add ffi measuring; continuation-based linebreaking
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#lang racket/base
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(require ffi/unsafe
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ffi/unsafe/define
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racket/draw/private/libs)
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(define-syntax-rule (define+provide id val)
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(begin
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(define id val)
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(provide id)))
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(define-runtime-lib freetype-lib
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[(unix) #f] ; todo: get unix runtime path
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[(macosx) (ffi-lib "libfreetype.6.dylib")]
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[(windows) (ffi-lib "libfreetype-6.dll")])
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(define-ffi-definer define-freetype freetype-lib #:provide provide)
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;; types
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(define _void-pointer (_cpointer 'void-pointer))
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(define _char _byte)
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(define _char-pointer (_cpointer 'char-pointer))
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(define _uchar _ubyte)
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(define _FT_Byte _ubyte)
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(define _FT_Bytes _bytes)
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(define _FT_Char _char)
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(define _FT_Int _int)
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(define _FT_UInt _uint)
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(define _FT_Int16 _short)
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(define _FT_UInt16 _ushort)
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(define _FT_Int32 _int32)
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(define _FT_UInt32 _uint32)
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(define _FT_Short _short)
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(define _FT_UShort _ushort)
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(define _FT_Long _long)
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(define _FT_ULong _ulong)
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(define _FT_Bool _byte)
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(define _FT_Offset _size) ;; equivalent to _size_t?
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(define _FT_PtrDist _ptrdiff) ;; equivalent to _longlong?
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(define _FT_String _char)
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(define _FT_String-pointer (_cpointer 'FT_String-pointer)) ;; char*
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(define _FT_Tag _FT_UInt32)
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(define _FT_Error _int)
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(define _FT_Fixed _long)
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(define _FT_Pointer _void-pointer)
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(define _FT_Pos _long)
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(define _FT_FWord _short)
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(define _FT_UFWord _ushort)
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(define _FT_F26Dot16 _short)
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(define _FT_F26Dot6 _long)
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(define _FT_Glyph_Format _int)
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(define _FT_Encoding _int)
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(define _FT_Generic_Finalizer (_cpointer '_FT_Generic_Finalizer (_fun _void-pointer -> _void)))
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(define _FT_LibraryRec (_cpointer 'FT_LibraryRec))
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(define _FT_Library (_cpointer 'FT_Library))
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(define-cstruct _FT_Bitmap_Size
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([height _FT_Short]
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[width _FT_Short]
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[size _FT_Pos]
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[x_ppem _FT_Pos]
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[y_ppem _FT_Pos]))
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(define-cstruct _FT_CharMapRec
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([face _void-pointer] ; should be FT_Face
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[encoding _FT_Encoding]
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[platform_id _FT_UShort]
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[encoding_id _FT_UShort]))
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(define _FT_Charmap _FT_CharMapRec-pointer)
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(define _FT_CharMap-pointer (_cpointer 'FT_CharMap-pointer))
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(define-cstruct _FT_Generic
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([data _void-pointer]
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[finalizer _FT_Generic_Finalizer]))
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(define-cstruct _FT_BBox
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([xMin _FT_Pos]
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[yMin _FT_Pos]
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[xMax _FT_Pos]
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[yMax _FT_Pos]))
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(define-cstruct _FT_Glyph_Metrics
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([width _FT_Pos]
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[height _FT_Pos]
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[horiBearingX _FT_Pos]
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[horiBearingY _FT_Pos]
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[horiAdvance _FT_Pos]
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[vertBearingX _FT_Pos]
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[vertBearingY _FT_Pos]
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[vertAdvance _FT_Pos]))
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(define-cstruct _FT_Vector
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([x _FT_Pos]
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[y _FT_Pos]))
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(provide (struct-out FT_Vector)
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_FT_Vector _FT_Vector-pointer)
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(define-cstruct _FT_Bitmap
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([rows _int]
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[width _int]
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[pitch _int]
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[buffer (_cpointer 'buffer)]
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[num_grays _short]
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[pixel_mode _ubyte]
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[palette_mode _char]
