| 1 | module font_mod |
| 2 | use, intrinsic :: iso_c_binding |
| 3 | use glyph_mod |
| 4 | implicit none |
| 5 | private |
| 6 | |
| 7 | public :: font_t |
| 8 | public :: font_load, font_destroy, font_render_glyph |
| 9 | public :: font_load_fallback, font_has_glyph, font_render_glyph_with_fallback |
| 10 | public :: font_find_for_codepoint, font_find_monospace |
| 11 | |
| 12 | ! Font handle and metrics |
| 13 | type :: font_t |
| 14 | type(c_ptr) :: ft_library = c_null_ptr |
| 15 | type(c_ptr) :: ft_face = c_null_ptr |
| 16 | type(c_ptr) :: ft_face_fallback = c_null_ptr |
| 17 | integer :: size_px = 0 |
| 18 | integer :: cell_width = 0 |
| 19 | integer :: cell_height = 0 |
| 20 | integer :: ascender = 0 |
| 21 | integer :: descender = 0 |
| 22 | integer :: fallback_ascender = 0 ! For baseline alignment with fallback font |
| 23 | logical :: loaded = .false. |
| 24 | logical :: has_fallback = .false. |
| 25 | end type font_t |
| 26 | |
| 27 | ! C interface to FreeType helpers |
| 28 | interface |
| 29 | integer(c_int) function fortty_ft_init(lib) bind(C, name="fortty_ft_init") |
| 30 | import :: c_int, c_ptr |
| 31 | type(c_ptr), intent(out) :: lib |
| 32 | end function fortty_ft_init |
| 33 | |
| 34 | subroutine fortty_ft_done(lib) bind(C, name="fortty_ft_done") |
| 35 | import :: c_ptr |
| 36 | type(c_ptr), value :: lib |
| 37 | end subroutine fortty_ft_done |
| 38 | |
| 39 | integer(c_int) function fortty_ft_load_font(lib, path, size_px, face) & |
| 40 | bind(C, name="fortty_ft_load_font") |
| 41 | import :: c_int, c_ptr, c_char |
| 42 | type(c_ptr), value :: lib |
| 43 | character(kind=c_char), intent(in) :: path(*) |
| 44 | integer(c_int), value :: size_px |
| 45 | type(c_ptr), intent(out) :: face |
| 46 | end function fortty_ft_load_font |
| 47 | |
| 48 | subroutine fortty_ft_done_face(face) bind(C, name="fortty_ft_done_face") |
| 49 | import :: c_ptr |
| 50 | type(c_ptr), value :: face |
| 51 | end subroutine fortty_ft_done_face |
| 52 | |
| 53 | subroutine fortty_ft_get_metrics(face, cell_width, cell_height, & |
| 54 | ascender, descender) & |
| 55 | bind(C, name="fortty_ft_get_metrics") |
| 56 | import :: c_int, c_ptr |
| 57 | type(c_ptr), value :: face |
| 58 | integer(c_int), intent(out) :: cell_width, cell_height |
| 59 | integer(c_int), intent(out) :: ascender, descender |
| 60 | end subroutine fortty_ft_get_metrics |
| 61 | |
| 62 | integer(c_int) function fortty_ft_render_glyph(face, codepoint, & |
| 63 | bitmap, width, height, bearing_x, bearing_y, advance) & |
| 64 | bind(C, name="fortty_ft_render_glyph") |
| 65 | import :: c_int, c_ptr |
| 66 | type(c_ptr), value :: face |
| 67 | integer(c_int), value :: codepoint |
| 68 | type(c_ptr), intent(out) :: bitmap |
| 69 | integer(c_int), intent(out) :: width, height |
| 70 | integer(c_int), intent(out) :: bearing_x, bearing_y, advance |
| 71 | end function fortty_ft_render_glyph |
| 72 | |
| 73 | integer(c_int) function fortty_ft_has_glyph(face, codepoint) & |
| 74 | bind(C, name="fortty_ft_has_glyph") |
| 75 | import :: c_int, c_ptr |
| 76 | type(c_ptr), value :: face |
| 77 | integer(c_int), value :: codepoint |
