[mapserver-dev] Removing Bitmap Font Support

[Stephen Woodbridge]

I use the bitmap fonts for quick and dirty stuff, but it looks like you 
have the case covered.

One other point I will mention (this is NOT a showstopper, just FYI), 
image sizes will also be slightly larger because truetype antialiases 
the characters which impacts image compression.

I'm ok with this change.

-Steve W

On 8/30/2013 11:08 AM, Lime, Steve D (MNIT) wrote:
> I'm ok with the change...
>
> -----Original Message-----
> From: mapserver-dev-bounces at lists.osgeo.org [mailto:mapserver-dev-bounces at lists.osgeo.org] On Behalf Of thomas bonfort
> Sent: Friday, August 30, 2013 4:30 AM
> To: MapServer Dev Mailing List
> Subject: Re: [mapserver-dev] Removing Bitmap Font Support
>
> The diff for this change can be seen at
> https://github.com/tbonfort/mapserver/compare/rfc98-b70...ttf-in-mem
>
> --
> thomas
>
> On 30 August 2013 11:16, thomas bonfort <thomas.bonfort at gmail.com> wrote:
>> Hi devs,
>>
>> This will become an RFC for 7.0 unless there's wild objection right away...
>>
>> With the dropping of the GD renderer, I would like to streamline our
>> text rendering some more and remove support for BITMAP fonts. I will
>> stress right away that backwards compatibility (aside from the actual
>> rendered output) will be maintained through the use of an embedded
>> truetype font.
>>
>> Bitmap font support has the following inconveniences:
>> - They are not supported by the cairo (svg+pdf) and kml renderers
>> - They do not support rotation
>> - They only cover the ASCII characters
>> - They are difficult if not impossible to place correctly as they
>> don't contain the information as to where their baseline is placed
>> - This can be left to the appreciation of the reader, but my opinion
>> is that they are far too ugly for any serious text rendering (c.f.
>> https://github.com/mapserver/msautotest/blob/branch-6-2/renderers/expected/labels-bitmap.png
>> )
>> - All the previous points imply that maintaining their support in the
>> codebase is brittle and painfull
>>
>> They are however usefull from a user's point of view, as they allow
>> creating maps without having to define a fontset. Their simplicity
>> also probably means that they are somewhat more performant to render
>> than truetype fonts (I don't have any metrics to back this up).
>>
>> I am thereby proposing that we drop support for bitmap fonts. To
>> maintain backwards compatibility, and to still allow quickly creating
>> mapfiles without referencing and creating a fontset, labels of type
>> bitmap, and/or labels with no font defined will fallback to an
>> embedded truetype font that freetype will load from memory. The TINY,
>> SMALL, MEDIUM, LARGE and GIANT keywords will map to equivalent pixel
>> sizes (proposed: 5,7,10,13,16).
>>
>> The downsides I see to this modification are an increased libmapserver
>> memory footprint (due to the embedded truetype font), and possibly
>> slower rendering for those specifically using bitmap fonts. In
>> exchange, we get nicer output, support for curved/angle labels,
>> support for all latin, greek and cyrillic glyphs, support for all
>> renderers, and a more maintainable codebase.
>>
>> regards,
>> Thomas
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