<div dir="ltr">Hi Anita,<div><br></div><div>A QgsFeatureSink is an interface for accepting features. This can be a QgsVectorLayer but does not have to be one. It can also be a spatial index, a vector file writer or others.</div><div>I.e. your algorithm specifies that it produces "features" which can be sent to a vector layer, another algorithm or [you-name-it]. It doesn't care if it's a vector layer, which also has other properties like style.</div><div>This even leaves room for future optimization of processing pipelines, for example, features could be sent through various algorithms without waiting for the first one to be finished.</div><div><br></div><div>I hope that sheds some light</div><div>Matthias</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Oct 23, 2022 at 1:48 PM Anita Graser via QGIS-Developer <<a href="mailto:qgis-developer@lists.osgeo.org">qgis-developer@lists.osgeo.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><span></span>Thank you very much, Thomas. This code comparison approach is very useful indeed. <br><br>If FeatureSink covers all functions of VectorDestination and more, that still leaves me wonder what is the downside of a FeatureSink<div><br></div><div>"Note: Consider using the more flexible <a href="https://api.qgis.org/api/3.22/classQgsProcessingParameterFeatureSink.html" title="A feature sink output for processing algorithms." target="_blank">QgsProcessingParameterFeatureSink</a> wherever possible."</div><div><br></div><div>i.e. where is it not possible to use a Feature Sink? Only in older versions of QGIS? </div><div><br></div><div>Regards,</div><div>Anita</div><div><br><br>On Saturday, 22. October 2022 23:32:11 (+02:00), Thomas Gratier wrote:<br><br><blockquote style="margin:0px 0px 0.8ex;border-left:2px solid rgb(0,0,255);padding-left:1ex"><div dir="ltr"><div>Hi,</div><div><br></div><div>Although, I do know the intend to recommend one against the other, doing some code differences helps to sort out things.</div><div>They both inherits from same classes but the constructor for QgsProcessingParameterFeatureSink accepts an additionnal arg bool <a href="https://api.qgis.org/api/3.22/classQgsProcessingParameterFeatureSink.html#acae2863d5dab37aec4c5466d7d3a84d9" target="_blank">supportsAppend</a>=false</div><div><br></div><div>You also find the additional methods in QgsProcessingParameterFeatureSink to manipulate the same supportsAppend.</div><div><br></div><div>```</div><div>a = QgsProcessingParameterVectorDestination(<br> 'OUTPUT',<br> 'Sortie'<br>)<br><br>b = QgsProcessingParameterFeatureSink(<br> 'OUTPUT',<br> 'Sortie'<br>)<br><br>methods_a = dir(a)<br>methods_b = dir(b)<br>common_methods = set(methods_a).intersection(methods_b)<br>print(common_methods)<br><br>only_in_a = set(methods_a).difference(methods_b)<br></div><div>print(only_in_a)</div><div><br>only_in_b = set(methods_b).difference(methods_a)</div><div>print(only_in_b)</div><div>```</div><div><br></div><div>Regards</div><div><br></div><div>Thomas Gratier</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Le ven. 21 oct. 2022 à 18:07, Anita Graser via QGIS-Developer <<a href="mailto:qgis-developer@lists.osgeo.org" target="_blank">qgis-developer@lists.osgeo.org</a>> a écrit :<br></div><blockquote class="gmail_quote" style="padding-left:1ex;border-left:1px solid rgb(204,204,204);margin:0px 0px 0px 0.8ex"><div><div>Thank you Stefan,</div><div><br></div><div>I saw that note but was hoping some developer could shed light on what they mean by "more flexible" and "wherever possible". I guess otherwise it's just trial and error. </div><div><br></div><div>Regards,</div><div>Anita</div><span></span><br><br>On Wednesday, 19. October 2022 07:44:05 (+02:00), Stefan Giese (WhereGroup) wrote:<br><br><blockquote style="padding-left:1ex;border-left:2px solid rgb(0,0,255);margin:0px 0px 0.8ex">
<p>Hi Anita,</p>
<p>they are very similar, but the API Documentation says to <span dir="ltr" style="margin-top:0px;margin-bottom:0px">QgsProcessingParameterVectorDestination:</span>
"Note: Consider using the more flexible <a href="https://api.qgis.org/api/3.22/classQgsProcessingParameterFeatureSink.html" title="A feature sink output for processing algorithms." target="_blank">QgsProcessingParameterFeatureSink</a>
wherever possible."
(<a href="https://api.qgis.org/api/3.22/classQgsProcessingParameterVectorDestination.html#details" target="_blank">https://api.qgis.org/api/3.22/classQgsProcessingParameterVectorDestination.html#details</a>)</p>
<p>Best regards</p>
<p>Stefan<br>
</p>
<div>Am 18.10.2022 um 20:35 schrieb Anita
Graser via QGIS-Developer:<br>
</div>
<blockquote type="cite">
<span dir="ltr" style="margin-top:0px;margin-bottom:0px">Hi. </span>
<br>
<br>
<span dir="ltr" style="margin-top:0px;margin-bottom:0px">Does any
one of you know the real difference between
QgsProcessingParameterVectorDestination versus
QgsProcessingParameterFeatureSink? They seem to be used
interchangably in the resources I can find.</span> <br>
<br>
<span dir="ltr" style="margin-top:0px;margin-bottom:0px">Thank you.</span>
<br>
<br>
<span dir="ltr" style="margin-top:0px;margin-bottom:0px">Anita</span>
<br>
<br>
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