| 78 | end function fortty_ft_has_glyph |
| 79 | |
| 80 | ! Fontconfig functions for portable font discovery |
| 81 | integer(c_int) function fortty_fc_find_font_for_char(codepoint, path, path_size) & |
| 82 | bind(C, name="fortty_fc_find_font_for_char") |
| 83 | import :: c_int, c_char |
| 84 | integer(c_int), value :: codepoint |
| 85 | character(kind=c_char), intent(out) :: path(*) |
| 86 | integer(c_int), value :: path_size |
| 87 | end function fortty_fc_find_font_for_char |
| 88 | |
| 89 | integer(c_int) function fortty_fc_find_monospace_font(path, path_size) & |
| 90 | bind(C, name="fortty_fc_find_monospace_font") |
| 91 | import :: c_int, c_char |
| 92 | character(kind=c_char), intent(out) :: path(*) |
| 93 | integer(c_int), value :: path_size |
| 94 | end function fortty_fc_find_monospace_font |
| 95 | end interface |
| 96 | |
| 97 | contains |
| 98 | |
| 99 | ! Load a font from file |
| 100 | function font_load(path, size_px) result(font) |
| 101 | character(len=*), intent(in) :: path |
| 102 | integer, intent(in) :: size_px |
| 103 | type(font_t) :: font |
| 104 | character(len=256) :: c_path |
| 105 | integer(c_int) :: err |
| 106 | integer(c_int) :: cw, ch, asc, desc |
| 107 | |
| 108 | ! Initialize FreeType |
| 109 | err = fortty_ft_init(font%ft_library) |
| 110 | if (err /= 0) then |
| 111 | print *, "Error: Failed to initialize FreeType, error ", err |
| 112 | return |
| 113 | end if |
| 114 | |
| 115 | ! Load font face |
| 116 | c_path = trim(path) // c_null_char |
| 117 | err = fortty_ft_load_font(font%ft_library, c_path, int(size_px, c_int), font%ft_face) |
| 118 | if (err /= 0) then |
| 119 | print *, "Error: Failed to load font '", trim(path), "', error ", err |
| 120 | call fortty_ft_done(font%ft_library) |
| 121 | font%ft_library = c_null_ptr |
| 122 | return |
| 123 | end if |
| 124 | |
| 125 | ! Get metrics |
| 126 | call fortty_ft_get_metrics(font%ft_face, cw, ch, asc, desc) |
| 127 | font%size_px = size_px |
| 128 | font%cell_width = cw |
| 129 | font%cell_height = ch |
| 130 | font%ascender = asc |
| 131 | font%descender = desc |
| 132 | font%loaded = .true. |
| 133 | |
| 134 | end function font_load |
| 135 | |
| 136 | ! Destroy font and free resources |
| 137 | subroutine font_destroy(font) |
| 138 | type(font_t), intent(inout) :: font |
| 139 | |
| 140 | if (c_associated(font%ft_face_fallback)) then |
| 141 | call fortty_ft_done_face(font%ft_face_fallback) |
| 142 | font%ft_face_fallback = c_null_ptr |
| 143 | end if |
| 144 | |
| 145 | if (c_associated(font%ft_face)) then |
| 146 | call fortty_ft_done_face(font%ft_face) |
| 147 | font%ft_face = c_null_ptr |
| 148 | end if |
| 149 | |
| 150 | if (c_associated(font%ft_library)) then |
| 151 | call fortty_ft_done(font%ft_library) |
| 152 | font%ft_library = c_null_ptr |
| 153 | end if |
| 154 | |
| 155 | font%loaded = .false. |
| 156 | font%has_fallback = .false. |
| 157 | end subroutine font_destroy |
| 158 | |
| 159 | ! Render a glyph and return its data |
| 160 | ! Returns bitmap pointer (valid until next render_glyph call) |
| 161 | function font_render_glyph(font, codepoint, bitmap_ptr) result(glyph) |
| 162 | type(font_t), intent(in) :: font |
