ANN: diagrams 0.4

[Brent Yorgey-2]

I am pleased to announce the release of version 0.4 of diagrams, a
full-featured framework and embedded domain-specific language for
declarative drawing.

The last announcement was of the 0.1 release; there have been quite a
few changes and improvements since then, including:

-   A new website including a gallery of examples:

      http://projects.haskell.org/diagrams/gallery.html

-   A new comprehensive user manual with lots of illustrative
    examples:

      http://projects.haskell.org/manual/diagrams-manual.html

-   New primitive shapes: rounded rectangles, wedges, and a new
    flexible API for generating polygons

-   Cubic splines

-   Basic text support

-   Support for external image primitives

-   Lots more convenient combinators, bug fixes, and improvements

Cool, how can I try it out?
---------------------------

For the truly impatient:

    cabal install gtk2hs-buildtools
    cabal install diagrams

For the slightly less impatient, read the quick tutorial, which has
detailed information about how to install the necessary packages and
will introduce you to the fundamentals of the framework:

  http://projects.haskell.org/diagrams/tutorial/DiagramsTutorial.html 

For those who are even less impatient but want to really dig in and
use the power features, read the user manual:

  http://projects.haskell.org/manual/diagrams-manual.html 

Cool, how can I contribute?
---------------------------

There are lots of ways you can contribute! First, you may want to
subscribe to the project mailing list
(http://groups.google.com/group/diagrams-discuss), and/or come hang
out in the #diagrams IRC channel on freenode.org.

-   There are lots of easy bug fixes, improvements, and feature requests
    just waiting for people wanting to get involved: see the bug
    tracker for a list of open tickets:

      http://code.google.com/p/diagrams/issues/list 

-   The source repositories are mirrored using both darcs (on
    patch-tag.com) and git (on github.com), and patches are accepted
    in either place, thanks to Owen Stephen's great work on
    darcs-bridge [1].

-   Create a higher-level module built on top of the diagrams framework
    (e.g. tree or graph layout, generating Turing machine
    configuration diagrams, Penrose tilings ... your imagination is
    the only limit!)  and submit it for inclusion in a special
    diagrams-contrib package which will be created for such
    higher-level user-contributed modules.

-   Use diagrams to create some cool graphics and submit them for
    inclusion in the gallery.

-   Start your own project built on top of diagrams and let us know how
    it goes!

-   Last but certainly not least, just try it out for your pet graphics
    generation needs and contribute your bug reports and feature
    requests.


Happy diagramming!


Brought to you by the diagrams team:

-   Brent Yorgey
-   Ryan Yates

with contributions from:

-   Sam Griffin
-   Claude Heiland-Allen
-   John Lato
-   Vilhelm Sjöberg
-   Luite Stegeman
-   Kanchalai Suveepattananont
-   Scott Walck


[1] http://wiki.darcs.net/DarcsBridgeUsage 

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[Ryan Yates]

The correct URL for the manual is:

http://projects.haskell.org/diagrams/manual/diagrams-manual.html

Ryan

On Sun, Oct 23, 2011 at 2:47 PM, Brent Yorgey <[hidden email]> wrote:

