Better text rendering

1 files changed, 41 insertions, 0 deletions

diff --git a/src/gui/font.h b/src/gui/font.h
new file mode 100644
index 00000000..050fbeb0
--- /dev/null
+++ b/src/gui/font.h
@@ -0,0 +1,41 @@
+// Tiny C shim over FreeType, so gui.zig only imports the stable renderer API.
+// The implementation owns FreeType's library and face objects and keeps the
+// caller's font bytes borrowed for the face lifetime.
+#ifndef UI_FONT_H
+#define UI_FONT_H
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct UIFont UIFont;
+
+// Parse the first face in an in-memory font. `data` must stay alive for the
+// lifetime of the font. Returns NULL on failure.
+UIFont *ui_font_new(const uint8_t *data, int32_t len);
+
+// Whether the selected Unicode charmap maps `cp` to a real glyph. Glyph zero is
+// the face's .notdef box and deliberately does not count for fallback choice.
+int ui_font_has_glyph(UIFont *f, int32_t cp);
+
+// The size token is a pixel height. Metrics and rasterization both configure
+// FreeType at that size, so hinted advances, baseline and bitmaps stay in step.
+float ui_font_scale_for_height(UIFont *f, float px);
+void ui_font_cell_metrics(UIFont *f, float px, int32_t *cell_w, int32_t *cell_h,
+                          int32_t *ascent);
+
+// Rasterize `cp` into `out` as a hinted grayscale cell mask (`stride` bytes per
+// row). The origin is the baseline `ascent` pixels from the top. Pixels outside
+// the glyph are zero. Missing codepoints render the face's .notdef glyph.
+// Returns 1 when the glyph produced coverage, 0 for blank/error.
+int ui_font_raster(UIFont *f, float px, int32_t cp, uint8_t *out,
+                   int32_t stride, int32_t cell_w, int32_t cell_h,
+                   int32_t ascent);
+
+void ui_font_free(UIFont *f);
+
+#ifdef __cplusplus
+}
+#endif
+#endif