On Thu, Mar 12, 2009 at 8:53 AM, Ben Abbott <address@hidden> wrote:
On Mar 11, 2009, at 2:37 PM, xianghang liu wrote:
Two functions below are two methods of computing bounding box of a
text
object. I wrote them following algorithms used in GD and Freetype.
Only a
slight diiference is between them. It is the computation of
bounding box of
a charachter. And the final result of them are slightly different
as well.
Please tell me if you find any mistakes or have suggestions.
I'm confused by what is meant by "bounding box", and as I'm
unfamiliar with
FreeType (and have poor c++ skills) I'm uncertain that this
implementation
will result in what is expected for the text object property,
"extent".
Consider the three examples below (from Matlab).
h1 =
text(0,0,'_','interpreter','none','units','points','fontsize',12);
h2 =
text(0,0,'|','interpreter','none','units','points','fontsize',12);
h3 =
text(0,0,'-','interpreter','none','units','points','fontsize',12);
get(h1,'extent')
ans =
0 -8.8 8.8 16
get(h2,'extent')
ans =
0 -8.8 5.6 16
get(h3,'extent')
ans =
0 -8.8 6.4 16
The choice of character only impacts the width of the extent. The
lower left
corner and height of the extent is constant.
I guess y and h (assuming the extent is [x y w h]) are
considered constant for a given font and computed from the
font ascent, descent and height ((0,0) being the baseline).
While the width is string dependent.
Does the extent takes the margin property into account?
Michael.