From 7f9043041494534b74054746efa5d5d004e29048 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Thu, 1 Feb 2018 12:05:07 +0530
Subject: [PATCH] Designating charsets should not switch to them

Fixes #301
---
 kitty/screen.c | 21 ++++++++++++---------
 kitty/screen.h |  4 +++-
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/kitty/screen.c b/kitty/screen.c
index 9a22606d8..bf0b56839 100644
--- a/kitty/screen.c
+++ b/kitty/screen.c
@@ -42,6 +42,7 @@ init_tabstops(bool *tabstops, index_type count) {
         self->g0_charset = translation_table(0); \
         self->g1_charset = self->g0_charset; \
         self->g_charset = self->g0_charset; \
+        self->current_charset = 0; \
         self->utf8_state = 0; \
         self->utf8_codepoint = 0; \
         self->use_latin1 = false;
@@ -245,25 +246,26 @@ void
 screen_change_charset(Screen *self, uint32_t which) {
     switch(which) {
         case 0:
-            self->g_charset = self->g0_charset; break;
+            self->current_charset = 0;
+            self->g_charset = self->g0_charset;
+            break;
         case 1:
-            self->g_charset = self->g1_charset; break;
+            self->current_charset = 1;
+            self->g_charset = self->g1_charset;
+            break;
     }
 }
 
 void
 screen_designate_charset(Screen *self, uint32_t which, uint32_t as) {
-    bool change_g = false;
-    switch(which & 1) {
+    switch(which) {
         case 0:
-            change_g = self->g_charset == self->g0_charset;
             self->g0_charset = translation_table(as);
-            if (change_g) self->g_charset = self->g0_charset;
+            if (self->current_charset == 0) self->g_charset = self->g0_charset;
             break;
         case 1:
-            change_g = self->g_charset == self->g1_charset;
             self->g1_charset = translation_table(as);
-            if (change_g) self->g_charset = self->g1_charset;
+            if (self->current_charset == 1) self->g_charset = self->g1_charset;
             break;
     }
 }
@@ -766,7 +768,7 @@ screen_linefeed(Screen *self) {
     sp->utf8_codepoint = self->utf8_codepoint; \
     sp->g0_charset = self->g0_charset; \
     sp->g1_charset = self->g1_charset; \
-    sp->g_charset = self->g_charset; \
+    sp->current_charset = self->current_charset; \
     sp->use_latin1 = self->use_latin1;
 
 void
@@ -800,6 +802,7 @@ screen_restore_cursor(Screen *self) {
         screen_reset_mode(self, DECSCNM);
     } else {
         COPY_CHARSETS(sp, self);
+        self->g_charset = self->current_charset ? self->g1_charset : self->g0_charset;
         set_mode_from_const(self, DECOM, sp->mDECOM);
         set_mode_from_const(self, DECAWM, sp->mDECAWM);
         set_mode_from_const(self, DECSCNM, sp->mDECSCNM);
diff --git a/kitty/screen.h b/kitty/screen.h
index 7c14e8d60..1a2b3c1ce 100644
--- a/kitty/screen.h
+++ b/kitty/screen.h
@@ -30,7 +30,8 @@ typedef struct {
 #define SAVEPOINTS_SZ 256
 
 typedef struct {
-    uint32_t utf8_state, utf8_codepoint, *g0_charset, *g1_charset, *g_charset;
+    uint32_t utf8_state, utf8_codepoint, *g0_charset, *g1_charset;
+    unsigned int current_charset;
     bool use_latin1;
     Cursor cursor;
     bool mDECOM, mDECAWM, mDECSCNM;
@@ -56,6 +57,7 @@ typedef struct {
     unsigned int columns, lines, margin_top, margin_bottom, charset, scrolled_by, last_selection_scrolled_by;
     id_type window_id;
     uint32_t utf8_state, utf8_codepoint, *g0_charset, *g1_charset, *g_charset;
+    unsigned int current_charset;
     Selection selection;
     SelectionBoundary last_rendered_selection_start, last_rendered_selection_end, last_rendered_url_start, last_rendered_url_end;
     Selection url_range;