Controls: refactor interactivity management system

[swharden]

This PR explores alternative strategies for customizing user interactivity in graphical environments.

Primary Goals

• Ability to re-map inputs with actions (e.g., right-click-drag pan)
• Ability to add arbitrary inputs (e.g., two-finger pinch)
• Ability to customize actions (e.g., increasing sensitivity of right-click-drag zoom)
• Ability to add arbitrary actions (e.g., holding left and right mouse buttons down while dragging only pans horizontally or vertically)
• Improved ability to unit test interactive behavior
• Ability to opt-in to the new system, allowing existing users to continue using the original Interaction.cs and PlotActions.cs system while the new system matures.
• Related: Controls: refactor input binding system #3186

Architecture

• User inputs are structs that inherit IUserInput and contain any properties that may be unique to that type of input (e.g., LeftMouseDown has a stores a Pixel and DateTime)

• User input actions are classes that contain logic for when and how to respond to user inputs, including whether to refresh the plot or stop processing further actions (e.g., LeftClickDragPan engages only after LeftMouseDown happens and MouseMove moved by more than 5 pixels, preventing other actions from being processed until LeftMouseUp occurs)

• Plot controls have a UserInputProcessor that they pass user inputs into, and it holds a collection of user input actions that decide if and how to respond to the events. Users can remove actions (like double-click benchmark), add custom actions (like holding the A key while left-click-dragging will only pan diagonally), and even pass custom input types through (like three-finger-drag).

Rules to Implement

Items are checked only when implemented and unit tests are in place

• Left-click-drag pan
• Shift+ left-click-drag pan vertically
• Ctrl + left-click-drag pan horizontally
• Right-click-drag zoom
• Shift + right-click-drag zoom
• Ctrl + right-click-drag zoom
• Scroll wheel zoom
• Shift + scroll wheel zoom vertically
• Ctrl + scroll wheel zoom horizontally
• Middle-click-drag zoom rectangle
• Shift + Middle-click-drag zoom rectangle horizontally
• Ctrl + Middle-click-drag zoom rectangle vertically
• Alt + left-click-drag zoom rectangle
• Right-click open context menu
• Single left-click custom action
• Double-click benchmark
• Arrow keys pan
• Alt + arrow keys zoom
• Create a mock IPlotControl that can simulate user inputs for testing
• Interactions initiated over an axis only act on that axis
• Test all actions with DPI scaling enabled
• Test all actions with custom ScaleFactor
• Create MultiAxisLimits to replace MultiAxisLimitManager
• Add a demo with examples of common user input customizations

[swharden]

I'm getting close to merging this. The new behavior is demonstrated in the "custom mouse behavior" demo app.

The code shows the general style of how the new API can be used.

ScottPlot/src/ScottPlot5/ScottPlot5 Demos/ScottPlot5 WinForms Demo/Demos/CustomMouseActions.cs

Lines 11 to 88 in 1bd1400

	public CustomMouseActions()
	{
	InitializeComponent();
	// Disable the old input system and enable the new one.
	// The new one will be enabled by default in a future release.
	formsPlot1.Interaction.IsEnabled = false;
	formsPlot1.UserInputProcessor.IsEnabled = true;
	formsPlot1.Plot.Add.Signal(ScottPlot.Generate.Sin());
	formsPlot1.Plot.Add.Signal(ScottPlot.Generate.Cos());
	btnDefault.Click += (s, e) =>
	{
	richTextBox1.Text = "left-click-drag pan, right-click-drag zoom, middle-click autoscale, " +
	"middle-click-drag zoom rectangle, alt+left-click-drag zoom rectangle, right-click menu, " +
	"double-click benchmark, scroll wheel zoom, arrow keys pan, " +
	"shift or alt with arrow keys pans more or less, ctrl+arrow keys zoom";
	formsPlot1.UserInputProcessor.IsEnabled = true;
	formsPlot1.UserInputProcessor.Reset();
	};
	btnDisable.Click += (s, e) =>
	{
	richTextBox1.Text = "Mouse and keyboard events are disabled";
	formsPlot1.UserInputProcessor.IsEnabled = false;
	};
	btnCustom.Click += (s, e) =>
	{
	richTextBox1.Text = "middle-click-drag pan, right-click-drag zoom rectangle, " +
	"right-click autoscale, left-click menu, Q key autoscale, WASD keys pan";
	formsPlot1.UserInputProcessor.IsEnabled = true;
	// remove all existing responses so we can create and add our own
	formsPlot1.UserInputProcessor.UserActionResponses.Clear();
	// middle-click-drag pan
	var panButton = ScottPlot.Interactivity.StandardMouseButtons.Middle;
	var panResponse = new ScottPlot.Interactivity.UserActionResponses.MouseDragPan(panButton);
	formsPlot1.UserInputProcessor.UserActionResponses.Add(panResponse);
	// right-click-drag zoom rectangle
	var zoomRectangleButton = ScottPlot.Interactivity.StandardMouseButtons.Right;
	var zoomRectangleResponse = new ScottPlot.Interactivity.UserActionResponses.MouseDragZoomRectangle(zoomRectangleButton);
	formsPlot1.UserInputProcessor.UserActionResponses.Add(zoomRectangleResponse);
	// right-click autoscale
	var autoscaleButton = ScottPlot.Interactivity.StandardMouseButtons.Right;
	var autoscaleResponse = new ScottPlot.Interactivity.UserActionResponses.SingleClickAutoscale(autoscaleButton);
	formsPlot1.UserInputProcessor.UserActionResponses.Add(autoscaleResponse);
	// left-click menu
	var menuButton = ScottPlot.Interactivity.StandardMouseButtons.Left;
	var menuResponse = new ScottPlot.Interactivity.UserActionResponses.SingleClickContextMenu(menuButton);
	formsPlot1.UserInputProcessor.UserActionResponses.Add(menuResponse);
	// Q key autoscale too
	var autoscaleKey = new ScottPlot.Interactivity.Key("Q");
	Action<ScottPlot.Plot, ScottPlot.Pixel> autoscaleAction = (plot, pixel) => plot.Axes.AutoScale();
	var autoscaleKeyResponse = new ScottPlot.Interactivity.UserActionResponses.KeyPressResponse(autoscaleKey, autoscaleAction);
	formsPlot1.UserInputProcessor.UserActionResponses.Add(autoscaleKeyResponse);
	// WASD keys pan
	var keyPanResponse = new ScottPlot.Interactivity.UserActionResponses.KeyboardPanAndZoom()
	{
	PanUpKey = new ScottPlot.Interactivity.Key("W"),
	PanLeftKey = new ScottPlot.Interactivity.Key("A"),
	PanDownKey = new ScottPlot.Interactivity.Key("S"),
	PanRightKey = new ScottPlot.Interactivity.Key("D"),
	};
	formsPlot1.UserInputProcessor.UserActionResponses.Add(keyPanResponse);
	};
	Load += (s, e) => btnDefault.PerformClick();
	}