Extract weird range-of-entries algorithm out of view.

This commit is contained in:
Jared Boone 2016-01-14 11:49:19 -08:00
parent f8d9cb318d
commit b1707298b7
2 changed files with 30 additions and 17 deletions

View File

@ -161,6 +161,28 @@ void AISRecentEntries::truncate_entries() {
}
}
AISRecentEntries::RangeType AISRecentEntries::range_around(
ContainerType::const_iterator item, const size_t count
) const {
auto start = item;
auto end = item;
size_t i = 0;
// Move start iterator toward first entry.
while( (start != std::begin(entries)) && (i < count / 2) ) {
std::advance(start, -1);
i++;
}
// Move end iterator toward last entry.
while( (end != std::end(entries)) && (i < count) ) {
std::advance(end, 1);
i++;
}
return { start, end };
}
namespace ui {
AISRecentEntriesView::AISRecentEntriesView(
@ -207,23 +229,9 @@ void AISRecentEntriesView::paint(Painter& painter) {
selected = std::begin(recent);
}
auto start = selected;
auto end = selected;
size_t i = 0;
auto range = recent.range_around(selected, visible_item_count);
// Move start iterator toward first entry.
while( (start != std::begin(recent)) && (i < visible_item_count / 2) ) {
std::advance(start, -1);
i++;
}
// Move end iterator toward last entry.
while( (end != std::end(recent)) && (i < visible_item_count) ) {
std::advance(end, 1);
i++;
}
for(auto p = start; p != end; p++) {
for(auto p = range.first; p != range.second; p++) {
const auto& entry = *p;
const auto is_selected_key = (selected_key == entry.mmsi);
ais_list_item_draw(entry, target_rect, painter, s, (has_focus() && is_selected_key));

View File

@ -68,6 +68,7 @@ struct AISRecentEntry {
class AISRecentEntries {
public:
using ContainerType = std::list<AISRecentEntry>;
using RangeType = std::pair<ContainerType::const_iterator, ContainerType::const_iterator>;
void on_packet(const ais::Packet& packet);
@ -89,6 +90,10 @@ public:
return entries.empty();
}
RangeType range_around(
ContainerType::const_iterator, const size_t count
) const;
private:
ContainerType entries;
const size_t entries_max = 64;