fortrangoingonforty/fortty / d016cd4

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Add FreeType bindings for font loading

- C helper functions for FreeType (init, load font, render glyph)
- Fortran font_mod module with font_t type
- Fortran glyph_mod module with glyph_t type
- Updated CMake to find and link FreeType
Authored by mfwolffe <wolffemf@dukes.jmu.edu>
SHA
d016cd47cf1808d3eaaa45af56b03dbf931115fd
Parents
14f0f3a
Tree
adb9533

4 changed files

StatusFile+-
M CMakeLists.txt 10 5
A c_src/freetype_helpers.c 101 0
A src/text/font.f90 158 0
A src/text/glyph.f90 39 0
CMakeLists.txtmodified
@@ -13,14 +13,17 @@ endif()
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 # Find dependencies
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 find_package(glfw3 REQUIRED)
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 find_package(OpenGL REQUIRED)
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+find_package(Freetype REQUIRED)
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-# GLAD loader library (C) and helper functions
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-add_library(glad STATIC
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+# C helper libraries (GLAD + FreeType wrappers)
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+add_library(helpers STATIC
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     src/gl/glad.c
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     c_src/gl_loader.c
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+    c_src/freetype_helpers.c
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 )
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-target_include_directories(glad PUBLIC ${CMAKE_SOURCE_DIR}/include)
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-target_link_libraries(glad PRIVATE glfw)
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+target_include_directories(helpers PUBLIC ${CMAKE_SOURCE_DIR}/include)
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+target_include_directories(helpers PRIVATE ${FREETYPE_INCLUDE_DIRS})
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+target_link_libraries(helpers PRIVATE glfw ${FREETYPE_LIBRARIES})
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 # Fortran module output directory
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 set(CMAKE_Fortran_MODULE_DIRECTORY ${CMAKE_BINARY_DIR}/modules)
@@ -29,6 +32,8 @@ set(CMAKE_Fortran_MODULE_DIRECTORY ${CMAKE_BINARY_DIR}/modules)
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 set(FORTRAN_SOURCES
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     src/core/types.f90
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     src/gl/gl_bindings.f90
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+    src/text/glyph.f90
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+    src/text/font.f90
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     src/window/glfw_bindings.f90
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     src/window/window.f90
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     src/fortty.f90
@@ -37,7 +42,7 @@ set(FORTRAN_SOURCES
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 # Main executable
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 add_executable(fortty ${FORTRAN_SOURCES})
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 target_include_directories(fortty PRIVATE ${CMAKE_BINARY_DIR}/modules)
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-target_link_libraries(fortty PRIVATE glad glfw OpenGL::GL)
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+target_link_libraries(fortty PRIVATE helpers glfw OpenGL::GL ${FREETYPE_LIBRARIES})
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 # For Linux, we need dl for GLAD's dlopen
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 if(UNIX AND NOT APPLE)
c_src/freetype_helpers.cadded
@@ -0,0 +1,101 @@
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+/*
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+ * FreeType helper functions for Fortran binding.
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+ * Provides simplified C wrappers around FreeType's complex structs.
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+ */
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+
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+#include <ft2build.h>
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+#include FT_FREETYPE_H
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+#include <stdlib.h>
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+#include <string.h>
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+
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+/* Initialize FreeType library */
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+int fortty_ft_init(FT_Library *lib) {
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+    return FT_Init_FreeType(lib);
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+}
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+
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+/* Cleanup FreeType library */
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+void fortty_ft_done(FT_Library lib) {
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+    FT_Done_FreeType(lib);
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+}
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+
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+/* Load a font face at specified pixel size */
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+int fortty_ft_load_font(FT_Library lib, const char *path, int size_px, FT_Face *face) {
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+    FT_Error err = FT_New_Face(lib, path, 0, face);
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+    if (err) return err;
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+
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+    err = FT_Set_Pixel_Sizes(*face, 0, size_px);
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+    if (err) {
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+        FT_Done_Face(*face);
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+        return err;
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+    }
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+
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+    return 0;
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+}
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+
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+/* Cleanup font face */
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+void fortty_ft_done_face(FT_Face face) {
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+    FT_Done_Face(face);
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+}
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+
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+/* Get font metrics for terminal cell sizing */
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+void fortty_ft_get_metrics(FT_Face face, int *cell_width, int *cell_height,
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+                           int *ascender, int *descender) {
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+    /* For monospace fonts, use the max advance width */
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+    if (face->face_flags & FT_FACE_FLAG_FIXED_WIDTH) {
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+        *cell_width = face->max_advance_width >> 6;
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+    } else {
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+        /* Fallback: measure 'M' character */
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+        if (FT_Load_Char(face, 'M', FT_LOAD_DEFAULT) == 0) {
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+            *cell_width = face->glyph->advance.x >> 6;
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+        } else {
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+            *cell_width = face->size->metrics.max_advance >> 6;
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+        }
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+    }
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+
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+    /* Height from font metrics (in 1/64 pixels, convert to pixels) */
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+    *ascender = face->size->metrics.ascender >> 6;
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+    *descender = -(face->size->metrics.descender >> 6); /* Make positive */
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+    *cell_height = *ascender + *descender;
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+}
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+
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+/* Render a glyph and return its bitmap data
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+ * Returns 0 on success, non-zero on error.
