Also
* in settings UI, add a 'Early resampling' checkbox
* in raster properties UI, add similar checkbox
* serialize/deserialize new settings in QgsRasterLayer XML
Fixes#36820
The way QGIS is currently handling resampling is sub-optimal given GDAL >= 2
capability of having sub-pixel accuracy. So when a QgsRasterResampleFilter
is set, make it try to delegate resampling back to the underlying input interface,
and implement that improved resampling in the GDAL provider.
The GDAL resampling will take into account the settings of the QGIS resample
filter: zoom-in resampling kernel, zoom-out resampling kernel and max resampling
factor. The later is important to avoid performance issues if not enough overview
levels are generated (in the case, we will fallback to the generic method, which
may introduce sub-pixel shifts)
Fixes#34813 by introducing a Prefetch rendering flag
and raster provider capability that can be set by
a provider when prefetching of out-of-viewport tiles
is allowed. For now it is only denied (hardcoded) for
OSM but the implementation allows per-layer setting when
a GUI element to set the flag will been created.
