LVGL：渐变方案-编程知识

仿照qt的QGradient::Preset渐变类型写的，因为lvgl只支持水平/垂直渐变，且只支持两种颜色的渐变，所以有些类型的渐变未能实现，有些则缺少中间颜色。

代码：

namespace Gradient
{
enum Preset
{WarmFlame = 1,NightFade = 2,SpringWarmth = 3,JuicyPeach = 4,YoungPassion = 5,LadyLips = 6,SunnyMorning = 7,RainyAshville = 8,FrozenDreams = 9,WinterNeva = 10,DustyGrass = 11,TemptingAzure = 12,HeavyRain = 13,AmyCrisp = 14,MeanFruit = 15,DeepBlue = 16,RipeMalinka = 17,CloudyKnoxville = 18,MalibuBeach = 19,NewLife = 20,TrueSunset = 21,MorpheusDen = 22,RareWind = 23,NearMoon = 24,WildApple = 25,SaintPetersburg = 26,PlumPlate = 28,EverlastingSky = 29,HappyFisher = 30,Blessing = 31,SharpeyeEagle = 32,LadogaBottom = 33,LemonGate = 34,ItmeoBranding = 35,ZeusMiracle = 36,OldHat = 37,StarWine = 38,HappyAcid = 41,AwesomePine = 42,NewYork = 43,ShyRainbow = 44,MixedHopes = 46,FlyHigh = 47,StrongBliss = 48,FreshMilk = 49,SnowAgain = 50,FebruaryInk = 51,KindSteel = 52,SoftGrass = 53,GrownEarly = 54,SharpBlues = 55,ShadyWater = 56,DirtyBeauty = 57,GreatWhale = 58,TeenNotebook = 59,PoliteRumors = 60,SweetPeriod = 61,WideMatrix = 62,SoftCherish = 63,RedSalvation = 64,BurningSpring = 65,NightParty = 66,SkyGlider = 67,HeavenPeach = 68,PurpleDivision = 69,AquaSplash = 70,SpikyNaga = 72,LoveKiss = 73,CleanMirror = 75,PremiumDark = 76,ColdEvening = 77,CochitiLake = 78,SummerGames = 79,PassionateBed = 80,MountainRock = 81,DesertHump = 82,JungleDay = 83,PhoenixStart = 84,OctoberSilence = 85,FarawayRiver = 86,AlchemistLab = 87,OverSun = 88,PremiumWhite = 89,MarsParty = 90,EternalConstance = 91,JapanBlush = 92,SmilingRain = 93,CloudyApple = 94,BigMango = 95,HealthyWater = 96,AmourAmour = 97,RiskyConcrete = 98,StrongStick = 99,ViciousStance = 100,PaloAlto = 101,HappyMemories = 102,MidnightBloom = 103,Crystalline = 104,PartyBliss = 106,ConfidentCloud = 107,LeCocktail = 108,RiverCity = 109,FrozenBerry = 110,ChildCare = 112,FlyingLemon = 113,NewRetrowave = 114,HiddenJaguar = 115,AboveTheSky = 116,Nega = 117,DenseWater = 118,Seashore = 120,MarbleWall = 121,CheerfulCaramel = 122,NightSky = 123,MagicLake = 124,YoungGrass = 125,ColorfulPeach = 126,GentleCare = 127,PlumBath = 128,HappyUnicorn = 129,AfricanField = 131,SolidStone = 132,OrangeJuice = 133,GlassWater = 134,NorthMiracle = 136,FruitBlend = 137,MillenniumPine = 138,HighFlight = 139,MoleHall = 140,SpaceShift = 142,ForestInei = 143,RoyalGarden = 144,RichMetal = 145,JuicyCake = 