> I am pleased to announce the release of version 0.4 of diagrams, a
> full-featured framework and embedded domain-specific language for
> declarative drawing.
>
> The last announcement was of the 0.1 release; there have been quite a
> few changes and improvements since then, including:
>
> -   A new website including a gallery of examples:
>
>      http://projects.haskell.org/diagrams/gallery.html
>
> -   A new comprehensive user manual with lots of illustrative
>    examples:
>
>      http://projects.haskell.org/manual/diagrams-manual.html
>
> -   New primitive shapes: rounded rectangles, wedges, and a new
>    flexible API for generating polygons
>
> -   Cubic splines
>
> -   Basic text support
>
> -   Support for external image primitives
>
> -   Lots more convenient combinators, bug fixes, and improvements
>
> Cool, how can I try it out?
> ---------------------------
>
> For the truly impatient:
>
>    cabal install gtk2hs-buildtools
>    cabal install diagrams
>
> For the slightly less impatient, read the quick tutorial, which has
> detailed information about how to install the necessary packages and
> will introduce you to the fundamentals of the framework:
>
>  http://projects.haskell.org/diagrams/tutorial/DiagramsTutorial.html
>
> For those who are even less impatient but want to really dig in and
> use the power features, read the user manual:
>
>  http://projects.haskell.org/manual/diagrams-manual.html
>
> Cool, how can I contribute?
> ---------------------------
>
> There are lots of ways you can contribute! First, you may want to
> subscribe to the project mailing list
> (http://groups.google.com/group/diagrams-discuss), and/or come hang
> out in the #diagrams IRC channel on freenode.org.
>
> -   There are lots of easy bug fixes, improvements, and feature requests
>    just waiting for people wanting to get involved: see the bug
>    tracker for a list of open tickets:
>
>      http://code.google.com/p/diagrams/issues/list
>
> -   The source repositories are mirrored using both darcs (on
>    patch-tag.com) and git (on github.com), and patches are accepted
>    in either place, thanks to Owen Stephen's great work on
>    darcs-bridge [1].
>
> -   Create a higher-level module built on top of the diagrams framework
>    (e.g. tree or graph layout, generating Turing machine
>    configuration diagrams, Penrose tilings ... your imagination is
>    the only limit!)  and submit it for inclusion in a special
>    diagrams-contrib package which will be created for such
>    higher-level user-contributed modules.
>
> -   Use diagrams to create some cool graphics and submit them for
>    inclusion in the gallery.
>
> -   Start your own project built on top of diagrams and let us know how
>    it goes!
>
> -   Last but certainly not least, just try it out for your pet graphics
>    generation needs and contribute your bug reports and feature
>    requests.
>
>
> Happy diagramming!
>
>
> Brought to you by the diagrams team:
>
> -   Brent Yorgey
> -   Ryan Yates
>
> with contributions from:
>
> -   Sam Griffin
> -   Claude Heiland-Allen
> -   John Lato
> -   Vilhelm Sjöberg
> -   Luite Stegeman
> -   Kanchalai Suveepattananont
> -   Scott Walck
>
>
> [1] http://wiki.darcs.net/DarcsBridgeUsage
>
> _______________________________________________
> Haskell-Cafe mailing list
> [hidden email]
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>

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[Rustom Mody]

Thanks.  This is attractive.
I remember (vaguely) a 'live page' ie where one could enter (into the browser) changes to the diagrams code and see the results immediately.
Is that page there? (Or am I mixing up with something else?)

How does diagrams compare with graphviz?  If this is an inappropriate (type-wrong?) question thats ok :-)  Its just that when I last looked at graphviz I found the documentation somewhat impenetrable -- like much else in Hackage -- lots of types, no examples.

On Mon, Oct 24, 2011 at 12:17 AM, Brent Yorgey <[hidden email]> wrote:

I am pleased to announce the release of version 0.4 of diagrams, a
full-featured framework and embedded domain-specific language for
declarative drawing.

The last announcement was of the 0.1 release; there have been quite a
few changes and improvements since then, including:

-   A new website including a gallery of examples:

     http://projects.haskell.org/diagrams/gallery.html

-   A new comprehensive user manual with lots of illustrative
   examples:

     http://projects.haskell.org/manual/diagrams-manual.html

-   New primitive shapes: rounded rectangles, wedges, and a new
   flexible API for generating polygons

-   Cubic splines

-   Basic text support

-   Support for external image primitives

-   Lots more convenient combinators, bug fixes, and improvements

Cool, how can I try it out?
---------------------------

For the truly impatient:

   cabal install gtk2hs-buildtools
   cabal install diagrams

For the slightly less impatient, read the quick tutorial, which has
detailed information about how to install the necessary packages and
will introduce you to the fundamentals of the framework:

 http://projects.haskell.org/diagrams/tutorial/DiagramsTutorial.html

For those who are even less impatient but want to really dig in and
use the power features, read the user manual:

 http://projects.haskell.org/manual/diagrams-manual.html

Cool, how can I contribute?
---------------------------

There are lots of ways you can contribute! First, you may want to
subscribe to the project mailing list
(http://groups.google.com/group/diagrams-discuss), and/or come hang
out in the #diagrams IRC channel on freenode.org.

-   There are lots of easy bug fixes, improvements, and feature requests
   just waiting for people wanting to get involved: see the bug
   tracker for a list of open tickets:

     http://code.google.com/p/diagrams/issues/list

-   The source repositories are mirrored using both darcs (on
   patch-tag.com) and git (on github.com), and patches are accepted
   in either place, thanks to Owen Stephen's great work on
   darcs-bridge [1].

