Implemented scroll-snap-type

CHANGELOG.md

@@ -11,6 +11,7 @@ Released on Tuesday, May 31 2022.
 - Added support for `@counter-style` (#102)
 - Added support for `@font-feature-values` (#102)
 - Added support for `conic-gradient` (#101)
+- Added support for `scroll-snap-type` declaration (#91)
 
 # 0.16.4
 

src/AngleSharp.Css/Constants/CssKeywords.cs

@@ -1576,5 +1576,25 @@ public static class CssKeywords
         /// The fit-content keyword.
         /// </summary>
         public static readonly String FitContent = "fit-content";
+
+        /// <summary>
+        /// The x keyword.
+        /// </summary>
+        public static readonly String X = "x";
+
+        /// <summary>
+        /// The y keyword.
+        /// </summary>
+        public static readonly String Y = "y";
+
+        /// <summary>
+        /// The proximity keyword.
+        /// </summary>
+        public static readonly String Proximity = "proximity";
+
+        /// <summary>
+        /// The mandatory keyword.
+        /// </summary>
+        public static readonly String Mandatory = "mandatory";
     }
 }

src/AngleSharp.Css/Constants/InitialValues.cs

@@ -206,5 +206,8 @@ static class InitialValues
         public static readonly ICssValue Scrollbar3dLightColorDecl = Color.White;
         public static readonly ICssValue LetterSpacingDecl = Length.Normal;
         public static readonly ICssValue FontSizeAdjustDecl = new Length(1.0, Length.Unit.Em);
+        public static readonly ICssValue ScrollSnapTypeDecl = new Constant<Object>(CssKeywords.None, null);
+        public static readonly ICssValue ScrollMarginDecl = Length.Zero;
+        public static readonly ICssValue ScrollSnapAlignDecl = new Constant<ScrollSnapAlign>(CssKeywords.None, ScrollSnapAlign.None);
     }
 }

src/AngleSharp.Css/Constants/Map.cs

@@ -904,5 +904,37 @@ static class Map
             { CssKeywords.Hidden, Visibility.Hidden },
             { CssKeywords.Collapse, Visibility.Collapse },
         };
+
+        /// <summary>
+        /// Contains the scroll-snap-axis mapping.
+        /// </summary>
+        public static readonly Dictionary<String, ScrollSnapAxis> ScrollSnapAxises = new Dictionary<String, ScrollSnapAxis>(StringComparer.OrdinalIgnoreCase)
+        {
+            { CssKeywords.X, ScrollSnapAxis.X },
+            { CssKeywords.Y, ScrollSnapAxis.Y },
+            { CssKeywords.Block, ScrollSnapAxis.Block },
+            { CssKeywords.Inline, ScrollSnapAxis.Inline },
+            { CssKeywords.Both, ScrollSnapAxis.Both },
+        };
+
+        /// <summary>
+        /// Contains the scroll-snap-strictness mapping.
+        /// </summary>
+        public static readonly Dictionary<String, ScrollSnapStrictness> ScrollSnapStrictnesses = new Dictionary<String, ScrollSnapStrictness>(StringComparer.OrdinalIgnoreCase)
+        {
+            { CssKeywords.Proximity, ScrollSnapStrictness.Proximity},
+            { CssKeywords.Mandatory, ScrollSnapStrictness.Mandatory },
+        };
+
+        /// <summary>
+        /// Contains the scroll-snap-align mapping.
+        /// </summary>
+        public static readonly Dictionary<String, ScrollSnapAlign> ScrollSnapAlignments = new Dictionary<String, ScrollSnapAlign>(StringComparer.OrdinalIgnoreCase)
+        {
+            { CssKeywords.None, ScrollSnapAlign.None },
+            { CssKeywords.Start, ScrollSnapAlign.Start},
+            { CssKeywords.End, ScrollSnapAlign.End },
+            { CssKeywords.Center, ScrollSnapAlign.Center },
+        };
     }
 }

src/AngleSharp.Css/Constants/PropertyNames.cs

@@ -1057,6 +1057,21 @@ public static class PropertyNames
         /// </summary>
         public static readonly String ScrollbarTrackColor = "scrollbar-track-color";
 
