editor: Fix handling of UTF-8 text

Fix display, cursor movement and text deletion for UTF-8 text.

Signed-off-by: Jan Arne Petersen <jpetersen@openismus.com>

diff --git a/clients/editor.c b/clients/editor.c
index d185137..cbc7218 100644 (file)
--- a/clients/editor.c
+++ b/clients/editor.c
@@ -66,6 +66,40 @@ struct editor {
        struct text_entry *editor;
 };
 
+static const char *
+utf8_start_char(const char *text, const char *p)
+{
+       for (; p >= text; --p) {
+               if ((*p & 0xc0) != 0x80)
+                       return p;
+       }
+       return NULL;
+}
+
+static const char *
+utf8_prev_char(const char *text, const char *p)
+{
+       if (p > text)
+               return utf8_start_char(text, --p);
+       return NULL;
+}
+
+static const char *
+utf8_end_char(const char *p)
+{
+       while ((*p & 0xc0) == 0x80)
+               p++;
+       return p;
+}
+
+static const char *
+utf8_next_char(const char *p)
+{
+       if (*p != 0)
+               return utf8_end_char(++p);
+       return NULL;
+}
+
 static struct text_layout *
 text_layout_create(void)
 {
@@ -148,6 +182,34 @@ text_layout_extents(struct text_layout *layout, cairo_text_extents_t *extents)
                                        extents);
 }
 
+static uint32_t
+bytes_from_glyphs(struct text_layout *layout, uint32_t index)
+{
+       int i;
+       uint32_t glyphs = 0, bytes = 0; 
+
+       for (i = 0; i < layout->num_clusters && glyphs < index; i++) {
+               bytes += layout->clusters[i].num_bytes;
+               glyphs += layout->clusters[i].num_glyphs;
+       }
+
+       return bytes;
+}
+
+static uint32_t
+glyphs_from_bytes(struct text_layout *layout, uint32_t index)
+{
+       int i;
+       uint32_t glyphs = 0, bytes = 0; 
+
+       for (i = 0; i < layout->num_clusters && bytes < index; i++) {
+               bytes += layout->clusters[i].num_bytes;
+               glyphs += layout->clusters[i].num_glyphs;
+       }
+
+       return glyphs;
+}
+
 static int
 text_layout_xy_to_index(struct text_layout *layout, double x, double y)
 {
@@ -168,20 +230,21 @@ text_layout_xy_to_index(struct text_layout *layout, double x, double y)
        for (i = 0; i < layout->num_glyphs - 1; ++i) {
                d = layout->glyphs[i + 1].x - layout->glyphs[i].x;
                if (x < layout->glyphs[i].x + d/2)
-                       return i;
+                       return bytes_from_glyphs(layout, i);
        }
 
        d = extents.width - layout->glyphs[layout->num_glyphs - 1].x;
        if (x < layout->glyphs[layout->num_glyphs - 1].x + d/2)
-               return layout->num_glyphs - 1;
+               return bytes_from_glyphs(layout, layout->num_glyphs - 1);
 
-       return layout->num_glyphs;
+       return bytes_from_glyphs(layout, layout->num_glyphs);
 }
 
 static void
 text_layout_index_to_pos(struct text_layout *layout, uint32_t index, cairo_rectangle_t *pos)
 {
        cairo_text_extents_t extents;
+       int glyph_index = glyphs_from_bytes(layout, index);
 
        if (!pos)
                return;
@@ -190,7 +253,7 @@ text_layout_index_to_pos(struct text_layout *layout, uint32_t index, cairo_recta
                                        layout->glyphs, layout->num_glyphs,
                                        &extents);
 
-       if ((int)index >= layout->num_glyphs) {
+       if (glyph_index >= layout->num_glyphs) {
                pos->x = extents.x_advance;
                pos->y = layout->num_glyphs ? layout->glyphs[layout->num_glyphs - 1].y : 0;
                pos->width = 1;
@@ -198,9 +261,9 @@ text_layout_index_to_pos(struct text_layout *layout, uint32_t index, cairo_recta
                return;
        }
 
-       pos->x = layout->glyphs[index].x;
-       pos->y = layout->glyphs[index].y;
-       pos->width = (int)index < layout->num_glyphs - 1 ? layout->glyphs[index + 1].x : extents.x_advance - pos->x;
+       pos->x = layout->glyphs[glyph_index].x;
+       pos->y = layout->glyphs[glyph_index].y;
+       pos->width = glyph_index < layout->num_glyphs - 1 ? layout->glyphs[glyph_index + 1].x : extents.x_advance - pos->x;
        pos->height = extents.height;
 }
 
@@ -268,6 +331,7 @@ text_model_delete_surrounding_text(void *data,
 {
        struct text_entry *entry = data;
        uint32_t cursor_index = index + entry->cursor;
+       const char *start, *end;
 
        if (cursor_index > strlen(entry->text)) {
                fprintf(stderr, "Invalid cursor index %d\n", index);
@@ -282,7 +346,12 @@ text_model_delete_surrounding_text(void *data,
        if (length == 0)
                return;
 
-       text_entry_delete_text(entry, cursor_index, length);
+       start = utf8_start_char(entry->text, entry->text + cursor_index);
+       end = utf8_end_char(entry->text + cursor_index + length);
+
+       text_entry_delete_text(entry,
+                              start - entry->text,
+                              end - start);
 }
 
 static void
@@ -300,6 +369,7 @@ text_model_key(void *data,
        struct text_entry *entry = data;
        const char *state_label;
        const char *key_label = "released";
+       const char *new_char;
 
        if (state == WL_KEYBOARD_KEY_STATE_PRESSED) {
                state_label = "pressed";
@@ -313,15 +383,17 @@ text_model_key(void *data,
                        key_label = "Enter";
                        break;
                case XKB_KEY_Left:
-                       if (entry->cursor > 0) {
-                               entry->cursor--;
+                       new_char = utf8_prev_char(entry->text, entry->text + entry->cursor);
+                       if (new_char != NULL) {
+                               entry->cursor = new_char - entry->text;
                                entry->anchor = entry->cursor;
                                widget_schedule_redraw(entry->widget);
                        }
                        break;
                case XKB_KEY_Right:
-                       if (entry->cursor < strlen(entry->text)) {
-                               entry->cursor++;
+                       new_char = utf8_next_char(entry->text + entry->cursor);
+                       if (new_char != NULL) {
+                               entry->cursor = new_char - entry->text;
                                entry->anchor = entry->cursor;
                                widget_schedule_redraw(entry->widget);
                        }