Function ColorEditRestoreHS

src/imgui/imgui_widgets.cpp:5668–5683

ColorEdit supports RGB and HSV inputs. In case of RGB input resulting color may have undefined hue and/or saturation. Since widget displays both RGB and HSV values we must preserve hue and saturation to prevent these values resetting.

// ColorEdit supports RGB and HSV inputs. In case of RGB input resulting color may have undefined hue and/or saturation.
// Since widget displays both RGB and HSV values we must preserve hue and saturation to prevent these values resetting.
static void ColorEditRestoreHS(const float* col, float* H, float* S, float* V)
{
    ImGuiContext& g = *GImGui;
    IM_ASSERT(g.ColorEditCurrentID != 0);
    if (g.ColorEditSavedID != g.ColorEditCurrentID || g.ColorEditSavedColor != ImGui::ColorConvertFloat4ToU32(ImVec4(col[0], col[1], col[2], 0)))
        return;

    // When S == 0, H is undefined.
    // When H == 1 it wraps around to 0.
    if (*S == 0.0f || (*H == 0.0f && g.ColorEditSavedHue == 1))
        *H = g.ColorEditSavedHue;

    // When V == 0, S is undefined.
    if (*V == 0.0f)
        *S = g.ColorEditSavedSat;
}

// Edit colors components (each component in 0.0f..1.0f range).
// See enum ImGuiColorEditFlags_ for available options. e.g. Only access 3 floats if ImGuiColorEditFlags_NoAlpha flag is set.