How to detect enter key being pressed on InputDouble?

[fghoussen]

Version/Branch of Dear ImGui:

a959617 unmodified docking

Back-ends:

imgui_impl_opengl3.cpp + imgui_impl_glfw.cpp

Compiler, OS:

g++-15.2, debian/linux

Full config/build information:

No response

Details:

My Issue/Question:

How to detect enter key being pressed on InputDouble?

The problem is to update a vector with normalized xyz values only after the user has finished to type the value of one component of the vector. I guess the problem here is that xyz are "re-entrant" as they are both modified by the GUI and the (normalized) vector: when you type a value for xyz and you are not done typing yet, the GUI displays some kind of crazy continuously changing values for xyz! (picture attached). After pressing enter key, values are stable.

I tried:

• Different flavors of if statements using xyzModif and ImGui::IsItemDeactivatedAfterEdit (see code attached): with this, the GUI has either "crazy" behavior or isn't updated.
• ImGuiInputTextFlags_EnterReturnsTrue: seems supported only for text (not for scalar)

Is there a way to handle or workaround this case?

Screenshots/Video:

Minimal, Complete and Verifiable Example code:

$ git diff

+double x = 1.;
+double y = 2.;
+double z = 3.;
+bool normalize = true;
+
 void initializeFrame() {
   // Clear.
   glClear(GL_COLOR_BUFFER_BIT);
@@ -95,7 +101,21 @@ void initializeFrame() {
 
   // Create main thread GUI.
   ImGui::Begin("Main thread");
+  bool xyzModif = false;
+  xyzModif |= ImGui::InputDouble("X", &x);
+  xyzModif |= ImGui::InputDouble("Y", &y);
+  xyzModif |= ImGui::InputDouble("Z", &z);
+  ImGui::Checkbox("Normalize", &normalize);
+  if (normalize) {
+  //if (xyzModif && normalize) {
+  //if (ImGui::IsItemDeactivatedAfterEdit() && normalize) {
+    double norm = std::sqrt(x*x + y*y + z*z);
+    if (norm > 1.e-6) {
+      x /= norm;
+      y /= norm;
+      z /= norm;
+    }
+  }
   ImGui::End();
 }

[GamingMinds-DanielC]

A hint first: you can use InputFloat3 and InputDoubleas a reference to wrap a more compact double variant:

namespace ImGui
{
    bool InputDouble3(const char* label, double v[3], const char* format = "%.6f", ImGuiInputTextFlags flags = 0)
    {
        return InputScalarN(label, ImGuiDataType_Double, v, 3, NULL, NULL, format, flags);
    }
}

If you want to keep using 3 separate inputs in 3 lines, I would still suggest to put them into a group (between ImGui::BeginGroup() and ImGui::EndGroup()` calls), that way you can check item deactivation for the entire group, the next code snippets rely on that. Without the group, you have to collect those flags after every item.

If it has to be enter specifically, you can do this:

    if ( ImGui::IsItemDeactivated() && ImGui::IsKeyPressed( ImGuiKey_Enter ) )
    {
        // normalize
    }

If you use this, your vector will not normalize if you deactivate the items by any other means than pressing enter, so I would suggest this version instead:

    // any item deactivated, none activated
    if ( ImGui::IsItemDeactivated() && !ImGui::IsItemActivated() )
    {
        // normalize
    }

This way you can switch between the inputs using tab and shift+tab or by clicking into another input of the group without normalizing. That happens when you press enter or tab/click out of the group. If you want the edited status as well, you need to track that yourself. Sadly, IsItemDeactivatedAfterEdit() will not help you here since a user can f.e. edit one component, switch to another and then press enter without editing that one.

[ocornut]

Also see #8665 #3946 i've been meaning to investigate the problem with ImGuiInputTextFlags_EnterReturnsTrue.

[ocornut]

I have reinstated ImGuiInputTextFlags_EnterReturnsTrue for InputInt, InputFloat, InputScalar etc.
(final commit is the simple 10c378c but it depends on various other changes done previously).

And fixed various aspects of it:

• Fixed the fact that it didn't return true when validating same value.
• Fixed losing underlying value when tabbing out or losing focus.
• Made it that pressing +/- step buttons also return true, which is in line with 1.91.4 behavior.

Note:

• You will not get a signal in the return value when tabbing out or losing focus.
• So you should probably still use IsItemDeactivatedAfterEdit() in most cases.
• Reminder, IMHO all of this is a workaround for the fact that we don't have a way to request value write-back to backing-data on validation only, and most people are trying to work around this. THIS SHOULD BE COMING SOON.

Please open a new Issue if you have an issue with ImGuiInputTextFlags_EnterReturnsTrue.

AFAIK, the remaining issue with IsItemDeactivatedAfterEdit() is: if intentionally NOT holding on backing data (aka always passing a temporary): the +/- buttons won't work because the IsItemDeactivatedAfterEdit() arrives one frame after writing-back. (#8149) If you think there is another issue with IsItemDeactivatedAfterEdit() please post a new issue 🙏