QrEncode.cs

using SkiaSharp;
using System;
using Waher.Content.QR;
using Waher.Content.QR.Encoding;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Graphs;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Script.Content.Functions.Encoding
{
    public class QrEncode : FunctionMultiVariate
    {
        private static readonly QrEncoder encoder = new QrEncoder();
 
        public QrEncode(ScriptNode Text, ScriptNode Level, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { Text, Level }, argumentTypes2Scalar, Start, Length, Expression)
        {
        }
 
        public QrEncode(ScriptNode Text, ScriptNode Level, ScriptNode Width, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { Text, Level, Width }, argumentTypes3Scalar, Start, Length, Expression)
        {
        }
 
        public QrEncode(ScriptNode Text, ScriptNode Level, ScriptNode Width, ScriptNode Height, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { Text, Level, Width, Height }, argumentTypes4Scalar, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(QrEncode);
 
        public override string[] DefaultArgumentNames => new string[] { "Text", "Level", "Width" };
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            string Text = Arguments[0].AssociatedObjectValue?.ToString();
            CorrectionLevel Level = this.ToEnum<CorrectionLevel>(Arguments[1]);
 
            if (Arguments.Length == 2)
                return new StringValue(encoder.GenerateMatrix(Level, Text).ToHalfBlockText());
 
            int Width = (int)(Expression.ToDouble(Arguments[2].AssociatedObjectValue) + 0.5);
            int Height;
 
            if (Arguments.Length == 3)
                Height = Width;
            else
                Height = (int)(Expression.ToDouble(Arguments[3].AssociatedObjectValue) + 0.5);
 
            QrMatrix M = encoder.GenerateMatrix(Level, Text);
            byte[] Rgba;
 
            EventHandler<ColorFunctionEventArgs> h = CustomColorFunction;
            if (h is null)
                Rgba = M.ToRGBA(Width, Height);
            else
            {
                ColorFunctionEventArgs e = new ColorFunctionEventArgs(Text);
                h(this, e);
 
                if (e.Function is null)
                    Rgba = M.ToRGBA(Width, Height);
                else
                    Rgba = M.ToRGBA(Width, Height, e.Function, e.AntiAlias);
            }
 
            return new GraphBitmap(Variables, PixelInformation.FromRaw(SKColorType.Rgba8888, Rgba, Width, Height, Width << 2));
        }
 
        public static event EventHandler<ColorFunctionEventArgs> CustomColorFunction;
 
    }
}