tdf#73691 Implement MSWord's Alt-X: toggle unicode notation

-toggles between characters and their unicode notation
-sets Alt-X as a global keyboard accelerator
-handles all of the unicode planes
-intelligently handles combining characters
-if text is selected, limits the input to that text
-implemented in Writer, Draw, Impress

Change-Id: Idcd8e7f0a4f1b81fa7f5f3200c76be19472ffa37
Reviewed-on: https://gerrit.libreoffice.org/17535
Tested-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>

1 files changed, 46 insertions, 0 deletions

diff --git a/include/i18nutil/unicode.hxx b/include/i18nutil/unicode.hxx
index 6561da039f6b..051da5bd9188 100644
--- a/include/i18nutil/unicode.hxx
+++ b/include/i18nutil/unicode.hxx
@@ -21,6 +21,7 @@
 
 #include <com/sun/star/i18n/UnicodeScript.hpp>
 #include <sal/types.h>
+#include <rtl/ustrbuf.hxx>
 #include <unicode/uscript.h>
 #include <i18nutil/i18nutildllapi.h>
 
@@ -58,6 +59,51 @@ public:
         const LanguageTag &rLangTag);
 };
 
+/*
+    Toggle between a character and its Unicode Notation.
+        -implements the concept found in Microsoft Word's Alt-X
+        -accepts sequences of up to 8 hex characters and converts into the corresponding Unicode Character
+            -example:  0000A78c   or   2bc
+        -accepts sequences of up to 256 characters in Unicode notation
+            -example:  U+00000065u+0331u+308
+        -handles complex characters (with combining elements) and the all of the Unicode planes.
+*/
+class I18NUTIL_DLLPUBLIC ToggleUnicodeCodepoint
+{
+private:
+    OUStringBuffer maInput;
+    OUStringBuffer maOutput;
+    OUStringBuffer maUtf16;
+    OUStringBuffer maCombining;
+    bool mbAllowMoreChars = true;
+    bool mbRequiresU = false;
+    bool mbIsHexString = false;
+
+public:
+    ToggleUnicodeCodepoint();
+
+    /**
+    Build an input string of valid UTF16 units to toggle.
+        -do not call the other functions until the input process is complete
+        -build string from Right to Left.  (Start from the character to the left of the cursor: move left.)
+    */
+    bool AllowMoreInput(sal_Unicode uChar);
+
+    /**
+    Validates (and potentially modifies) the input string.
+        -all non-input functions must use this function to first to validate the input string
+        -additional input may be prevented after this function is called
+    */
+    OUString StringToReplace();
+    OUString ReplacementString();
+
+    /**
+    While sInput.getLength() returns the number of utf16 units to delete,
+        this function returns the number of "characters" to delete - potentially a smaller number
+    */
+    sal_uInt32 CharsToDelete();
+};
+
 #endif