What is "VML" and basic knowledge of VML_VML related

HTML is the standard format of WEB web pages. The web pages we see are all written with HTML tags, but the tags are limited
- VML is a markup language that uses code tags to draw pictures on web pages. It is similar to HTML, or can be said to be the complement of HTML.
-The output image is in vector graphics format, and the graphics supports presentation in the form of 2D, 3D, and dynamic animation
-It is very compatible with HTML and CSS2 (style sheet), which means that these 3 are easy to Mixed together and complementary
- It is also very compatible with DHTML (programming language based on HTML objects), JS & VBS (script program)
- It is compatible with XML (general WEB data description language), XSL (style sheet) ), DOM (Object Interface), etc. are very compatible
-it can be directly parsed and output by browsers that support it, but currently only IE browser supports VML

-it is the same as PGML and SVG They are all based on XML format, and have similar graphic effects to SWF (flash), PDF and other graphics
-VML was produced and launched by Microsoft before 1999 (I don’t know the specific time) and integrated into the IE5+ browser
-Similarly It is also the core structure of Microsoft Office Art (art graphics, such as word art text)
-VML is recommended to W3C (WWW Supreme Rights Association) by Microsoft Visio, Autodesk, Macromedia and other companies
-Adopts and integrates various Recommended by Fang, W3C began to develop SVG in early 1999, and launched
soon afterwards - SVG is a comprehensive improvement of VML, GML, etc. (output efficiency, graphic quality, markup extension), and was recommended as a standard
- but SVG requires a specialized image reader such as (Adobe SVG Viewer) and cannot be directly parsed by the browser engine
- In my opinion, SVG is more suitable for the development of precision vector graphics application software, while VML is suitable for application on WEB pages
-There are many articles saying that VML is outdated, but benevolent people have different opinions. I feel that VML is quite sound (graphic quality
and output speed). It is easy to write, can be parsed by browsers, and is compatible with HTML and other languages. Compatibility, feasibility of actual
web page application, feasibility of in-depth development

-but we cannot just mention the advantages of VML. VML encountered the shortcomings of "efficiency" in my in-depth application development , of course
only refers to deep applications (making large-scale precision vector images, Vml animations, gorgeous 2D/3D effects, etc...),
ordinary simple applications cannot be felt, or may be Not to mention general applications.
-Hardware efficiency: Maybe VML only needs one or a few lines of code to describe a vector graphic. There is no reason why
slow output efficiency will occur. But in fact, the output of VML vector graphics (2D/3D) requires a comprehensive graphics card, memory
, CPU, screen refresh rate, etc. to work at the same time. This is directly related to the performance of the hardware and requires certain settings, and also
That is, the larger the VML vector graphics, the more colors, the more complex the graphics processing, and the faster the animation updates, the easier it is to cause CPU100% and slower output efficiency, otherwise it will be very fast.
-Data efficiency: Based on the above-mentioned problems such as larger graphics and more colors, it is not only related to the hardware. In fact, the graphic described by a few lines of code
becomes a veritable "digital image" after being parsed by the browser. Just browsing the data parsed by
, what we see is a graph. Who knows how many "numbers" are needed behind the scenes to output such a
graph? When the display refreshes, it means to read these "numbers" again... This is the reason why if you don’t
look at this graphic (switch to another webpage), the machine will run faster, but if you look at it, the machine will run slower
.
-Image vector efficiency: In future chapters, you will learn VML’s image, imagedata, fill and other tags
. These tags can be used to convert http://(online), file:///( Local) path protocol images in jpg, gif,
bmp and other formats are inserted into the WEB page in vector form. You will find that if the inserted image is larger (
number of bytes), it will be slower, and vice versa it will be faster.
-Based on the above efficiency issues, it is the biggest shortcoming of VML. After understanding the shortcomings of VML, in the future learning and application of VML, we should try our best to learn from each other's strengths to avoid hitting a snag on this shortcoming. After fully mastering VML technology,
this is not difficult or something to be afraid of. At least, the output efficiency of VML graphics is fast enough:)