The old sip based approach to handling property -> getter/setter
conversion is broken on sip6, so move the patching into Python.
Also fix incorrect checks in tests, and add additional test
for compatiblity code.
This mode is purely for animated map movies -- the user can set
the total number of frames, and the animation will progress
frame by frame for that number of frames, advancing the current
map settings frame at each step (also the @frame_number expression
variable).
No time based filtering of data is performed when in this mode.
starting PyQGIS
We can't use `None` as a keyword exposed to python, it's reserved.
Also move the enum to Qgis before making it part of public stable
API.
The old behaviour was always to just redraw the layer, without
refreshing data. This was by design, as the feature was originally
developed to allow animated layers which needed to be regular,
quickly redrawn.
But there's also a use case for automatically refetching layer
data on a regular interval too. So now we expose a choice
of mode for the automatic refresh for users to decided which
is appropriate for their requirements.
The options are:
- "Reload Data": The layer will be completely refreshed. Any cached
data will be discarded and refetched from the provider. This mode
may result in slower map refreshes.
- "Redraw Layer Only": This mode is useful for animation or when
the layer's style will be updated at regular intervals. Canvas
updates are deferred in order to avoid refreshing multiple times
if more than one layer has an auto update interval set.
The changes are all wrapped up in a new reusable widget, so that
we can easily expose this setting for non vector/raster layers
if we want to in future.
Fixes https://github.com/qgis/QGIS/issues/39830
progress preview render results while drawing the layer, which
differ from the final layer render
The immediate use case here is for rendering tiled scene layers.
In order to generate the actual final render for these layers,
we need to first fetch ALL content for the render and then sort
the primitives by z value. But this means that the layer renders
can be extremely slow, with no visible changes on the map until
all the content fetching is complete. Not great user experience!
Instead, here we add the infrastructure so that a layer renderer
can get a temporary image to paint to for any partial renders.
This image gets used during map composition up until the layer
finally finishes rendering, at which time the layer's actual
destination image will be used for the composition.
This means that tiled scene renderers can now draw all tiles
(with unsorted primitives, and the artifacts which come with
that) as soon as we fetch each tile. This gives the user an
immediate visual reflection that the tiles are being fetched
and that how quickly (or slowly) that is happening. As soon
as we've got all tiles, the layer render will be immediately
switched to the version in which all content is rendered
in the correct z order.
As a bonus, we draw these temporary in progress renders
over any previously transformed cache version of the layer
available. So eg when you zoom in, you'll get a zoomed in pixelated
version of the last render which gets progressively drawn
over with each tile as it is fetched.
This same API could be used in future eg with point cloud
rendering when points are being sorted by z value to give
timely visual feedback.
