Re: Documentation and explanatory diagrams

On 3 July 2010 13:59, Thom Brown <thombrown@gmail.com> wrote:
> On 3 July 2010 03:41, Bruce Momjian <bruce@momjian.us> wrote:
>> Peter Eisentraut wrote:
>>> On fre, 2010-07-02 at 22:15 -0400, Bruce Momjian wrote:
>>> > > 500k of source for just half a dozen simple images?  There's
>>> > something
>>> > > seriously wrong there.  I suspect the PNGs could be compressed a lot
>>> > > more, but right now I'm wondering exactly how verbose the dia
>>> > "source"
>>> > > representation is.
>>> >
>>> > Here is the PNG URL:
>>> >
>>> >         http://momjian.us/expire/pgsql-docs/img/
>>> >
>>> > and the dia files:
>>> >
>>> >         http://momjian.us/expire/pgsql-docs/dia/
>>>
>>> The dia stuff is XML that should compress well.
>>
>> Gzip takes the dia directory from 526k to 42k.  And of course gzip does
>> little for the PNG files.
>>
>
> How configurable is the generation process for these PNGs?  It's just
> that they don't appear to be optimised.
>
> For example, pgclient_server.png is created at 75,089 bytes, but can
> be reduced to 15,643 bytes like in the attached file
> (pgclient_server2.png) by using a 16-colour indexed palette.
>
> Thom
>

Being a bit more generous, and using a 32-colour palette, it looks
like it yields a typical saving of 75%

Original images:

40290    file_based_log_shipping.png
54211    hot_standby.png
52400    page_layout.png
75089    pgclient_server.png
49117    pg_dir_layout.png
17692    pg_lines_code.png
41723    pg_standby.png
25135    pitr.png
10946    postgresql_hist.png
34156    streaming_replication.png
68679    tablespaces.png
18197    vacuum.png

TOTAL: 487635 bytes

32-colour palette images (compression %):

10700    file_based_log_shipping2.png (73.44%)
14245    hot_standby2.png (73.72%)
9896     page_layout2.png (81.11%)
13786    pg_dir_layout2.png (81.64%)
6347     pg_lines_code2.png (87.08%)
11211    pg_standby2.png (36.63%)
18173    pgclient_server2.png (56.44%)
7148     pitr2.png (71.56%)
3873     postgresql_hist2.png (64.62%)
8969     streaming_replication2.png (73.74%)
15338    tablespaces2.png (77.67%)
5846     vacuum2.png (67.87%)

TOTAL: 125532 bytes (74.26%)

..just an idea anyway.

Thom