Drag should move all selected pages

[jeromerobert]

Select multiple pages, drag to different position -> should drag all selected pages and not only one. (sf, savannah) (quoting @darkdragon-001)

When starting the drag one must click on one page of among those who are selected. The problem is that clicking on an already selected icon in a Gtk IconView, unselect it.

Here are the only relevant pages Google gave to me:

• https://kevinmehall.net/2010/pygtk_multi_select_drag_drop
• https://stackoverflow.com/questions/48836650/python3-gtk3-iconview-drag-multiple-items

The first one is about TreeView and I was not able to adapt it to IconView. The second one still have no answer.

Thunar is using Gtk3 and properly handle multi-selection in IconView but they are exo IconView, not plain Gtk IconView.

I need help on that bug. If someone know a simple Gtk application (even better a pyGtk one) that properly handle multi-section in IconView that would help.

[dreua]

Here is my work in progress: dreua/pdfshuffler@a0a3b6a
It uses self.iconview.drag_begin_with_coordinates to initiate the drag and returns True on iv_button_press_event so the automatic deselection is prevented but the drag & drop is still possible. It is a proof of concept and already feels quite good but there is work to do, here is what I found so far:

• Unable to deselect pages by clicking on the selection. Especially a problem if you selected all pages.
• Simple clicking on the selection can lead to dnd being "stuck" even if mouse button is released.
• When dragging from one window to another a + symbol is displayed even if "move" operation is performed.

I belive this is all fixable using the ideas from your first link and maybe some mouse movement detection to decide if the user wants to click or drag. (E.g. emit the drag_begin_with_coordinates only after the mouse was moved some pixels from the mouse down location.)
I wanted to share this with you as I might not have the time to continue development on theses points this month. Everyone feel free to pick this up and improve.

Disclaimer: This might not be the best and easiest solution but I'm quite sure it is a doable solution. If there is a way to prevent the automatic deselection on button_press_event but keep the built in drag and drop intact, that might be a better solution. (More similar to the one in the first link.)

[dreua]

Ready for testing and input: master...dreua:wip_fix_multi_dnd

[jeromerobert]

@dreua Thank you, this is just brillant.