input: make key bindings like "Shift+X" work (for ASCII)

"Shift+X" didn't actually map any key, as opposed to "Shift+x". This is
because shift usually changes the case of a character, so a plain
printable character like "X" simply can never be combined with shift.

But this is not very intuitive. Always remove the shift code from
printable characters. Also, for ASCII, actually apply the case mapping
to uppercase characters if combined with shift. Doing this for unicode
in general would be nice, but that would require lookup tables. In
general, we don't know anyway what character a key produces when
combined with shift - it could be anything, and depends on the keyboard
layout.

3 files changed, 30 insertions, 13 deletions

diff --git a/input/input.c b/input/input.c
index 1dd029219f..e85d16ccd2 100644
--- a/input/input.c
+++ b/input/input.c
@@ -613,15 +613,6 @@ static struct mp_cmd *resolve_key(struct input_ctx *ictx, int code)
 
 static void interpret_key(struct input_ctx *ictx, int code, double scale)
 {
-    /* On normal keyboards shift changes the character code of non-special
-     * keys, so don't count the modifier separately for those. In other words
-     * we want to have "a" and "A" instead of "a" and "Shift+A"; but a separate
-     * shift modifier is still kept for special keys like arrow keys.
-     */
-    int unmod = code & ~MP_KEY_MODIFIER_MASK;
-    if (unmod >= 32 && unmod < MP_KEY_BASE)
-        code &= ~MP_KEY_MODIFIER_SHIFT;
-
     int state = code & (MP_KEY_STATE_DOWN | MP_KEY_STATE_UP);
     code = code & ~(unsigned)state;
 
@@ -633,7 +624,7 @@ static void interpret_key(struct input_ctx *ictx, int code, double scale)
         talloc_free(key);
     }
 
-    if (MP_KEY_DEPENDS_ON_MOUSE_POS(unmod))
+    if (MP_KEY_DEPENDS_ON_MOUSE_POS(code & ~MP_KEY_MODIFIER_MASK))
         ictx->mouse_event_counter++;
     mp_input_wakeup(ictx);
 
@@ -687,6 +678,7 @@ static void interpret_key(struct input_ctx *ictx, int code, double scale)
 
 static void mp_input_feed_key(struct input_ctx *ictx, int code, double scale)
 {
+    code = mp_normalize_keycode(code);
     int unmod = code & ~MP_KEY_MODIFIER_MASK;
     if (code == MP_INPUT_RELEASE_ALL) {
         MP_DBG(ictx, "release all\n");
diff --git a/input/keycodes.c b/input/keycodes.c
index 078e29f361..00f983e140 100644
--- a/input/keycodes.c
+++ b/input/keycodes.c
@@ -239,14 +239,14 @@ found:
     struct bstr rest;
     int code = bstr_decode_utf8(bname, &rest);
     if (code >= 0 && rest.len == 0)
-        return code + modifiers;
+        return mp_normalize_keycode(code + modifiers);
 
     if (bstr_startswith0(bname, "0x"))
-        return strtol(name, NULL, 16) + modifiers;
+        return mp_normalize_keycode(strtol(name, NULL, 16) + modifiers);
 
     for (int i = 0; key_names[i].name != NULL; i++) {
         if (strcasecmp(key_names[i].name, name) == 0)
-            return key_names[i].key + modifiers;
+            return mp_normalize_keycode(key_names[i].key + modifiers);
     }
 
     return -1;
@@ -330,3 +330,25 @@ void mp_print_key_list(struct mp_log *out)
     for (int i = 0; key_names[i].name != NULL; i++)
         mp_info(out, "%s\n", key_names[i].name);
 }
+
+int mp_normalize_keycode(int keycode)
+{
+    if (keycode <= 0)
+        return keycode;
+    int code = keycode & ~MP_KEY_MODIFIER_MASK;
+    int mod = keycode & MP_KEY_MODIFIER_MASK;
+    /* On normal keyboards shift changes the character code of non-special
+     * keys, so don't count the modifier separately for those. In other words
+     * we want to have "a" and "A" instead of "a" and "Shift+A"; but a separate
+     * shift modifier is still kept for special keys like arrow keys. */
+    if (code >= 32 && code < MP_KEY_BASE) {
+        /* Still try to support ASCII case-modifications properly. For example,
+         * we want to change "Shift+a" to "A", not "a". Doing this for unicode
+         * in general would require huge lookup tables, or a libc with proper
+         * unicode support, so we don't do that. */
+        if (code >= 'a' && code <= 'z' && (mod & MP_KEY_MODIFIER_SHIFT))
+            code &= 0x5F;
+        mod &= ~MP_KEY_MODIFIER_SHIFT;
+    }
+    return code | mod;
+}
diff --git a/input/keycodes.h b/input/keycodes.h
index 4d13c653a3..53fb682e46 100644
--- a/input/keycodes.h
+++ b/input/keycodes.h
@@ -256,6 +256,9 @@
                               MP_KEY_MODIFIER_ALT | MP_KEY_MODIFIER_META | \
                               MP_KEY_STATE_DOWN | MP_KEY_STATE_UP)
 
+// Makes adjustments like turning "shift+z" into "Z"
+int mp_normalize_keycode(int keycode);
+
 // Get input key from its name.
 int mp_input_get_key_from_name(const char *name);