void
GridView::MoveFocus(Direction direction)
{
signed focusPos = GetIndexOfItemInFocus();
if (focusPos == -1)
// We are on a page without enabled items.
// We should show the next page if exists
ShowNextPage(direction);
else {
signed newFocusPos = GetNextItemIndex(focusPos, direction);
if (newFocusPos != -1) {
// we are on the same page
items[newFocusPos]->SetFocus();
if (!items[newFocusPos]->HasFocus()) {
/* unable to set the focus, let's try simple Tab/Shift-Tab
behavior instead */
newFocusPos = GetNextEnabledItemIndex(focusPos, direction);
if (newFocusPos != -1)
items[newFocusPos]->SetFocus();
}
RefreshLayout();
} else
ShowNextPage(direction);
}
}
void
GridView::RefreshLayout()
{
const PixelRect rc = GetClientRect();
unsigned maxColumns = (rc.right - rc.left + horizontal_spacing)
/ (column_width + horizontal_spacing);
if (maxColumns == 0)
maxColumns = 1;
unsigned maxRows = (rc.bottom - rc.top + vertical_spacing)
/ (row_height + vertical_spacing);
if (maxRows == 0)
maxRows = 1;
if (maxColumns < num_columns)
num_columns = maxColumns;
if (maxRows < num_rows)
num_rows = maxRows;
unsigned pageSize = num_columns * num_rows;
// Center grid in the client area
unsigned reminderH = rc.right - rc.left + horizontal_spacing
- num_columns * (column_width + horizontal_spacing);
unsigned reminderV = rc.bottom - rc.top + vertical_spacing
- num_rows * (row_height + vertical_spacing);
unsigned leftOrigin = rc.left + reminderH / 2;
unsigned topOrigin= rc.top + reminderV / 2;
// Determine current page from item that has focus
// If there is no item with focus or the item with focus is on current page,
// the current page remains unchanged
signed focusPos = GetIndexOfItemInFocus();
if (focusPos != -1)
current_page = focusPos / pageSize;
for (unsigned i = items.size(); i--;) {
unsigned pagePos = i % pageSize;
unsigned itemPage = i / pageSize;
unsigned colNum = pagePos % num_columns;
unsigned rowNum = pagePos / num_columns;
items[i]->Move(leftOrigin + colNum * (column_width + horizontal_spacing),
topOrigin + rowNum * (row_height + vertical_spacing),
column_width, row_height);
items[i]->SetVisible(itemPage == current_page);
}
}
void
GridView::ShowNextPage(Direction direction)
{
signed newPos = -1;
unsigned pageSize = num_columns * num_rows;
unsigned lastPage = items.size() / pageSize;
if (direction == Direction::LEFT && current_page > 0)
current_page--;
else if (direction == Direction::RIGHT && current_page < lastPage)
current_page++;
else
return;
unsigned currentPageSize = current_page == lastPage
? items.size() % pageSize
: pageSize;
signed focusPos = GetIndexOfItemInFocus();
if (focusPos != -1) {
unsigned oldPagePos = focusPos % pageSize;
unsigned oldRowNum = oldPagePos / num_columns;
if (direction == Direction::LEFT)
// last column in the same row
newPos = current_page * pageSize + (oldRowNum + 1) * num_columns - 1;
else { // direction == Direction::RIGHT
// first column in the same row
newPos = current_page * pageSize + oldRowNum * num_columns;
if (newPos >= (signed)items.size()) {
// first columns in the last row
newPos = current_page * pageSize + currentPageSize
- (currentPageSize - 1) % num_columns - 1;
}
}
}
if (newPos != -1) {
items[newPos]->SetFocus();
/* unable to set the focus on the desired item, let's try
Tab/Shift-Tab behavior instead */
if (!items[newPos]->HasFocus()) {
if (direction == Direction::LEFT)
newPos = GetNextEnabledItemIndex(current_page * pageSize
+ currentPageSize, direction);
else
newPos = GetNextEnabledItemIndex(current_page * pageSize - 1,
direction);
// set focus only if it is on the same page
if (newPos != -1 &&
newPos >= (signed)(current_page * pageSize) &&
newPos < (signed)(current_page * pageSize + currentPageSize)) {
items[newPos]->SetFocus();
}
} else if (focusPos != -1) {
#ifdef USE_WINUSER
HWND oldFocusHwnd = ::GetFocus();
if (oldFocusHwnd != nullptr)
::SendMessage(oldFocusHwnd, WM_CANCELMODE, 0, 0);
#else
items[focusPos]->ClearFocus();
#endif /* USE_WINUSER */
}
RefreshLayout();
}
}
