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Diffstat (limited to 'lib/nes/app/ui/selection.hh')
| -rw-r--r-- | lib/nes/app/ui/selection.hh | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/lib/nes/app/ui/selection.hh b/lib/nes/app/ui/selection.hh new file mode 100644 index 0000000..fafa4a6 --- /dev/null +++ b/lib/nes/app/ui/selection.hh @@ -0,0 +1,125 @@ +#pragma once + +#include "nes/common/types.hh" +#include "nes/app/graphics/renderer.hh" +#include "nes/app/graphics/color.hh" + +namespace nes::app +{ + /// A selection menu managing a fixed number of items and pagination. + template<typename Item, u32 PageSize> + class selection + { + Item items_[PageSize]; + u32 count_{ 0 }; + u32 page_count_{ 0 }; + i32 x_{}; + i32 y_{}; + u32 width_{}; + i32 selected_{ -1 }; + i32 current_page_{ -1 }; + + public: + explicit selection(i32 const x, i32 const y, u32 const width) + : x_{ x } + , y_{ y } + , width_{ width } + { + } + + virtual ~selection() = default; + + selection(selection const&) = delete; + selection(selection&&) = delete; + auto operator=(selection const&) -> selection& = delete; + auto operator=(selection&&) -> selection& = delete; + + auto set_page_count(u32 const page_count) -> void + { + page_count_ = page_count; + set_page(page_count_ > 0 ? 0 : -1); + } + + auto get_page_count() const -> u32 { return page_count_; } + auto get_current_page() const -> i32 { return current_page_; } + auto get_selected() const -> Item const* { return selected_ >= 0 ? &items_[selected_] : nullptr; } + + auto render(renderer& renderer) const -> void + { + for (auto i = u32{ 0 }; i < count_; ++i) + { + auto const y = y_ + static_cast<i32>(3 * i); + auto const is_selected = static_cast<i32>(i) == selected_; + auto const color = is_selected ? color::accent_primary : color::foreground_primary; + if (is_selected) + { + renderer.render_text(x_, y, ">", color); + } + + render_item(renderer, items_[i], x_ + 2, y, width_ - 2, color); + } + } + + auto go_next() -> void + { + if (selected_ < 0) { return; } + + selected_ += 1; + if (selected_ == static_cast<i32>(count_)) { selected_ = 0; } + } + + auto go_up() -> void + { + if (selected_ <= 0) + { + if (current_page_ <= 0) { return; } + + set_page(current_page_ - 1, true); + return; + } + selected_ -= 1; + } + + auto go_down() -> void + { + if (selected_ < 0 || selected_ + 1 == static_cast<i32>(count_)) + { + if (current_page_ < 0 || current_page_ + 1 == static_cast<i32>(page_count_)) { return; } + + set_page(current_page_ + 1, false); + return; + } + selected_ += 1; + } + + protected: + /// Render an item's caption at the given position and width. + virtual auto render_item(renderer&, Item const&, i32 x, i32 y, u32 width, color) const -> void = 0; + + /// Load the items for a page (max. PageSize items) and return the number of loaded items. + virtual auto load_page(Item(&)[PageSize], u32 page) -> u32 = 0; + + private: + auto set_page(i32 const page, bool const select_last = false) -> void + { + if (page < 0) + { + current_page_ = -1; + count_ = 0; + selected_ = -1; + return; + } + + current_page_ = page; + count_ = load_page(items_, static_cast<u32>(page)); + if (count_ > 0) + { + selected_ = select_last ? static_cast<i32>(count_) - 1 : 0; + } + else + { + selected_ = -1; + } + } + }; +} // namespace nes::app
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