libili9341怎么用micropython编写Positive Gamma Correction

在使用libili9341驱动液晶屏时，可以通过以下步骤实现Positive Gamma Correction：

1. 定义Gamma校正表：在代码中定义一个包含Gamma校正表的列表，其中每个元素对应于输入像素值的Gamma校正输出值。例如，以下代码定义了一个Gamma校正表，将输入像素值从0到255依次映射到0到4095的值：

GAMMA_TABLE = (
    0, 8, 16, 25, 33, 41, 50, 58, 66, 75, 83, 91, 100, 108, 116, 125,
    133, 141, 150, 158, 166, 175, 183, 191, 200, 208, 216, 225, 233, 241, 250, 258,
    266, 275, 283, 291, 300, 308, 316, 325, 333, 341, 350, 358, 366, 375, 383, 391,
    400, 408, 416, 425, 433, 441, 450, 458, 466, 475, 483, 491, 500, 508, 516, 525,
    533, 541, 550, 558, 566, 575, 583, 591, 600, 608, 616, 625, 633, 641, 650, 658,
    666, 675, 683, 691, 700, 708, 716, 725, 733, 741, 750, 758, 766, 775, 783, 791,
    800, 808, 816, 825, 833, 841, 850, 858, 866, 875, 883, 891, 900, 908, 916, 925,
    933, 941, 950, 958, 966, 975, 983, 991, 1000, 1008, 1016, 1025, 1033, 1041, 1050, 1058,
    1066, 1075, 1083, 1091, 1100, 1108, 1116, 1125, 1133, 1141, 1150, 1158, 1166, 1175, 1183, 1191,
    1200, 1208, 1216, 1225, 1233, 1241, 1250, 1258, 1266, 1275, 1283, 1291, 1300, 1308, 1316, 1325,
    1333, 1341, 1350, 1358, 1366, 1375, 1383, 1391, 1400, 1408, 1416, 1425, 1433, 1441, 1450, 1458,
    1466, 1475, 1483, 1491, 1500, 1508, 1516, 1525, 1533, 1541, 1550, 1558, 1566, 1575, 1583, 1591,
    1600, 1608, 1616, 1625, 1633, 1641, 1650, 1658, 1666, 1675, 1683, 1691, 1700, 1708, 1716, 1725,
    1733, 1741, 1750, 1758, 1766, 1775, 1783, 1791, 1800, 1808, 1816, 1825, 1833, 1841, 1850, 1858,
    1866, 1875, 1883, 1891, 1900, 1908, 1916, 1925, 1933, 1941, 1950, 1958, 1966, 1975, 1983, 1991,
    2000, 2008, 2016, 2025, 2033, 2041, 2050, 2058, 2066, 2075, 2083, 2091, 2100, 2108, 2116, 2125,
    2133, 2141, 2150, 2158, 2166, 2175, 2183, 2191, 2200, 2208, 2216, 2225, 2233, 2241, 2250, 2258,
    2266, 2275, 2283, 2291, 2300, 2308, 2316, 2325, 2333, 2341, 2350, 2358, 2366, 2375, 2383, 2391,
    2400, 2408, 2416, 2425, 2433, 2441, 2450, 2458, 2466, 2475, 2483, 2491, 2500, 2508, 2516, 2525,
    2533, 2541, 2550, 2558, 2566, 2575, 2583, 2591, 2600, 2608, 2616, 2625, 2633, 2641, 2650, 2658,
    2666, 2675, 2683, 2691, 2700, 2708, 2716, 2725, 2733, 2741, 2750, 2758, 2766, 2775, 2783, 2791,
    2800, 2808, 2816, 2825, 2833, 2841, 2850, 2858, 2866, 2875, 2883, 2891, 2900, 2908, 2916, 2925,
    2933, 2941, 2950, 2958, 2966, 2975, 2983, 2991, 3000, 3008, 3016, 3025, 3033, 3041, 3050, 3058,
    3066, 3075, 3083, 3091, 3100, 3108, 3116, 3125, 3133, 3141, 3150, 3158, 3166, 3175, 3183, 3191,
    3200, 3208, 3216, 3225, 3233, 3241, 3250, 3258, 3266, 3275, 3283, 3291, 3300, 3308, 3316, 3325,
    3333, 3341, 3350, 3358, 3366, 3375, 3383, 3391, 3400, 3408, 3416, 3425, 3433, 3441, 3450, 3458,
    3466, 3475, 3483, 3491, 3500, 3508, 3516, 3525, 3533, 3541, 3550, 3558, 3566, 3575, 3583, 3591,
    3600, 3608, 3616, 3625, 3633, 3641, 3650, 3658, 3666, 3675, 3683, 3691, 3700, 3708, 3716, 3725,
    3733, 3741, 3750, 3758, 3766, 3775, 3783, 3791, 3800, 3808, 3816, 3825, 3833, 3841, 3850, 3858,
    3866, 3875, 3883, 3891, 3900, 3908, 3916, 3925, 3933, 3941, 3950, 3958, 3966, 3975, 3983, 3991,
    4000, 4008, 4016, 4025, 4033, 4041, 4050, 4058, 4066, 4075, 4083, 4091
)

2. 读取像素值：使用libili9341库中的read_pixel()方法读取像素值。例如，以下代码将从液晶屏的(0, 0)位置读取一个像素：

from ili9341 import ili9341

# 初始化液晶屏
lcd = ili9341()

# 读取像素值
x = 0
y = 0
pixel_value = lcd.read_pixel(x, y)

3. Gamma校正：使用Gamma校正表将读取的像素值映射到Gamma校正后的输出值。例如，以下代码将读取的像素值进行Gamma校正，并将校正后的值写回液晶屏：

from ili9341 import ili9341

# 定义Gamma校正表
GAMMA_TABLE = (
    # ...
)

# 初始化液晶屏
lcd = ili9341()

# 读取像素值
x = 0
y = 0
pixel_value = lcd.read_pixel(x, y)

# 进行Gamma校正
gamma_value = GAMMA_TABLE[pixel_value]

# 将校正后的值写回液晶屏
lcd.draw_pixel(x, y, gamma_value)

通过以上步骤，即可在使用libili9341库驱动液晶屏时实现Positive Gamma Correction。需要注意的是，Gamma校正表的定义需要根据具体的应用场景进行调整，以获得最佳的Gamma校正效果。