| 163 | integer, intent(in) :: codepoint |
| 164 | type(c_ptr), intent(out) :: bitmap_ptr |
| 165 | type(glyph_t) :: glyph |
| 166 | integer(c_int) :: err, w, h, bx, by, adv |
| 167 | |
| 168 | call glyph_init(glyph) |
| 169 | |
| 170 | if (.not. font%loaded) then |
| 171 | bitmap_ptr = c_null_ptr |
| 172 | return |
| 173 | end if |
| 174 | |
| 175 | err = fortty_ft_render_glyph(font%ft_face, int(codepoint, c_int), & |
| 176 | bitmap_ptr, w, h, bx, by, adv) |
| 177 | if (err /= 0) then |
| 178 | bitmap_ptr = c_null_ptr |
| 179 | return |
| 180 | end if |
| 181 | |
| 182 | glyph%codepoint = codepoint |
| 183 | glyph%width = w |
| 184 | glyph%height = h |
| 185 | glyph%bearing_x = bx |
| 186 | glyph%bearing_y = by |
| 187 | glyph%advance = adv |
| 188 | glyph%valid = .true. |
| 189 | |
| 190 | end function font_render_glyph |
| 191 | |
| 192 | ! Load a fallback font (for missing glyphs) |
| 193 | subroutine font_load_fallback(font, path) |
| 194 | type(font_t), intent(inout) :: font |
| 195 | character(len=*), intent(in) :: path |
| 196 | character(len=256) :: c_path |
| 197 | integer(c_int) :: err |
| 198 | integer(c_int) :: fb_cell_w, fb_cell_h, fb_asc, fb_desc |
| 199 | |
| 200 | if (.not. font%loaded) return |
| 201 | if (len_trim(path) == 0) return |
| 202 | |
| 203 | c_path = trim(path) // c_null_char |
| 204 | err = fortty_ft_load_font(font%ft_library, c_path, int(font%size_px, c_int), & |
| 205 | font%ft_face_fallback) |
| 206 | if (err /= 0) then |
| 207 | ! Silently fail - fallback is optional |
| 208 | font%ft_face_fallback = c_null_ptr |
| 209 | font%has_fallback = .false. |
| 210 | return |
| 211 | end if |
| 212 | |
| 213 | font%has_fallback = .true. |
| 214 | |
| 215 | ! Get fallback font metrics for baseline alignment |
| 216 | call fortty_ft_get_metrics(font%ft_face_fallback, fb_cell_w, fb_cell_h, fb_asc, fb_desc) |
| 217 | font%fallback_ascender = fb_asc |
| 218 | end subroutine font_load_fallback |
| 219 | |
| 220 | ! Check if a glyph exists in the primary font |
| 221 | function font_has_glyph(font, codepoint) result(has) |
| 222 | type(font_t), intent(in) :: font |
| 223 | integer, intent(in) :: codepoint |
| 224 | logical :: has |
| 225 | |
| 226 | has = .false. |
| 227 | if (.not. font%loaded) return |
| 228 | |
| 229 | has = fortty_ft_has_glyph(font%ft_face, int(codepoint, c_int)) /= 0 |
| 230 | end function font_has_glyph |
| 231 | |
| 232 | ! Render glyph with fallback support |
| 233 | ! used_fallback is set to .true. if glyph came from fallback font |
| 234 | function font_render_glyph_with_fallback(font, codepoint, bitmap_ptr, used_fallback) result(glyph) |
| 235 | type(font_t), intent(in) :: font |
| 236 | integer, intent(in) :: codepoint |
| 237 | type(c_ptr), intent(out) :: bitmap_ptr |
| 238 | logical, intent(out) :: used_fallback |
| 239 | type(glyph_t) :: glyph |
| 240 | integer(c_int) :: err, w, h, bx, by, adv |
| 241 | type(c_ptr) :: face_to_use |
| 242 | integer(c_int) :: primary_has, fallback_has |
| 243 | |
| 244 | call glyph_init(glyph) |
| 245 | used_fallback = .false. |
| 246 | |
| 247 | if (.not. font%loaded) then |
| 248 | bitmap_ptr = c_null_ptr |
