Issue numbers (#) refer to github issues listed at https://github.com/ocornut/imgui/issues/XXXX
The list below consist mostly of ideas noted down before they are requested/discussed by users (at which point they usually exist on the github issue tracker).
It's mostly a bunch of personal notes, probably incomplete. Feel free to query if you have any questions.
- doc/test: add a proper documentation+regression testing system (#435)
- doc/test: checklist app to verify binding/integration of imgui (test inputs, rendering, callback, etc.).
- doc/tips: tips of the day: website? applet in imgui_club?
- project: folder or separate repository with maintained helpers (e.g. imgui_memory_editor.h, imgui_stl.h, maybe imgui_dock would be there?)
- window: calling SetNextWindowSize() every frame with <= 0 doesn't do anything, may be useful to allow (particularly when used for a single axis). (#690)
- window: add a way for very transient windows (non-saved, temporary overlay over hundreds of objects) to "clean" up from the global window list. perhaps a lightweight explicit cleanup pass.
- window: auto-fit feedback loop when user relies on any dynamic layout (window width multiplier, column) appears weird to end-user. clarify.
- window: allow resizing of child windows (possibly given min/max for each axis?.)
- window: using SetWindowPos() inside Begin() and moving the window with the mouse reacts a very ugly glitch. We should just defer the SetWindowPos() call.
- drawlist: end-user probably can't call Clear() directly because we expect a texture to be pushed in the stack.
- drawlist: maintaining bounding box per command would allow to merge draw command when clipping isn't relied on (typical non-scrolling window or non-overflowing column would merge with previous command).
- drawlist: primitives/helpers to manipulate vertices post submission, so e.g. a quad/rect can be resized to fit later submitted content, _without_ using the ChannelSplit api
- drawlist: would be good to be able to deep copy of ImDrawData (we have a deep copy of ImDrawList now).
- drawlist: rendering: provide a way for imgui to output to a single/global vertex buffer, re-order indices only at the end of the frame (ref: https://gist.github.com/floooh/10388a0afbe08fce9e617d8aefa7d302)
- drawlist: callback: add an extra void* in ImDrawCallback to allow passing render-local data to the callback (would break API).
- drawlist/opt: store rounded corners in texture to use 1 quad per corner (filled and wireframe) to lower the cost of rounding. (#1962)
- main: considering adding an Init() function? some constructs are awkward in the implementation because of the lack of them.
- main: find a way to preserve relative orders of multiple reappearing windows (so an app toggling between "modes" e.g. fullscreen vs all tools) won't lose relative ordering.
- main: IsItemHovered() make it more consistent for various type of widgets, widgets with multiple components, etc. also effectively IsHovered() region sometimes differs from hot region, e.g tree nodes
- main: IsItemHovered() info stored in a stack? so that 'if TreeNode() { Text; TreePop; } if IsHovered' return the hover state of the TreeNode?
- main: rename the main "Debug" window to avoid ID collision with user who may want to use "Debug" with specific flags.
- widgets: display mode: widget-label, label-widget (aligned on column or using fixed size), label-newline-tab-widget etc. (#395)
- widgets: clean up widgets internal toward exposing everything and stabilizing imgui_internals.h.
- widgets: a way to represent "mixed" values, so e.g. all values replaced with **, including check-boxes, colors, etc. with support for multi-components widgets (e.g. SliderFloat3, make only "Y" mixed)
- input text: easier ways to update buffer (from source char*) while owned. preserve some sort of cursor position for multi-line text.
- input text: add discard flag (e.g. ImGuiInputTextFlags_DiscardActiveBuffer) or make it easier to clear active focus for text replacement during edition (#725)
- input text: display bug when clicking a drag/slider after an input text in a different window has all-selected text (order dependent). actually a very old bug but no one appears to have noticed it.
- input text: allow centering/positioning text so that ctrl+clicking Drag or Slider keeps the textual value at the same pixel position.
- input text: what's the easiest way to implement a nice IP/Mac address input editor?
- input text multi-line: don't directly call AddText() which does an unnecessary vertex reserve for character count prior to clipping. and/or more line-based clipping to AddText(). and/or reorganize TextUnformatted/RenderText for more efficiency for large text (e.g TextUnformatted could clip and log separately, etc).
