pistondevelopers / drag_controller Goto Github PK

All I really want out of DragController is to know when an area is being dragged, and by how much each frame. It'd be really cool if it could do that. I might implement this myself real quick.

The event method takes f: |Drag| -> bool which in code is not self documenting, since one usually puts true or false at the end of the closure.

By using an enum DragAction with Continue and Cancel the code will be easier to read.

Tried to fix myself, but couldn't quite figure it out.

   Compiling piston2d-drag_controller v0.0.2 (file:///Users/aaronmcleod/Documents/programming/rust/drag_controller)
src/lib.rs:69:17: 69:49 error: mismatched types:
 expected `input::Button`,
    found `input::Button`
(expected enum `input::Button`,
    found a different enum `input::Button`) [E0308]
src/lib.rs:69                 Button::Mouse(MouseButton::Left) => {
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/lib.rs:83:17: 83:49 error: mismatched types:
 expected `input::Button`,
    found `input::Button`
(expected enum `input::Button`,
    found a different enum `input::Button`) [E0308]
src/lib.rs:83                 Button::Mouse(MouseButton::Left) => {
                              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 2 previous errors
Could not compile `piston2d-drag_controller`.

I'm using piston with gfx and glutin, and when I resize the window, it starts a drag once I let go of the mouse button on the window resize, and a drag is happening without having the mouse button pressed.

If the mouse cursor leaves the window while a drag is in progress, the drag controller will continue the drag when it re-enters, even if the mouse button was released while the cursor was out of view. This is generally undesirable behavior, as far as I can tell.

Some window back-ends do not emit mouse events outside the window, which might cause undesirable behavior.

For example, when dragging and left mouse button is released outside the window, when entering this might mess up something and with no way to cancel the operation.

I think there should be a way to cancel drag operations. This can be a useful feature also when you can continue dragging outside the window.

A = dealing with interruption, such as window loosing focus
B = dealing with cancelling
M = mess up behavior

A, B, !M. When dealing with interruption, you can also deal with cancelling operations.

!A, !B, ?!M. When not dealing with interruption or cancelling, you usually don't mess up behavior. Cancelling can simply be ignored.

When building the current Piston, I get the following:

$ cargo build --verbose
[...]
Compiling input v0.0.0 (https://github.com/pistondevelopers/input#fb351501)
[...]
Compiling drag_controller v0.0.0 (https://github.com/pistondevelopers/drag_controller#a797ac06)
[...]
src/lib.rs:17:5: 17:10 error: unresolved import `input::Mouse`. There is no `Mouse` in `input`
src/lib.rs:17     Mouse,
                  ^~~~~
error: aborting due to previous error
Build failed, waiting for other jobs to finish...
Could not compile `drag_controller`.

where it bails as indicated. Checking input, there is indeed no input::Mouse present.