/// <summary>
/// Draws text string at specified location. Only the sub-string up to the end is drawn.
/// </summary>
public static float Text(this Nvg nvg, Vector2D <float> pos, string @string, string end)
{
Fontstash fons = nvg.fontManager.Fontstash;
State state = nvg.stateStack.CurrentState;
FonsQuad q = new();
float scale = nvg.fontManager.GetFontScale() * nvg.pixelRatio.DevicePxRatio;
float invscale = 1.0f / scale;
bool isFlipped = Maths.IsTransformFlipped(state.Transform);
if (state.FontId == Fontstash.INVALID)
{
return(pos.X);
}
fons.SetSize(state.FontSize * scale);
fons.SetSpacing(state.LetterSpacing * scale);
fons.SetBlur(state.FontBlur * scale);
fons.SetAlign((int)state.TextAlign);
fons.SetFont(state.FontId);
List <Vertex> vertices = new();
fons.TextIterInit(out FonsTextIter iter, pos.X * scale, pos.Y * scale, @string, end, FonsGlyphBitmap.Requiered);
FonsTextIter prevIter = iter;
while (fons.TextIterNext(ref iter, ref q))
{
Vector2D <float>[] c = new Vector2D <float> [4];
if (iter.prevGlyphIndex == -1)
{
if (vertices.Count != 0)
{
nvg.fontManager.RenderText(vertices);
vertices.Clear();
}
if (!nvg.fontManager.AllocTextAtlas()) // no memory
{
break;
}
iter = prevIter;
_ = fons.TextIterNext(ref iter, ref q);
if (iter.prevGlyphIndex == -1)
{
break;
}
}
prevIter = iter;
if (isFlipped)
{
float tmp = q.y0;
q.y0 = q.y1;
q.y1 = tmp;
tmp = q.t0;
q.t0 = q.t1;
q.t1 = tmp;
}
c[0] = nvg.TransformPoint(state.Transform, q.x0 * invscale, q.y0 * invscale);
c[1] = nvg.TransformPoint(state.Transform, q.x1 * invscale, q.y0 * invscale);
c[2] = nvg.TransformPoint(state.Transform, q.x1 * invscale, q.y1 * invscale);
c[3] = nvg.TransformPoint(state.Transform, q.x0 * invscale, q.y1 * invscale);
vertices.Add(new Vertex(c[0], q.s0, q.t0));
vertices.Add(new Vertex(c[2], q.s1, q.t1));
vertices.Add(new Vertex(c[1], q.s1, q.t0));
vertices.Add(new Vertex(c[0], q.s0, q.t0));
vertices.Add(new Vertex(c[3], q.s0, q.t1));
vertices.Add(new Vertex(c[2], q.s1, q.t1));
}
nvg.fontManager.FlushTextTexture();
nvg.fontManager.RenderText(vertices);
return(iter.nextx / scale);
}
