using System;
using System.Runtime.InteropServices;

namespace FastReport.Fonts
{

    /////////////////////////////////////////////////////////////////////////////////////////////////
    // HorizontalHeader table
    /////////////////////////////////////////////////////////////////////////////////////////////////
    class HorizontalHeaderClass : TrueTypeTable
    {
        #region "Type definition"
        [StructLayout(LayoutKind.Explicit, Pack = 1)]
        public struct HorizontalHeader
        {
            [FieldOffset(0)]
            public uint Version; // version number	0x00010000 for version 1.0.
            [FieldOffset(4)]
            public short Ascender; // Typographic ascent.
            [FieldOffset(6)]
            public short Descender; // Typographic descent.
            [FieldOffset(8)]
            public short LineGap; //	Typographic line gap. Negative LineGap values are treated as zero in Windows 3.1, System 6, and System 7.
            [FieldOffset(10)]
            public ushort advanceWidthMax; //	Maximum advance width value in ‘hmtx’ table.
            [FieldOffset(12)]
            public short minLeftSideBearing; // Minimum left sidebearing value in ‘hmtx’ table.
            [FieldOffset(14)]
            public short minRightSideBearing; // Minimum right sidebearing value; calculated as Min(aw - lsb - (xMax - xMin)).
            [FieldOffset(16)]
            public short xMaxExtent;     //  Max(lsb + (xMax - xMin)).
            [FieldOffset(18)]
            public short caretSlopeRise; // Used to calculate the slope of the cursor (rise/run); 1 for vertical.
            [FieldOffset(20)]
            public short caretSlopeRun;  // 0 for vertical.
            [FieldOffset(22)]
            public short reserved1;  // set to 0
            [FieldOffset(24)]
            public short reserved2;  // set to 0
            [FieldOffset(26)]
            public short reserved3;  // set to 0
            [FieldOffset(28)]
            public short reserved4;  // set to 0
            [FieldOffset(30)]
            public short reserved5;  // set to 0
            [FieldOffset(32)]
            public short metricDataFormat; //	0 for current format.
            [FieldOffset(34)]
            public ushort numberOfHMetrics; //	Number of hMetric entries in  ‘hmtx’ table; may be smaller than the total number of glyphs in the font.
        }
        #endregion

        private HorizontalHeader horizontal_header;

        internal override void Load(FontStream stream)
        {
            stream.Position = this.Offset;
            horizontal_header.Version = stream.ReadUInt32(); // version number	0x00010000 for version 1.0.
            horizontal_header.Ascender = stream.ReadInt16(); // Typographic ascent.
            horizontal_header.Descender = stream.ReadInt16(); // Typographic descent.
            horizontal_header.LineGap = stream.ReadInt16(); //	Typographic line gap. Negative LineGap values are treated as zero in Windows 3.1, System 6, and System 7.
            horizontal_header.advanceWidthMax = stream.ReadUInt16(); //	Maximum advance width value in ‘hmtx’ table.
            horizontal_header.minLeftSideBearing = stream.ReadInt16(); // Minimum left sidebearing value in ‘hmtx’ table.
            horizontal_header.minRightSideBearing = stream.ReadInt16(); // Minimum right sidebearing value; calculated as Min(aw - lsb - (xMax - xMin)).
            horizontal_header.xMaxExtent = stream.ReadInt16();     //  Max(lsb + (xMax - xMin)).
            horizontal_header.caretSlopeRise = stream.ReadInt16(); // Used to calculate the slope of the cursor (rise/run); 1 for vertical.
            horizontal_header.caretSlopeRun = stream.ReadInt16();  // 0 for vertical.
            horizontal_header.reserved1 = stream.ReadInt16();  // set to 0
            horizontal_header.reserved2 = stream.ReadInt16();  // set to 0
            horizontal_header.reserved3 = stream.ReadInt16();  // set to 0
            horizontal_header.reserved4 = stream.ReadInt16();  // set to 0
            horizontal_header.reserved5 = stream.ReadInt16();  // set to 0
            horizontal_header.metricDataFormat = stream.ReadInt16(); //	0 for current format.
            horizontal_header.numberOfHMetrics = stream.ReadUInt16(); //	Number of hMetric entries in  ‘hmtx’ table; may be smaller than the total number of glyphs in the font.
        }

        internal override uint Save(FontStream source_not_used, FontStream stream, uint offset)
        {
            stream.Position = offset;

            stream.WriteUInt32(horizontal_header.Version);          // version number	0x00010000 for version 1.0.
            stream.WriteInt16(horizontal_header.Ascender);          // Typographic ascent.
            stream.WriteInt16(horizontal_header.Descender);         // Typographic descent.
            stream.WriteInt16(horizontal_header.LineGap);           //	Typographic line gap. Negative LineGap values are treated as zero in Windows 3.1, System 6, and System 7.
            stream.WriteUInt16(horizontal_header.advanceWidthMax);  //	Maximum advance width value in ‘hmtx’ table.
            stream.WriteInt16(horizontal_header.minLeftSideBearing);// Minimum left sidebearing value in ‘hmtx’ table.
            stream.WriteInt16(horizontal_header.minRightSideBearing);// Minimum right sidebearing value; calculated as Min(aw - lsb - (xMax - xMin)).
            stream.WriteInt16(horizontal_header.xMaxExtent);        //  Max(lsb + (xMax - xMin)).
            stream.WriteInt16(horizontal_header.caretSlopeRise);    // Used to calculate the slope of the cursor (rise/run); 1 for vertical.
            stream.WriteInt16(horizontal_header.caretSlopeRun);     // 0 for vertical.
            stream.WriteInt16(horizontal_header.reserved1);  // set to 0
            stream.WriteInt16(horizontal_header.reserved2);  // set to 0
            stream.WriteInt16(horizontal_header.reserved3);  // set to 0
            stream.WriteInt16(horizontal_header.reserved4);  // set to 0
            stream.WriteInt16(horizontal_header.reserved5);  // set to 0
            stream.WriteInt16(horizontal_header.metricDataFormat);      //	0 for current format.
            stream.WriteUInt16(horizontal_header.numberOfHMetrics); //	Number of hMetric entries in  ‘hmtx’ table; may be smaller than the total number of glyphs in the font.

            return offset + (uint)this.Length;
        }

        public short Ascender { get { return horizontal_header.Ascender; } }
        public short Descender { get { return horizontal_header.Descender; } }
        public short LineGap { get { return horizontal_header.LineGap; } }
        public ushort MaxWidth { get { return horizontal_header.advanceWidthMax; } }
        public short MinLeftSideBearing { get { return horizontal_header.minLeftSideBearing; } }
        public ushort NumberOfHMetrics { get { return horizontal_header.numberOfHMetrics; } set { horizontal_header.numberOfHMetrics = value; } }
        public HorizontalHeaderClass(TrueTypeTable src) : base(src)
        {
        }
    }

}