pango-font-metrics-test.c

pango-font-metrics-test.c

/*
 * $ cc `pkg-config pangocairo --cflags --libs` pango-font-metrics-test.c
 *
 * $ LC_ALL=C ./a.out
 * lang=default ascent=13.000000 descent=4.000000
 * lang=C       ascent=13.000000 descent=4.000000
 * lang=ja-jp   ascent=13.000000 descent=4.000000
 *
 * $ LC_ALL=en_US.UTF-8 ./a.out
 * lang=default ascent=13.000000 descent=4.000000
 * lang=C       ascent=13.000000 descent=4.000000
 * lang=ja-jp   ascent=13.000000 descent=4.000000
 *
 * $ LC_ALL=ja_JP.UTF-8 ./a.out
 * lang=default ascent=12.000000 descent=2.000000
 * lang=C       ascent=13.000000 descent=4.000000
 * lang=ja-jp   ascent=12.000000 descent=2.000000
 */

#include <stdio.h>
#include <string.h>
#include <locale.h>
#include <pango/pangocairo.h>

cairo_t *cr;
cairo_surface_t *surface;

void test(const char *font, const char *lang)
{
    PangoContext *context;
    PangoLanguage *language;
    PangoLayout *layout;
    PangoFontDescription *desc;
    PangoFontMetrics *metrics;
    double ascent, descent;

    layout = pango_cairo_create_layout(cr);

    context = pango_layout_get_context(layout);

    if (strcmp(lang, "default") == 0) {
        language = pango_language_get_default();
    } else {
        language = pango_language_from_string(lang);
    }

    desc = pango_font_description_from_string(font);
    pango_layout_set_font_description(layout, desc);

    metrics = pango_context_get_metrics(context, desc, language);

    ascent = (double)pango_font_metrics_get_ascent(metrics) / PANGO_SCALE;
    descent = (double)pango_font_metrics_get_descent(metrics) / PANGO_SCALE;

    printf("lang=%s ascent=%f descent=%f\n", lang, ascent, descent);

    pango_font_description_free(desc);
    g_object_unref(layout);
}

int main()
{
    setlocale(LC_ALL, "");

    surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 100, 100);
    cr = cairo_create(surface);

    test("Monospace 10", "default");
    test("Monospace 10", "C");
    test("Monospace 10", "ja-jp");

    cairo_destroy(cr);
    cairo_surface_destroy(surface);

    return 0;
}