Mouse delta from DeviceEvent #1614

enomado · 2022-05-10T16:31:06Z

This can enhance usability of DragValue much. #1611

2022-05-10.19-27-13.mp4

emilk

Thanks! This needs a line in the egui changelog so other integrations knows to use the new event.

Also: should this be implemented for eframe web?

egui-winit/src/lib.rs

egui/src/data/input.rs

enomado · 2022-05-11T13:19:40Z

Also: should this be implemented for eframe web?

it could be, i think. web-event has delta already. anyway, as i said it should not break existing behavior, if there was no MouseDelta emmited

enomado · 2022-05-11T14:15:36Z

Bad news. web just cant delta. I thought this numeric input works, I thought this works https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/movementX

But seems not. So in wasm it works the old way.

emilk

There is a problem with this approach: the units emitted by MouseMotion is in unspecified units: https://docs.rs/winit/latest/winit/event/enum.DeviceEvent.html#variant.MouseMotion

For instance, these units may be ignoring mouse sensitivity or acceleration. Therefor it is not equivalent to comparing changes in pointer position. I think if you really want to use this in a UI we need to assign it to something else than PointerState::delta, and keep that to mean "mosue movements in points", and perhaps add a separate motion: Vec2 for these unspecified units (which can still fall back to changes in pointer position for integrations that don't emit MosueDelta events.

emilk · 2022-05-11T17:08:32Z

egui/src/data/input.rs

+    /// The mouse delta from winit::DeviceEvent. MouseDelta and PointerMoved can be emmited simultaneously.
+    /// If MouseDelta accumulated value is zero per frame, then `old_pos-new_pos` will be used as fallback.
+    /// For now it used in situations when we need delta but mouse pointer is on screen edge.
+    MouseDelta(Vec2),


Suggested change

/// The mouse delta from winit::DeviceEvent. MouseDelta and PointerMoved can be emmited simultaneously.

/// If MouseDelta accumulated value is zero per frame, then `old_pos-new_pos` will be used as fallback.

/// For now it used in situations when we need delta but mouse pointer is on screen edge.

MouseDelta(Vec2),

/// Mouse movement in unspecified units.

///

/// Both [`Self::MouseDelta`] and [`Self::PointerMoved`] can both be emitted for the same movement,

/// but when a pointer is grabbed or at the edge of the screen, only [`Self::MouseDelta`] is emitted.

///

/// Some integrations do not emit any [`Self::MouseDelta`]. In these cases the change in [`Self::PointerMoved`] will be used for [`PointerState::delta`].

MouseDelta(Vec2),

"The mouse delta from winit::DeviceEvent." is true for one of many backends, but not for all.

These docstrings have two targets: egui users, and people writing egui integrations.

egui/src/input_state.rs

enomado · 2022-05-11T22:55:01Z

perhaps add a separate motion: Vec2 for these unspecified units
Great idea. I'll do it. And change DragValue to use them.

enomado · 2022-05-20T01:59:38Z

Squashed and rebased

emilk · 2022-05-21T11:11:04Z

egui/src/data/input.rs

+    /// The mouse delta from winit::DeviceEvent. MouseDelta and PointerMoved can be emmited simultaneously.
+    /// If MouseDelta accumulated value is zero per frame, then `old_pos-new_pos` will be used as fallback.
+    /// For now it used in situations when we need delta but mouse pointer is on screen edge.
+    MouseDelta(Vec2),


"The mouse delta from winit::DeviceEvent." is true for one of many backends, but not for all.

These docstrings have two targets: egui users, and people writing egui integrations.

egui/src/response.rs

enomado · 2022-05-22T18:58:04Z

Sorry. Is any changes still needed? I was trying to document my best, but there is long story behind this stuff

emilk · 2022-08-20T07:55:41Z

egui/src/response.rs

+                res
+            }
+        }
+    }


It's not eguis responsibility to have platform-specific code like this. Instead it is up to the integrations to feed egui with the correct input.

In this case the winit backend should feed different data than the web backend. Other integrations needs to do whats right for them.

So if this is called mtion_delta then it should probably use self.ctx.input().pointer.motion() regardless of what the compilation target is.

Also: 'wasm" doesn't mean "web". There are egui users who run egui in wasmtime on desktop.

emilk · 2022-08-20T07:58:34Z

egui/src/response.rs

+                // in a case of touchscreen or whatever
+                self.ctx.input().pointer.delta()


maybe touch screens should set motion too?

Better yet: RawInput could have motion: Option<Vec2> and then InputState::begin_frame would use it if set, or else fall back to the pointer delta. That way it will work correctly for all existing backends.

Raw mouse movement is unaccelerated and unclamped by screen boundaries, and does not relate to any position on the screen. It is useful in certain situations such as draggable values and 3D cameras, where screen position does not matter. https://github.com/emilk/egui/assets/1700581/1400e6a6-0573-41b9-99a1-a9cd305aa1a3 Added `Event::MouseMoved` for integrations to supply raw mouse movement. Added `Response:drag_motion` to get the raw mouse movement, but will fall back to delta in case the integration does not supply it. Nothing should be breaking, but third-party integrations that can send `Event::MouseMoved` should be updated to do so. Based on #1614 but updated to the current version, and with better fallback behaviour. * Closes #1611 * Supersedes #1614

Raw mouse movement is unaccelerated and unclamped by screen boundaries, and does not relate to any position on the screen. It is useful in certain situations such as draggable values and 3D cameras, where screen position does not matter. https://github.com/emilk/egui/assets/1700581/1400e6a6-0573-41b9-99a1-a9cd305aa1a3 Added `Event::MouseMoved` for integrations to supply raw mouse movement. Added `Response:drag_motion` to get the raw mouse movement, but will fall back to delta in case the integration does not supply it. Nothing should be breaking, but third-party integrations that can send `Event::MouseMoved` should be updated to do so. Based on emilk#1614 but updated to the current version, and with better fallback behaviour. * Closes emilk#1611 * Supersedes emilk#1614

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enomado force-pushed the better_mouse_delta branch from 5cd6bde to 8ffe94c Compare May 11, 2022 13:14

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enomado force-pushed the better_mouse_delta branch from 33b6a5f to 8e334d6 Compare May 15, 2022 18:01

Mouse delta from DeviceEvent

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enomado force-pushed the better_mouse_delta branch from 2984981 to e401fa4 Compare May 20, 2022 01:58

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enomado added 2 commits May 21, 2022 16:59

better docs

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better docs

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emilk marked this pull request as draft January 7, 2024 15:56

GiantBlargg mentioned this pull request Feb 17, 2024

Add API for raw mouse motion #4063

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Mouse delta from DeviceEvent #1614

Mouse delta from DeviceEvent #1614

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emilk Aug 20, 2022

		// in a case of touchscreen or whatever
		self.ctx.input().pointer.delta()

Mouse delta from DeviceEvent #1614

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Mouse delta from DeviceEvent #1614

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