[mapguide-internals] RFC15 - Addendum 4

Chris Claydon chris.claydon at autodesk.com
Thu Apr 5 12:16:44 EDT 2007


Following Trevor's suggestion, I have updated the RFC to describe the
use of a bitmask value to allow selective filtering of features based on
whether the layer is visible, selectable and/or has tooltips.

Please let me know if you have comments.

Chris.

-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org
[mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Trevor
Wekel
Sent: March 30, 2007 11:56 AM
To: MapGuide Internals Mail List
Subject: RE: [mapguide-internals] RFC15 - Addendum 3

Hi Chris,

A single isVisible flag may be sufficient.  And I think the HTTP request
should follow the same syntax as the API call.  Based on the flags, a
zero bitmask would query all layers.  I believe the previous release
behaviour would be isSelectable + isVisible.

Thanks,
Trevor 

-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org
[mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Chris
Claydon
Sent: Friday, March 30, 2007 11:30 AM
To: MapGuide Internals Mail List
Subject: RE: [mapguide-internals] RFC15 - Addendum 3

I think a bitmask makes a lot of sense. I have a few comments and
questions...

1) Do we need separate flags for isVisible and isWithinScaleRange? It
seems to me that if you're ignoring the scale range, you are
automatically ignoring the current visibility. It seems like a single
isVisible flag would suffice.

2) We have to be careful that we don't run into any byte ordering issues
in Windows vs. Linux. But that's just an implementation caveat.

3) What are your thoughts on the HTTP request syntax? Should we use
separate parameters (ONLYVISIBLE, ONLYSELECTABLE, ONLYTOOLTIPS), or roll
those into an integer value too?

My initial thought was that a bitmask value of zero should give the same
behavior as the previous release, but I guess defaulting it to a
non-zero value would be OK.

Chris.

-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org
[mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Trevor
Wekel
Sent: March 29, 2007 5:54 PM
To: MapGuide Internals Mail List
Subject: RE: [mapguide-internals] RFC15 - Addendum 3

Hi Jason,

I don't think this addendum will cover the performance hit.  Chris will
probably hate me but I wonder if it makes sense to add a bitmask?

QueryFeatures/QueryFeatureProperties(MgMap* map,
                                     MgStringCollection* layerNames,
                                     MgGeometry* filterGeometry,
                                     INT32 selectionVariant,
                                     CREFSTRING featureFilter,
                                     INT32 maxFeatures,
                                     INT32 layerAttributes);

Where layerAttributes would be the sum of any/all

isWithinScaleRange = 1,  // layer must be visible at current scale to be
included isVisible = 2,  // visibility flag must be checked for layer to
be included isSelectable = 4, // layer must be selectable to be included
hasTooltip = 8, // layer must have a tooltip defined to be included

Examples:

layerAttributes = (nothing)
Queries every single layer on the map.

layerAttributes = hasTooltip
Queries any layers with a tooltip regardless of whether the layer is
currently visible or is within scale

layerAttributes = isSelectable + isWithinScaleRange Query only
selectable layers visible at the current scale range.  Layers turned off
by the user will be included.

layerAttributes = isWithinScaleRange + isVisible + hasTooltip Queries
currently visible layers with a tooltip.  Layers turned off by the user
will not be included.  This will result in a performance improvement
because only layers at the current scale, and visible, with a tooltip
will be included. 

I suspect this will be a pain to implement but it is more flexible.


Thanks,
Trevor


-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org
[mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Jason
Birch
Sent: Thursday, March 29, 2007 5:01 PM
To: MapGuide Internals Mail List
Subject: RE: [mapguide-internals] RFC15 - Addendum 3


Is this going to deal with some of the problems that this (unpopulated)
RFC was to cover:

http://trac.osgeo.org/mapguide/wiki/MapGuideRfc7

Which was the result of this email thread:

http://www.nabble.com/Tooltip-performance-tf2652498s16610.html#a7401729

Jason 

-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org
[mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Chris
Claydon
Sent: Thursday, March 29, 2007 15:52
To: MapGuide Internals Mail List
Subject: [mapguide-internals] RFC15 - Addendum 3

Yet another addendum to this RFC...
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