+        /// <summary>
+        /// The scroll-snap-type declaration.
+        /// </summary>
+        public static readonly String ScrollSnapType = "scroll-snap-type";
+
+        /// <summary>
+        /// The scroll-margin declaration.
+        /// </summary>
+        public static readonly String ScrollMargin = "scroll-margin";
+
+        /// <summary>
+        /// The scroll-snap-align declaration.
+        /// </summary>
+        public static readonly String ScrollSnapAlign = "scroll-snap-aling";
+
         /// <summary>
         /// The stroke declaration.
         /// </summary>

src/AngleSharp.Css/Converters/SeparatedEnumsConverter.cs

@@ -0,0 +1,42 @@
+namespace AngleSharp.Css.Converters
+{
+    using AngleSharp.Css.Dom;
+    using AngleSharp.Css.Parser;
+    using AngleSharp.Text;
+    using System;
+
+    sealed class SeparatedEnumsConverter : IValueConverter
+    {
+        private readonly IValueConverter[] _converters;
+        private readonly Char _seperator;
+
+        public SeparatedEnumsConverter(IValueConverter[] converters, Char seperator)
+        {
+            _converters = converters;
+            _seperator = seperator;
+        }
+        public ICssValue Convert(StringSource source)
+        {
+            var value = _converters[0].Convert(source);
+
+            if (value != null)
+            {
+                var c = source.SkipSpacesAndComments();
+
+                if (!source.IsDone)
+                {
+                    if (c == _seperator)
+                    {
+                        source.SkipCurrentAndSpaces();
+                    }
+                    else
+                    {
+                        value = null;
+                    }
+                }
+            }
+
+            return value;
+        }
+    }
+}

src/AngleSharp.Css/Declarations/ScrollSnapTypeDeclaration.cs

@@ -0,0 +1,25 @@
+namespace AngleSharp.Css.Declarations
+{
+    using AngleSharp.Css.Converters;
+    using AngleSharp.Css.Dom;
+    using AngleSharp.Css.Values;
+    using System;
+    using static ValueConverters;
+
+    /// <summary>
+    /// For more information, see:
+    /// https://developer.mozilla.org/en-US/docs/Web/CSS/scroll-snap-type
+    /// </summary>
+    static class ScrollSnapTypeDeclaration
+    {
+        private static readonly ICssValue defaultStrictness = new Constant<ScrollSnapStrictness>(CssKeywords.Proximity, ScrollSnapStrictness.Proximity);
+
+        public static String Name = PropertyNames.ScrollSnapType;
+
+        public static IValueConverter Converter = Or(None, WithOrder(ScrollSnapAxisConverter, ScrollSnapStrictnessConverter.Option(defaultStrictness)));
+
+        public static ICssValue InitialValue = InitialValues.ScrollSnapTypeDecl;
+
+        public static PropertyFlags Flags = PropertyFlags.None;
+    }
+}

src/AngleSharp.Css/Dom/ScrollSnapAlign.cs

@@ -0,0 +1,25 @@
+namespace AngleSharp.Css.Dom
+{
+    /// <summary>
+    /// An enumeration with all possible scroll snap align options.
+    /// </summary>
+    public enum ScrollSnapAlign : byte
+    {
+        /// <summary>
+        /// This box does not define a snap position in the specified axis
+        /// </summary>
+        None,
+        /// <summary>
+        /// Start alignment of this box’s scroll snap area within the scroll container’s snapport is a snap position in the specified axis
+        /// </summary>
+        Start,
+        /// <summary>
+        /// End alignment of this box’s scroll snap area within the scroll container’s snapport is a snap position in the specified axis
+        /// </summary>
+        End,
+        /// <summary>
+        /// Center alignment of this box’s scroll snap area within the scroll container’s snapport is a snap position in the specified axis
+        /// </summary>
+        Center,
+    }
+}