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+ * Caller should NOT free the bitmap pointer - it points to FreeType's internal buffer.
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+ */
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+int fortty_ft_render_glyph(FT_Face face, unsigned int codepoint,
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+                           unsigned char **bitmap, int *width, int *height,
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+                           int *bearing_x, int *bearing_y, int *advance) {
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+    FT_Error err = FT_Load_Char(face, codepoint, FT_LOAD_RENDER);
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+    if (err) return err;
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+
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+    FT_GlyphSlot g = face->glyph;
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+
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+    *bitmap = g->bitmap.buffer;
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+    *width = g->bitmap.width;
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+    *height = g->bitmap.rows;
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+    *bearing_x = g->bitmap_left;
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+    *bearing_y = g->bitmap_top;
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+    *advance = g->advance.x >> 6;  /* Convert from 26.6 fixed point */
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+
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+    return 0;
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+}
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+
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+/* Get size of glyph bitmap without rendering (for atlas planning) */
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+int fortty_ft_get_glyph_size(FT_Face face, unsigned int codepoint,
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+                              int *width, int *height) {
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+    FT_Error err = FT_Load_Char(face, codepoint, FT_LOAD_BITMAP_METRICS_ONLY);
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+    if (err) return err;
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+
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+    *width = face->glyph->bitmap.width;
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+    *height = face->glyph->bitmap.rows;
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+
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+    /* If metrics-only didn't give us size, do full load */
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+    if (*width == 0 && *height == 0) {
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+        err = FT_Load_Char(face, codepoint, FT_LOAD_DEFAULT);
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+        if (err) return err;
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+        *width = face->glyph->bitmap.width;
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+        *height = face->glyph->bitmap.rows;
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+    }
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+
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+    return 0;
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+}
src/text/font.f90added
@@ -0,0 +1,158 @@
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+module font_mod
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+  use, intrinsic :: iso_c_binding
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+  use glyph_mod
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+  implicit none
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+  private
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+
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+  public :: font_t
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+  public :: font_load, font_destroy, font_render_glyph
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+
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+  ! Font handle and metrics
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+  type :: font_t
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+    type(c_ptr) :: ft_library = c_null_ptr
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+    type(c_ptr) :: ft_face = c_null_ptr
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+    integer :: size_px = 0
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+    integer :: cell_width = 0
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+    integer :: cell_height = 0
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+    integer :: ascender = 0
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+    integer :: descender = 0
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+    logical :: loaded = .false.
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+  end type font_t
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+
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+  ! C interface to FreeType helpers
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+  interface
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+    integer(c_int) function fortty_ft_init(lib) bind(C, name="fortty_ft_init")
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+      import :: c_int, c_ptr
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+      type(c_ptr), intent(out) :: lib
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+    end function fortty_ft_init
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+
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+    subroutine fortty_ft_done(lib) bind(C, name="fortty_ft_done")
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+      import :: c_ptr
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+      type(c_ptr), value :: lib
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+    end subroutine fortty_ft_done
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+
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+    integer(c_int) function fortty_ft_load_font(lib, path, size_px, face) &
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+        bind(C, name="fortty_ft_load_font")
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+      import :: c_int, c_ptr, c_char
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+      type(c_ptr), value :: lib
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+      character(kind=c_char), intent(in) :: path(*)
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+      integer(c_int), value :: size_px
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+      type(c_ptr), intent(out) :: face
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+    end function fortty_ft_load_font
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+
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+    subroutine fortty_ft_done_face(face) bind(C, name="fortty_ft_done_face")
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+      import :: c_ptr
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+      type(c_ptr), value :: face
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+    end subroutine fortty_ft_done_face
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+
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+    subroutine fortty_ft_get_metrics(face, cell_width, cell_height, &
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+                                      ascender, descender) &
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+        bind(C, name="fortty_ft_get_metrics")
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+      import :: c_int, c_ptr
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+      type(c_ptr), value :: face
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+      integer(c_int), intent(out) :: cell_width, cell_height
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+      integer(c_int), intent(out) :: ascender, descender
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+    end subroutine fortty_ft_get_metrics
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+
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+    integer(c_int) function fortty_ft_render_glyph(face, codepoint, &
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+        bitmap, width, height, bearing_x, bearing_y, advance) &
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+        bind(C, name="fortty_ft_render_glyph")
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+      import :: c_int, c_ptr
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+      type(c_ptr), value :: face
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+      integer(c_int), value :: codepoint
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+      type(c_ptr), intent(out) :: bitmap
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+      integer(c_int), intent(out) :: width, height
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+      integer(c_int), intent(out) :: bearing_x, bearing_y, advance
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+    end function fortty_ft_render_glyph
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+  end interface
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+
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+contains
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+
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+  ! Load a font from file
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+  function font_load(path, size_px) result(font)
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+    character(len=*), intent(in) :: path
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+    integer, intent(in) :: size_px
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+    type(font_t) :: font
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+    character(len=256) :: c_path
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+    integer(c_int) :: err
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+    integer(c_int) :: cw, ch, asc, desc
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+
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+    ! Initialize FreeType
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+    err = fortty_ft_init(font%ft_library)
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+    if (err /= 0) then
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+      print *, "Error: Failed to initialize FreeType, error ", err
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+      return
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+    end if
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+
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+    ! Load font face
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+    c_path = trim(path) // c_null_char
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+    err = fortty_ft_load_font(font%ft_library, c_path, int(size_px, c_int), font%ft_face)
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+    if (err /= 0) then
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+      print *, "Error: Failed to load font '", trim(path), "', error ", err
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+      call fortty_ft_done(font%ft_library)
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+      font%ft_library = c_null_ptr
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+      return
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+    end if
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+
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+    ! Get metrics
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+    call fortty_ft_get_metrics(font%ft_face, cw, ch, asc, desc)
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+    font%size_px = size_px
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+    font%cell_width = cw
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+    font%cell_height = ch
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+    font%ascender = asc
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+    font%descender = desc
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+    font%loaded = .true.