-   Create a higher-level module built on top of the diagrams framework
   (e.g. tree or graph layout, generating Turing machine
   configuration diagrams, Penrose tilings ... your imagination is
   the only limit!)  and submit it for inclusion in a special
   diagrams-contrib package which will be created for such
   higher-level user-contributed modules.

-   Use diagrams to create some cool graphics and submit them for
   inclusion in the gallery.

-   Start your own project built on top of diagrams and let us know how
   it goes!

-   Last but certainly not least, just try it out for your pet graphics
   generation needs and contribute your bug reports and feature
   requests.


Happy diagramming!


Brought to you by the diagrams team:

-   Brent Yorgey
-   Ryan Yates

with contributions from:

-   Sam Griffin
-   Claude Heiland-Allen
-   John Lato
-   Vilhelm Sjöberg
-   Luite Stegeman
-   Kanchalai Suveepattananont
-   Scott Walck


[1] http://wiki.darcs.net/DarcsBridgeUsage

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[Ivan Lazar Miljenovic]

On 24 October 2011 13:51, Rustom Mody <[hidden email]> wrote:
> How does diagrams compare with graphviz?  If this is an inappropriate
> (type-wrong?) question thats ok :-)  Its just that when I last looked at
> graphviz I found the documentation somewhat impenetrable -- like much else
> in Hackage -- lots of types, no examples.

How is it now, better?  If not, what kind of more documentation would you like?

The difference between the two is: graphviz requires an external
command to create the visualisations and is suited towards converting
graph data into an image using various heuristics to try and make it
look nice; diagrams seems to be more towards drawing specific images
following specified rules.

So, you could implement something like graphviz using diagrams as a
backend, but you'd then need to have some transformation from a list
of points+edges to actual 2D coords, etc.

Hmmm... might be interesting to try and use dot/neato/etc. to do the
layout of a graph, and then use diagrams for the actual
visualisation...

--
Ivan Lazar Miljenovic
[hidden email]
IvanMiljenovic.wordpress.com

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[David Barbour]

Is there any way to `query` a diagram, i.e. associate data with each pixel for mouse clicks? Or are the composition rules mostly write-only?

On Sun, Oct 23, 2011 at 11:47 AM, Brent Yorgey <[hidden email]> wrote:

I am pleased to announce the release of version 0.4 of diagrams, a
full-featured framework and embedded domain-specific language for
declarative drawing.

The last announcement was of the 0.1 release; there have been quite a
few changes and improvements since then, including:

-   A new website including a gallery of examples:

     http://projects.haskell.org/diagrams/gallery.html

-   A new comprehensive user manual with lots of illustrative
   examples:

     http://projects.haskell.org/manual/diagrams-manual.html

-   New primitive shapes: rounded rectangles, wedges, and a new
   flexible API for generating polygons

-   Cubic splines

-   Basic text support

-   Support for external image primitives

-   Lots more convenient combinators, bug fixes, and improvements

Cool, how can I try it out?
---------------------------

For the truly impatient:

   cabal install gtk2hs-buildtools
   cabal install diagrams

For the slightly less impatient, read the quick tutorial, which has
detailed information about how to install the necessary packages and
will introduce you to the fundamentals of the framework:

 http://projects.haskell.org/diagrams/tutorial/DiagramsTutorial.html

For those who are even less impatient but want to really dig in and
use the power features, read the user manual:

 http://projects.haskell.org/manual/diagrams-manual.html

Cool, how can I contribute?
---------------------------

There are lots of ways you can contribute! First, you may want to
subscribe to the project mailing list
(http://groups.google.com/group/diagrams-discuss), and/or come hang
out in the #diagrams IRC channel on freenode.org.

-   There are lots of easy bug fixes, improvements, and feature requests
   just waiting for people wanting to get involved: see the bug
   tracker for a list of open tickets:

     http://code.google.com/p/diagrams/issues/list

-   The source repositories are mirrored using both darcs (on
   patch-tag.com) and git (on github.com), and patches are accepted
   in either place, thanks to Owen Stephen's great work on
   darcs-bridge [1].

-   Create a higher-level module built on top of the diagrams framework
   (e.g. tree or graph layout, generating Turing machine
   configuration diagrams, Penrose tilings ... your imagination is
   the only limit!)  and submit it for inclusion in a special
   diagrams-contrib package which will be created for such
   higher-level user-contributed modules.

-   Use diagrams to create some cool graphics and submit them for
   inclusion in the gallery.