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[palette _void-pointer]))
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(define-cstruct _FT_Outline
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([n_contours _short]
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[n_points _short]
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[points _FT_Vector-pointer]
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[tags (_cpointer 'tags)]
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[contours (_cpointer 'contours)]
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[flags _int]))
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(define-cstruct _FT_GlyphSlotRec
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([library _FT_Library]
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[face _void-pointer]
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[next _void-pointer]
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[reserved _uint]
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[generic _FT_Generic]
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[metrics _FT_Glyph_Metrics]
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[linearHoriAdvance _FT_Fixed]
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[linearVertAdvance _FT_Fixed]
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[advance _FT_Vector]
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[format _FT_Glyph_Format]
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[bitmap _FT_Bitmap]
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[bitmap_left _FT_Int]
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[bitmap_top _FT_Int]
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[outline _FT_Outline]
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[num_subglyphs _FT_UInt]
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[subglyphs _void-pointer]
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[control_data _void-pointer]
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[control_len _long]
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[lsb_delta _FT_Pos]
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[rsb_delta _FT_Pos]
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[other _void-pointer]
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[internal _void-pointer]))
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(define _FT_GlyphSlot _FT_GlyphSlotRec-pointer)
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(provide (struct-out FT_GlyphSlotRec)
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_FT_GlyphSlotRec _FT_GlyphSlotRec-pointer)
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(define-cstruct _FT_Size_Metrics
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([x_ppem _FT_UShort]
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[y_ppem _FT_UShort]
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[x_scale _FT_Fixed]
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[y_scale _FT_Fixed]
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[ascender _FT_Pos]
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[descender _FT_Pos]
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[height _FT_Pos]
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[max_advance _FT_Pos]))
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(define-cstruct _FT_SizeRec
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([face _void-pointer]
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[generic _FT_Generic]
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[metrics _FT_Size_Metrics]
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[internal _void-pointer]))
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(define _FT_Size _FT_SizeRec-pointer)
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(define-cstruct _FT_FaceRec
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([num_faces _FT_Long]
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[face_index _FT_Long]
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[face_flag _FT_Long]
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[style_flags _FT_Long]
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[num_glyphs _FT_Long]
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[family_name _string] ; probably _string is a better choice
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[style_name _string]
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[num_fixed_sizes _FT_Int]
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[available_sizes _FT_Bitmap_Size-pointer]
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[num_charmaps _FT_Int]
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[charmaps _FT_CharMap-pointer]
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[generic _FT_Generic]
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[bbox _FT_BBox]
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[units_per_EM _FT_UShort]
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[ascender _FT_Short]
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[descender _FT_Short]
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[height _FT_Short]
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[max_advance_width _FT_Short]
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[max_advance_height _FT_Short]
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[underline_position _FT_Short]
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[underline_thickness _FT_Short]
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[glyph _FT_GlyphSlot]
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[size _FT_Size]
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[charmap _FT_Charmap]
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[driver _void-pointer]
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[memory _void-pointer]
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[stream _void-pointer]
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[sizes_list_head _void-pointer]
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[sizes_list_tail _void-pointer]
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[autohint _FT_Generic]
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[extensions _void-pointer]
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[internal _void-pointer]))
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(define _FT_Face _FT_FaceRec-pointer)
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(provide (struct-out FT_FaceRec)
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_FT_FaceRec _FT_FaceRec-pointer)
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(define _full-path
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(make-ctype _path
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path->complete-path
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values))
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(define-freetype FT_Init_FreeType (_fun (ftl : (_ptr o _FT_Library))
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-> (err : _FT_Error)
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-> (if (zero? err) ftl (error 'FT_Init_FreeType))))
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(define-freetype FT_New_Face (_fun _FT_Library _full-path _FT_Long
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(ftf : (_ptr o (_or-null _FT_Face)))
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-> (err : _FT_Error)
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-> (if (zero? err) ftf (error 'FT_New_Face (format "error ~a" err)))))
