ScrollContainer.h

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#pragma once
 
#include "Nodes/Widgets/Widget.h"
#include "AssetRef.h"
 
class Quad;
class Button;
class Texture;
 
enum class ScrollSizeMode : uint8_t
{
    FitWidth,       // Content fills parent width, scrolls vertically
    FitHeight,      // Content fills parent height, scrolls horizontally
    FitBoth,        // Content fills both dimensions
    None,           // Content uses explicit size
    Count
};
 
enum class ScrollbarMode : uint8_t
{
    Hidden,         // Never show scrollbars
    Auto,           // Show only when needed
    AlwaysVisible,  // Always show
    Count
};
 
class POLYPHASE_API ScrollContainer : public Widget
{
public:
 
    DECLARE_NODE(ScrollContainer, Widget);
 
    virtual void Create() override;
    virtual void GatherProperties(std::vector<Property>& props) override;
    virtual void Tick(float deltaTime) override;
    virtual void PreRender() override;
 
    // Scroll Position
    void SetScrollOffset(glm::vec2 offset);
    glm::vec2 GetScrollOffset() const;
    void SetScrollOffsetX(float x);
    void SetScrollOffsetY(float y);
    void ScrollToTop();
    void ScrollToBottom();
    void ScrollToLeft();
    void ScrollToRight();
 
    // Size Mode
    void SetScrollSizeMode(ScrollSizeMode mode);
    ScrollSizeMode GetScrollSizeMode() const;
 
    // Scrollbar Configuration
    void SetHorizontalScrollbarMode(ScrollbarMode mode);
    ScrollbarMode GetHorizontalScrollbarMode() const;
    void SetVerticalScrollbarMode(ScrollbarMode mode);
    ScrollbarMode GetVerticalScrollbarMode() const;
    void SetScrollbarWidth(float width);
    float GetScrollbarWidth() const;
 
    // Scroll Behavior
    void SetScrollSpeed(float speed);
    float GetScrollSpeed() const;
    void SetMomentumEnabled(bool enabled);
    bool IsMomentumEnabled() const;
    void SetMomentumFriction(float friction);
    float GetMomentumFriction() const;
 
    // Query
    bool CanScrollHorizontally() const;
    bool CanScrollVertically() const;
    glm::vec2 GetContentSize() const;
    glm::vec2 GetMaxScrollOffset() const;
    bool IsDragging() const;
    bool IsScrolling() const;
 
    // Child Input Priority
    void SetChildInputPriority(bool priority);
    bool GetChildInputPriority() const;
 
    // Content Access
    Widget* GetContentWidget();
 
    // Explicit content override. Use this when the ScrollContainer's actual
    // content child is marked transient (e.g. ListViewWidget's internal
    // ArrayWidget) and would otherwise be skipped by the
    // "first non-transient child" fallback. Setting nullptr restores the
    // fallback behaviour. Caller owns the widget's lifecycle.
    void SetContentWidget(Widget* widget);
 
    // Visual Customization - Colors
    void SetScrollbarColor(glm::vec4 color);
    glm::vec4 GetScrollbarColor() const;
    void SetScrollbarHoveredColor(glm::vec4 color);
    glm::vec4 GetScrollbarHoveredColor() const;
    void SetScrollbarTrackColor(glm::vec4 color);
    glm::vec4 GetScrollbarTrackColor() const;
 
    // Visual Customization - Textures
    void SetScrollbarTexture(Texture* texture);
    Texture* GetScrollbarTexture();
    void SetTrackTexture(Texture* texture);
    Texture* GetTrackTexture();
 
    // Scroll Buttons
    void SetShowScrollButtons(bool show);
    bool GetShowScrollButtons() const;
    void SetButtonSize(float size);
    float GetButtonSize() const;
    void SetUpButtonTexture(Texture* texture);
    Texture* GetUpButtonTexture();
    void SetDownButtonTexture(Texture* texture);
    Texture* GetDownButtonTexture();
    void SetLeftButtonTexture(Texture* texture);
    Texture* GetLeftButtonTexture();
    void SetRightButtonTexture(Texture* texture);
    Texture* GetRightButtonTexture();
    void SetButtonColor(glm::vec4 color);
    glm::vec4 GetButtonColor() const;
 
