Did most of the work for grapheme cluster boundary based text layout characters on GTK+.

unix/GNUfiles.mk

@@ -19,6 +19,7 @@ CFILES += \
 	unix/editablecombo.c \
 	unix/entry.c \
 	unix/fontbutton.c \
+	unix/graphemes.c \
 	unix/group.c \
 	unix/label.c \
 	unix/main.c \

unix/drawtext.c

@@ -173,34 +173,22 @@ void uiDrawTextFontGetMetrics(uiDrawTextFont *font, uiDrawTextFontMetrics *metri
 // note: PangoCairoLayouts are tied to a given cairo_t, so we can't store one in this device-independent structure
 struct uiDrawTextLayout {
 	char *s;
-	ptrdiff_t *charsToBytes;
+	PangoGlyphString *glyphString;
 	PangoFont *defaultFont;
 	double width;
 	PangoAttrList *attrs;
 };
 
-static ptrdiff_t *computeCharsToBytes(const char *s)
-{
-	ptrdiff_t *charsToBytes;
-	glong i, charlen;
-
-	// we INCLUDE the null terminator as a character in the string
-	// g_utf8_offset_to_pointer() doesn't stop on null terminator so this should work
-	charlen = g_utf8_strlen(s, -1) + 1;
-	charsToBytes = (ptrdiff_t *) uiAlloc(charlen * sizeof (ptrdiff_t), "ptrdiff_t[]");
-	// TODO speed this up by not needing to scan the whole string again
-	for (i = 0; i < charlen; i++)
-		charsToBytes[i] = g_utf8_offset_to_pointer(s, i) - s;
-	return charsToBytes;
-}
-
 uiDrawTextLayout *uiDrawNewTextLayout(const char *text, uiDrawTextFont *defaultFont, double width)
 {
 	uiDrawTextLayout *layout;
+	PangoContext *context;
 
 	layout = uiNew(uiDrawTextLayout);
 	layout->s = g_strdup(text);
-	layout->charsToBytes = computeCharsToBytes(layout->s);
+	context = mkGenericPangoCairoContext();
+	layout->glyphString = graphemes(layout->s, context);
+	g_object_unref(context);
 	layout->defaultFont = defaultFont->f;
 	g_object_ref(layout->defaultFont);		// retain a copy
 	uiDrawTextLayoutSetWidth(layout, width);
@@ -212,7 +200,7 @@ void uiDrawFreeTextLayout(uiDrawTextLayout *layout)
 {
 	pango_attr_list_unref(layout->attrs);
 	g_object_unref(layout->defaultFont);
-	uiFree(layout->charsToBytes);
+	pango_glyph_string_free(layout->glyphString);
 	g_free(layout->s);
 	uiFree(layout);
 }
@@ -279,8 +267,8 @@ void uiDrawText(uiDrawContext *c, double x, double y, uiDrawTextLayout *layout)
 
 static void addAttr(uiDrawTextLayout *layout, PangoAttribute *attr, intmax_t startChar, intmax_t endChar)
 {
-	attr->start_index = layout->charsToBytes[startChar];
+	attr->start_index = layout->glyphString->log_clusters[startChar];
-	attr->end_index = layout->charsToBytes[endChar];
+	attr->end_index = layout->glyphString->log_clusters[endChar];
 	pango_attr_list_insert(layout->attrs, attr);
 	// pango_attr_list_insert() takes attr; we don't free it
 }

unix/graphemes.c

@@ -0,0 +1,41 @@
+// 25 may 2016
+#include "uipriv_unix.H"
+
+// TODO this breaks for non-BMP characters?
+
+struct gparam {
+	const char *text;
+	PangoGlyphString *glyphString;
+};
+
+static void runItem(gpointer it, gpointer data)
+{
+	PangoItem *item = (PangoItem *) it;
+	struct gparam *gparam = (struct gparam *) data;
+
+	pango_shape(gparam->text + item->offset,
+		item->length,
+		&(item->analysis),
+		gparam->glyphString);
+	pango_item_free(item);
+}
+
+PangoGlyphString *graphemes(const char *text, PangoContext *context)
+{
+	size_t len;
+	GList *list;
+	struct gparam gparam;
+
+	len = strlen(text);
+	list = pango_itemize(context,
+		text, 0, len,
+		NULL, NULL);
+
+	gparam.text = text;
+	gparam.glyphString = pango_glyph_string_new();
+
+	g_list_foreach(list, runItem, &gparam);
+
+	g_list_free(list);
+	return gparam.glyphString;
+}

unix/uipriv_unix.h

@@ -7,6 +7,7 @@
 #include <math.h>
 #include <dlfcn.h>		// see drawtext.c
 #include <langinfo.h>
+#include <string.h>
 #include "../ui.h"
 #include "../ui_unix.h"
 #include "../common/uipriv.h"
@@ -42,5 +43,10 @@ extern void childSetMargined(struct child *c, int margined);
 // draw.c
 extern uiDrawContext *newContext(cairo_t *);
 extern void freeContext(uiDrawContext *);
+
+// drawtext.c
 extern uiDrawTextFont *mkTextFont(PangoFont *f, gboolean add);
 extern PangoFont *pangoDescToPangoFont(PangoFontDescription *pdesc);
+
+// graphemes.c
+extern PangoGlyphString *graphemes(const char *text, PangoContext *context);

windows/GNUfiles.mk

@@ -28,7 +28,7 @@ CXXFILES += \
 	windows/events.cpp \
 	windows/fontbutton.cpp \
 	windows/fontdialog.cpp \
-	windows/grapheme.cpp \
+	windows/graphemes.cpp \
 	windows/group.cpp \
 	windows/init.cpp \
 	windows/label.cpp \

windows/uipriv_windows.hpp

@@ -140,7 +140,7 @@ extern BOOL showColorDialog(HWND parent, struct colorDialogRGBA *c);
 // sizing.cpp
 extern void getSizing(HWND hwnd, uiWindowsSizing *sizing, HFONT font);
 
-// grapheme.cpp
+// graphemes.cpp
 extern size_t *graphemes(WCHAR *msg);