panopainter/engine/layout.h

#pragma once
#include "shape.hpp"
#include "util.hpp"
#include "shader.hpp"

enum class kAttribute : uint16_t 
{
    Width       = const_hash("width"), 
    MinWidth    = const_hash("max-width"),
    MaxWidth    = const_hash("min-width"),
    Height      = const_hash("height"),
    MinHeight   = const_hash("min-height"),
    MaxHeight   = const_hash("max-height"),
    Divisions   = const_hash("divisions"),
    InnerRadius = const_hash("inner-radius"),
    OuterRadius = const_hash("outer-radius"),
    Grow        = const_hash("grow"), 
    Shrink      = const_hash("shrink"),
    FlexDir     = const_hash("dir"),
    FlexWrap    = const_hash("wrap"),
    Padding     = const_hash("pad"),
    Margin      = const_hash("margin"),
    Color       = const_hash("color"),
    Thickness   = const_hash("thickness"),
    BorderColor = const_hash("border-color"),
};

enum class kWidget : uint16_t
{
    Border = const_hash("border"),
};

class Widget
{
public:
    glm::mat4 mvp;
    glm::vec4 clip;
    virtual void draw() { };
    virtual void parse_attributes(kAttribute ka, const tinyxml2::XMLAttribute* attr) { };
};

class WidgetBorder : public Widget
{
public:
    static Plane m_plane;
    glm::vec4 m_color;
    glm::vec4 m_border_color;
    float m_thinkness{ 1 };
    virtual void draw() override
    {
        ShaderManager::use(kShader::Color);
        ShaderManager::u_mat4(kShaderUniform::MVP, mvp);

        ShaderManager::u_vec4(kShaderUniform::Col, m_color);
        m_plane.draw_fill();
        
        glLineWidth(m_thinkness);
        ShaderManager::u_vec4(kShaderUniform::Col, m_border_color);
        m_plane.draw_stroke();
    }
    virtual void parse_attributes(kAttribute id, const tinyxml2::XMLAttribute* attr)
    {
        switch (id)
        {
        case kAttribute::Color:
        {
            glm::vec4 pad;
            int n = sscanf(attr->Value(), "%f %f %f %f", &pad.x, &pad.y, &pad.z, &pad.w);
            if (n == 1)
                m_color = glm::vec4(pad.x);
            else
                m_color = pad;
            break;
        }
        case kAttribute::BorderColor:
        {
            glm::vec4 pad;
            int n = sscanf(attr->Value(), "%f %f %f %f", &pad.x, &pad.y, &pad.z, &pad.w);
            if (n == 1)
                m_border_color = glm::vec4(pad.x);
            else
                m_border_color = pad;
            break;
        }
        case kAttribute::Thickness:
            m_thinkness = attr->FloatValue();
            break;
        }
    }
};

class Node
{
    const Node* parent{ nullptr };
    YGNodeRef y_node{ nullptr };
    struct stat m_file_info { 0 };
    std::string m_path;

public:
    std::vector<Node> m_children;
    std::unique_ptr<Widget> m_widget;
    glm::vec2 m_pos;
    glm::vec2 m_size;
    glm::vec4 m_clip;
    std::string m_name;
    Node(const Node&) = delete;
    Node& operator=(const Node&) = delete;
    Node&& operator=(Node&& o) { return std::forward<Node>(o); }
    Node(Node&& o)
    {
        m_children = std::move(o.m_children);
        for (auto& c : m_children)
            c.parent = this;
        parent = o.parent;
        y_node = o.y_node;
        m_pos = o.m_pos;
        m_size = o.m_size;
        m_clip = o.m_clip;
        m_file_info = o.m_file_info;
        o.y_node = nullptr;
        o.parent = nullptr;
    }
    Node() { y_node = YGNodeNew(); }
    ~Node() 
    {
        m_children.clear();
        if (y_node) 
            YGNodeFree(y_node); 
    }

    void SetWidth(float value) { YGNodeStyleSetWidth(y_node, value); }
    void SetWidthP(float value) { YGNodeStyleSetWidthPercent(y_node, value); }
    void SetHeight(float value) { YGNodeStyleSetHeight(y_node, value); }
    void SetHeightP(float value) { YGNodeStyleSetHeightPercent(y_node, value); }

    void SetPadding(float t, float r, float b, float l) 
    {
        YGNodeStyleSetPadding(y_node, YGEdgeTop, t);
        YGNodeStyleSetPadding(y_node, YGEdgeRight, r);
        YGNodeStyleSetPadding(y_node, YGEdgeBottom, b);
        YGNodeStyleSetPadding(y_node, YGEdgeLeft, l);
    }

    void SetFlexGrow(float value) { YGNodeStyleSetFlexGrow(y_node, value); }
    void SetFlexShrink(float value) { YGNodeStyleSetFlexShrink(y_node, value); }
    void SetFlexDir(YGFlexDirection value) { YGNodeStyleSetFlexDirection(y_node, value); }
    void SetFlexWrap(YGWrap value) { YGNodeStyleSetFlexWrap(y_node, value); }

    glm::vec4 rect_intersection(glm::vec4 a, glm::vec4 b)
    {
        // convert from [x,y,w,h] to [x1,y1,x2,y1]
        a = glm::vec4(a.xy(), a.xy() + a.zw());
        b = glm::vec4(b.xy(), b.xy() + b.zw());
        auto o = glm::vec4(glm::max(a.xy(), b.xy()), glm::min(a.zw(), b.zw()));
        o = glm::vec4(o.xy(), glm::max({ 0, 0 }, o.zw() - o.xy()));
        return o;
    }

    void update(float width, float height);
    void update_internal(const glm::vec2& origin, const glm::mat4& proj);
    void parse_attributes(kAttribute ka, const tinyxml2::XMLAttribute* attr);
    void load(const char* path);
    void load_internal(const tinyxml2::XMLElement* x_node);
    void reload();
    void draw();

    class iterator
    {
        std::stack<Node*> m_nodes;
        Node* m_current;
    public:
        iterator(Node* root)
        {
            m_current = root;
            if (root)
                m_nodes.push(root);
        }
        iterator& operator++() 
        { 
            m_nodes.pop();
            for (auto& c : m_current->m_children)
                m_nodes.push(&c);
            m_current = m_nodes.size() ? m_nodes.top() : nullptr;
            return *this;
        }
        Node& operator*() { return *m_current; }
        Node* operator->() { return m_current; }
        bool operator==(const iterator& rhs) { return m_current == rhs.m_current; }
        bool operator!=(const iterator& rhs) { return m_current != rhs.m_current; }
    };
    iterator begin()
    {
        return this;
    }
    iterator end()
    {
        return nullptr;
    }
};