146,SmartIndigo = 147,SandStrike = 148,NorseBeauty = 149,AquaGuidance = 150,SunVeggie = 151,SeaLord = 152,BlackSea = 153,GrassShampoo = 154,LandingAircraft = 155,WitchDance = 156,SleeplessNight = 157,AngelCare = 158,CrystalRiver = 159,SoftLipstick = 160,SaltMountain = 161,PerfectWhite = 162,FreshOasis = 163,StrictNovember = 164,MorningSalad = 165,DeepRelief = 166,SeaStrike = 167,NightCall = 168,SupremeSky = 169,LightBlue = 170,MindCrawl = 171,LilyMeadow = 172,SugarLollipop = 173,SweetDessert = 174,MagicRay = 175,TeenParty = 176,FrozenHeat = 177,GagarinView = 178,FabledSunset = 179,PerfectBlue = 180,NumPresets
};void setGradient(Gradient::Preset gradient,lv_draw_rect_dsc_t * rect_dsc);
}void Gradient::setGradient(Preset gradient, lv_draw_rect_dsc_t *rect_dsc)
{std::map<Preset,std::tuple<lv_color_t,lv_color_t,lv_grad_dir_t>> map;map[WarmFlame] = std::make_tuple(lv_color_make(0xff,0x9a,0x9e),lv_color_make(0xfa,0xd0,0xc4),LV_GRAD_DIR_HOR);map[NightFade] = std::make_tuple(lv_color_make(0xfb,0xc2,0xeb),lv_color_make(0xa1,0x8c,0xd1),LV_GRAD_DIR_VER);map[SpringWarmth] = std::make_tuple(lv_color_make(0xff,0xd1,0xff),lv_color_make(0xfa,0xd0,0xc4),LV_GRAD_DIR_VER);map[JuicyPeach] = std::make_tuple(lv_color_make(0xff,0xec,0xd2),lv_color_make(0xfc,0xb6,0x9f),LV_GRAD_DIR_HOR);map[YoungPassion] = std::make_tuple(lv_color_make(0xff,0x81,0x77),lv_color_make(0xb1,0x2a,0x5b),LV_GRAD_DIR_HOR);map[LadyLips] = std::make_tuple(lv_color_make(0xfe,0xcf,0xef),lv_color_make(0xff,0x9a,0x9e),LV_GRAD_DIR_VER);map[SunnyMorning] = std::make_tuple(lv_color_make(0xf6,0xd3,0x65),lv_color_make(0xfd,0xa0,0x85),LV_GRAD_DIR_HOR);map[RainyAshville] = std::make_tuple(lv_color_make(0xa6,0xc1,0xee),lv_color_make(0xfb,0xc2,0xeb),LV_GRAD_DIR_VER);map[FrozenDreams] = std::make_tuple(lv_color_hex(0xe6dee9),lv_color_hex(0xfdcbf1),LV_GRAD_DIR_VER);map[WinterNeva] = std::make_tuple(lv_color_hex(0xa1c4fd),lv_color_hex(0xc2e9fb),LV_GRAD_DIR_HOR);map[DustyGrass] = std::make_tuple(lv_color_hex(0xd4fc79),lv_color_hex(0x96e6a1),LV_GRAD_DIR_HOR);map[TemptingAzure] = std::make_tuple(lv_color_hex(0x84fab0),lv_color_hex(0x8fd3f4),LV_GRAD_DIR_HOR);map[HeavyRain] = std::make_tuple(lv_color_hex(0xe2ebf0),lv_color_hex(0xcfd9df),LV_GRAD_DIR_VER);map[AmyCrisp] = std::make_tuple(lv_color_hex(0xa6c0fe),lv_color_hex(0xf68084),LV_GRAD_DIR_HOR);map[MeanFruit] = std::make_tuple(lv_color_hex(0xfccb90),lv_color_hex