Scaling text to fit in window

[Mark Tiede]

I have a rectangle in which I must put text. The rectangle gets resized
from time to time and I must figure out how to scale the font to still
fit in the rectangle. Trouble is, the font is user selectable and could
be proportional. So I have to use TextWidth and TextHeight to figure
out whether the text will still fit and then, somehow, figure out what
to scale it to. I ran into troubles trying to calculate a scaling
factor. It would alternately pick a font height that would be scaled
too big and then scale it too small.

Any suggestions for maintaining a font scale inside a resizable
rectangle?

[Steve Schafer (TeamB)]

Because font glyphs have to be an integral number of pixels wide, you
are unlikely to find a font size such that the text will fit exactly
within the specified width. What you should do is figure out an
approximate scale factor as a first step:

ScaleFactor := MyRect.Width / TextWidth(...);

Then multiply the Height of the font by this factor to get a new font
height:

Font.Height := Round(ScaleFactor * Abs(Font.Height));

And then iteratively test the width of the resulting text and decrease
the font height one pixel at a time until the text fits:

W := TextWidth(...);
while W > MyRect.Width do begin
Font.Height := Abs(Font.Height) - 1;
W := TextWidth(...) end;

-Steve

[Mark L. Tiede]

Steve,

Thanks. I am already scaling things. I thought the iterative process
seemed inefficient and maybe there was a trick I should know, but it sounds
like there isn't. I thought of the iterative algorithm also. Only I tried a
couple of others first :-)

I guess that means there aren't any nice tricks on this one.

[Steve Schafer (TeamB)]

On Mon, 19 Jul 1999 10:23:17 -0400, "Mark L. Tiede"
<mti...@mjwcorp.com> wrote:

> I guess that means there aren't any nice tricks on this one.

The reason there aren't any tricks is that it is essentially
impossible to predict how a glyph width will "round off" when you
change the font the size slightly.

-Steve