-   Start your own project built on top of diagrams and let us know how
   it goes!

-   Last but certainly not least, just try it out for your pet graphics
   generation needs and contribute your bug reports and feature
   requests.


Happy diagramming!


Brought to you by the diagrams team:

-   Brent Yorgey
-   Ryan Yates

with contributions from:

-   Sam Griffin
-   Claude Heiland-Allen
-   John Lato
-   Vilhelm Sjöberg
-   Luite Stegeman
-   Kanchalai Suveepattananont
-   Scott Walck


[1] http://wiki.darcs.net/DarcsBridgeUsage

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[Ketil Malde-5]

Rustom Mody <[hidden email]> writes:

> I remember (vaguely) a 'live page' ie where one could enter (into the
> browser) changes to the diagrams code and see the results immediately.
> Is that page there? (Or am I mixing up with something else?)

Chris Smith's web interface to Ben Lippmeier's Gloss, perhaps?
http://dac4.designacourse.com:8000/

-k
--
If I haven't seen further, it is by standing in the footprints of giants

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[Stephen Tetley-2]

> Rustom Mody <[hidden email]> writes:
>
>> I remember (vaguely) a 'live page' ie where one could enter (into the
>> browser) changes to the diagrams code and see the results immediately.
>> Is that page there? (Or am I mixing up with something else?)

Maybe it was Péter Diviánszky's 'dia' (entirely different to 'diagrams') ?

 http://pnyf.inf.elte.hu/fp/Diagrams_en.xml

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[Brent Yorgey-2]

On Mon, Oct 24, 2011 at 08:21:30AM +0530, Rustom Mody wrote:
> Thanks.  This is attractive.
> I remember (vaguely) a 'live page' ie where one could enter (into the
> browser) changes to the diagrams code and see the results immediately.
> Is that page there? (Or am I mixing up with something else?)

You might also have been thinking of Luite Stegeman's "Wolfgang
Lambda" project, which supports diagrams in this way (as well as many
other things!).  There was an early preview version of it up for a
little while which a bunch of people saw, but it's not ready for
release yet.

> How does diagrams compare with graphviz?  If this is an inappropriate
> (type-wrong?) question thats ok :-)  Its just that when I last looked at
> graphviz I found the documentation somewhat impenetrable -- like much else
> in Hackage -- lots of types, no examples.

graphviz is a special-purpose tool for doing graph layout and
visualization.  diagrams is a general-purpose framework for drawing
anything at all.  As for documentation, you do realize that the graphviz
package on Hackage is a set of bindings? So there's a lot of helpful
documentation at http://www.graphviz.org/ .

One of my goals with diagrams is to have excellent documentation, so
if you find anything that is unclear or poorly documented, please file
a bug report (http://code.google.com/p/diagrams/issues/list)!

-Brent

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[Brent Yorgey-2]

On Mon, Oct 24, 2011 at 03:46:26PM +1100, Ivan Lazar Miljenovic wrote:
>
> Hmmm... might be interesting to try and use dot/neato/etc. to do the
> layout of a graph, and then use diagrams for the actual
> visualisation...

I agree!  This has been on my list of
things-to-do-with-diagrams-eventually for quite a while. It shouldn't
even be very hard since your graphviz bindings can so nicely
round-trip a graph description through dot/neato/etc. (right?)
graphviz is great at graph layout but not so hot at graph *drawing*.

-Brent

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[Brent Yorgey-2]

On Sun, Oct 23, 2011 at 11:06:19PM -0700, David Barbour wrote:
> Is there any way to `query` a diagram, i.e. associate data with each pixel
> for mouse clicks?

Yes.  Every diagram has an associated 'query function', which
associates a monoidal value to every point.  By default it just
returns True/False indicating whether the given point is in the
interior of any shape, but you can use any monoid you like.  I believe
John Lato has been using this in conjunction with the support for
rendering directly to a gtk widget to develop some sort of interactive
graphical application (I don't know many details).

For more info see

  http://projects.haskell.org/diagrams/manual/diagrams-manual.html#using-queries

-Brent


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[David Barbour]

Thanks. 

Diagrams package seems it could be promising for a declarative UI model - i.e. integration with functional reactive programming and similar models - so long as I'm willing to sacrifice `native` look and feel, which doesn't seem like a big problem.

