shape-image-threshold属性用于设置在将图像用于 shape-outside 时用于提取形状的 alpha 通道的阈值。
句法：
shape-image-threshold: 属性值：
- alpha-value：用于设置提取形状的阈值。大于阈值的像素将被视为形状。 0.0 到 1.0 之间的十进制值可用于设置从完全透明到完全不透明的阈值。如果值超出范围，它们将被限制在此范围内。
下面的例子说明了shape-image-threshold 属性：
示例 1：在此示例中，我们将阈值设置为 0.5
CSS | shape-image-threshold
GeeksforGeeks
CSS | shape-image-threshold: 0.5;
GeeksforGeeks is a computer science portal
with a huge variety of well written and
explained computer science and programming
articles, quizzes and interview questions.
The portal also has dedicated GATE preparation
and competitive programming sections.
GeeksforGeeks is a computer science portal
with a huge variety of well written and
explained computer science and programming
articles, quizzes and interview questions.
The portal also has dedicated GATE preparation
and competitive programming sections.
输出： 
示例 2：在此示例中，我们将阈值设置为 0.2
CSS | shape-image-threshold
GeeksforGeeks
CSS | shape-image-threshold: 0.2;
GeeksforGeeks is a computer science portal
with a huge variety of well written and
explained computer science and programming
articles, quizzes and interview questions.
The portal also has dedicated GATE preparation
and competitive programming sections.
GeeksforGeeks is a computer science portal
with a huge variety of well written and
explained computer science and programming
articles, quizzes and interview questions.
The portal also has dedicated GATE preparation
and competitive programming sections.
输出： 
支持的浏览器： shape-image-threshold属性支持的浏览器如下：
- 谷歌浏览器
- 浏览器 9
- 火狐
- 苹果浏览器
- 歌剧