Changeset 2cc1ec0 in mainline for uspace/lib/draw/font.h

Timestamp:

2014-08-27T21:23:01Z (10 years ago)

Author:

Martin Sucha <sucha14@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

a9763c6

Parents:

613d644

Message:

Refactor drawing of fonts into multiple layers.

This will need further work to split glyph resolution
process to separate functions in order to support ligatures,
addition of kerning support, separate text layout functions,
etc.

File:

• uspace/lib/draw/font.h (modified) (2 diffs)

uspace/lib/draw/font.h

@@ -1 +1 @@
 /*
  * Copyright (c) 2012 Petr Koupy
+ * Copyright (c) 2014 Martin Sucha
  * All rights reserved.
  *
@@ -45 +46 @@
 typedef struct drawctx drawctx_t;
 
-typedef enum {
-        FONT_DECODER_EMBEDDED
-} font_decoder_type_t;
+typedef int metric_t;
 
 typedef struct {
-        void (*init)(char *, uint16_t *, void **);
-        uint16_t (*resolve)(const wchar_t, void *);
-        surface_t *(*render)(uint16_t, uint16_t);
+        /* Horizontal distance between origin and left side of the glyph */ 
+        metric_t left_side_bearing;
+        
+        /* Width of the actual glyph drawn */
+        metric_t width;
+        
+        /* Horizontal distance between right side of the glyph and origin
+           of the next glyph */
+        metric_t right_side_bearing;
+        
+        /* Vertical distance between baseline and top of the glyph
+           (positive to top) */
+        metric_t ascender;
+        
+        /* Height of the actual glyph drawn */
+        metric_t height;
+} glyph_metrics_t;
+
+static inline metric_t glyph_metrics_get_descender(glyph_metrics_t *gm)
+{
+        return gm->height - gm->ascender;
+}
+
+static inline metric_t glyph_metrics_get_advancement(glyph_metrics_t *gm)
+{
+        return gm->left_side_bearing + gm->width + gm->right_side_bearing;
+}
+
+typedef struct {
+        /* Distance between top of the line and baseline */
+        metric_t ascender;
+        
+        /* Distance between baseline and bottom of the line */
+        metric_t descender;
+        
+        /* Distance between bottom of the line and top of the next line */
+        metric_t leading;
+} font_metrics_t;
+
+typedef uint32_t glyph_id_t;
+
+typedef struct {
+        int (*get_font_metrics)(void *, font_metrics_t *);
+        int (*resolve_glyph)(void *, wchar_t, glyph_id_t *);
+        int (*get_glyph_metrics)(void *, glyph_id_t, glyph_metrics_t *);
+        int (*render_glyph)(void *, drawctx_t *, source_t *, sysarg_t,
+            sysarg_t, glyph_id_t);
         void (*release)(void *);
-} font_decoder_t;
+} font_backend_t;
 
-typedef struct font {
-        uint16_t points;
-        uint16_t glyph_count;
-        surface_t **glyphs;
-        font_decoder_t *decoder;
-        void *decoder_data;
+typedef struct {
+        font_backend_t *backend;
+        void *backend_data;
 } font_t;
 
-extern void font_init(font_t *, font_decoder_type_t, char *, uint16_t);
+extern font_t *font_create(font_backend_t *, void *);
+extern int font_get_metrics(font_t *, font_metrics_t *);
+extern int font_resolve_glyph(font_t *, wchar_t, glyph_id_t *);
+extern int font_get_glyph_metrics(font_t *, glyph_id_t, glyph_metrics_t *);
+extern int font_render_glyph(font_t *, drawctx_t *, source_t *,
+    sysarg_t, sysarg_t, glyph_id_t);
 extern void font_release(font_t *);
 
-extern void font_get_box(font_t *, char *, sysarg_t *, sysarg_t *);
-extern void font_draw_text(font_t *, drawctx_t *, source_t *, const char *,
+extern int font_get_box(font_t *, char *, sysarg_t *, sysarg_t *);
+extern int font_draw_text(font_t *, drawctx_t *, source_t *, const char *,
     sysarg_t, sysarg_t);