A couple more questions:

1) Am I right in assuming that Diagrams does very little `occlusion` of its own - i.e. when rendering a soda-straw view of a complex diagram, or masking large areas with a rectangle or sphere? There won't be any competition or redundancy with an external index and backend (e.g. Cairo-GL layer) occlusion?

2) Is there support for Cairo-like linear and radial gradients?

Also, it seems that for Cairo rendering, we cannot currently supply our own Cairo context.

> renderDia Cairo (CairoOptions "foo.png" (PNG (100,100))) myDiagram

This section of your manual is incomplete, I admit, but from browsing the code it seems you provide a simplified interface that fully encapsulates the Cairo rendering. Is there any way to render a diagram within the Cairo stack? or leverage Cairo's own experimental backends (like OpenGL)?

Regards,

Dave

On Mon, Oct 24, 2011 at 10:41 AM, Brent Yorgey <[hidden email]> wrote:

On Sun, Oct 23, 2011 at 11:06:19PM -0700, David Barbour wrote:
> Is there any way to `query` a diagram, i.e. associate data with each pixel
> for mouse clicks?

Yes.  Every diagram has an associated 'query function', which
associates a monoidal value to every point.  By default it just
returns True/False indicating whether the given point is in the
interior of any shape, but you can use any monoid you like.  I believe
John Lato has been using this in conjunction with the support for
rendering directly to a gtk widget to develop some sort of interactive
graphical application (I don't know many details).

For more info see

 http://projects.haskell.org/diagrams/manual/diagrams-manual.html#using-queries

-Brent

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[Jason Dagit-3]

On Sun, Oct 23, 2011 at 11:47 AM, Brent Yorgey <[hidden email]> wrote:

> I am pleased to announce the release of version 0.4 of diagrams, a
> full-featured framework and embedded domain-specific language for
> declarative drawing.
>
> The last announcement was of the 0.1 release; there have been quite a
> few changes and improvements since then, including:
>
> -   A new website including a gallery of examples:
>
>      http://projects.haskell.org/diagrams/gallery.html
>
> -   A new comprehensive user manual with lots of illustrative
>    examples:
>
>      http://projects.haskell.org/manual/diagrams-manual.html
>
> -   New primitive shapes: rounded rectangles, wedges, and a new
>    flexible API for generating polygons
>
> -   Cubic splines
>
> -   Basic text support

What do you use for text support?  I know at one point you were
interested in my freetype2 binding (which is still very raw and
immature), but you must be using gtk for font loading and rendering?

Jason

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[Ivan Lazar Miljenovic]

On 25 October 2011 04:25, Brent Yorgey <[hidden email]> wrote:

> On Mon, Oct 24, 2011 at 03:46:26PM +1100, Ivan Lazar Miljenovic wrote:
>>
>> Hmmm... might be interesting to try and use dot/neato/etc. to do the
>> layout of a graph, and then use diagrams for the actual
>> visualisation...
>
> I agree!  This has been on my list of
> things-to-do-with-diagrams-eventually for quite a while. It shouldn't
> even be very hard since your graphviz bindings can so nicely
> round-trip a graph description through dot/neato/etc. (right?)

Yup, it can.  It also has support for more easily adding and pulling
out "custom" attributes if you want to be able to tag them with more
information (albeit only with Text values at the moment); for example,
I use this for the round-trip'ing to be able to distinguish multiple
edges from each other.

--
Ivan Lazar Miljenovic
[hidden email]
IvanMiljenovic.wordpress.com

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[Rustom Mody]

On Mon, Oct 24, 2011 at 10:17 PM, Stephen Tetley <[hidden email]> wrote:

> Rustom Mody <[hidden email]> writes:
>
>> I remember (vaguely) a 'live page' ie where one could enter (into the
>> browser) changes to the diagrams code and see the results immediately.
>> Is that page there? (Or am I mixing up with something else?)

Maybe it was Péter Diviánszky's 'dia' (entirely different to 'diagrams') ?

 http://pnyf.inf.elte.hu/fp/Diagrams_en.xml

Yes that was it (It is called diagrams :-)

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[Rustom Mody]

On Mon, Oct 24, 2011 at 10:16 AM, Ivan Lazar Miljenovic <[hidden email]> wrote:

On 24 October 2011 13:51, Rustom Mody <[hidden email]> wrote:
> How does diagrams compare with graphviz?  If this is an inappropriate
> (type-wrong?) question thats ok :-)  Its just that when I last looked at
> graphviz I found the documentation somewhat impenetrable -- like much else
> in Hackage -- lots of types, no examples.