src/AngleSharp.Css/Dom/ScrollSnapAxis.cs

@@ -0,0 +1,29 @@
+namespace AngleSharp.Css.Dom
+{
+    /// <summary>
+    /// An enumeration with all possible scroll snap axis options.
+    /// </summary>
+    public enum ScrollSnapAxis : byte
+    {
+        /// <summary>
+        /// The scroll container snaps to snap positions in its horizontal axis only
+        /// </summary>
+        X,
+        /// <summary>
+        /// The scroll container snaps to snap positions in its horizontal axis only
+        /// </summary>
+        Y,
+        /// <summary>
+        /// The scroll container snaps to snap positions in its block axis only
+        /// </summary>
+        Block,
+        /// <summary>
+        /// The scroll container snaps to snap positions in its inline axis only
+        /// </summary>
+        Inline,
+        /// <summary>
+        /// The scroll container snaps to snap positions in its inline axis only
+        /// </summary>
+        Both,
+    }
+}

src/AngleSharp.Css/Dom/ScrollSnapStrictness.cs

@@ -0,0 +1,21 @@
+namespace AngleSharp.Css.Dom
+{
+    /// <summary>
+    /// An enumeration with all possible scroll snap strictness options.
+    /// </summary>
+    public enum ScrollSnapStrictness : byte
+    {
+        /// <summary>
+        /// If specified on a scroll container, the scroll container is required to be snapped
+        /// to a snap position when there are no active scrolling operations.
+        /// If a valid snap position exists then the scroll container must snap
+        /// at the termination of a scroll (if none exist then no snapping occurs)
+        /// </summary>
+        Mandatory,
+        /// <summary>
+        /// If specified on a scroll container, the scroll container may snap to a snap position
+        /// at the termination of a scroll, at the discretion of the UA given the parameters of the scroll
+        /// </summary>
+        Proximity,
+    }
+}

src/AngleSharp.Css/Factories/DefaultDeclarationFactory.cs

@@ -1749,6 +1749,13 @@ public class DefaultDeclarationFactory : IDeclarationFactory
                     initialValue: FillDeclaration.InitialValue,
                     flags: FillDeclaration.Flags)
             },
+            {
+                ScrollSnapTypeDeclaration.Name, new DeclarationInfo(
+                    name: ScrollSnapTypeDeclaration.Name,
+                    converter: ScrollSnapTypeDeclaration.Converter,
+                    initialValue: ScrollSnapTypeDeclaration.InitialValue,
+                    flags: ScrollSnapTypeDeclaration.Flags)
+            },
         };
 
         /// <summary>

src/AngleSharp.Css/ValueConverters.cs

@@ -22,6 +22,8 @@ static class ValueConverters
 
         public static IValueConverter SlashSeparated(IValueConverter converter) => new SeparatorConverter(converter, Symbols.Solidus);
 
+        public static IValueConverter SpaceSeparated(IValueConverter converter) => new SeparatorConverter(converter, Symbols.Space);
+
         /// <summary>
         /// Creates a converter for the initial keyword with the given value.
         /// </summary>
@@ -565,6 +567,21 @@ static class ValueConverters
         /// </summary>
         public static readonly IValueConverter ContentVisibilityConverter = Map.Visibilities.ToConverter();
 
+        /// <summary>
+        /// Represents a converter for the ScrollSnapAlignment enumeration.
+        /// </summary>
+        public static readonly IValueConverter ScrollSnapAlignmentConverter = Map.ScrollSnapAlignments.ToConverter();
+
+        /// <summary>
+        /// Represents a converter for the ScrollSnapAxis enumeration.
+        /// </summary>
+        public static readonly IValueConverter ScrollSnapAxisConverter = Map.ScrollSnapAxises.ToConverter();
+
+        /// <summary>
+        /// Represents a converter for the ScrollSnapStrictness enumeration.
+        /// </summary>
+        public static readonly IValueConverter ScrollSnapStrictnessConverter = Map.ScrollSnapStrictnesses.ToConverter();
+
         #endregion
 
         #region Specific