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(define-freetype FT_Done_Face (_fun _FT_Face
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-> (err : _FT_Error)
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-> (unless (zero? err) (error 'FT_Done_Face (format "error ~a" err)))))
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(define-freetype FT_Done_FreeType (_fun _FT_Library -> (err : _FT_Error) -> (if (zero? err) (void) (error 'FT_Done_FreeType))))
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(define-freetype FT_Get_Kerning (_fun _FT_Face _FT_UInt _FT_UInt _FT_UInt
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(ftv : (_ptr o _FT_Vector))
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-> (err : _FT_Error)
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-> (if (zero? err) ftv (error 'FT_Get_Kerning (format "error ~a" err)))))
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(define-freetype FT_Get_Char_Index (_fun _FT_Face _FT_ULong
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-> _FT_UInt))
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(define-freetype FT_Load_Glyph (_fun _FT_Face _FT_UInt _FT_Int32
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-> (err : _FT_Error)))
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(define-freetype FT_Load_Char (_fun _FT_Face _FT_ULong _FT_Int32
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-> (err : _FT_Error)))
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(define+provide FT_KERNING_UNSCALED 2)
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(define+provide FT_LOAD_DEFAULT 0)
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(define+provide FT_LOAD_RENDER (expt 2 2))
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(define+provide FT_LOAD_LINEAR_DESIGN (expt 2 13))
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(define+provide FT_LOAD_NO_RECURSE (expt 2 10))
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@ -0,0 +1,64 @@
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#lang quad/dev
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(require "freetype-ffi.rkt")
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(provide (all-defined-out))
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(define measure-char
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(let ([measure-cache (make-hash)]
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[glyph-idx-cache (make-hash)]
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[glyph-width-cache (make-hash)]
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[em-size-cache (make-hash)])
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(λ (font-pathstring char)
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(define (do-measure)
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(define ft-library (FT_Init_FreeType))
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(define ft-face (FT_New_Face ft-library font-pathstring 0))
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(define prev-glyph-idx #f)
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(define sum
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(let ([glyph-idx (hash-ref! glyph-idx-cache (cons char font-pathstring)
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(λ () (FT_Get_Char_Index ft-face (char->integer char))))])
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(hash-ref! glyph-width-cache (cons glyph-idx font-pathstring)
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(λ ()
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(FT_Load_Glyph ft-face glyph-idx FT_LOAD_NO_RECURSE) ; loads into FTFace's 'glyph' slot
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(FT_Vector-x (FT_GlyphSlotRec-advance (FT_FaceRec-glyph ft-face)))))))
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(define em-size
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(hash-ref! em-size-cache font-pathstring (λ () (+ (FT_FaceRec-units_per_EM ft-face) 0.0))))
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; will anything bad happen if I skip these?
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(FT_Done_Face ft-face)
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(FT_Done_FreeType ft-library)
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(/ sum em-size)) ; normalize to em size
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(hash-ref! measure-cache (cons font-pathstring char) do-measure))))
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(define measure-chars
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(let ([measure-cache (make-hash)]
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[glyph-idx-cache (make-hash)]
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[glyph-width-cache (make-hash)]
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[kern-cache (make-hash)])
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(λ (font-pathstring chars)
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(define (do-measure)
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(define ft-library (FT_Init_FreeType))
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(define ft-face (FT_New_Face ft-library font-pathstring 0))
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(define prev-glyph-idx #f)
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(define sum
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(for/sum ([char (in-list chars)])
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(define glyph-idx (hash-ref! glyph-idx-cache (cons char font-pathstring)
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(λ () (FT_Get_Char_Index ft-face (char->integer char)))))
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(define glyph-width (hash-ref! glyph-width-cache (cons glyph-idx font-pathstring)
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(λ ()
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(FT_Load_Glyph ft-face glyph-idx FT_LOAD_NO_RECURSE) ; loads into FTFace's 'glyph' slot
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(FT_Vector-x (FT_GlyphSlotRec-advance (FT_FaceRec-glyph ft-face))))))
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(define kern (if prev-glyph-idx
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(hash-ref! kern-cache (cons prev-glyph-idx (cons glyph-idx font-pathstring))
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(λ ()
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(FT_Vector-x (FT_Get_Kerning ft-face prev-glyph-idx glyph-idx FT_KERNING_UNSCALED))))
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0))
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(set! prev-glyph-idx glyph-idx)
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(+ glyph-width kern)))
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; will anything bad happen if I skip these?
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(FT_Done_Face ft-face)
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(FT_Done_FreeType ft-library)
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sum)
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(hash-ref! measure-cache (cons font-pathstring chars) do-measure))))
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(module+ test
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(require rackunit)
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(check-equal? (measure-chars "charter.ttf" '(#\f)) 321))
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