GuiPaint.h

/****************************************************************************
 * libgui
 * Daryl Borth 2026
 * GuiPaint.h
 *
 * Platform-agnostic description of how a shape looks: fill, outline and
 * shadow, plus the per-state sets a widget switches between (normal,
 * focused, pressed, disabled). Paints are plain values that can be copied,
 * compared and blended, which is what lets a highlight fade in instead of
 * snapping.
 ***************************************************************************/
#pragma once
#include "GuiGeometry.h"

enum class SHAPE {
    RECTANGLE, 
    ELLIPSE, 
    TRIANGLE_UP, 
    TRIANGLE_DOWN, 
    TRIANGLE_LEFT,
    TRIANGLE_RIGHT
};

struct GuiPaint {
    GuiFill fill;           
    bool hasFill;            
    GuiFill strokeFill;      
    float strokeWidth;      
    STROKE strokeAlign;       
    PixelColor shadowColor;   
    float shadowBlur;       
    float shadowSpread;     
    float shadowDx;         
    float shadowDy;         

    GuiPaint();

    GuiPaint& color(PixelColor c);
    GuiPaint& gradient(PixelColor from, PixelColor to, float angleDeg = 90.0f);
    GuiPaint& stroke(float width, PixelColor c, STROKE align = STROKE::INSIDE);
    GuiPaint& shadow(float blur, PixelColor c, float dx = 0.0f, float dy = 0.0f, float spread = 0.0f);
    GuiPaint& glow(float blur, PixelColor c, float spread = 0.0f);

    bool operator==(const GuiPaint& o) const;
    bool operator!=(const GuiPaint& o) const { return !(*this == o); }

    static GuiPaint mix(const GuiPaint& a, const GuiPaint& b, float t);
};

PixelColor GuiMixColor(PixelColor a, PixelColor b, float t);

enum class SHAPE_STATE {
    NORMAL,
    FOCUSED, 
    PRESSED,
    DISABLED
};

struct GuiShapeStyle {
    GuiPaint normal;
    GuiPaint focused;
    GuiPaint pressed;
    GuiPaint disabled;
    bool hasFocused;
    bool hasPressed;
    bool hasDisabled;
 
    GuiShapeStyle(const GuiPaint& normalPaint = GuiPaint());
    GuiShapeStyle& onFocus(const GuiPaint& p);
    GuiShapeStyle& onPress(const GuiPaint& p);
    GuiShapeStyle& onDisable(const GuiPaint& p);
    const GuiPaint& forState(SHAPE_STATE s) const;
};

void GuiAddPaintedShape(GuiMesh& mesh, SHAPE shape, const GuiRect& r, const GuiCorners& corners, const GuiPaint& paint);