TwipsPerPixelX: When change? What mean?

[Guv]

I have been confused by some sample code from MSDN Library.

What causes TwipsPerPixelX & TwipsPerPixelY to change? What do they tell me about my Monitor? They do not seem to change when I change Display resolution from 640 X 480 to some other resolution. The MSDN Sample implied to me that they would.

Thanx --- Live long & prosper.

No, TwipsPerPixel shouldn't change from resolution to resolution because a TWIP is an absolute measure like an inch or centimeter. Look in your MSDN library under "twip" (i'm sure you have already) and you'll see one twip = 1/20 point = 1/72 of an inch. Therefore, since the size of each pixel doesn't change, neither will the twipsperpixel variables. (Think of it this way: you're measuring the size of a physical "pixel" with calibers calculated in Twips). One useful application of the twipsperpixel variables is determining screen resolution as in:

screen.width / screen.twipsperpixel = pixelsAcrossScreen