| 249 | return |
| 250 | end if |
| 251 | |
| 252 | ! Check if primary font has this glyph |
| 253 | primary_has = fortty_ft_has_glyph(font%ft_face, int(codepoint, c_int)) |
| 254 | if (primary_has /= 0) then |
| 255 | face_to_use = font%ft_face |
| 256 | else if (font%has_fallback .and. c_associated(font%ft_face_fallback)) then |
| 257 | ! Try fallback font |
| 258 | fallback_has = fortty_ft_has_glyph(font%ft_face_fallback, int(codepoint, c_int)) |
| 259 | if (fallback_has /= 0) then |
| 260 | face_to_use = font%ft_face_fallback |
| 261 | used_fallback = .true. |
| 262 | else |
| 263 | ! Neither font has this glyph |
| 264 | bitmap_ptr = c_null_ptr |
| 265 | return |
| 266 | end if |
| 267 | else |
| 268 | ! No fallback available, try primary anyway (may show .notdef) |
| 269 | face_to_use = font%ft_face |
| 270 | end if |
| 271 | |
| 272 | err = fortty_ft_render_glyph(face_to_use, int(codepoint, c_int), & |
| 273 | bitmap_ptr, w, h, bx, by, adv) |
| 274 | if (err /= 0) then |
| 275 | bitmap_ptr = c_null_ptr |
| 276 | return |
| 277 | end if |
| 278 | |
| 279 | glyph%codepoint = codepoint |
| 280 | glyph%width = w |
| 281 | glyph%height = h |
| 282 | glyph%bearing_x = bx |
| 283 | glyph%bearing_y = by |
| 284 | glyph%advance = adv |
| 285 | glyph%valid = .true. |
| 286 | |
| 287 | ! Normalize baseline: adjust bearing_y for ascender difference between fonts |
| 288 | if (used_fallback) then |
| 289 | glyph%bearing_y = glyph%bearing_y - (font%fallback_ascender - font%ascender) |
| 290 | end if |
| 291 | |
| 292 | end function font_render_glyph_with_fallback |
| 293 | |
| 294 | ! Find a font that supports a specific codepoint using fontconfig |
| 295 | ! Returns empty string if fontconfig not available or no font found |
| 296 | function font_find_for_codepoint(codepoint) result(path) |
| 297 | integer, intent(in) :: codepoint |
| 298 | character(len=256) :: path |
| 299 | character(len=256) :: c_path |
| 300 | integer(c_int) :: err |
| 301 | integer :: i |
| 302 | |
| 303 | path = '' |
| 304 | c_path = '' |
| 305 | err = fortty_fc_find_font_for_char(int(codepoint, c_int), c_path, 256_c_int) |
| 306 | if (err == 0) then |
| 307 | ! Convert C string to Fortran string |
| 308 | do i = 1, 256 |
| 309 | if (c_path(i:i) == c_null_char) exit |
| 310 | path(i:i) = c_path(i:i) |
| 311 | end do |
| 312 | end if |
| 313 | end function font_find_for_codepoint |
| 314 | |
| 315 | ! Find a monospace font using fontconfig |
| 316 | ! Returns empty string if fontconfig not available or no font found |
| 317 | function font_find_monospace() result(path) |
| 318 | character(len=256) :: path |
| 319 | character(len=256) :: c_path |
| 320 | integer(c_int) :: err |
| 321 | integer :: i |
| 322 | |
| 323 | path = '' |
| 324 | c_path = '' |
| 325 | err = fortty_fc_find_monospace_font(c_path, 256_c_int) |
| 326 | if (err == 0) then |
| 327 | ! Convert C string to Fortran string |
| 328 | do i = 1, 256 |
| 329 | if (c_path(i:i) == c_null_char) exit |
| 330 | path(i:i) = c_path(i:i) |
| 331 | end do |
| 332 | end if |
| 333 | end function font_find_monospace |
| 334 | |
| 335 | end module font_mod |
| 336 |