ImGui::SetItemKeyOwner does not work on images

[nasiratif]

Version/Branch of Dear ImGui:

Version 1.91.8, Branch: master

Back-ends:

imgui_impl_win32.cpp + imgui_impl_dx9.cpp

Compiler, OS:

WIndows 11 + MSVC 2022

Full config/build information:

Dear ImGui 1.91.8 (19180)
--------------------------------
sizeof(size_t): 8, sizeof(ImDrawIdx): 2, sizeof(ImDrawVert): 20
define: __cplusplus=199711
define: _WIN32
define: _WIN64
define: _MSC_VER=1941
define: _MSVC_LANG=201402
--------------------------------
io.BackendPlatformName: imgui_impl_win32
io.BackendRendererName: imgui_impl_dx9
io.ConfigFlags: 0x00000003
 NavEnableKeyboard
 NavEnableGamepad
io.ConfigNavCaptureKeyboard
io.ConfigInputTextCursorBlink
io.ConfigWindowsResizeFromEdges
io.ConfigMemoryCompactTimer = 60.0
io.BackendFlags: 0x0000000E
 HasMouseCursors
 HasSetMousePos
 RendererHasVtxOffset
--------------------------------
io.Fonts: 1 fonts, Flags: 0x00000000, TexSize: 512,64
io.DisplaySize: 1264.00,761.00
io.DisplayFramebufferScale: 1.00,1.00
--------------------------------
style.WindowPadding: 8.00,8.00
style.WindowBorderSize: 1.00
style.FramePadding: 4.00,3.00
style.FrameRounding: 0.00
style.FrameBorderSize: 0.00
style.ItemSpacing: 8.00,4.00
style.ItemInnerSpacing: 4.00,4.00

Details:

I haven't tested other keys, but If you use ImGui::SetItemKeyOwner(ImGuiKey_MouseWheelY) on Images, it doesn't work as you can still scroll on the window.

I needed to do this because in my project I'm writing a 2D animation editor where you can preview the image and zoom in/out, but I can't have the window scroll along with the image.

The only thing I've tried was calling SetItemKeyOwner before Image, but that of course did not fix the problem.

Screenshots/Video:

Minimal, Complete and Verifiable Example code:

ImGui::Begin("Hello, world!");

ImGui::Button("Scrolling doesn't work on this button as expected:");
ImGui::SetItemKeyOwner(ImGuiKey_MouseWheelY);

ImGui::Text("But scrolling still works on this image:");
ImGui::Image(0, ImVec2(128, 128));
ImGui::SetItemKeyOwner(ImGuiKey_MouseWheelY);

ImGui::End();

[cfillion]

Images, like text, don't have an item ID (0). You can use ImGui::ImageButton instead to create an interactive item for SetItemKeyOwner to act upon.

ImGui::PushStyleVar(ImGuiStyleVar_FramePadding, {0, 0});
ImGui::ImageButton("foo", 0, {128, 128});
ImGui::PopStyleVar();
ImGui::SetItemKeyOwner(ImGuiKey_MouseWheelY);