(0xd57eeb),LV_GRAD_DIR_HOR);map[DeepBlue] = std::make_tuple(lv_color_hex(0xe0c3fc),lv_color_hex(0x8ec5fc),LV_GRAD_DIR_HOR);map[RipeMalinka] = std::make_tuple(lv_color_hex(0xf093fb),lv_color_hex(0xf5576c),LV_GRAD_DIR_HOR);map[CloudyKnoxville] = std::make_tuple(lv_color_hex(0xfdfbfb),lv_color_hex(0xebedee),LV_GRAD_DIR_HOR);map[MalibuBeach] = std::make_tuple(lv_color_hex(0x4facfe),lv_color_hex(0x00f2fe),LV_GRAD_DIR_HOR);map[NewLife] = std::make_tuple(lv_color_hex(0x38f9d7),lv_color_hex(0x43e97b),LV_GRAD_DIR_HOR);//20map[TrueSunset] = std::make_tuple(lv_color_hex(0xfee140),lv_color_hex(0xfa709a),LV_GRAD_DIR_HOR);map[MorpheusDen] = std::make_tuple(lv_color_hex(0x330867),lv_color_hex(0x30cfd0),LV_GRAD_DIR_VER);map[RareWind] = std::make_tuple(lv_color_hex(0xfed6e3),lv_color_hex(0xa8edea),LV_GRAD_DIR_VER);map[NearMoon] = std::make_tuple(lv_color_hex(0xb490ca),lv_color_hex(0x5ee7df),LV_GRAD_DIR_VER);map[WildApple] = std::make_tuple(lv_color_hex(0xfef9d7),lv_color_hex(0xd299c2),LV_GRAD_DIR_VER);map[SaintPetersburg] = std::make_tuple(lv_color_hex(0xf5f7fa),lv_color_hex(0xc3cfe2),LV_GRAD_DIR_HOR);map[PlumPlate] = std::make_tuple(lv_color_hex(0x667eea),lv_color_hex(0x764ba2),LV_GRAD_DIR_HOR);map[EverlastingSky] = std::make_tuple(lv_color_hex(0xfdfcfb),lv_color_hex(0xe2d1c3),LV_GRAD_DIR_HOR);map[HappyFisher] = std::make_tuple(lv_color_hex(0x89f7fe),lv_color_hex(0x66a6ff),LV_GRAD_DIR_HOR);map[Blessing] = std::make_tuple(lv_color_hex(0xd1fdff),lv_color_hex(0xfddb92),LV_GRAD_DIR_VER);map[SharpeyeEagle] = std::make_tuple(lv_color_hex(0xb1f4cf),lv_color_hex(0x9890e3),LV_GRAD_DIR_VER);map[LadogaBottom] = std::make_tuple(lv_color_hex(0xd9ded8),lv_color_hex(0xebc0fd),LV_GRAD_DIR_VER);map[LemonGate] = std::make_tuple(lv_color_hex(0xf9f586),lv_color_hex(0x96fbc4),LV_GRAD_DIR_VER);map[ItmeoBranding] = std::make_tuple(lv_color_hex(0x2af598),lv_color_hex(0x009efd),LV_GRAD_DIR_VER);map[ZeusMiracle] = std::make_tuple(lv_color_hex(0xf6f3ff),lv_color_hex(0xcd9cf2),LV_GRAD_DIR_VER);//35// map[OldHat] =// map[StarWine] =map[HappyAcid] = std::make_tuple(lv_color_hex(0x72afd3),lv_color_hex(0x37ecba),LV_GRAD_DIR_VER);map[AwesomePine] = std::make_tuple(lv_color_hex(0xcfc7f8),lv_color_hex(0xebbba7),LV_GRAD_DIR_VER);map[NewYork] = std::make_tuple(lv_color_hex(0xace0f9),lv_color_hex(0xfff1eb),LV_GRAD_DIR_VER);// map[ShyRainbow] =map[MixedHopes] = std::make_tuple(lv_color_hex(0