- input text multi-line: support for cut/paste without selection (cut/paste the current line)
- input text multi-line: line numbers? status bar? (follow up on #200)
- input text multi-line: behave better when user changes input buffer while editing is active (even though it is illegal behavior). namely, the change of buffer can create a scrollbar glitch (#725)
- input text multi-line: better horizontal scrolling support (#383, #1224)
- input number: optional range min/max for Input*() functions
- input number: holding [-]/[+] buttons could increase the step speed non-linearly (or user-controlled)
- input number: use mouse wheel to step up/down
- input number: applying arithmetics ops (+,-,*,/) messes up with text edit undo stack.
- layout: helper or a way to express ImGui::SameLine(ImGui::GetCursorStartPos().x + ImGui::CalcItemWidth() + ImGui::GetStyle().ItemInnerSpacing.x); in a simpler manner.
- layout: generalization of the above: a concept equivalent to word processor ruler tab stop ~ mini columns (position in X, no clipping implied) (vaguely relate to #267, #395, also what is used internally for menu items)
- layout: horizontal layout helper (#97)
- layout: horizontal flow until no space left (#404)
- layout: more generic alignment state (left/right/centered) for single items?
- layout: clean up the InputFloatN/SliderFloatN/ColorEdit4 layout code. item width should include frame padding.
- layout: BeginGroup() needs a border option. (~#1496)
- plot: add a helper e.g. Plot(char* label, float value, float time_span=2.0f) that stores values and Plot them for you - probably another function name. and/or automatically allow to plot ANY displayed value (more reliance on stable ID)
- clipper: ability to force display 1 item in the list would be convenient (for patterns where we need to set active id etc.)
- clipper: ability to disable the clipping through a simple flag/bool.
- clipper: ability to run without knowing full count in advance.
- splitter/separator: formalize the splitter idiom into an official api (we want to handle n-way split) (#319)
- dock: docking extension
- dock: dock out from a collapsing header? would work nicely but need emitting window to keep submitting the code.
- tabs: re-ordering, close buttons, context menu, persistent order (#261, #351)
- image/image button: misalignment on padded/bordered button?
- image/image button: parameters are confusing, image() has tint_col,border_col whereas imagebutton() has bg_col/tint_col. Even thou they are different parameters ordering could be more consistent. can we fix that?
- image button: not taking an explicit id is odd.
- slider: allow using the [-]/[+] buttons used by InputFloat()/InputInt()
- drag float: added leeway on edge (e.g. a few invisible steps past the clamp limits)
- combo: use clipper: make it easier to disable clipper with a single flag.
- combo: flag for BeginCombo to not return true when unchanged (#1182)
- combo: a way/helper to customize the combo preview (#1658)
- combo/listbox: keyboard control. need InputText-like non-active focus + key handling. considering keyboard for custom listbox (pr #203)
- listbox: refactor and clean the begin/end api
- listbox: multiple selection.
- listbox: unselect option (#1208)
- listbox: make it easier/more natural to implement range-select (need some sort of info/ref about the last clicked/focused item that user can translate to an index?) (wip stash)
- listbox: user may want to initial scroll to focus on the one selected value?
- listbox: expose hovered item for a basic ListBox
- listbox: keyboard navigation.
- listbox: scrolling should track modified selection.
!- popups/menus: clarify usage of popups id, how MenuItem/Selectable closing parent popups affects the ID, etc. this is quite fishy needs improvement! (#331, #402)
- popups: reopening context menu at new position should be the behavior by default? (equivalent to internal OpenPopupEx() with reopen_existing=true) (~#1497)
- popups: if the popup functions took explicit ImGuiID it would allow the user to manage the scope of those ID. (#331)
- popups: clicking outside (to close popup) and holding shouldn't drag window below.
- popups: add variant using global identifier similar to Begin/End (#402)
- popups: border options. richer api like BeginChild() perhaps? (#197)
- tooltip: drag and drop with tooltip near monitor edges lose/changes its last direction instead of locking one. The drag and drop tooltip should always follow without changing direction.
- tooltip: tooltips with delay timers? or general timer policy? (instantaneous vs timed): IsItemHovered() with timer + implicit aabb-id for items with no ID. (#1485)
- menus: hovering from menu to menu on a menu-bar has 1 frame without any menu, which is a little annoying. ideally either 0 either longer.
