0000ff"><!</span><span style="color: #ff00ff">DOCTYPE html</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">html </span><span style="color: #ff0000">lang</span><span style="color: #0000ff">="en"</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">meta </span><span style="color: #ff0000">charset</span><span style="color: #0000ff">="UTF-8"</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>Title<span style="color: #0000ff"></</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">style</span><span style="color: #0000ff">></span><span style="background-color: #f5f5f5; color: #800000">
        .location</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
            position</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> relative</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            top</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 150px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            left</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 150px</span><span style="background-color: #f5f5f5; color: #000000">;</span>
        <span style="background-color: #f5f5f5; color: #000000">}</span><span style="background-color: #f5f5f5; color: #800000">
         .picture</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
             width</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 600px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             transform</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> rotate(45deg)</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
             overflow</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> hidden</span><span style="background-color: #f5f5f5; color: #000000">;</span>
         <span style="background-color: #f5f5f5; color: #000000">}</span><span style="background-color: #f5f5f5; color: #800000">
        .picture>img</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
            max-width</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 100%</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            transform</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> rotate(-45deg)</span><span style="background-color: #f5f5f5; color: #000000">;</span>
        <span style="background-color: #f5f5f5; color: #000000">}</span>
    <span style="color: #0000ff"></</span><span style="color: #800000">style</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">div </span><span style="color: #ff0000">class</span><span style="color: #0000ff">="location picture"</span><span style="color: #0000ff">><</span><span style="color: #800000">img </span><span style="color: #ff0000">src</span><span style="color: #0000ff">="1.jpeg"</span><span style="color: #0000ff">></</span><span style="color: #800000">div</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">html</span><span style="color: #0000ff">></span>

登入後複製

　　是個挺漂亮的正八邊形呢，如果你能說服產品經理，那工作也算完成啦。好吧，我猜你不能說服。。。

　　這裡由於旋轉方向不一致，外層div截取了超出的部分（注意overflow:hidden），然後一部分又空出來了。只要填滿空出的部分就是菱形啦，這裡你可以畫個草圖用勾股定理算一算。

　　算出的結果是放大1.42倍填充完全。我們在img的transform屬性改為transform: rotate(45deg) scale(1.42)

　　這個構造菱形的方案有一個缺陷，就是當原圖不是正方形就需要使用更大的放大係數，截取的圖片內容就更有限了。

　　而且方案本身也不算簡潔優雅。這裡要跟大家介紹一個屬性clip-path（遺憾的是支持性似乎並不好）

，它可以透過傳入固定的位置點將圖片裁剪成任意的多邊形。

<span style="color: #0000ff"><!</span><span style="color: #ff00ff">DOCTYPE html</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">html </span><span style="color: #ff0000">lang</span><span style="color: #0000ff">="en"</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">meta </span><span style="color: #ff0000">charset</span><span style="color: #0000ff">="UTF-8"</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>Title<span style="color: #0000ff"></</span><span style="color: #800000">title</span><span style="color: #0000ff">></span>
    <span style="color: #0000ff"><</span><span style="color: #800000">style</span><span style="color: #0000ff">></span><span style="background-color: #f5f5f5; color: #800000">
        .location</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
            position</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> relative</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            top</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 150px</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            left</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 150px</span><span style="background-color: #f5f5f5; color: #000000">;</span>
        <span style="background-color: #f5f5f5; color: #000000">}</span><span style="background-color: #f5f5f5; color: #800000">
        .picture</span><span style="background-color: #f5f5f5; color: #000000">{</span><span style="background-color: #f5f5f5; color: #ff0000">
            -webkit-clip-path</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> polygon(50% 0, 100% 50%, 50% 100%, 0 50%)</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            -moz-clip-path</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> polygon(50% 0, 100% 50%, 50% 100%, 0 50%)</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            clip-path</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> polygon(50% 0, 100% 50%, 50% 100%, 0 50%)</span><span style="background-color: #f5f5f5; color: #000000">;</span><span style="background-color: #f5f5f5; color: #ff0000">
            transition</span><span style="background-color: #f5f5f5; color: #000000">:</span><span style="background-color: #f5f5f5; color: #0000ff"> 1s clip-path</span><span style="background-color: #f5f5f5; color: #000000">;</span>
        <span style="background-color: #f5f5f5; color: #000000">}</span>

    <span style="color: #0000ff"></</span><span style="color: #800000">style</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">head</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"><</span><span style="color: #800000">img </span><span style="color: #ff0000">class</span><span style="color: #0000ff">="location picture"</span><span style="color: #ff0000"> src</span><span style="color: #0000ff">="1.jpeg"</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">body</span><span style="color: #0000ff">></span>
<span style="color: #0000ff"></</span><span style="color: #800000">html</span><span style="color: #0000ff">></span>

登入後複製

　　希望在不遠的將來clip-path這個屬性在各遊覽器得到更好的支援。