This class implements an optimised method for generating a profile
from a raster layer in a thread-safe way:
On the main thread:
- The data provider is cloned during preparation, and all other
required properties from the raster layer are copied and stored
for later thread-safe use on a background thread
On the background thread:
- The profile line is transformed to the raster's native CRS
- We then iterate over the portion of the raster which intersects
the profile line's bounding box in small tiles. We use small tiles
here as we will shortcut by skipping straight over any tiles which
don't intersect the profile line at all, without requesting their
raster data at all. Since the profile line will only cover a very
small portion of an overall raster extent, by using small tiles
we end up shortcutting and avoiding the costly tile pixel iteration
for most of the raster's coverage.
- For any tiles which DO intersect the profile curve, we fetch the
tile data and then iterate over the pixels, keeping only those
which actually intersect the profile curve. These pixel centroids
are then transformed back to the original CRS of the profile line.
- After collecting the filtered pixels centroids and their raster
(height) values, we then convert the pixel x/y locations to a
distance/chainage along the profile line, giving us an array of
distance vs height values for all pixels which intersect the profile
line.
Allows elevation properties to be set for raster layers, including:
- whether raster values represent heights
- scale
- offset
These properties can be set through the new "Elevation" tab in
the raster layer properties dialog
as "basemap" layers
This flag identifies if the layer is considered a 'basemap' layer, where
certain properties of the layer should be ignored when calculating
project-level properties. For instance, the extent of basemap layers
should be ignored when calculating the overall extent of a project,
as these layers are typically global and extend outside of a project's
area of interest.
Changes in the layer API:
* The setDatasource() methods become non-virtual public method
* The virtual private setDataSourcePrivate() method is defined and the provider setDataSource implementations have been moved to this new virtual method
The trust flag at the projetc level is only used to read vector layer extent from xml, not from provider.
This flag was not available at the vector layer and data provider level.
We propose a new QgsMapLayer reading flag to propagate the trust layer metadata prohect's read flag an d a new provider options to trust datasource config.
Trusting the datasource config means that the provider can use estimated metadata, the primary key is unique and the detectable geometry type and srid are the same as the requested.
Also
* in settings UI, add a 'Early resampling' checkbox
* in raster properties UI, add similar checkbox
* serialize/deserialize new settings in QgsRasterLayer XML
CRS validation, regardless of the user's settings
This avoids hacks put in place in other parts of QGIS code or in plugins
to temporarily deactivate the CRS validation prompt, providing a supported,
stable method to indicate that when loading a particular layer no CRS
validation is required.
The extent reported by raster layers may be smaller than the area
which can be rendered.
Notably for WMS with symbology that takes more space than the data.
Fix#30251
Adds a new visitor pattern API for creation of visitors which visit
all the style entities (symbols, color ramps, text formats, and
label styles) associated with different objects. Can be used on a
renderer, map layer, or project wide level.
E.g. on a project wide level, allows collection of ALL the style
symbols/color ramps/text settings inside a project, including those
in layouts or annotations!