- text: selectable text (for copy) as a generic feature (ItemFlags?)
- text: proper alignment options in imgui_internal.h
- text wrapped: figure out better way to use TextWrapped() in an always auto-resize context (tooltip, etc.) (#249)
- text: it's currently impossible to have a window title with "##". perhaps an official workaround would be nice. \ style inhibitor? non-visible ascii code to insert between #?
- text: provided a framed text helper, e.g. https://pastebin.com/1Laxy8bT
- text link/url button: underlined. should api expose an ID or use text contents as ID? which colors enum to use?
- tree node / optimization: avoid formatting when clipped.
- tree node: tree-node/header right-most side doesn't take account of horizontal scrolling.
- tree node: add treenode/treepush int variants? not there because (void*) cast from int warns on some platforms/settings?
- tree node: try to apply scrolling at time of TreePop() if node was just opened and end of node is past scrolling limits?
- tree node / selectable render mismatch which is visible if you use them both next to each other (e.g. cf. property viewer)
- tree node: tweak color scheme to distinguish headers from selected tree node (#581)
- tree node: leaf/non-leaf highlight mismatch.
- settings: write more decent code to allow saving/loading new fields: columns, selected tree nodes?
- settings: api for per-tool simple persistent data (bool,int,float,columns sizes,etc.) in .ini file (#437)
- stb: add defines to disable stb implementations
!- style: better default styles. (#707)
- style: add a highlighted text color (for headers, etc.)
- style: border types: out-screen, in-screen, etc. (#447)
- style: add window shadow (fading away from the window. Paint-style calculation of vertices alpha after drawlist would be easier)
- style: a concept of "compact style" that the end-user can easily rely on (e.g. PushStyleCompact()?) that maps to other settings? avoid implementing duplicate helpers such as SmallCheckbox(), etc.
- style: try to make PushStyleVar() more robust to incorrect parameters (to be more friendly to edit & continues situation).
- style: global scale setting.
- style: WindowPadding needs to be EVEN as the 0.5 multiplier used on this value probably have a subtle effect on clip rectangle
- style: have a more global HSV setter (e.g. alter hue on all elements). consider replacing active/hovered by offset in HSV space? (#438, #707, #1223)
- style: gradients fill (#1223) ~ 2 bg colors for each fill? tricky with rounded shapes and using textures for corners.
- style editor: color child window height expressed in multiple of line height.
- log: have more control over the log scope (e.g. stop logging when leaving current tree node scope)
- log: be able to log anything (e.g. right-click on a window/tree-node, shows context menu? log into tty/file/clipboard)
- log: let user copy any window content to clipboard easily (CTRL+C on windows? while moving it? context menu?). code is commented because it fails with multiple Begin/End pairs.
- filters: set a current filter that tree node can automatically query to hide themselves
- drag and drop: make it easier and provide a demo to have tooltip both are source and target site, with a more detailed one on target site (tooltip ordering problem)
- markup: simple markup language for color change? (#902)
!- font: need handling of missing glyphs by not packing/rasterizing glyph 0 of a given font.
- font: MergeMode: flags to select overwriting or not.
- font: MergeMode: duplicate glyphs are stored in the atlas texture which is suboptimal.
- font: free the Alpha buffer if user only requested RGBA.
!- font: better CalcTextSizeA() API, at least for simple use cases. current one is horrible (perhaps have simple vs extended versions).
- font: a CalcTextHeight() helper could run faster than CalcTextSize().y
- font: enforce monospace through ImFontConfig (for icons?) + create dual ImFont output from same input, reusing rasterized data but with different glyphs/AdvanceX
- font: imgui_freetype.h alternative renderer (#618)
- font: optimization: for monospace font (like the default one) we can trim IndexXAdvance as long as trailing value is == FallbackXAdvance (need to make sure TAB is still correct).
- font: add support for kerning, probably optional. A) perhaps default to (32..128)^2 matrix ~ 9K entries = 36KB, then hash for non-ascii?. B) or sparse lookup into per-char list?