    // Access internal widgets
    Quad* GetHScrollbar();
    Quad* GetVScrollbar();
    Quad* GetHTrack();
    Quad* GetVTrack();
    Button* GetUpButton();
    Button* GetDownButton();
    Button* GetLeftButton();
    Button* GetRightButton();
 
protected:
 
    static bool HandlePropChange(Datum* datum, uint32_t index, const void* newValue);
 
    void UpdateScrollbars();
    void UpdateContentPosition();
    void UpdateScrollButtons();
    void ClampScrollOffset();
    void HandleInput(float deltaTime);
    void HandleMomentum(float deltaTime);
    void HandleButtonInput();
    bool ShouldShowHScrollbar() const;
    bool ShouldShowVScrollbar() const;
    bool IsPointerOverChildWidget(float x, float y) const;
 
    // Scroll State
    glm::vec2 mScrollOffset = glm::vec2(0.0f);
    glm::vec2 mScrollVelocity = glm::vec2(0.0f);
    glm::vec2 mDragStartOffset = glm::vec2(0.0f);
    glm::vec2 mDragStartMouse = glm::vec2(0.0f);
    glm::vec2 mLastMousePos = glm::vec2(0.0f);
 
    // Size & Mode
    ScrollSizeMode mScrollSizeMode = ScrollSizeMode::FitWidth;
    ScrollbarMode mHScrollbarMode = ScrollbarMode::Auto;
    ScrollbarMode mVScrollbarMode = ScrollbarMode::Auto;
 
    // Scroll Behavior
    float mScrollSpeed = 30.0f;          // Pixels per scroll wheel notch
    float mMomentumFriction = 5.0f;      // Deceleration factor
    bool mMomentumEnabled = true;
 
    // Visual - Dimensions
    float mScrollbarWidth = 8.0f;
    float mButtonSize = 16.0f;
    bool mShowScrollButtons = false;
 
    // Visual - Colors
    glm::vec4 mScrollbarColor = glm::vec4(0.5f, 0.5f, 0.5f, 0.8f);
    glm::vec4 mScrollbarHoveredColor = glm::vec4(0.7f, 0.7f, 0.7f, 1.0f);
    glm::vec4 mScrollbarTrackColor = glm::vec4(0.2f, 0.2f, 0.2f, 0.5f);
    glm::vec4 mButtonColor = glm::vec4(0.4f, 0.4f, 0.4f, 1.0f);
 
    // Visual - Textures
    TextureRef mScrollbarTexture;
    TextureRef mTrackTexture;
    TextureRef mUpButtonTexture;
    TextureRef mDownButtonTexture;
    TextureRef mLeftButtonTexture;
    TextureRef mRightButtonTexture;
 
    // State
    bool mDragging = false;
    bool mDraggingHScrollbar = false;
    bool mDraggingVScrollbar = false;
    bool mHScrollbarHovered = false;
    bool mVScrollbarHovered = false;
 
    // Input Behavior
    bool mChildInputPriority = false;  // If true, children receive input before scroll drag starts
 
    // Cached content size (updated during PreRender)
    glm::vec2 mCachedContentSize = glm::vec2(0.0f);
 
    // Explicit content widget. When non-null, GetContentWidget() returns it
    // instead of scanning children. Lets ListViewWidget point at its internal
    // transient ArrayWidget without changing fallback behaviour for everyone
    // else. Raw pointer matches the existing internal-widget convention; the
    // ListViewWidget owns the lifecycle and clears it on teardown via the
    // owning hierarchy.
    Widget* mContentOverride = nullptr;
 
    // Transient child widgets - Scrollbars
    Quad* mHScrollbarTrack = nullptr;
    Quad* mHScrollbarGrabber = nullptr;
    Quad* mVScrollbarTrack = nullptr;
    Quad* mVScrollbarGrabber = nullptr;
 
    // Transient child widgets - Buttons
    Button* mUpButton = nullptr;
    Button* mDownButton = nullptr;
    Button* mLeftButton = nullptr;
    Button* mRightButton = nullptr;
};