Function BoxSelectScrollWithMouseDrag

src/imgui/imgui_widgets.cpp:7673–7699

}

static void BoxSelectScrollWithMouseDrag(ImGuiBoxSelectState* bs, ImGuiWindow* window, const ImRect& inner_r)
{
    ImGuiContext& g = *GImGui;
    IM_ASSERT(bs->Window == window);
    for (int n = 0; n < 2; n++) // each axis
    {
        const float mouse_pos = g.IO.MousePos[n];
        const float dist = (mouse_pos > inner_r.Max[n]) ? mouse_pos - inner_r.Max[n] : (mouse_pos < inner_r.Min[n]) ? mouse_pos - inner_r.Min[n] : 0.0f;
        const float scroll_curr = window->Scroll[n];
        if (dist == 0.0f || (dist < 0.0f && scroll_curr < 0.0f) || (dist > 0.0f && scroll_curr >= window->ScrollMax[n]))
            continue;

        const float speed_multiplier = ImLinearRemapClamp(g.FontSize, g.FontSize * 5.0f, 1.0f, 4.0f, ImAbs(dist)); // x1 to x4 depending on distance
        const float scroll_step = g.FontSize * 35.0f * speed_multiplier * ImSign(dist) * g.IO.DeltaTime;
        bs->ScrollAccum[n] += scroll_step;

        // Accumulate into a stored value so we can handle high-framerate
        const float scroll_step_i = ImFloor(bs->ScrollAccum[n]);
        if (scroll_step_i == 0.0f)
            continue;
        if (n == 0)
            ImGui::SetScrollX(window, scroll_curr + scroll_step_i);
        else
            ImGui::SetScrollY(window, scroll_curr + scroll_step_i);
        bs->ScrollAccum[n] -= scroll_step_i;
    }
}

bool ImGui::BeginBoxSelect(const ImRect& scope_rect, ImGuiWindow* window, ImGuiID box_select_id, ImGuiMultiSelectFlags ms_flags)
{