implot/TODO.md

The list below represents a combination of high-priority work, nice-to-have features, and random ideas. We make no guarantees that all of this work will be completed or even started. If you see something that you need or would like to have, let us know, or better yet consider submitting a PR for the feature.

API

Axes

• add flag to remove weekends on Time axis
• pixel space scale (ImPlotTransform_Display), normalized space scale (ImPlotTransform_Axes), data space scale (ImPlotTransform_Data)
• make ImPlotFlags_Equal not a flag -> SetupEqual(ImPlotAxis x, ImPlotAxis y)
• allow inverted arguments SetAxes to transpose data?
• SetupAxisColors()
• SetupAxisHome()

Plot Items

• add PlotBubbles (see MATLAB bubble chart)
• add non-zero references for PlotBars etc.
• add exploding to PlotPieChart (on hover-highlight?)
• fix appearance of PlotBars spacing

Styling

• support gradient and/or colormap sampled fills (e.g. ImPlotFillStyle_)
• API for setting different fonts for plot elements

Colormaps

• gradient editing tool
• RemoveColormap
• enum ImPlotColorRule_ { Solid, Faded, XValue, YValue, ZValue }

Legend

• ImPlotLegendFlags_SortItems
• ImPlotLegendFlags_Scroll
• improve legend icons (e.g. adopt markers, gradients, etc)
• make legend frame use ButtonBehavior (maybe impossible)

Tools / Misc.

• add IsPlotChanging to detect change in limits
• add ability to extend plot/axis context menus
• add LTTB downsampling for lines
• add box selection to axes
• first frame render delay might fix "fit pop" effect
• move some code to new implot_tools.cpp
• ColormapSlider (see metrics)
• FillAlpha should not affect markers?
• fix mouse text for time axes

Optimizations

• find faster way to buffer data into ImDrawList (very slow)
• reduce number of calls to PushClipRect
• explore SIMD operations for high density plot items

Plotter Pipeline

Ideally every PlotX function should use our faster rendering pipeline when it is applicable.

User Data > Getter > Fitter > Renderer > RenderPrimitives

Plotter	Getter	Fitter	Renderer	RenderPrimitives
PlotLine	Yes	Yes	Yes	Yes
PlotScatter	Yes	Yes	Yes	Yes
PlotStairs	Yes	Yes	Yes	Yes
PlotShaded	Yes	Yes	Yes	Yes
PlotBars	Yes	Yes	Yes	Yes
PlotBarGroups	:	:	:	:
PlotHistogram	:	:	:	:
PlotErrorBars	Yes	Yes	No	No
PlotStems	Yes	Yes	Yes	Yes
PlotInfLines	Yes	Yes	Yes	Yes
PlotPieChart	No	No	No	No
PlotHeatmap	Yes	No	Yes	Mixed
PlotHistogram2D	:	:	:	:
PlotDigital	Yes	No	No	No
PlotImage	-	-	-	-
PlotText	-	-	-	-
PlotDummy	-	-	-	-

Completed

• make BeginPlot take fewer args:
• make query a tool -> DragRect
• rework DragLine/Point to use ButtonBehavior
• add support for multiple x-axes and don't limit count to 3
• make axis side configurable (top/left, right/bottom) via new flag ImPlotAxisFlags_Opposite
• add support for setting tick label strings via callback
• give each axis an ID, remove ad-hoc DND solution
• allow axis to be drag to opposite side (ala ImGui Table headers)
• legend items can be hovered even if plot is not
• fix frame delay on DragX tools
• remove tag from drag line/point -> add Tag tool
• add shortcut/legacy overloads for BeginPlot
• SetupAxisConstraints()
• SetupAxisScale()
• add ImPlotLineFlags, ImPlotBarsFlags, etc. for each plot type
• add PlotBarGroups wrapper that makes rendering groups of bars easier, with stacked bar support
• PlotBars restore outlines
• add hover/active color for plot axes