Why doesn't we always use a fixed mapping mode, why to change it?

I find that it is so difficult to master it because it's so confusing.

I find your question even more confusing. Please provide some context.

I mean why must change from MM_TEXT to MM_LOENGLISH or something. Change mapping mode then translate window origin and viewport origin, ...
It is so confusing.

I think MM_TEXT itself is easy to use, client area is positive in both axis. so why must use negative values?
0 ----------->x+
|
|
|
V
y+

thank you.

I'm betting this goes way back. Probably has to do with the way western languages are written on paper, then later on printing presses, then typewriters, teletypes, then CRT's, and finally modern monitors. We start in the upper left and work our way across then down and across again.

Did you have a question, or was this just a rant?

my wild guess is that to give the programmer the choice of text editor type of programming or the graphics type of programming. the origin to the letter/note is upper left where as the virtual world is the center of the screen.I feel more comfortable to mathematically find center myself a lot easier too