Thanks for your response Atle, I'm trying to achieve a result that when I draw lots of lines on a page, that I can erase everything underneath a path, preserving the parts of the features not touched by the eraser. This isn't therefore a case of removing the entire feature (more of a 'hide' feature) but cutting out parts of the drawing. I've tried deleting points from the geometry, but found it imprecise and slow.
Thanks, Dan Atle Frenvik Sveen wrote: > Hmm, I think your proposal looks overly complicated. Why don't just > remove the feature from the layer it is drawn on? > > And possibly store it somewhere else if you want to regret the deletion? > > Or am I misunderstanding you here? > > -atle > > On Wed, 2010-01-27 at 12:28 +0000, Dan Garland wrote: >> Any takers? Or am I on the wrong track here? >> >> Thanks in advance, >> Dan >> >> Dan Garland wrote: >>> Hi all, >>> >>> I'm a Ruby on Rails developer working on my first project with >>> OpenLayers. I'm tasked with developing an free-hand eraser tool that can >>> erase features created by the drawFeatures tool. Amongst other things >>> we've tried, my thinking is moving towards creating a SVG mask, based on >>> the existing drawing tool, in which the 'erased' line is actually a >>> black line within a white, rectangular SVG mask, which when applied over >>> the top of the tile layer would mask any drawn features from underneath. >>> I anticipate something like this: >>> >>> <svg width="8cm" height="8cm" viewBox="0 0 800 800" version="1.1" >>> xmlns="http://www.w3.org/2000/svg"; >>> xmlns:xlink="http://www.w3.org/1999/xlink";> >>> <defs> >>> <mask id="Mask" maskUnits="userSpaceOnUse" x="0" y="0" width="3968" >>> height="2964"> >>> <rect x="0" y="0" width="3968" height="2964" fill="white" /> >>> <!-- The 'eraser' line --> >>> <polyline fill="none" stroke="black" stroke-width="25" >>> points="400,0 400,800" /> >>> </mask> >>> </defs> >>> >>> <!-- Example drawn features --> >>> >>> <polyline id="myline" points="0,0 800,800" fill="none" >>> stroke-opacity="1" stroke-width="25" stroke-linecap="round" >>> stroke-linejoin="round" stroke-dasharray="none"/> >>> <polyline id="myline2" points="0,100 800,100" fill="none" >>> stroke-opacity="1" stroke-width="25" stroke-linecap="round" >>> stroke-linejoin="round" stroke-dasharray="none"/> >>> <polyline id="myline3" points="0,400 800,400" fill="none" >>> stroke-opacity="1" stroke-width="25" stroke-linecap="round" >>> stroke-linejoin="round" stroke-dasharray="none"/> >>> >>> <use xlink:href="#myline" stroke="red" mask="url(#Mask)" /> >>> <use xlink:href="#myline2" stroke="red" mask="url(#Mask)" /> >>> <use xlink:href="#myline3" stroke="red" mask="url(#Mask)" /> >>> >>> </svg> >>> >>> The problems I face with this approach is knowing how best to manipulate >>> the existing SVG object being referenced by OpenLayers. I wonder whether >>> it is feasible in OpenLayers to develop a control based on the >>> drawFeature tool that >>> >>> 1) Adds the mask <defs> section to the SVG Root at startup >>> 2) Creates polyline elements with the mask >>> 3) Adds <use> elements for each element in the tile layer to connect the >>> id and the mask >>> >>> Before I dive in and spent hours in an unfamiliar area I wonder if any >>> OpenLayers developers have encountered this use case and have a better >>> solution, or can shed any light on this proposed approach. >>> >>> Best Regards, >>> Dan Garland >>> >>> _______________________________________________ >>> Users mailing list >>> [email protected] >>> http://openlayers.org/mailman/listinfo/users >> _______________________________________________ >> Users mailing list >> [email protected] >> http://openlayers.org/mailman/listinfo/users >> > > _______________________________________________ Users mailing list [email protected] http://openlayers.org/mailman/listinfo/users
