menu.h

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/*
    MIT License

    Copyright (c) 2020,2022, Alexey Dynda

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all
    copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    SOFTWARE.
*/
#ifndef _LCDGFX_MENU_H_
#define _LCDGFX_MENU_H_

#include "nano_gfx_types.h"
#include "canvas/point.h"
#include "canvas/rect.h"
#include "canvas/font.h"

#ifndef lcd_gfx_min

#define lcd_gfx_min(x, y) ((x) < (y) ? (x) : (y))
#endif

#ifndef lcd_gfx_max

#define lcd_gfx_max(x, y) ((x) > (y) ? (x) : (y))
#endif

class LcdGfxMenu
{
public:
    LcdGfxMenu(const char **items, uint8_t count, const NanoRect &rect = {});

    template <typename D> void show(D &d);

    template <typename D> void update(D &d) { show(d); }

    void invalidate() { m_initialized = false; }

    void down();

    void up();

    uint8_t selection();

    void setSelection(uint8_t s);

    void setRect(const NanoRect &rect = {});

    uint8_t size();

    template <typename D> void updateSize(D &d)
    {
        if ( !menu.width )
        {
            menu.width = d.width() - menu.left;
        }
        if ( !menu.height )
        {
            menu.height = d.height() - menu.top;
        }
    }

    template <typename D> uint8_t itemAtPoint(D &d, lcdint_t x, lcdint_t y)
    {
        updateSize(d);
        if ( x < menu.left || x >= (lcdint_t)(menu.left + menu.width) ) return 0xFF;
        if ( y < menu.top || y >= (lcdint_t)(menu.top + menu.height) ) return 0xFF;
        lcdint_t itemsTop = 8 + menu.top;
        lcduint_t itemH = d.getFont().getHeader().height;
        if ( itemH == 0 ) return 0xFF;
        uint8_t maxItems = getMaxScreenItems(d);
        lcdint_t itemsBot = itemsTop + maxItems * (lcdint_t)itemH;
        if ( y < itemsTop || y >= itemsBot ) return 0xFF;
        uint8_t row = (uint8_t)((y - itemsTop) / itemH);
        uint8_t index = menu.scrollPosition + row;
        if ( index >= menu.count ) return 0xFF;
        return index;
    }

    template <typename D> bool onTouch(D &d, lcdint_t x, lcdint_t y)
    {
        updateSize(d);
        if ( x < menu.left || x >= (lcdint_t)(menu.left + menu.width) ) return false;
        if ( y < menu.top || y >= (lcdint_t)(menu.top + menu.height) ) return false;
        lcdint_t borderTop = 4 + menu.top;
        lcdint_t borderBot = menu.height + menu.top - 5;
        lcdint_t itemsTop = 8 + menu.top;
        lcduint_t itemH = d.getFont().getHeader().height;
        if ( itemH == 0 ) return false;
        uint8_t maxItems = getMaxScreenItems(d);
        lcdint_t itemsBot = itemsTop + maxItems * (lcdint_t)itemH;
        if ( y >= borderTop && y < itemsTop )
        {
            if ( menu.scrollPosition > 0 )
            {
                up();
                return true;
            }
            return false;
        }
        if ( y >= itemsBot && y < borderBot )
        {
            if ( menu.scrollPosition + maxItems < menu.count )
            {
                down();
                return true;
            }
            return false;
        }
        if ( y >= itemsTop && y < itemsBot )
        {
            uint8_t row = (uint8_t)((y - itemsTop) / itemH);
            uint8_t index = menu.scrollPosition + row;
            if ( index < menu.count )
            {
                setSelection(index);
                return true;
            }
        }
        return false;
    }

private:
    SAppMenu menu;
    uint8_t m_oldScrollPosition = 0;
    bool m_initialized = false;

    template <typename D> uint8_t getMaxScreenItems(D &d)
    {
        return (menu.height - 16) / d.getFont().getHeader().height;
    }

    template <typename D> uint8_t calculateScrollPosition(D &d, uint8_t selection)
    {
        if ( selection < menu.scrollPosition )
        {
            return selection;
        }
        else if ( selection - menu.scrollPosition > getMaxScreenItems(d) - 1 )
        {
            return selection - getMaxScreenItems(d) + 1;
        }
        return menu.scrollPosition;
    }