How is it now, better?  If not, what kind of more documentation would you like?

Without claiming to have looked very hard, I looked up grahhviz in hayoo, gathered I should be looking at Data.GraphViz and tried clicking everything that looked reasonable here
but still cant find an example of a graph :-) ie a graphviz graph in haskell.

Is this a complaint against graphviz or against hackage/cabal etc?? Dunno.
[Maybe I am just tired]

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[Ivan Lazar Miljenovic]

On 25 October 2011 16:02, Rustom Mody <[hidden email]> wrote:

> On Mon, Oct 24, 2011 at 10:16 AM, Ivan Lazar Miljenovic
> <[hidden email]> wrote:
>>
>> On 24 October 2011 13:51, Rustom Mody <[hidden email]> wrote:
>> > How does diagrams compare with graphviz?  If this is an inappropriate
>> > (type-wrong?) question thats ok :-)  Its just that when I last looked at
>> > graphviz I found the documentation somewhat impenetrable -- like much
>> > else
>> > in Hackage -- lots of types, no examples.
>>
>> How is it now, better?  If not, what kind of more documentation would you
>> like?
>
>
> Without claiming to have looked very hard, I looked up grahhviz in hayoo,
> gathered I should be looking at Data.GraphViz and tried clicking everything
> that looked reasonable here
> but still cant find an example of a graph :-) ie a graphviz graph in
> haskell.

Well, there are indeed examples in there, but not in Data.GraphViz:
that module is aimed more at "how can I convert my existing data into
a Dot representation", not constructing one by hand.  As of the latest
version (2999.12.*), there are indeed examples for anyone that wants
them:

* Sample graph in Dot representation used as a base case:
http://hackage.haskell.org/packages/archive/graphviz/2999.12.0.3/doc/html/Data-GraphViz-Types.html
* Using the canonical representation:
http://hackage.haskell.org/packages/archive/graphviz/2999.12.0.3/doc/html/Data-GraphViz-Types-Canonical.html
* Using the graph representation:
http://hackage.haskell.org/packages/archive/graphviz/2999.12.0.3/doc/html/Data-GraphViz-Types-Generalised.html
* Using the Monadic representation (based upon the dotgen package):
http://hackage.haskell.org/packages/archive/graphviz/2999.12.0.3/doc/html/Data-GraphViz-Types-Graph.html

The Data.GraphViz.Types module also has a short description of how to
choose which representation.

However, I'll add a note in Data.GraphViz telling people to look in
Data.GraphViz.Types if they want to construct a Dot graph by hand.

> Is this a complaint against graphviz or against hackage/cabal etc?? Dunno.

I'd say it's more a case of: to the maintainer, it's _obvious_ how to
do stuff since they're intimately familiar with the details; as such,
if something isn't clear let them know that you're confused by
something (which at least in my case jogs me to go and add extra
clarification on such matters)!

--
Ivan Lazar Miljenovic
[hidden email]
IvanMiljenovic.wordpress.com

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[Rustom Mody]

On Tue, Oct 25, 2011 at 10:40 AM, Ivan Lazar Miljenovic <[hidden email]> wrote:

On 25 October 2011 16:02, Rustom Mody <[hidden email]> wrote:
> On Mon, Oct 24, 2011 at 10:16 AM, Ivan Lazar Miljenovic
> <[hidden email]> wrote:
>>
>> On 24 October 2011 13:51, Rustom Mody <[hidden email]> wrote:
>> > How does diagrams compare with graphviz?  If this is an inappropriate
>> > (type-wrong?) question thats ok :-)  Its just that when I last looked at
>> > graphviz I found the documentation somewhat impenetrable -- like much
>> > else
>> > in Hackage -- lots of types, no examples.
>>
>> How is it now, better?  If not, what kind of more documentation would you
>> like?
>
>
> Without claiming to have looked very hard, I looked up grahhviz in hayoo,
> gathered I should be looking at Data.GraphViz and tried clicking everything
> that looked reasonable here
> but still cant find an example of a graph :-) ie a graphviz graph in
> haskell.

