Unity imgui vertical label

vartical_label.cs

public void VerticalLabel(Rect rect, Vector2 clipSize, string text)
{
    // the issue:
    // while we transforming gui, whe clip area rotates with it
    // so, if we want to draw somewhere on untrasformed screen, we have invalid clip area to deal with.

    // the best idea I have is to draw on (0,0) of current clip area and move label to desized position using gui matrix intead of label coordinates
    // limitations:
    // we need to apply clip effect to transformed label manually, we need to know clip area size for that, but I see no way to obrain it
    // original clip is still applied, and width and height is now inverted. So, original clip have no space to render the label *horizontaly*, the vertical label will not be rendered correctly either.

    Matrix4x4 matrix = GUI.matrix;
    GUI.matrix = Matrix4x4.identity;

    Vector2 unclipped = UnclipVector2(Vector2.zero);

    GUI.matrix =
        matrix *
        // move origin to (0,0) of current clip; rotate around (0,0)
        Matrix4x4.TRS(unclipped, Quaternion.Euler(0f, 0f, -90), Vector3.one) *
        // move (0,0) to label possition
        Matrix4x4.TRS(new Vector2(-rect.yMax - unclipped.x, rect.xMin - unclipped.y), Quaternion.identity, Vector3.one);

    // calculating clipping effects
    var leftClip = Mathf.Min(rect.xMin, 0);
    var rightClip = Mathf.Max(rect.xMax - clipSize.x, 0);
    var topClip = Mathf.Min(rect.yMin, 0);
    var bottomClip = Mathf.Max(rect.yMax - clipSize.y, 0);

    // applying clip
    var clip = new Rect(bottomClip, -leftClip, rect.height + topClip - bottomClip, rect.width + leftClip - rightClip);
    GUI.BeginClip(clip);

    // rendering whatever we want to render
    var adjusted = new Rect(-bottomClip, leftClip, rect.height, rect.width);
    GUI.color = Color.black;
    GUI.DrawTexture(adjusted, BaseContent.WhiteTex);
    Text.Font = GameFont.Medium;
    GUI.color = Color.white;
    Widgets.Label(adjusted, text);

    GUI.EndClip();

    // restoring GUI matrix
    GUI.matrix = matrix;
}