Move FreeType handling into the Platform dll.

OpenRA.Platforms.Default/FreeTypeFont.cs

@@ -0,0 +1,83 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2019 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using OpenRA.Primitives;
+using SharpFont;
+
+namespace OpenRA.Platforms.Default
+{
+	public sealed class FreeTypeFont : IFont
+	{
+		static readonly Library Library = new Library();
+		readonly Face face;
+
+		public FreeTypeFont(byte[] data)
+		{
+			face = new Face(Library, data, 0);
+		}
+
+		public FontGlyph CreateGlyph(char c, int size, float deviceScale)
+		{
+			try
+			{
+				var scaledSize = (uint) (size * deviceScale);
+				face.SetPixelSizes(scaledSize, scaledSize);
+			
+				face.LoadChar(c, LoadFlags.Default, LoadTarget.Normal);
+				face.Glyph.RenderGlyph(RenderMode.Normal);
+
+				var glyphSize = new Size((int)face.Glyph.Metrics.Width, (int)face.Glyph.Metrics.Height);
+
+				var g = new FontGlyph
+				{
+					Advance = (float)face.Glyph.Metrics.HorizontalAdvance,
+					Offset = new int2(face.Glyph.BitmapLeft, -face.Glyph.BitmapTop),
+					Size = glyphSize,
+					Data = new byte[glyphSize.Width * glyphSize.Height]
+				};
+
+				// A new bitmap is generated each time this property is accessed, so we do need to dispose it.
+				using (var bitmap = face.Glyph.Bitmap)
+				{
+					unsafe
+					{
+						var p = (byte*)bitmap.Buffer;
+						var k = 0;
+						for (var j = 0; j < glyphSize.Height; j++)
+						{
+							for (var i = 0; i < glyphSize.Width; i++)
+								g.Data[k++] = p[i];
+
+							p += bitmap.Pitch;
+						}
+					}
+				}
+
+				return g;
+			}
+			catch (FreeTypeException)
+			{
+				return new FontGlyph
+				{
+					Offset = int2.Zero,
+					Size = new Size(0, 0),
+					Advance = 0,
+					Data = null
+				};
+			}
+		}
+
+		public void Dispose()
+		{
+			face.Dispose();
+		}
+	}
+}