Re: about contibuting to octave

[Ben Abbott]

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.

Does your implementation produce such a result, or does it produce a  
bounding box representing the smallest box that encompasses the text  
object?

Ben