- font: add a simpler CalcTextSizeA() api? current one ok but not welcome if user needs to call it directly (without going through ImGui::CalcTextSize)
- font: fix AddRemapChar() to work before font has been built.
- font: (api breaking) removed "TTF" from symbol names. also because it now supports OTF.
- nav: wrap around logic to allow e.g. grid based layout (pressing NavRight on the right-most element would go to the next row, etc.). see internal's NavMoveRequestTryWrapping().
- nav: patterns to make it possible for arrows key to update selection
- nav: restore/find nearest navid when current one disappear (e.g. pressed a button that disappear, or perhaps auto restoring when current button change name)
- nav: SetItemDefaultFocus() level of priority, so widget like Selectable when inside a popup could claim a low-priority default focus on the first selected iem
- nav: allow input system to be be more tolerant of io.DeltaTime=0.0f
- nav: ESC within a menu of a child window seems to exit the child window.
- nav: NavFlattened: ESC on a flattened child should select something.
- nav: NavFlattened: broken: in typical usage scenario, the items of a fully clipped child are currently not considered to enter into a NavFlattened child.
- nav: NavFlattened: init request doesn't select items that are part of a NavFlattened child
- nav: NavFlattened: cannot access menu-bar of a flattened child window with Alt/menu key (not a very common use case..).
- nav: Left within a tree node block as a fallback (ImGuiTreeNodeFlags_NavLeftJumpsBackHere by default?)
- nav: menus: pressing left-right on a vertically clipped menu bar tends to jump to the collapse/close buttons.
- nav: menus: allow pressing Menu to leave a sub-menu.
- nav: simulate right-click or context activation? (SHIFT+F10)
- nav: tabs should go through most/all widgets (in submission order?).
- nav: when CTRL-Tab/windowing is active, the HoveredWindow detection doesn't take account of the window display re-ordering.
- nav: esc/enter default behavior for popups, e.g. be able to mark an "ok" or "cancel" button that would get triggered by those keys.
- nav: when activating a button that changes label (without a static ID) or disappear, can we somehow automatically recover into a nearest highlight item?
- nav: there's currently no way to completely clear focus with the keyboard. depending on patterns used by the application to dispatch inputs, it may be desirable.
- nav: configuration flag to disable global shortcuts (currently only CTRL-tab) ?
- focus: preserve ActiveId/focus stack state, e.g. when opening a menu and close it, previously selected InputText() focus gets restored (#622)
- focus: SetKeyboardFocusHere() on with >= 0 offset could be done on same frame (else latch and modulate on beginning of next frame)
- focus: unable to use SetKeyboardFocusHere() on clipped widgets. (#787)
- inputs: we need an explicit flag about whether the imgui window is focused, to be able to distinguish focused key releases vs alt-tabbing all release behaviors.
- inputs: rework IO system to be able to pass actual ordered/timestamped events. use an event queue? (~#335, #71)
- inputs: support track pad style scrolling & slider edit.
- misc: imgui_cpp: perhaps a misc/ header file with more friendly helper (e.g. type-infer versions of DragScalar, vector<> variants if appropriate for some functions).
- web/emscriptem: with refactored examples, we could provide a direct imgui_impl_emscripten platform layer (see eg. https://github.com/floooh/sokol-samples/blob/master/html5/imgui-emsc.cc#L42)
- examples: provide a zero frame-rate/idle example.
- examples: apple: example_apple should be using modern GL3.
- examples: glfw: could go idle when minimized? if (glfwGetWindowAttrib(window, GLFW_ICONIFIED)) { glfwWaitEvents(); continue; } // issue: DeltaTime will be super high on resume, perhaps provide a way to let impl know (#440)
- optimization: replace vsnprintf with stb_printf? or enable the defines/infrastructure to allow it (#1038)
- optimization: add clipping for multi-component widgets (SliderFloatX, ColorEditX, etc.). one problem is that nav branch can't easily clip parent group when there is a move request.
- optimization: add a flag to disable most of rendering, for the case where the user expect to skip it (#335)
- optimization: use another hash function than crc32, e.g. FNV1a
- optimization/render: merge command-lists with same clip-rect into one even if they aren't sequential? (as long as in-between clip rectangle don't overlap)?
- optimization: turn some the various stack vectors into statically-sized arrays