    template <typename D> void drawMenuItem(D &d, uint8_t index)
    {
        if ( index == menu.selection )
        {
            d.invertColors();
        }
        lcdint_t item_top = 8 + menu.top + (index - menu.scrollPosition) * d.getFont().getHeader().height;
        uint16_t color = d.getColor();
        d.setColor(0x0000);
        // Clear only the trailing portion (from the end of the new label
        // to just inside the right border / scrollbar). printFixed paints
        // the cell backgrounds under the new text itself, so this single
        // trailing fillRect is enough — even after scrolling, when a
        // shorter label replaces a longer one at the same screen row.
        d.fillRect(menu.left + 8 + d.getFont().getTextSize(menu.items[index]), item_top,
                   menu.width + menu.left - 9, item_top + d.getFont().getHeader().height - 1);
        d.setColor(color);
        d.printFixed(menu.left + 8, item_top, menu.items[index], STYLE_NORMAL);
        if ( index == menu.selection )
        {
            d.invertColors();
        }
    }

    template <typename D> void drawScrollIndicators(D &d, uint8_t maxItems)
    {
        // Scrollbar on the right edge conveys the visible-window position;
        // it lives entirely in the item-area pages (page-aligned) so a
        // partial fillRect for the thumb is safe even on SSD1306-style
        // 1bpp drivers that stream whole 8-pixel page bytes.
        uint16_t color = d.getColor();
        lcdint_t itemsTop = 8 + menu.top;
        lcdint_t itemsBot = itemsTop + maxItems * d.getFont().getHeader().height;
        lcdint_t sbX = menu.width + menu.left - 8;
        lcdint_t sbH = itemsBot - itemsTop - 1;
        if ( sbH > 4 )
        {
            lcdint_t thumbH = lcd_gfx_max((lcdint_t)2, (lcdint_t)(sbH * maxItems / menu.count));
            lcdint_t maxScroll = menu.count - maxItems;
            lcdint_t thumbY = itemsTop;
            if ( maxScroll > 0 )
            {
                thumbY = itemsTop + (lcdint_t)((long)(sbH - thumbH) * menu.scrollPosition / maxScroll);
            }
            d.setColor(0x0000);
            d.fillRect(sbX, itemsTop, sbX + 1, itemsTop + sbH);
            d.setColor(color);
            d.fillRect(sbX, thumbY, sbX + 1, thumbY + thumbH);
        }
        d.setColor(color);
    }
};

template <typename D> void LcdGfxMenu::show(D &d)
{
    updateSize(d);
    uint8_t maxItems = getMaxScreenItems(d);
    uint8_t newScroll = this->calculateScrollPosition(d, menu.selection);

    // Incremental fast path: nothing about the visible window changed,
    // only the selection moved within it. Repaint just the two affected
    // item rows. They live on page-aligned y offsets so redrawing them
    // does not disturb the border or neighbouring items even on
    // SSD1306-style 1bpp drivers that stream whole 8-pixel page bytes.
    if ( m_initialized && newScroll == m_oldScrollPosition )
    {
        if ( menu.selection != menu.oldSelection )
        {
            menu.scrollPosition = newScroll;
            uint8_t prev = menu.oldSelection;
            this->drawMenuItem(d, prev);
            this->drawMenuItem(d, menu.selection);
            menu.oldSelection = menu.selection;
        }
        return;
    }

    // Full redraw: first call, or visible window scrolled. Each
    // drawMenuItem clears its own row, so no full-interior fillRect is
    // needed here — the border stays painted without flicker.
    menu.scrollPosition = newScroll;
    d.drawRect(4 + menu.left, 4 + menu.top, menu.width + menu.left - 5, menu.height + menu.top - 5);
    for ( uint8_t i = menu.scrollPosition; i < lcd_gfx_min(menu.count, (menu.scrollPosition + maxItems)); i++ )
    {
        this->drawMenuItem(d, i);
    }
    menu.oldSelection = menu.selection;
    m_oldScrollPosition = menu.scrollPosition;
    m_initialized = true;
    if ( menu.count > maxItems )
    {
        this->drawScrollIndicators(d, maxItems);
    }
}

#endif