What is "VML", the base knowledge of VML _VML related

HTML is a standard format for Web pages, and the pages we see are written in HTML tags, but with limited markup
-VML is a markup language that uses code tags to draw within a Web page, like HTML, or an HTML supplement.
-The output of the image is vector graphics format, graphics and support in the form of 2D, 3D, dynamic animation rendering
-its compatibility with HTML, CSS2 (style sheet) is very good, that is to say that these 3 are easily mixed together, complementary
-It is also compatible with DHTML (HTML object based programming language), Js&vbs (scripting)
-It's compatible with XML (common Web Data Description language), XSL (style sheet), DOM (Object interface), and so on.
-It can be supported by its browser directly parse, output, but currently only IE browser support VML

-With PGML, SVG, etc. are based on XML format, but also with SWF (Flash), PDF and other graphic effects similar
-VML was made by Microsoft 1999 years ago (I was not known), and integrated into the ie5+ browser
-is also the core structure of Microsoft Office Art (art graphics, such as Word's artistic text)
-VML by Microsoft Visio, Autodesk, Macromedia and other enterprises recommended to the WWW (Highest rights association)
-taking and synthesizing the recommendations of the Parties, the consortium began to develop SVG in early 1999 and shortly thereafter launched
-svg is a combination of VML, GML and other improvements (output efficiency, graphic quality, markup extension), is recommended as a standard
-but SVG requires specialized image readers such as Adobe SVG viewer, which cannot be directly parsed by the browser engine
-In my opinion, SVG is more suitable for precision vector graphics application software development, VML is suitable for application in Web pages
-There are many articles saying that VML is outdated, but I feel quite healthy in the view of the beholder.
volume, output speed) and its easy to write, browser can be resolved, and HTML and other language compatibility, real
Feasibility of application of Web pages and the feasibility of deep development

-but not to mention the advantages of VML, VML in my deep application development, met the "efficiency" disadvantage, of course, only
It is said that deep application (bigger and more precision vector image, VML animation, gorgeous 2d/3d effect, etc.), a
Simple application, it is not felt, or can be said that the general application is not a cinch.
-Hardware efficiency: Perhaps VML describes a vector graphic with just a line, a few lines of code, and no reason to cause
The problem of slow output. But in fact, the output of VML vector graphics (2d/3d) is the integrated graphics card, memory
, CPU, screen refresh rate and so on, which is directly related to the performance of the hardware, the need for certain settings, but also
It's the VML. The larger the vector graph, the more colors, the more complex the image processing, the faster the animation update, the more
Easy to cause cpu100%, the slower the output efficiency problem, otherwise it will be very fast.
-Data efficiency: The larger the above figure, the more color and so on, not only related to hardware. In fact, a few line generations
Code description of the pattern, in the browser parsing, it becomes a veritable "digital image." Just browsing
After the analysis of the data, we see the figure, behind the scenes to know how many "numbers" to output this
What, a pattern? Once the monitor is refreshed, it is repetition of these "numbers" .... That's what you don't
Look at this graphic (switch to other pages) The machine works faster, whereas, you see, the machine slows down.
The reason.
-Image vector efficiency: In future chapters, you will learn about VML image, ImageData, fill, etc.
Note that these tags can be http://(online), file:///(local) path protocol jpg, GIF,
Images in BMP format are inserted into a Web page in vector form. You will find that if the image being inserted is larger (
Number of bytes), the slower it will be, and it will be very fast.
-to synthesize the above efficiency problems is the biggest drawback of VML. Understand the shortcomings of VML, in the future study, application
In VML, we should try our best to avoid touching nails on this shortcoming, and after fully mastering the technology of VML
, it is not difficult and insufficient to fear. At the very least, the output of VML graphics is fast enough: