1 files changed, 115 insertions, 0 deletions
diff --git a/libass/ass_shaper.c b/libass/ass_shaper.c
new file mode 100644
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--- /dev/null
+++ b/libass/ass_shaper.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2011 Grigori Goronzy <greg@chown.ath.cx>
+ *
+ * This file is part of libass.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <fribidi/fribidi.h>
+
+#include "ass_render.h"
+#include "ass_shaper.h"
+
+/**
+ * \brief Shape an event's text. Calculates directional runs and shapes them.
+ * \param text_info event's text
+ * \param ctypes returns character types
+ * \param emblevels returns embedding levels (directional runs)
+ */
+void ass_shaper_shape(TextInfo *text_info, FriBidiCharType *ctypes,
+                      FriBidiLevel *emblevels)
+{
+    int i, last_break;
+    FriBidiParType dir;
+    FriBidiChar *event_text = calloc(sizeof(*event_text), text_info->length);
+    GlyphInfo *glyphs = text_info->glyphs;
+
+    // Get bidi character types and embedding levels
+    last_break = 0;
+    for (i = 0; i < text_info->length; i++) {
+        event_text[i] = glyphs[i].symbol;
+        // embedding levels should be calculated paragraph by paragraph
+        if (glyphs[i].symbol == '\n' || i == text_info->length - 1) {
+            //printf("paragraph from %d to %d\n", last_break, i);
+            dir = FRIBIDI_PAR_ON;
+            fribidi_get_bidi_types(event_text + last_break, i - last_break + 1,
+                    ctypes + last_break);
+            fribidi_get_par_embedding_levels(ctypes + last_break,
+                    i - last_break + 1, &dir, emblevels + last_break);
+            last_break = i + 1;
+        }
+    }
+
+#if 0
+    printf("levels ");
+    for (i = 0; i < text_info->length; i++) {
+        printf("%d:%d ", ctypes[i], emblevels[i]);
+    }
+    printf("\n");
+#endif
+
+    // Call FriBidi's glyph mirroring shaper.
+    // This shaper implements rule L4 of the bidi algorithm
+    fribidi_shape_mirroring(emblevels, text_info->length, event_text);
+    for (i = 0; i < text_info->length; i++) {
+        glyphs[i].symbol = event_text[i];
+    }
+
+    // XXX: insert HarfBuzz shaper here
+
+    // Skip direction override characters
+    // NOTE: Behdad said HarfBuzz is supposed to remove these, but this hasn't
+    // been implemented yet
+    for (i = 0; i < text_info->length; i++) {
+        if (glyphs[i].symbol <= 0x202F && glyphs[i].symbol >= 0x202a) {
+            glyphs[i].symbol = 0;
+            glyphs[i].skip++;
+        }
+    }
+
+    free(event_text);
+}
+
+void ass_shaper_reorder(TextInfo *text_info, FriBidiCharType *ctypes,
+                        FriBidiLevel *emblevels, FriBidiStrIndex *cmap)
+{
+    int i;
+    FriBidiParType dir = FRIBIDI_PAR_LTR;
+
+    // Initialize reorder map
+    for (i = 0; i < text_info->length; i++)
+        cmap[i] = i;
+
+    // Create reorder map line-by-line
+    for (i = 0; i < text_info->n_lines; i++) {
+        LineInfo *line = text_info->lines + i;
+        int level;
+
+        // FIXME: we should actually specify
+        // the correct paragraph base direction
+        level = fribidi_reorder_line(FRIBIDI_FLAGS_DEFAULT,
+                ctypes + line->offset, line->len, 0, dir,
+                emblevels + line->offset, NULL, cmap + line->offset);
+        //printf("reorder line %d to level %d\n", i, level);
+    }
+
+#if 0
+    printf("map ");
+    for (i = 0; i < text_info->length; i++) {
+        printf("%d ", cmap[i]);
+    }
+    printf("\n");
+#endif
+
+}