checkbox_menu.h

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/*
    MIT License

    Copyright (c) 2020,2022,2025 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_CHECKBOX_MENU_H_
#define _LCDGFX_CHECKBOX_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 LcdGfxCheckboxMenu
{
public:
    LcdGfxCheckboxMenu(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();

    void toggle();

    bool isChecked(uint8_t index);

    void setChecked(uint8_t index, bool checked);

    uint16_t checkedMask();

    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;
        }
    }

private:
    SAppMenu menu;
    uint16_t m_checked;
    uint16_t m_oldChecked = 0;
    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)
    {
        lcduint_t fh = d.getFont().getHeader().height;
        lcdint_t item_top = 8 + menu.top + (index - menu.scrollPosition) * fh;

        // Checkbox box size scales with font
        lcduint_t boxSize = (fh >= 12) ? 7 : 5;
        lcdint_t boxX = menu.left + 6;
        lcdint_t boxY = item_top + (fh - boxSize) / 2;
        lcdint_t textX = boxX + boxSize + 3;

        // Clear the small checkbox area (so a previous filled box gets
        // wiped on toggle / scroll) and the trailing area beyond the
        // label. printFixed repaints the cells under the new text itself.
        uint16_t fg = d.getColor();
        d.setColor(0x0000);
        d.fillRect(menu.left + 5, item_top, textX - 1, item_top + fh - 1);

        // Checkbox box: drawn with the current (non-inverted) colors so
        // it stays visible on the highlighted row.
        d.setColor(fg);
        if ( m_checked & (1u << index) )
        {
            d.fillRect(boxX, boxY, boxX + boxSize - 1, boxY + boxSize - 1);
        }
        else
        {
            d.drawRect(boxX, boxY, boxX + boxSize - 1, boxY + boxSize - 1);
        }

        // Text strip: invert only here so the highlight bar covers just
        // the label, not the checkbox. printFixed + trailing fillRect
        // handles leftover characters from a longer previous label.
        if ( index == menu.selection )
        {
            d.invertColors();
        }
        uint16_t textColor = d.getColor();
        d.setColor(0x0000);
        d.fillRect(textX + d.getFont().getTextSize(menu.items[index]), item_top,
                   menu.width + menu.left - 9, item_top + fh - 1);
        d.setColor(textColor);
        d.printFixed(textX, 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 is the sole overflow indicator. It
        // lives entirely in page-aligned item rows so partial fillRect for
        // the thumb is safe even on SSD1306-style 1bpp drivers.
        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 LcdGfxCheckboxMenu::show(D &d)
{
    updateSize(d);
    uint8_t maxItems = getMaxScreenItems(d);
    uint8_t newScroll = this->calculateScrollPosition(d, menu.selection);

    // Incremental fast path: only the selection moved within the visible
    // window and/or some checkbox bits flipped — repaint just the affected
    // page-aligned rows.
    if ( m_initialized && newScroll == m_oldScrollPosition )
    {
        menu.scrollPosition = newScroll;
        uint16_t changedCheck = m_checked ^ m_oldChecked;
        if ( menu.selection == menu.oldSelection && changedCheck == 0 )
        {
            return;
        }
        if ( menu.oldSelection != menu.selection )
        {
            this->drawMenuItem(d, menu.oldSelection);
            this->drawMenuItem(d, menu.selection);
        }
        else if ( changedCheck & (1u << menu.selection) )
        {
            // Selection didn't move, but its checkbox was toggled —
            // redraw it so the user sees the change immediately.
            this->drawMenuItem(d, menu.selection);
        }
        // Redraw any other on-screen item whose checked-state flipped.
        for ( uint8_t i = menu.scrollPosition; i < lcd_gfx_min(menu.count, (menu.scrollPosition + maxItems)); i++ )
        {
            if ( (changedCheck & (1u << i)) && i != menu.selection && i != menu.oldSelection )
            {
                this->drawMenuItem(d, i);
            }
        }
        menu.oldSelection = menu.selection;
        m_oldChecked = m_checked;
        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_oldChecked = m_checked;
    m_initialized = true;
    if ( menu.count > maxItems )
    {
        this->drawScrollIndicators(d, maxItems);
    }
}

#endif