slider.h

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/*
    MIT License

    Copyright (c) 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_SLIDER_H_
#define _LCDGFX_SLIDER_H_

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

enum class LcdGfxSliderOrientation
{
    Horizontal,
    Vertical,
};

class LcdGfxSlider
{
public:
    LcdGfxSlider(const NanoRect &rect, int16_t minValue, int16_t maxValue, int16_t value, int16_t step = 1,
                 LcdGfxSliderOrientation orientation = LcdGfxSliderOrientation::Horizontal);

    template <typename D> void show(D &d)
    {
        uint16_t color = d.getColor();
        if ( m_orientation == LcdGfxSliderOrientation::Horizontal )
        {
            // Find a page (8-row band) strictly between the top and bottom
            // border rows. The 3 fillRects (black-left, knob, black-right)
            // all live in this single page — full-byte writes per column —
            // so the border lines (in other pages) are never touched.
            const lcdint_t kPage = 8;
            lcdint_t bandTop = (m_rect.p1.y + kPage) & ~(kPage - 1);
            lcdint_t bandBot = (m_rect.p2.y & ~(kPage - 1)) - 1;
            if ( bandBot < bandTop || bandBot >= m_rect.p2.y )
            {
                bandTop = m_rect.p1.y + 1;
                bandBot = m_rect.p2.y - 1;
            }
            lcdint_t innerLeft = m_rect.p1.x + 1;
            lcdint_t innerRight = m_rect.p2.x - 1;
            lcdint_t innerW = innerRight - innerLeft - 2;
            if ( innerW < 1 ) innerW = 1;
            lcdint_t span = m_max - m_min;
            lcdint_t knobX = innerLeft + 1 + (span > 0 ? (lcdint_t)(((int32_t)(m_value - m_min) * innerW) / span) : 0);
            lcdint_t knobW = bandBot - bandTop + 1;
            lcdint_t knobL = knobX - knobW / 2;
            lcdint_t knobR = knobL + knobW - 1;
            if ( knobL < innerLeft ) { knobL = innerLeft; knobR = knobL + knobW - 1; }
            if ( knobR > innerRight ) { knobR = innerRight; knobL = knobR - knobW + 1; if ( knobL < innerLeft ) knobL = innerLeft; }

            d.setColor(0x0000);
            if ( knobL > innerLeft )
            {
                d.fillRect(innerLeft, bandTop, knobL - 1, bandBot);
            }
            if ( knobR < innerRight )
            {
                d.fillRect(knobR + 1, bandTop, innerRight, bandBot);
            }
            d.setColor(color);
            d.fillRect(knobL, bandTop, knobR, bandBot);
        }
        else
        {
            lcdint_t innerLeft = m_rect.p1.x + 1;
            lcdint_t innerRight = m_rect.p2.x - 1;
            lcdint_t innerTop = m_rect.p1.y + 1;
            lcdint_t innerBot = m_rect.p2.y - 1;
            lcdint_t innerH = innerBot - innerTop - 2;
            if ( innerH < 1 ) innerH = 1;
            lcdint_t span = m_max - m_min;
            lcdint_t knobY = innerTop + 1 + (span > 0 ? (lcdint_t)(((int32_t)(m_value - m_min) * innerH) / span) : 0);
            lcdint_t knobW = innerRight - innerLeft + 1;
            lcdint_t knobH = knobW;
            if ( knobH < 4 ) knobH = 4;
            lcdint_t knobT = knobY - knobH / 2;
            lcdint_t knobB = knobT + knobH - 1;
            if ( knobT < innerTop ) { knobT = innerTop; knobB = knobT + knobH - 1; }
            if ( knobB > innerBot ) { knobB = innerBot; knobT = knobB - knobH + 1; if ( knobT < innerTop ) knobT = innerTop; }

            d.setColor(0x0000);
            if ( knobT > innerTop )
            {
                d.fillRect(innerLeft, innerTop, innerRight, knobT - 1);
            }
            if ( knobB < innerBot )
            {
                d.fillRect(innerLeft, knobB + 1, innerRight, innerBot);
            }
            d.setColor(color);
            d.fillRect(innerLeft, knobT, innerRight, knobB);
        }
        d.drawRect(m_rect);
    }

    void up();

    void down();

    void setValue(int16_t value);

    int16_t value() const
    {
        return m_value;
    }

    int16_t minValue() const
    {
        return m_min;
    }

    int16_t maxValue() const
    {
        return m_max;
    }

    const NanoRect &getRect() const
    {
        return m_rect;
    }

private:
    NanoRect m_rect;
    int16_t m_min;
    int16_t m_max;
    int16_t m_value;
    int16_t m_step;
    LcdGfxSliderOrientation m_orientation;
};

#endif