Proposal: Optional zero-cost ImDrawList hooks for vector / alternative backends #9556

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opened 2026-09-24 21:05:00 +00:00 by hotredman · 2 comments

hotredman commented

2026-09-24 21:05:00 +00:00

(Migrated from github.com)

Hi,
I built a vector backend for Dear ImGui using ThorVG:
https://github.com/hotredman/imthorgui
To render true vector shapes, I need to intercept primitives (AddRectFilled, AddText, etc.) at the ImDrawList level.
I added minimal hook macros in imgui_draw.cpp (zero runtime overhead when disabled, following the IMGUI_ENABLE_TEST_ENGINE pattern).
Only 2 small commits in my fork:
https://github.com/hotredman/imgui/commits/drawlist-hooks
Would you be open to a clean PR adding these optional hooks upstream?

Hi, I built a vector backend for Dear ImGui using ThorVG: https://github.com/hotredman/imthorgui To render true vector shapes, I need to intercept primitives (`AddRectFilled`, `AddText`, etc.) at the `ImDrawList` level. I added minimal hook macros in `imgui_draw.cpp` (zero runtime overhead when disabled, following the `IMGUI_ENABLE_TEST_ENGINE` pattern). Only 2 small commits in my fork: https://github.com/hotredman/imgui/commits/drawlist-hooks Would you be open to a clean PR adding these optional hooks upstream?

ocornut commented

2026-09-25 09:55:10 +00:00

(Migrated from github.com)

May I ask - wouldn't it simpler to add a define to remove the ImDrawList implementation, and let you compile with your own?

I'm generally supportive of those efforts but I feel the hooks could be added on your side for a while. If there's a proven lasting interest in the feature and your solution we can consider adding the hooks but for now they seem pretty simple to add on your side? May I ask - wouldn't it simpler to add a define to remove the `ImDrawList` implementation, and let you compile with your own?

ocornut commented

2026-09-25 09:55:10 +00:00

(Migrated from github.com)

May I ask - wouldn't it simpler to add a define to remove the ImDrawList implementation, and let you compile with your own?