The ado|css| filter DropShadow property is to add the shadow effect of an object. The effect it does looks like leaving the original object out of the page and then displaying the object's projection on the page. Take a look at its expression:
Filter:dropshadow (Color=color,offx=offx,offy=offy,
positive=positive)
There are four parameters for this property: color represents the colors of the cast shadow. OFFX and Offy The offset of the shadow in the X and Y directions respectively. The offset must be set with an integer value. If set to a positive integer, represents the right direction of the x-axis and the downward direction of the y-axis. Set to a negative integer is the opposite.
The positive parameter has two values: true to create a visible projection for any non-transparent pixel, and false to create a visible projection for the transparent pixel portion.
Again, let's take a look at an example (see figure below):
Look, the text in the picture is like flying out of the page, and leaving a faint shadow.
What actually applies here is the CSS DropShadow attribute, let's take a look at its code:
<title>dropshadow </title>
<style>//* define CSS styles *//
<!--
div {position:absolute;top:20;width:300;
Filter:dropshadow (color= #FFCCFF, offx=15,offy=10,positive=1);
-->
* Define DIV range style, absolute positioning, projection color for #ffccff,
The projection coordinates are offset 15 pixels to the right and 10 pixels down *//
</style>
<body>
<div>
<p style= "Font-family:matisse itc;font-size:64;
Font-weight:bold;color: #CC00CC; ">
//* Define font name, size, weight, color *//
Love Leaf </p>
</div>
</body>
Like the Chroma property, the DropShadow attribute is not good for the image, I mean the JPEG, GIF format image file.
The reason for not supporting is the same as Chroma, because the color of the image is very rich, it is difficult to find a projection shadow position.