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+
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+  end function font_load
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+
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+  ! Destroy font and free resources
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+  subroutine font_destroy(font)
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+    type(font_t), intent(inout) :: font
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+
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+    if (c_associated(font%ft_face)) then
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+      call fortty_ft_done_face(font%ft_face)
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+      font%ft_face = c_null_ptr
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+    end if
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+
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+    if (c_associated(font%ft_library)) then
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+      call fortty_ft_done(font%ft_library)
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+      font%ft_library = c_null_ptr
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+    end if
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+
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+    font%loaded = .false.
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+  end subroutine font_destroy
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+
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+  ! Render a glyph and return its data
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+  ! Returns bitmap pointer (valid until next render_glyph call)
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+  function font_render_glyph(font, codepoint, bitmap_ptr) result(glyph)
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+    type(font_t), intent(in) :: font
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+    integer, intent(in) :: codepoint
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+    type(c_ptr), intent(out) :: bitmap_ptr
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+    type(glyph_t) :: glyph
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+    integer(c_int) :: err, w, h, bx, by, adv
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+
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+    call glyph_init(glyph)
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+
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+    if (.not. font%loaded) then
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+      bitmap_ptr = c_null_ptr
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+      return
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+    end if
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+
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+    err = fortty_ft_render_glyph(font%ft_face, int(codepoint, c_int), &
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+                                  bitmap_ptr, w, h, bx, by, adv)
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+    if (err /= 0) then
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+      bitmap_ptr = c_null_ptr
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+      return
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+    end if
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+
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+    glyph%codepoint = codepoint
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+    glyph%width = w
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+    glyph%height = h
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+    glyph%bearing_x = bx
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+    glyph%bearing_y = by
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+    glyph%advance = adv
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+    glyph%valid = .true.
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+
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+  end function font_render_glyph
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+
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+end module font_mod
src/text/glyph.f90added
@@ -0,0 +1,39 @@
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+module glyph_mod
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+  use, intrinsic :: iso_c_binding
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+  implicit none
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+  public
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+
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+  ! Glyph information for a single character
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+  type :: glyph_t
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+    integer :: codepoint = 0         ! Unicode codepoint
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+    integer :: tex_x = 0, tex_y = 0  ! Position in texture atlas
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+    integer :: width = 0, height = 0 ! Bitmap dimensions
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+    integer :: bearing_x = 0         ! Offset from cursor X to left edge
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+    integer :: bearing_y = 0         ! Offset from baseline to top edge
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+    integer :: advance = 0           ! Horizontal advance to next character
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+    real(c_float) :: u0 = 0.0, v0 = 0.0  ! UV coords (top-left)
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+    real(c_float) :: u1 = 0.0, v1 = 0.0  ! UV coords (bottom-right)
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+    logical :: valid = .false.       ! Whether glyph data is loaded
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+  end type glyph_t
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+
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+contains
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+
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+  ! Initialize a glyph with default values
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+  subroutine glyph_init(g)
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+    type(glyph_t), intent(out) :: g
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+    g%codepoint = 0
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+    g%tex_x = 0
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+    g%tex_y = 0
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+    g%width = 0
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+    g%height = 0
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+    g%bearing_x = 0
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+    g%bearing_y = 0
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+    g%advance = 0
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+    g%u0 = 0.0
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+    g%v0 = 0.0
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+    g%u1 = 0.0
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+    g%v1 = 0.0
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+    g%valid = .false.
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+  end subroutine glyph_init
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+
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+end module glyph_mod