initial grid implementation

This allows us to render *something*, even though it's inefficient,
stupid and far far away from the real thing.

font.c

@@ -0,0 +1,85 @@
+#include "font.h"
+
+#include <stdlib.h>
+#include <stdbool.h>
+
+#include <fontconfig/fontconfig.h>
+#include <cairo-ft.h>
+
+#define LOG_MODULE "font"
+#include "log.h"
+
+static void __attribute__((constructor))
+init(void)
+{
+    FcInit();
+}
+
+static void __attribute__((destructor))
+fini(void)
+{
+    FcFini();
+}
+cairo_scaled_font_t *
+font_from_name(const char *name)
+{
+    FcPattern *pattern = FcNameParse((const unsigned char *)name);
+    if (pattern == NULL) {
+        LOG_ERR("%s: failed to lookup font", name);
+        return NULL;
+    }
+
+    if (!FcConfigSubstitute(NULL, pattern, FcMatchPattern)) {
+        LOG_ERR("%s: failed to do config substitution", name);
+        FcPatternDestroy(pattern);
+        return NULL;
+    }
+
+    FcDefaultSubstitute(pattern);
+
+    FcResult result;
+    FcPattern *final_pattern = FcFontMatch(NULL, pattern, &result);
+    FcPatternDestroy(pattern);
+
+    if (final_pattern == NULL) {
+        LOG_ERR("%s: failed to match font", name);
+        return NULL;
+    }
+
+    double size;
+    if (FcPatternGetDouble(final_pattern, FC_PIXEL_SIZE, 0, &size)) {
+        LOG_ERR("%s: failed to get size", name);
+        FcPatternDestroy(final_pattern);
+        return NULL;
+    }
+
+    cairo_font_face_t *face = cairo_ft_font_face_create_for_pattern(
+        final_pattern);
+
+    FcPatternDestroy(final_pattern);
+
+    if (cairo_font_face_status(face) != CAIRO_STATUS_SUCCESS) {
+        LOG_ERR("%s: failed to create cairo font face", name);
+        cairo_font_face_destroy(face);
+        return NULL;
+    }
+
+    cairo_matrix_t matrix, ctm;
+    cairo_matrix_init_identity(&ctm);
+    cairo_matrix_init_scale(&matrix, size, size);
+
+    cairo_font_options_t *options = cairo_font_options_create();
+    cairo_scaled_font_t *scaled_font = cairo_scaled_font_create(
+        face, &matrix, &ctm, options);
+
+    cairo_font_options_destroy(options);
+    cairo_font_face_destroy(face);
+
+    if (cairo_scaled_font_status(scaled_font) != CAIRO_STATUS_SUCCESS) {
+        LOG_ERR("%s: failed to create scaled font", name);
+        cairo_scaled_font_destroy(scaled_font);
+        return NULL;
+    }
+
+    return scaled_font;
+}