Re: [Freetype-devel] Re: GSOC - Distance Fields

[suzuki toshiya]

Dear Werner,

Werner LEMBERG wrote:
>> Oh, I see the value to be stored is in a range [-1.0, 1.0].
>> I want to hear the comments from other developers :-),
>> whether the initial implementation should be FT_F2Dot14 (16bit)
>> or float (32bit, at least).
> 
> Well, we have dropped 16bit support already, so it's only a question
> about storage size.

Ah, I think you mean 16bit "platform" are dropped.

>>> But, for now I think the storing part can be postponed until we
>>> have compared the accuracy.  If there isn't a much difference in
>>> the accuracy of floats vs integers, then we can simply use 8 bits
>>> per pixel and store them as something like PNG.  What do you think
>>> about this?
>> If the Distance Fields should be stored as an image (PNG, or
>> something like that), I want to withdraw my shallow idea.  XML and
>> JSON are not the best options to store the image (using dataURL and
>> base64 bitstream? what a stupid idea!), please ignore that.
> 
> What exactly do you mean with 'stored as something like PNG'?  Is this
> the output that FreeType returns to the calling application?  Or is
> this a temporary storage within FreeType?  In both cases I'm not sure
> that this is the best solution, since compression and decompression
> costs a lot of time.

My understanding is that Anuj is planning to store the rasterized-then-
blurred glyph images as the extra TrueType table, aslike sbix table.
I slipped to think about the size of the memory buffer to store these
data. I'm not in full understanding about "how to use that".

>  What 'image' dimensions are we talking about?
> Usually, Freetype glyph bitmaps are very small, and compressing them
> would be a complete waste of time.

Ah, the (assumed/estimated) number of the pixels should be discussed
for first... Anuj, please give us some informations.

Regards,
mpsuzuki