Well, there are indeed examples in there, but not in Data.GraphViz:
that module is aimed more at "how can I convert my existing data into
a Dot representation", not constructing one by hand.  As of the latest
version (2999.12.*), there are indeed examples for anyone that wants
them:

* Sample graph in Dot representation used as a base case:
http://hackage.haskell.org/packages/archive/graphviz/2999.12.0.3/doc/html/Data-GraphViz-Types.html
* Using the canonical representation:
http://hackage.haskell.org/packages/archive/graphviz/2999.12.0.3/doc/html/Data-GraphViz-Types-Canonical.html
* Using the graph representation:
http://hackage.haskell.org/packages/archive/graphviz/2999.12.0.3/doc/html/Data-GraphViz-Types-Generalised.html
* Using the Monadic representation (based upon the dotgen package):
http://hackage.haskell.org/packages/archive/graphviz/2999.12.0.3/doc/html/Data-GraphViz-Types-Graph.html

Thanks.

In the Data.GraphViz.Types.Generalised page you have the starting line:

It is sometimes useful to be able to manipulate a Dot graph as an actual graph. This representation lets you do so...

Evidently some other context is needed to understand this line?
[Sorry if I am dense]

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[Brent Yorgey-2]

On Mon, Oct 24, 2011 at 11:55:53AM -0700, David Barbour wrote:
> Thanks.
>
> Diagrams package seems it could be promising for a declarative UI model -
> i.e. integration with functional reactive programming and similar models -
> so long as I'm willing to sacrifice `native` look and feel, which doesn't
> seem like a big problem.

Yes, I imagine it could.  Not one of the use cases I personally had in
mind -- but I've been hoping that people will find it useful for
things I had not thought of.

>
> A couple more questions:
> 1) Am I right in assuming that Diagrams does very little `occlusion` of its
> own - i.e. when rendering a soda-straw view of a complex diagram, or masking
> large areas with a rectangle or sphere? There won't be any competition or
> redundancy with an external index and backend (e.g. Cairo-GL layer)
> occlusion?

Right, diagrams currently doesn't do any sort of "culling", occlusion,
etc., that's all up to the backend.

> 2) Is there support for Cairo-like linear and radial gradients?

Not yet, but it's on the todo list.

> Also, it seems that for Cairo rendering, we cannot currently supply our own
> Cairo context.
>
> > renderDia Cairo (CairoOptions "foo.png" (PNG (100,100))) myDiagram
>
> This section of your manual is incomplete, I admit, but from browsing the
> code it seems you provide a simplified interface that fully encapsulates the
> Cairo rendering. Is there any way to render a diagram within the Cairo
> stack? or leverage Cairo's own experimental backends (like OpenGL)?

You're right, currently there's no way do these sorts of things.
However, there's no fundamental limitation here and adding this sort
of functionality should not be hard, and I'd be quite open to
extending the cairo backend in this direction.

-Brent

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[Brent Yorgey-2]

On Mon, Oct 24, 2011 at 01:58:33PM -0700, Jason Dagit wrote:
> On Sun, Oct 23, 2011 at 11:47 AM, Brent Yorgey <[hidden email]> wrote:
> > I am pleased to announce the release of version 0.4 of diagrams, a
> > full-featured framework and embedded domain-specific language for
> > declarative drawing.
>
> What do you use for text support?  I know at one point you were
> interested in my freetype2 binding (which is still very raw and
> immature), but you must be using gtk for font loading and rendering?

At the moment, text is completely delegated to backends.  diagrams
itself doesn't do any font loading or rendering at all.  However, the
obvious downside to this is that the framework itself has no idea how
big a given piece of text is and can't position it relative to other
things.  On the todo list is to use your freetype2 binding (or
something like it) to actually do more work within the framework
itself, so it can position text correctly, convert text outlines into
paths, and so on.

-Brent

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[Ivan Lazar Miljenovic]

On 26 October 2011 02:17, Rustom Mody <[hidden email]> wrote:
>
> In the Data.GraphViz.Types.Generalised page you have the starting line:
>
> It is sometimes useful to be able to manipulate a Dot graph as an actual
> graph. This representation lets you do so...
>
> Evidently some other context is needed to understand this line?
> [Sorry if I am dense]

It means that you can treat it as a graph data structure: add/delete
nodes/edges, get neighbours of a node, etc.  Whereas if you wanted to
delete a node from the other representations, you would manually have
to traverse the entire data structure explicitly to delete that node
and any edge it may be in.

The use case is is for manipulating existing Dot code better;
generally speaking, if you are converting data _into_ a Dot graph,
then you would do any such manipulations before you do the
conversions.

--
Ivan Lazar Miljenovic
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IvanMiljenovic.wordpress.com

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