xfa71cd),lv_color_hex(0xc471f5),LV_GRAD_DIR_VER);map[FlyHigh] = std::make_tuple(lv_color_hex(0x6f86d6),lv_color_hex(0x48c6ef),LV_GRAD_DIR_VER);// map[StrongBliss] =map[FreshMilk] = std::make_tuple(lv_color_hex(0xf5efef),lv_color_hex(0xfeada6),LV_GRAD_DIR_VER);map[SnowAgain] = std::make_tuple(lv_color_hex(0xeef1f5),lv_color_hex(0xe6e9f0),LV_GRAD_DIR_VER);map[FebruaryInk] = std::make_tuple(lv_color_hex(0xe7f0fd),lv_color_hex(0xaccbee),LV_GRAD_DIR_VER);map[KindSteel] = std::make_tuple(lv_color_hex(0xe9defa),lv_color_hex(0xfbfcdb),LV_GRAD_DIR_HOR);map[SoftGrass] = std::make_tuple(lv_color_hex(0xdeecdd),lv_color_hex(0xc1dfc4),LV_GRAD_DIR_VER);map[GrownEarly] = std::make_tuple(lv_color_hex(0x3cba92),lv_color_hex(0x0ba360),LV_GRAD_DIR_VER);map[SharpBlues] = std::make_tuple(lv_color_hex(0x005bea),lv_color_hex(0x00c6fb),LV_GRAD_DIR_VER);map[ShadyWater] = std::make_tuple(lv_color_hex(0x74ebd5),lv_color_hex(0x9face6),LV_GRAD_DIR_HOR);map[DirtyBeauty] = std::make_tuple(lv_color_hex(0xbac8e0),lv_color_hex(0x6a85b6),LV_GRAD_DIR_VER);map[GreatWhale] = std::make_tuple(lv_color_hex(0x6991c7),lv_color_hex(0xa3bded),LV_GRAD_DIR_VER);map[TeenNotebook] = std::make_tuple(lv_color_hex(0xfbc8d4),lv_color_hex(0x9795f0),LV_GRAD_DIR_VER);map[PoliteRumors] = std::make_tuple(lv_color_hex(0x8989ba),lv_color_hex(0xa7a6cb),LV_GRAD_DIR_VER);// map[SweetPeriod] =// map[WideMatrix] =// map[SoftCherish] =map[RedSalvation] = std::make_tuple(lv_color_hex(0x453a94),lv_color_hex(0xf43b47),LV_GRAD_DIR_VER);// map[BurningSpring] =map[NightParty] = std::make_tuple(lv_color_hex(0xd43f8d),lv_color_hex(0x0250c5),LV_GRAD_DIR_VER);map[SkyGlider] = std::make_tuple(lv_color_hex(0x6e45e2),lv_color_hex(0x88d3ce),LV_GRAD_DIR_VER);map[HeavenPeach] = std::make_tuple(lv_color_hex(0x97d9e1),lv_color_hex(0xd9afd9),LV_GRAD_DIR_VER);map[PurpleDivision] = std::make_tuple(lv_color_hex(0xe5b2ca),lv_color_hex(0x7028e4),LV_GRAD_DIR_VER);map[AquaSplash] = std::make_tuple(lv_color_hex(0x13547a),lv_color_hex(0x80d0c7),LV_GRAD_DIR_HOR);// map[SpikyNaga] =map[LoveKiss] = std::make_tuple(lv_color_hex(0xffb199),lv_color_hex(0xff0844),LV_GRAD_DIR_VER);map[CleanMirror] = std::make_tuple(lv_color_hex(0x93a5cf),lv_color_hex(0xe4efe9),LV_GRAD_DIR_HOR);map[PremiumDark] = std::make_tuple(lv_color_hex(0x434343),lv_color_hex(0x000000),LV_GRAD_DIR_HOR);map[ColdEvening] = std::make_tuple(lv_color_hex(0xa2b6df),lv_color_hex(0x0c3483),LV_GRAD_DIR_VER);map[CochitiLake] = std::make_tuple(lv_color_hex(0x93a5cf),lv_color_hex(0xe4efe9),LV_GRAD_DIR_HOR);map[SummerGames] = std::make_tuple(lv_color_hex(0x92fe9d),lv_color_hex(0x00c9ff),LV_GRAD_DIR_HOR);map[PassionateBed] = std::make_tuple(lv_color_hex(0xff758c),lv_color_hex(0xff7eb3),LV_GRAD_DIR_HOR);map[MountainRock] = std::make_tuple(lv_color_hex(0x868f96),lv_color_hex(0x596164),LV_GRAD_DIR_HOR);map[DesertHump] = std::make_tuple(lv_color_hex(0xdfa579),lv_color_hex(0xc79081),LV_GRAD_DIR_VER);map[JungleDay] = std::make_tuple(lv_color_hex(0x8baaaa),lv_color_hex(0xae8b9c),LV_GRAD_DIR_HOR);map[PhoenixStart] = std::make_tuple(lv_color_hex(0xf83600),lv_color_hex(0xf9d423),LV_GRAD_DIR_HOR);map[OctoberSilence] = std::make_tuple(lv_color_hex(0xb721ff),lv_color_hex(0x21d4fd),LV_GRAD_DIR_HOR);map[FarawayRiver] = std::make_tuple(lv_color_hex(0x6e45e2),lv_color_hex(0x88d3ce),LV_GRAD_DIR_HOR);map[AlchemistLab] = std::make_tuple(lv_color_hex(0xd558c8),lv_color_hex(0x24d292),LV_GRAD_DIR_HOR);map[OverSun] = std::make_tuple(lv_color_hex(0xabecd6),lv_color_hex(0xfbed96),LV_GRAD_DIR_HOR);// map[PremiumWhite] =map[MarsParty] = std::make_tuple(lv_color_hex(0x9b23ea),lv_color_hex(0x5f72bd),LV_GRAD_DIR_VER);map[EternalConstance] = std::make_tuple(lv_color_hex(0x537895),lv_color_hex(0x09203f),LV_GRAD_DIR_VER);map[JapanBlush] = std::make_tuple(lv_color_hex(0xddd6f3),lv_color_hex(0xfaaca8),LV_GRAD_DIR_HOR);map[SmilingRain] = std::make_tuple(lv_color_hex(0xdcb0ed),lv_color_hex(0x99c99c),LV_GRAD_DIR_HOR);map[CloudyApple] = std::make_tuple(lv_color_hex(0xe3eeff),lv_color_hex(0xf3e7e9),LV_GRAD_DIR_VER);map[BigMango] = std::make_tuple(lv_color_hex(0xd09693),lv_color_hex(0xc71d6f),LV_GRAD_DIR_VER);map[HealthyWater] = std::make_tuple(lv_color_hex(0x96deda),lv_color_hex(0x50c9c3),LV_GRAD_DIR_HOR);map[AmourAmour] = std::make_tuple(lv_color_hex(0xfe5196),lv_color_hex(0xf77062),LV_GRAD_DIR_VER);map[RiskyConcrete] = std::make_tuple(lv_color_hex(0xebebeb),lv_color_hex(0xc4c5c7),LV_GRAD_DIR_VER);map[StrongStick] = std::make_tuple(lv_color_hex(0xa8caba),lv_color_hex(0x5d4157),LV_GRAD_DIR_HOR);map[ViciousStance] = std::make_tuple(lv_color_hex(0x29323c),lv_color_hex(0x485563),LV_GRAD_DIR_HOR);map[PaloAlto] = std::make_tuple(lv_color_hex(0xf4d03f),lv_color_hex(0x16a085),LV_GRAD_DIR_HOR);map[HappyMemories] = std::make_tuple(lv_color_hex(0xf09819),lv_color_hex