| Re: Using imagettfbbox with Arial Bold [message #173256 is a reply to message #173255] |
Thu, 31 March 2011 13:27   |
The Natural Philosoph
Messages: 993
Registered: September 2010
Karma:
|
Senior Member |
|
|
Álvaro G. Vicario wrote:
> El 31/03/2011 9:47, jwcarlton escribió/wrote:
>> Technically, it's being set via CSS in a<div>. When it renders on the
>> screen, it's actually more like:
>>
>> <div style="font-family: Arial, Tahoma, Helvetica; font-size: 9pt">
>> $variable
>> </div>
>>
>> * Not a copy& paste, so please ignore any typos
>>
>>
>>> The way TTF fonts get rendered is not unique and universal. It depends
>>> on the renderer and its settings. What GD2 can tell you (and should be
>>> telling you) is the size of the font as rendered by GD2 in that
>>> computer. If you want to establish a correct comparison you need to
>>> actually draw the font from PHP and grab a screenshot.
>>
>> I'm not sure that I follow. This is my first attempt with
>> imagettfbbox() (and I've only barely used GD, mostly with Perl), so I
>> could be wrong, but I thought that this was what the above script did?
>>
>> Is there a reason that it would be correct with arial.ttf, but not
>> arialbd.tff?
>
> I'll try to explain myself better. A font file is basically a collection
> of mathematical primitives: a line here, a circle there, that stuff.
>
> If you want to display a letter on a printed document you need a program
> that takes those primitives and converts them into instructions for the
> printer on how to drop ink on the sheet. If you want to display a letter
> on a computer screen you need a program that converts the primitives
> into coloured pixels. And there are many possible ways to do that
> because random geometrical shapes do not normally map uniquely to pixel
> grids. Even in your own PC you'll see that fonts look completely
> different if you disable anti-aliasing, or if you optimise it for LCD
> panels or CRT monitors.
>
> Your CSS rules are rendered by the browser in the local PC and the
> browser can choose to handle the task to the operating system font
> libraries or use its own library. GD2 uses whatever version of the
> FreeType library is installed on the server.
>
> Why can't you compare GD2 with CSS? Because they use different programs
> to render the font, programs that do not even run on the same computer.
> Furthermore, you have certain amount control about the server (until you
> host upgrades PHP) but zero control about the browser.
>
>
Exactly.
HOWEVER if its the same library (gd) that's dong the rendering as is
doing the text measurement, it ought to get things right.
|
|
|
|
Calendar
Search
Help
Members
Register
Login
Home
]