Bool
XkbComputeRowBounds(XkbGeometryPtr geom, XkbSectionPtr section, XkbRowPtr row)
{
register int k, pos;
XkbKeyPtr key;
XkbBoundsPtr bounds, sbounds;
if ((!geom) || (!section) || (!row))
return False;
bounds = &row->bounds;
bzero(bounds, sizeof(XkbBoundsRec));
for (key = row->keys, pos = k = 0; k < row->num_keys; k++, key++) {
sbounds = &XkbKeyShape(geom, key)->bounds;
_XkbCheckBounds(bounds, pos, 0);
if (!row->vertical) {
if (key->gap != 0) {
pos += key->gap;
_XkbCheckBounds(bounds, pos, 0);
}
_XkbCheckBounds(bounds, pos + sbounds->x1, sbounds->y1);
_XkbCheckBounds(bounds, pos + sbounds->x2, sbounds->y2);
pos += sbounds->x2;
}
else {
if (key->gap != 0) {
pos += key->gap;
_XkbCheckBounds(bounds, 0, pos);
}
_XkbCheckBounds(bounds, pos + sbounds->x1, sbounds->y1);
_XkbCheckBounds(bounds, pos + sbounds->x2, sbounds->y2);
pos += sbounds->y2;
}
}
return True;
}
static guint
compute_above_tab_keycode (Display *xdisplay)
{
XkbDescPtr keyboard;
XkbGeometryPtr geometry;
int i, j, k;
int tab_keycode;
char *tab_name;
XkbSectionPtr tab_section;
XkbBoundsRec tab_bounds;
XkbKeyPtr best_key = NULL;
guint best_keycode = (guint)-1;
int best_x_dist = G_MAXINT;
int best_y_dist = G_MAXINT;
/* We need only the Names and the Geometry, but asking for these results
* in the Keyboard information retrieval failing for unknown reasons.
* (Testing with xorg-1.9.1.) So we ask for a part that we don't need
* as well.
*/
keyboard = XkbGetKeyboard (xdisplay,
XkbGBN_ClientSymbolsMask | XkbGBN_KeyNamesMask | XkbGBN_GeometryMask,
XkbUseCoreKbd);
if (!keyboard)
return best_keycode;
geometry = keyboard->geom;
/* There could potentially be multiple keys with the Tab keysym on the keyboard;
* but XKeysymToKeycode() returns us the one that the alt-Tab binding will
* use which is good enough
*/
tab_keycode = XKeysymToKeycode (xdisplay, XK_Tab);
if (tab_keycode == 0 || tab_keycode < keyboard->min_key_code || tab_keycode > keyboard->max_key_code)
goto out;
/* The keyboard geometry is stored by key "name" rather than keycode.
* (Key names are 4-character strings like like TAB or AE01.) We use the
* 'names' part of the keyboard description to map keycode to key name.
*
* XKB has a "key aliases" feature where a single keyboard key can have
* multiple names (with separate sets of aliases in the 'names' part and
* in the 'geometry' part), but I don't really understand it or how it is used,
* so I'm ignoring it here.
*/
tab_name = keyboard->names->keys[tab_keycode].name; /* Not NULL terminated! */
/* First, iterate through the keyboard geometry to find the tab key; the keyboard
* geometry has a three-level heirarchy of section > row > key
*/
for (i = 0; i < geometry->num_sections; i++)
{
XkbSectionPtr section = &geometry->sections[i];
for (j = 0; j < section->num_rows; j++)
{
int x = 0;
int y = 0;
XkbRowPtr row = §ion->rows[j];
for (k = 0; k < row->num_keys; k++)
{
XkbKeyPtr key = &row->keys[k];
XkbShapePtr shape = XkbKeyShape (geometry, key);
if (row->vertical)
y += key->gap;
else
x += key->gap;
if (strncmp (key->name.name, tab_name, XkbKeyNameLength) == 0)
{
tab_section = section;
tab_bounds = shape->bounds;
tab_bounds.x1 += row->left + x;
tab_bounds.x2 += row->left + x;
tab_bounds.y1 += row->top + y;
tab_bounds.y2 += row->top + y;
goto found_tab;
}
if (row->vertical)
y += (shape->bounds.y2 - shape->bounds.y1);
else
x += (shape->bounds.x2 - shape->bounds.x1);
}
}
}
/* No tab key found */
goto out;
found_tab:
/* Now find the key that:
* - Is in the same section as the Tab key
* - Has a horizontal center in the Tab key's horizonal bounds
* - Is above the Tab key at a distance closer than any other key
* - In case of ties, has its horizontal center as close as possible
* to the Tab key's horizontal center
*/
for (j = 0; j < tab_section->num_rows; j++)
{
int x = 0;
int y = 0;
XkbRowPtr row = &tab_section->rows[j];
for (k = 0; k < row->num_keys; k++)
{
XkbKeyPtr key = &row->keys[k];
XkbShapePtr shape = XkbKeyShape(geometry, key);
XkbBoundsRec bounds = shape->bounds;
int x_center;
int x_dist, y_dist;
if (row->vertical)
y += key->gap;
else
x += key->gap;
bounds.x1 += row->left + x;
bounds.x2 += row->left + x;
bounds.y1 += row->top + y;
bounds.y2 += row->top + y;
y_dist = tab_bounds.y1 - bounds.y2;
if (y_dist < 0)
continue;
x_center = (bounds.x1 + bounds.x2) / 2;
if (x_center < tab_bounds.x1 || x_center > tab_bounds.x2)
continue;
x_dist = ABS (x_center - (tab_bounds.x1 + tab_bounds.x2) / 2);
if (y_dist < best_y_dist ||
(y_dist == best_y_dist && x_dist < best_x_dist))
{
best_key = key;
best_x_dist = x_dist;
best_y_dist = y_dist;
}
if (row->vertical)
y += (shape->bounds.y2 - shape->bounds.y1);
else
x += (shape->bounds.x2 - shape->bounds.x1);
}
}
if (best_key == NULL)
goto out;
/* Now we need to resolve the name of the best key back to a keycode */
for (i = keyboard->min_key_code; i < keyboard->max_key_code; i++)
{
if (strncmp (best_key->name.name, keyboard->names->keys[i].name, XkbKeyNameLength) == 0)
{
best_keycode = i;
break;
}
}
out:
XkbFreeKeyboard (keyboard, 0, True);
return best_keycode;
}
