[ft-devel] Points in FT_Outline

[Jjgod Jiang]

Hi,

I'm trying to fetch all the points from FT_Outline of a glyph, here is
a minimal example,

    /* testft.c: test FreeType capabilities */

    #include <stdio.h>
    #include <stdlib.h>
    #include <assert.h>
    #include <ft2build.h>
    #include FT_FREETYPE_H
    #include FT_OUTLINE_H

    #define DOUBLE_TO_16_16(d) ((FT_Fixed)((d) * 65536.0))
    #define DOUBLE_FROM_26_6(t) ((double)(t) / 64.0)

    int move_to(const FT_Vector *to, void *user);
    int line_to(const FT_Vector *to, void *user);
    int conic_to(const FT_Vector *control, const FT_Vector *to, void *user);
    int cubic_to(const FT_Vector *control1, const FT_Vector *control2,
                 const FT_Vector *to, void *user);

    int main(int argc, char *argv[])
    {
        FT_Error    error;
        FT_Library  library;
        FT_Face     face;
        FT_UInt     glyph_index;
        FT_Outline *outline;
        FT_ULong    charcode = 'Z';

        error = FT_Init_FreeType(&library);
        assert(error == 0);

        error = FT_New_Face(library, argv[1], 0, &face);
        assert(error == 0);

        glyph_index = FT_Get_Char_Index(face, charcode);
        assert(glyph_index != 0);

        error = FT_Load_Glyph(face, glyph_index,
                              FT_LOAD_DEFAULT);
        assert(error == 0);

        assert(face->glyph->format == FT_GLYPH_FORMAT_OUTLINE);

        outline = &face->glyph->outline;
        printf("n_contours = %d\n", outline->n_contours);
        printf("n_points   = %d\n", outline->n_points);

        FT_Outline_Funcs outline_funcs = { move_to, line_to, conic_to,
cubic_to, 0, 0 };
        FT_Outline_Decompose(outline, &outline_funcs, NULL);

        FT_Done_Face(face);
        FT_Done_FreeType(library);

        return 0;
    }

    void print4bytes(const char *bytes)
    {
        int i;

        for (i = 0; i < 4; i++)
            printf("%02X ", bytes[i]);

        printf("\n");
    }

    int move_to(const FT_Vector *to, void *user)
    {
        print4bytes((char *) &(to->x));
        print4bytes((char *) &(to->y));

        printf("move_to([%g, %g])\n",
                DOUBLE_FROM_26_6(to->x), DOUBLE_FROM_26_6(to->y));

        return 0;
    }

    int line_to(const FT_Vector *to, void *user)
    {
        printf("line_to([%g, %g])\n",
               DOUBLE_FROM_26_6(to->x), DOUBLE_FROM_26_6(to->y));

        return 0;
    }

    int conic_to(const FT_Vector *control, const FT_Vector *to, void *user)
    {
        printf("conic_to(c = [%g, %g], to = [%g, %g])\n",
               DOUBLE_FROM_26_6(control->x), DOUBLE_FROM_26_6(control->y),
               DOUBLE_FROM_26_6(to->x), DOUBLE_FROM_26_6(to->y));

        return 0;
    }

    int cubic_to(const FT_Vector *control1, const FT_Vector *control2,
                 const FT_Vector *to, void *user)
    {
        printf("cubic_to(c1 = [%g, %g], c2 = [%g, %g], to = [%g, %g])\n",
               DOUBLE_FROM_26_6(control1->x), DOUBLE_FROM_26_6(control1->y),
               DOUBLE_FROM_26_6(control2->x), DOUBLE_FROM_26_6(control2->y),
               DOUBLE_FROM_26_6(to->x), DOUBLE_FROM_26_6(to->y));
        return 0;
    }

The n_points and n_contours printed is correct, but the point FT_Vector
does not contain any useful values, for example:

$ ./testft /Library/Fonts/Arial.ttf
n_contours = 1
n_points   = 13
00 00 00 00
04 00 00 00
move_to([0, 0.0625])
line_to([0, 0.0625])
line_to([0, 0.0625])
conic_to(c = [0, 0.0625], to = [0, 0.0625])
line_to([0, 0.0625])
line_to([0, 0.0625])
line_to([0, 0.0625])
line_to([0, 0.0625])
line_to([0, 0.0625])
line_to([0, 0.0625])
line_to([0, 0.0625])
line_to([0, 0.0625])
line_to([0, 0.0625])

I'm wondering what's wrong with my code. Thanks!

- Jiang