Add initial prototype.

3-mid/opengl/source/lean/text/private/opengl-fontimpl.ads

@@ -0,0 +1,153 @@
+with
+     openGL.Glyph.Container,
+     freetype.Face,
+     freetype.charMap,
+     Freetype_C,
+     interfaces.C.Pointers;
+
+limited
+with
+     openGL.Font;
+
+private
+with
+     freetype.face_Size;
+
+package openGL.FontImpl
+--
+--  Implements an openGL font.
+--
+is
+   type Item is tagged limited private;
+   type View is access all Item'Class;
+
+
+   ---------
+   --  Types
+   --
+
+   type RenderMode is (RENDER_FRONT, RENDER_BACK, RENDER_SIDE, RENDER_ALL);
+
+   for RenderMode use (RENDER_FRONT => 16#0001#,
+                       RENDER_BACK  => 16#0002#,
+                       RENDER_SIDE  => 16#0004#,
+                       RENDER_ALL   => 16#ffff#);
+
+   type TextAlignment is (ALIGN_LEFT, ALIGN_CENTER, ALIGN_RIGHT, ALIGN_JUSTIFY);
+
+   for TextAlignment use (ALIGN_LEFT    => 0,
+                          ALIGN_CENTER  => 1,
+                          ALIGN_RIGHT   => 2,
+                          ALIGN_JUSTIFY => 3);
+
+
+   --  unsigned_char_Pointer
+   --
+
+   use Interfaces;
+
+   type    unsigned_char_array    is array (C.size_t range <>) of aliased C.unsigned_char;
+
+   package unsigned_char_Pointers is new C.Pointers (Index              => C.size_t,
+                                                     Element            => C.unsigned_char,
+                                                     Element_array      => unsigned_char_array,
+                                                     default_Terminator => 0);
+   subtype unsigned_char_Pointer  is unsigned_char_Pointers.Pointer;
+
+
+   ---------
+   --  Forge
+   --
+
+   procedure define   (Self : access Item;   ftFont            : access Font.item'Class;
+                                             fontFilePath      : in     String);
+
+   procedure define   (Self : access Item;   ftFont            : access Font.item'Class;
+                                             pBufferBytes      : access C.unsigned_char;
+                                             bufferSizeInBytes : in     Integer);
+   procedure destruct (Self : in out Item);
+
+
+   ---------------
+   --  'Protected' ~ For derived class use only.
+   --
+
+   function  Err            (Self : in     Item) return freetype_c.FT_Error;
+
+   function  attach         (Self : access Item;   fontFilePath      : in     String)  return Boolean;
+   function  attach         (Self : access Item;   pBufferBytes      : access C.unsigned_char;
+                                                   bufferSizeInBytes : in     Integer) return Boolean;
+
+   function  FaceSize       (Self : access Item;   Size     : in Natural;
+                                                   x_Res,
+                                                   y_Res    : in Natural) return Boolean;
+   function  FaceSize       (Self : in     Item)                          return Natural;
+
+   procedure Depth          (Self : in out Item;   Depth    : in Real);
+   procedure Outset         (Self : in out Item;   Outset   : in Real);
+   procedure Outset         (Self : in out Item;   Front    : in Real;
+                                                   Back     : in Real);
+
+   procedure GlyphLoadFlags (Self : in out Item;   Flags    : in freetype_c.FT_Int);
+
+   function  CharMap        (Self : access Item;   Encoding : in freetype_c.FT_Encoding) return Boolean;
+   function  CharMapCount   (Self : in     Item)                                         return Natural;
+   function  CharMapList    (Self : access Item)                                         return freetype.face.FT_Encodings_view;
+
+   function  Ascender       (Self : in     Item) return Real;
+   function  Descender      (Self : in     Item) return Real;
+   function  LineHeight     (Self : in     Item) return Real;
+
+   function  BBox           (Self : access Item;   Text     : in String;
+                                                   Length   : in Integer;
+                                                   Position : in Vector_3;
+                                                   Spacing  : in Vector_3)  return Bounds;
+
+   function  Advance        (Self : access Item;   Text     : in String;
+                                                   Length   : in Integer;
+                                                   Spacing  : in Vector_3)  return Real;
+
+   function  kern_Advance   (Self : in     Item;   From, To : in Character) return Real;
+
+
+   function  x_PPEM         (Self : in     Item) return Real;
+   function  x_Scale        (Self : in     Item) return Real;
+   function  y_Scale        (Self : in     Item) return Real;
+
+   function  render         (Self : access Item;   Text       : in String;
+                                                   Length     : in Integer;
+                                                   Position   : in Vector_3;
+                                                   Spacing    : in Vector_3;
+                                                   renderMode : in Integer) return Vector_3;
+
+
+private
+
+   type glyph_Container_view is access all openGL.Glyph.Container.item'Class;
+
+
+   type Item is tagged limited
+      record
+         Face       : aliased freetype.Face.item;          -- Current face object.
+         charSize   :         freetype.face_Size.item;     -- Current size object.
+
+         load_Flags :         freetype_c.FT_Int;           -- The default glyph loading flags.
+         Err        :         freetype_c.FT_Error;         -- Current error code. Zero means no error.
+
+         Intf       : access  Font.item'Class;             -- A link back to the interface of which we implement.
+         glyphList  :         Glyph_Container_view;        -- An object that holds a list of glyphs
+
+         Pen        :         Vector_3;                    -- Current pen or cursor position;
+      end record;
+
+
+   function CheckGlyph (Self : access Item;   Character : in freetype.charmap.CharacterCode) return Boolean;
+   --
+   --  Check that the glyph at <code>chr</code> exist. If not load it.
+   --
+   --  Character: The character index.
+   --
+   --  Returns true if the glyph can be created.
+
+
+end openGL.FontImpl;