Squashed 'libraries/ZWidget/' changes from 96501b6ef..cecd34301

cecd34301 Delay load DPI-related functions
bfc172f70 Added exception to some unimplemented functions
7c8d469bc Added item modifications functions
847d0e6d9 Improved keyboard navigation
8c4270e0f Dropdown can now be closed by re-selecting it
91402c31e Fix dropdown positioning in x11 and win32
02da8cdc0 Added ListView::GetPreferredWidth, ListView::GetPreferredHeight, ListView::GetMinHeight
04bf153d9 Added event subscriber system
1ce55e5da Added Dropdown Known issues: does not hide when parent widget's visibility changes

git-subtree-dir: libraries/ZWidget
git-subtree-split: cecd34301d369400227eb0f27bad2ab41ad756d2

include/zwidget/core/widget.h

@@ -4,6 +4,7 @@
 #include <memory>
 #include <variant>
 #include <unordered_map>
+#include <unordered_set>
 #include "canvas.h"
 #include "rect.h"
 #include "colorf.h"
@@ -11,6 +12,7 @@
 
 class Canvas;
 class Timer;
+class Dropdown;
 
 enum class WidgetType
 {
@@ -19,6 +21,13 @@ enum class WidgetType
 	Popup
 };
 
+enum class WidgetEvent
+{
+	VisibilityChange,
+
+	// TODO: add more events
+};
+
 class Widget : DisplayWindowHost
 {
 public:
@@ -93,6 +102,9 @@ public:
 	void ShowNormal();
 	void Hide();
 
+	void Subscribe(Widget* subscriber);
+	void Unsubscribe(Widget* subscriber);
+
 	void ActivateWindow();
 
 	void Close();
@@ -178,6 +190,8 @@ protected:
 	virtual void OnLostFocus() { }
 	virtual void OnEnableChanged() { }
 
+	virtual void Notify(Widget* source, const WidgetEvent type) { };
+
 private:
 	void DetachFromParent();
 
@@ -201,6 +215,8 @@ private:
 	void OnWindowDeactivated() override;
 	void OnWindowDpiScaleChanged() override;
 
+	void NotifySubscribers(const WidgetEvent type);
+
 	WidgetType Type = {};
 
 	Widget* ParentObj = nullptr;
@@ -234,8 +250,12 @@ private:
 	Widget(const Widget&) = delete;
 	Widget& operator=(const Widget&) = delete;
 
+	std::unordered_set<Widget*> Subscribers;
+	std::unordered_set<Widget*> Subscriptions;
+
 	friend class Timer;
 	friend class OpenFileDialog;
 	friend class OpenFolderDialog;
 	friend class SaveFileDialog;
+	friend class Dropdown;
 };

include/zwidget/widgets/dropdown/dropdown.h

@@ -0,0 +1,69 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <functional>
+
+#include "../../core/widget.h"
+#include "../../widgets/listview/listview.h"
+
+class DropdownList : public ListView
+{
+public:
+	DropdownList(Widget* parent, Dropdown* owner);
+protected:
+	void OnKeyDown(InputKey key) override;
+	Dropdown* owner;
+};
+
+class Dropdown : public Widget
+{
+public:
+	Dropdown(Widget* parent);
+
+	void AddItem(const std::string& text, int index = -1);
+	bool UpdateItem(const std::string& text, int index);
+	bool RemoveItem(int index = -1);
+	void ClearItems();
+	const std::string& GetItem(int index);
+
+	void SetMaxDisplayItems(int items);
+	void SetDropdownDirection(bool below);
+
+	int GetSelectedItem() const { return selectedItem; }
+	void SetSelectedItem(int index);
+
+	double GetPreferredHeight() const;
+	double GetPreferredWidth() const;
+
+	std::function<void(int)> OnChanged;
+
+protected:
+	void OnPaint(Canvas* canvas) override;
+	bool OnMouseDown(const Point& pos, InputKey key) override;
+	void OnKeyDown(InputKey key) override;
+	void OnGeometryChanged() override;
+	void OnLostFocus() override;
+	void Notify(Widget* source, const WidgetEvent type) override;
+
+private:
+	void ItemsChanged();
+	bool OpenDropdown();
+	bool CloseDropdown();
+	void OnDropdownActivated();
+
+	size_t GetDisplayItems();
+
+	std::vector<std::string> items;
+	int selectedItem = -1;
+	std::string text;
+
+	bool dropdownOpen = false;
+	Widget* dropdown = nullptr;
+	DropdownList* listView = nullptr;
+
+	int maxDisplayItems = 0;
+	bool dropdownDirection = true;
+
+	friend DropdownList;
+};

include/zwidget/widgets/listview/listview.h

@@ -6,6 +6,7 @@
 #include <functional>
 
 class Scrollbar;
+class Dropdown;
 
 class ListView : public Widget
 {
@@ -22,6 +23,10 @@ public:
 	void SetSelectedItem(int index);
 	void ScrollToItem(int index);
 
+	double GetPreferredWidth();
+	double GetPreferredHeight();
+	double GetMinimumHeight() const;
+
 	void Activate();
 
 	std::function<void(int)> OnChanged;
@@ -43,4 +48,6 @@ protected:
 	std::vector<std::vector<std::string>> items;
 	std::vector<double> columnwidths;
 	int selectedItem = 0;
+
+	friend Dropdown;
 };