overScaleMode

[joshkel]

Is there any way to allow both overScaleMode and regular zooming? I'd like to allow both regular zooming (to zoom both axes via mouse wheel or pinch on the main chart area) and zooming a specific scale (to zoom only one axis via mouse wheel or pinch over the scale axis), but it seems that overScaleMode prevents regular zooming from working.

I would have expected that mode control regular zooming, while overScaleMode controls scale zooming in particular. For example:

• {mode: 'xy', overScaleMode: 'y'} would mean that zooming over the regular chart scales X and Y, and zooming over the Y axis scales Y.
• {mode: 'x', overScaleMode: 'y'} would mean that zooming over the regular chart scales X, and zooming over the Y axis scales Y.
• {mode: 'xy', overScaleMode: 'xy'} would mean that zooming over the regular chart scales X and Y, and zooming over the X or Y axis scales X or Y, respectively.

Instead, it appears that overScaleMode restricts and modifies mode:

• {mode: 'xy', overScaleMode: 'y'} would mean that zooming over the regular chart scales only X, and zooming over the Y axis scales Y.
• {mode: 'x', overScaleMode: 'y'} is an invalid configuration.
• {mode: 'xy', overScaleMode: 'xy'} would mean that zooming over the regular chart does nothing, and zooming over the X or Y axis scales X or Y, respectively.

chartjs-plugin-zoom/src/core.js

Line 69 in bb6dee3

const enabledScales = overScaleMode && getEnabledScalesByPoint(overScaleMode, focalPoint, chart);

chartjs-plugin-zoom/src/utils.js

Line 57 in bb6dee3

/** This function return only one scale whose position is under mouse cursor and which direction is enabled.

[joshkel]

See #658