How to get resizable child in window? about imgui

[ElectroidDes]

How to get resizable child in window?

enum ImGuiChildFlags_
{
    ImGuiChildFlags_None                    = 0,
    ImGuiChildFlags_Border                  = 1 << 0,   // Show an outer border and enable WindowPadding. (IMPORTANT: this is always == 1 == true for legacy reason)
    ImGuiChildFlags_AlwaysUseWindowPadding  = 1 << 1,   // Pad with style.WindowPadding even if no border are drawn (no padding by default for non-bordered child windows because it makes more sense)
    ImGuiChildFlags_ResizeX                 = 1 << 2,   // Allow resize from right border (layout direction). Enable .ini saving (unless ImGuiWindowFlags_NoSavedSettings passed to window flags)
    ImGuiChildFlags_ResizeY                 = 1 << 3,   // Allow resize from bottom border (layout direction). "
    ImGuiChildFlags_AutoResizeX             = 1 << 4,   // Enable auto-resizing width. Read "IMPORTANT: Size measurement" details above.
    ImGuiChildFlags_AutoResizeY             = 1 << 5,   // Enable auto-resizing height. Read "IMPORTANT: Size measurement" details above.
    ImGuiChildFlags_AlwaysAutoResize        = 1 << 6,   // Combined with AutoResizeX/AutoResizeY. Always measure size even when child is hidden, always return true, always disable clipping optimization! NOT RECOMMENDED.
    ImGuiChildFlags_FrameStyle              = 1 << 7,   // Style the child window like a framed item: use FrameBg, FrameRounding, FrameBorderSize, FramePadding instead of ChildBg, ChildRounding, ChildBorderSize, WindowPadding.
};

Use flags: ImGuiChildFlags_ResizeX and ImGuiChildFlags_ResizeY

[fghoussen]

Use flags: ImGuiChildFlags_ResizeX and ImGuiChildFlags_ResizeY

Just tried: same behavior / problem.

[ElectroidDes]

        bool open = true;
        ImGui::Begin("Viewport", &open);

        ImGui::BeginChild("Viewport", { 100,100 }, ImGuiChildFlags_Border| ImGuiChildFlags_ResizeX | ImGuiChildFlags_ResizeY, ImGuiWindowFlags_None);

        ImGui::EndChild();

        ImGui::End();

Try it. It works for me, guaranteed.

[fghoussen]

Trying suppressing image and adding border to see child frontiers:

  bool open = true;
  ImGui::Begin("Viewport", &open);
  ImGui::BeginChild("Viewport", size, ImGuiChildFlags_Border | ImGuiChildFlags_ResizeX | ImGuiChildFlags_ResizeY,
  //                                    ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoScrollWithMouse);
                                      ImGuiWindowFlags_None);
  //ImGui::Image(reinterpret_cast<void*>(tex), ImGui::GetContentRegionAvail(), ImVec2(0, 1), ImVec2(1, 0));
  ImGui::EndChild();
  ImGui::End();

And get:

[ocornut]

Your question is ambiguous. The child window in your picture should be user resizable, which is what you have asked for. I don’t understand what you are expecting.

[fghoussen]

I expected the child borders to stick to the ones of the parent window. I guess I misunderstood the meaning of the resize options.

[ocornut]

If you use BeginChild() with the default 0,0 size it will fill all available space. Size=0,0 is the same as using GetContentRegionAvail().

However if you have a window with only a child filling all space inside, then the child window is not necessary.

[ocornut]

Closing as answered, let us know if you have another issue.!