[Feature thought] Allow to drag input layers into graphical modeler

[CWen001]

Feature description.

Thanks very much for the excellent open-source project. The graphical modeler is helpful not only to execute as a complex process on a different set of inputs, but also to act as a workplace to record/test different parameters and inputs. For the latter reason, users often have to modify the model and then to execute it back and forth. However, when executing, it is tedious for users to point input layers and parameters by hand every time, especially if there are many. QGIS so for doesn't allow to drag input layers directly into the model and save, like model builder in ArcGIS. I'm wondering if it is worth consideration?

Additional context

I understand that the graphical modeler system in QGIS is more like returning a function. Users can only provide the type of input data rather than the pointer to the data itself. if my feature request is far from its original design, possibly an alternative to solve the tedious-point-model-inputs-every-time problem is to add a "model run history" selection in the model calling window. The selection can help automatically pop-up previous executed inputs layers and parameters into the right positions.

Thank you very much. Hope the thoughts can help.
Chen

[baswein]

Is your "model run history" idea different than the history function found in Processing>History? That is what I use if I want to run a model and tweak a single input.

[CWen001]

Thanks for the comments. the 'Processing > History' is a general-purpose tool to record inputs and parameters. However, I expect something more from a recorder specifically for the graphical modeler, possibly a wrapper of the 'History' with other enhancement.

It would be convenient that the recorder can also record the model outputs and intermediate variables of the last runtimes, like checkpoints. It means that the custom model can have a clue what steps are computed and the middle variables available. When users further develop the model by adding new steps, the model (users) can choose whether to start from the checkpoints and only compute the necessary steps, or start from the beginning. It will be much helpful when the model is time-consuming or involves large datasets.

I guess this mimics the nice points of Modelbuilder (ArcGIS) that "both the tools (the yellow rectangles) and output variables (the green ovals) show a drop shadow around them indicating that these tools have been run". Users can decide only run some steps or branches of a model, and newly added steps can start from already-computed variables.

[alexbruy]

Duplicates #28828.