reflower/main/scenes/scene_menu.c

#include <malloc.h>
#include <graphics/bitmaps.h>
#include <sys/param.h>
#include <stdbool.h>
#include <liquid/input_event.h>

#include "liquid.h"
#include "graphics/drawing.h"

#include "scene_menu.h"

static void paint(struct MenuScene *self)
{
    LCD_clearDisplay(0);

    int row = 0;
    for (int i = self->scroll_up; i < MIN(self->items_len, self->scroll_up + 6); i++, row++) {
        bool selected = self->selected==i;
        LCD_setStrEx(self->items[i].label, 0, row * 8, selected?WHITE:BLACK,FONT_NORMAL|(selected?FONT_BG:0));
    }
}

static struct SceneEvent onInput(struct MenuScene *self, struct InputEvent event) {
    switch (event.kind) {
        case InputEventKind_Wheel:;
            self->selected += event.wheel.direction;
            if (self->selected < 0) {
                self->selected = 0;
            }
            else if (self->selected >= self->items_len) {
                self->selected = self->items_len - 1;
            }

            // hacky scroll adjust
            while (self->selected - self->scroll_up < 1 && self->scroll_up > 0) {
                self->scroll_up--;
            }

            while (self->selected - self->scroll_up >= 5 && self->scroll_up < self->items_len - 6) {
                self->scroll_up++;
            }

            return SceneEvent_Repaint();

        case InputEventKind_Button:
            if (event.button.state) {
                if (self->onSelect) {
                    return self->onSelect(self);
                }
                return SceneEvent_Close(0, NULL);
            }
            // fall through
        default:
            return SceneEvent_None();
    }
}

struct MenuScene *NewScene_Menu(struct MenuItem *items, size_t items_len) {
    struct MenuScene *scene = calloc(1, sizeof(struct MenuScene));

    scene->base.paint = (Scene_paint_t) paint;
    scene->base.onInput = (Scene_onInput_t) onInput;

    scene->items = items;
    scene->items_len = items_len;

    return scene;
}