Thread: Font Sizes

I have discovered a unwanted feature in my app.

I use a bitmap from resource on a dialog box, also made in resource editor of MSVC 6.

If the users PC has LARGE fonts (not the default SMALL fonts) it changes the bitmaps dimensions (and other dialog resource dimensions).

The problem is I have placed frame controls below areas of the bitmap to process mouse clicks ie 'hot spots'. If the bmp's dimensions change then these mouse clicks are no longer correctly processed.

I can rewrite the dialog to draw its own bmp and so avoid the problem.

Any other ideas?

Especially how to detect these large fonts (while I implement the change)?

(By large fonts I mean under the display settings, advanced. You get a chioce of three, small large or custom)

>>> Especially how to detect these large fonts (while I implement the change)?

Try passing the DC of the desktop to GetDeviceCaps() with LOGPIXELSX as the second parameter. If the system is set to small, this value should be 96.

I believe the size of the frame/buttons/other controls are proportional to the font used, so if you draw the bitmap relative to those it will most likely get changed too (especially if you stretch it).

>>Try passing the DC of the desktop to GetDeviceCaps() with LOGPIXELSX as the second parameter. If the system is set to small, this value should be 96.

Thanks, I had not thought of that.

I have not tested it yet but is better than looking at a registry value I found.


I'm still not sure why the BMP in a frame control changes in size differently than the frame controls without imbedded BMP's.
At this point I would rather have a solution than a reason though.

Many applications seem to suffer from scaling problems when using large fonts, not just yours.

I use VCL & have a scaled property associated with all my windows. If scaled is true, I have sizing problems with large fonts, if it false I don't.

VCL is simply wrapping the win api. Therefore, there should be some api call or property you could set to turn of scaling on your windows.

I'm not sure what the advantages of scaling are, but it seems to cause more problems than it's worth IMHO.

You could use the following function to render the size in a portable way, too:

Code:

int FontSize( int points ) {
  HDC common = GetDC(NULL);
  int height =  ((points * GetDeviceCaps( common, LOGPIXELY ))/72);
  ReleaseDC(NULL, common);
  return height;
 }