LengthAttribute.cs

using System;
using System.Xml;
using Waher.Content;
using Waher.Layout.Layout2D.Exceptions;
using Waher.Script;
using Waher.Script.Objects;
using Waher.Script.Units;
 
namespace Waher.Layout.Layout2D.Model.Attributes
{
    public class LengthAttribute : Attribute<Length>
    {
        public LengthAttribute(string AttributeName, Length Value, Layout2DDocument Document)
            : base(AttributeName, Value, Document)
        {
        }
 
        public LengthAttribute(XmlElement E, string AttributeName, Layout2DDocument Document)
            : base(E, AttributeName, true, Document)
        {
        }
 
        public LengthAttribute(string AttributeName, Expression Expression, Layout2DDocument Document)
            : base(AttributeName, Expression, Document)
        {
        }
 
        public override bool TryConvert(object Result, out Length Value)
        {
            if (Result is double d)
            {
                Value = new Length((float)(d * 100), LengthUnit.Percent);
                return true;
            }
            else if (Result is IPhysicalQuantity PQ)
            {
                PhysicalQuantity Q = PQ.ToPhysicalQuantity();
 
                switch (Q.Unit.ToString().ToLower())
                {
                    case "px":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Px);
                        return true;
 
                    case "pt":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Pt);
                        return true;
 
                    case "pc":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Pc);
                        return true;
 
                    case "cm":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Cm);
                        return true;
 
                    case "in":
                        Value = new Length((float)Q.Magnitude, LengthUnit.In);
                        return true;
 
                    case "mm":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Mm);
                        return true;
 
                    case "em":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Em);
                        return true;
 
                    case "ex":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Ex);
                        return true;
 
                    case "ch":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Ch);
                        return true;
 
                    case "rem":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Rem);
                        return true;
 
                    case "vw":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Vw);
                        return true;
 
                    case "vh":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Vh);
                        return true;
 
                    case "vmin":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Vmin);
                        return true;
 
                    case "vmax":
                        Value = new Length((float)Q.Magnitude, LengthUnit.Vmax);
                        return true;
 
                    default:
                        if (Unit.TryConvert(Q.Magnitude, Q.Unit, pixels, out double Pixels))
                        {
                            Value = new Length((float)Pixels, LengthUnit.Px);
                            return true;
                        }
                        else
                        {
                            Value = null;
                            return false;
                        }
                }
            }
            else
                return base.TryConvert(Result, out Value);
        }
 
        private static readonly Unit pixels = new Unit("px");
 
        public override bool TryParse(string StringValue, out Length Value)
        {
            LengthUnit Unit;
            int c = StringValue.Length;
            int i = c;
            char ch = StringValue[--i];
 
            if (ch == '%')
                Unit = LengthUnit.Percent;
            else
            {
                char ch2 = StringValue[--i];
 
                switch (ch)
                {
                    case 'x':
                        switch (ch2)
                        {
                            case 'p':
                                Unit = LengthUnit.Px;
                                break;
 
                            case 'e':
                                Unit = LengthUnit.Ex;
                                break;
 
                            case 'a':
                                if (c < 4 ||
                                    StringValue[--i] != 'm' ||
                                    StringValue[--i] != 'v')
                                {
                                    throw InvalidLengthException(StringValue);
                                }
 
                                Unit = LengthUnit.Vmax;
                                break;
 
                            default:
                                throw InvalidLengthException(StringValue);
                        }
                        break;
 
                    case 't':
                        if (ch2 != 'p')
                            throw InvalidLengthException(StringValue);
 
                        Unit = LengthUnit.Pt;
                        break;
 
                    case 'c':
                        if (ch2 != 'p')
                            throw InvalidLengthException(StringValue);
 
                        Unit = LengthUnit.Pc;
                        break;
 
                    case 'm':
                        switch (ch2)
                        {
                            case 'c':
                                Unit = LengthUnit.Cm;
                                break;
 
                            case 'm':
                                Unit = LengthUnit.Mm;
                                break;
 
                            case 'e':
                                if (c >= 3 && StringValue[i - 1] == 'r')
                                {
                                    Unit = LengthUnit.Rem;
                                    i--;
                                }
                                else
                                    Unit = LengthUnit.Em;
                                break;
 
                            default:
                                throw InvalidLengthException(StringValue);
                        }
                        break;
 
                    case 'n':
                        if (c >= 4 && StringValue[i - 1] == 'm')
                        {
                            i--;
 
                            if (StringValue[--i] == 'v')
                                Unit = LengthUnit.Vmin;
                            else
                                throw InvalidLengthException(StringValue);
                        }
                        else
                            Unit = LengthUnit.In;
                        break;
 
                    case 'h':
                        switch (ch2)
                        {
                            case 'c':
                                Unit = LengthUnit.Ch;
                                break;
 
                            case 'v':
                                Unit = LengthUnit.Vh;
                                break;
 
                            default:
                                throw InvalidLengthException(StringValue);
                        }
                        break;
 
                    case 'w':
                        if (ch2 != 'v')
                            throw InvalidLengthException(StringValue);
 
                        Unit = LengthUnit.Vw;
                        break;
 
                    default:
                        throw InvalidLengthException(StringValue);
                }
            }
 
            while (i >= 0 && ((ch = StringValue[i]) <= ' ' || ch == 160))
                i--;
 
            StringValue = StringValue.Substring(0, i);
 
            if (!CommonTypes.TryParse(StringValue, out float d))
                throw InvalidLengthException(StringValue);
 
            Value = new Length(d, Unit);
 
            return true;
        }
 
        private static Exception InvalidLengthException(string AttributeValue)
        {
            return new LayoutSyntaxException("Invalid length: " + AttributeValue);
        }
 
        public override string ToString(Length Value)
        {
            string s = CommonTypes.Encode(Value.Value);
 
            switch (Value.Unit)
            {
                case LengthUnit.Px: return s + " px";
                case LengthUnit.Pt: return s + " pt";
                case LengthUnit.Pc: return s + " pc";
                case LengthUnit.Cm: return s + " cm";
                case LengthUnit.In: return s + " in";
                case LengthUnit.Mm: return s + " mm";
                case LengthUnit.Em: return s + " em";
                case LengthUnit.Ex: return s + " ex";
                case LengthUnit.Ch: return s + " ch";
                case LengthUnit.Rem: return s + " rem";
                case LengthUnit.Vw: return s + " vw";
                case LengthUnit.Vh: return s + " vh";
                case LengthUnit.Vmin: return s + " vmin";
                case LengthUnit.Vmax: return s + " vmax";
                case LengthUnit.Percent: return s + " %";
                default: return s;
            }
        }
 
        public LengthAttribute CopyIfNotPreset(Layout2DDocument ForDocument)
        {
            if (this.HasPresetValue)
                return this;
            else
                return new LengthAttribute(this.Name, this.Expression, ForDocument);
        }
 
    }
}