Add checks for GD true/free type functions

[marijn]

The GD Drawer implementation should be checking for the existence of the following true/free type functions:

• imageftbbox
• imagettfbbox

They might not be enabled on some platforms...
As far as I can see it is the result of compiling GD without the correct --with-freetype-dir.

How would you like the test case formatted?

[avalanche123]

wouldn't this solve it? https://github.com/avalanche123/Imagine/blob/develop/lib/Imagine/Gd/Imagine.php#L210

[marijn]

Apparently not, I run into the issue yesterday, it was not caught by the free type support option.

[avalanche123]

I see, I will add checks then, thanks

[marijn]

I have confirmed that it's because of the lacking --with-freetype-dir flag.

I guess it would be best to throw an exception and refer to the fact that one needs to compile php --with-freetype-dir.