(0xff5858),LV_GRAD_DIR_HOR);map[MidnightBloom] = std::make_tuple(lv_color_hex(0x4e4376),lv_color_hex(0x2b5876),LV_GRAD_DIR_HOR);map[Crystalline] = std::make_tuple(lv_color_hex(0x8ddad5),lv_color_hex(0x00cdac),LV_GRAD_DIR_HOR);map[PartyBliss] = std::make_tuple(lv_color_hex(0x04befe),lv_color_hex(0x4481eb),LV_GRAD_DIR_VER);map[ConfidentCloud] = std::make_tuple(lv_color_hex(0xf3e7e9),lv_color_hex(0xdad4ec),LV_GRAD_DIR_VER);map[LeCocktail] = std::make_tuple(lv_color_hex(0x874da2),lv_color_hex(0xc43a30),LV_GRAD_DIR_HOR);map[RiverCity] = std::make_tuple(lv_color_hex(0x04befe),lv_color_hex(0x4481eb),LV_GRAD_DIR_VER);map[FrozenBerry] = std::make_tuple(lv_color_hex(0xc7eafd),lv_color_hex(0xe8198b),LV_GRAD_DIR_VER);map[ChildCare] = std::make_tuple(lv_color_hex(0xfdd6bd),lv_color_hex(0xf794a4),LV_GRAD_DIR_HOR);map[FlyingLemon] = std::make_tuple(lv_color_hex(0x64b3f4),lv_color_hex(0xc2e59c),LV_GRAD_DIR_HOR);map[NewRetrowave] = std::make_tuple(lv_color_hex(0xa981bb),lv_color_hex(0x3b41c5),LV_GRAD_DIR_VER);map[HiddenJaguar] = std::make_tuple(lv_color_hex(0xf9f047),lv_color_hex(0x0fd850),LV_GRAD_DIR_VER);// map[AboveTheSky] =map[Nega] = std::make_tuple(lv_color_hex(0xee9ca7),lv_color_hex(0xffdde1),LV_GRAD_DIR_HOR);map[DenseWater] = std::make_tuple(lv_color_hex(0x3ab5b0),lv_color_hex(0x56317a),LV_GRAD_DIR_HOR);map[Seashore] = std::make_tuple(lv_color_hex(0x68e0cf),lv_color_hex(0x209cff),LV_GRAD_DIR_VER);map[MarbleWall] = std::make_tuple(lv_color_hex(0xe6dee9),lv_color_hex(0xbdc2e8),LV_GRAD_DIR_VER);map[CheerfulCaramel] = std::make_tuple(lv_color_hex(0xeacda3),lv_color_hex(0xe6b980),LV_GRAD_DIR_VER);map[NightSky] = std::make_tuple(lv_color_hex(0x2a5298),lv_color_hex(0x1e3c72),LV_GRAD_DIR_VER);map[MagicLake] = std::make_tuple(lv_color_hex(0xc9ffbf),lv_color_hex(0xffafbd),LV_GRAD_DIR_VER);map[YoungGrass] = std::make_tuple(lv_color_hex(0x00e3ae),lv_color_hex(0x9be15d),LV_GRAD_DIR_VER);map[ColorfulPeach] = std::make_tuple(lv_color_hex(0xed6ea0),lv_color_hex(0xec8c69),LV_GRAD_DIR_HOR);map[GentleCare] = std::make_tuple(lv_color_hex(0xffc3a0),lv_color_hex(0xffafbd),LV_GRAD_DIR_HOR);map[PlumBath] = std::make_tuple(lv_color_hex(0x6713d2),lv_color_hex(0xcc208e),LV_GRAD_DIR_VER);map[HappyUnicorn] = std::make_tuple(lv_color_hex(0x12fff7),lv_color_hex(0xb3ffab),LV_GRAD_DIR_VER);map[AfricanField] = std::make_tuple(lv_color_hex(0xFF6B95),lv_color_hex(0xFFC796),LV_GRAD_DIR_HOR);map[SolidStone] = std::make_tuple(lv_color_hex(0x243949),lv_color_hex(0x517fa4),LV_GRAD_DIR_HOR);map[OrangeJuice] = std::make_tuple(lv_color_hex(0xff9a44),lv_color_hex(0xfc6076),LV_GRAD_DIR_VER);map[GlassWater] = std::make_tuple(lv_color_hex(0xffffff),lv_color_hex(0xdfe9f3),LV_GRAD_DIR_VER);map[NorthMiracle] = std::make_tuple(lv_color_hex(0x00dbde),lv_color_hex(0xfc00ff),LV_GRAD_DIR_HOR);map[FruitBlend] = std::make_tuple(lv_color_hex(0xf9d423),lv_color_hex(0xff4e50),LV_GRAD_DIR_HOR);map[MillenniumPine] = std::make_tuple(lv_color_hex(0xf5d100),lv_color_hex(0x50cc7f),LV_GRAD_DIR_VER);map[HighFlight] = std::make_tuple(lv_color_hex(0x0acffe),lv_color_hex(0x495aff),LV_GRAD_DIR_HOR);map[MoleHall] = std::make_tuple(lv_color_hex(0x9bc5c3),lv_color_hex(0x616161),LV_GRAD_DIR_HOR);// map[SpaceShift] =map[ForestInei] = std::make_tuple(lv_color_hex(0xbfd9fe),lv_color_hex(0xdf89b5),LV_GRAD_DIR_VER);map[RoyalGarden] = std::make_tuple(lv_color_hex(0xed6ea0),lv_color_hex(0xec8c69),LV_GRAD_DIR_HOR);map[RichMetal] = std::make_tuple(lv_color_hex(0xd7d2cc),lv_color_hex(0x304352),LV_GRAD_DIR_HOR);map[JuicyCake] = std::make_tuple(lv_color_hex(0xf9d423),lv_color_hex(0xe14fad),LV_GRAD_DIR_VER);map[SmartIndigo] = std::make_tuple(lv_color_hex(0x7579ff),lv_color_hex(0xb224ef),LV_GRAD_DIR_VER);map[SandStrike] = std::make_tuple(lv_color_hex(0xc1c161),lv_color_hex(0xd4d4b1),LV_GRAD_DIR_HOR);map[NorseBeauty] = std::make_tuple(lv_color_hex(0xec77ab),lv_color_hex(0x7873f5),LV_GRAD_DIR_HOR);map[AquaGuidance] = std::make_tuple(lv_color_hex(0x00ecbc),lv_color_hex(0x007adf),LV_GRAD_DIR_VER);map[SunVeggie] = std::make_tuple(lv_color_hex(0x20E2D7),lv_color_hex(0xF9FEA5),LV_GRAD_DIR_HOR);// map[SeaLord] =// map[BlackSea] =map[GrassShampoo] = std::make_tuple(lv_color_hex(0xDFFFCD),lv_color_hex(0x39F3BB),LV_GRAD_DIR_HOR);// map[LandingAircraft] =map[WitchDance] = std::make_tuple(lv_color_hex(0xA8BFFF),lv_color_hex(0x884D80),LV_GRAD_DIR_HOR);map[SleeplessNight] = std::make_tuple(lv_color_hex(0x5271C4),lv_color_hex(0xECA1FE),LV_GRAD_DIR_HOR);map[AngelCare] = std::make_tuple(lv_color_hex(0xFFE29F),lv_color_hex(0xFF719A),LV_GRAD_DIR_HOR);map[CrystalRiver] = std::make_tuple(lv_color_hex(0x22E1FF),lv_color_hex(0x625EB1),LV_GRAD_DIR_HOR);map[SoftLipstick] = std::make_tuple(lv_color_hex(0xB6CEE8),lv_color_hex(0xF578DC),LV_GRAD_DIR_HOR);map[SaltMountain] = std::make_tuple(lv_color_hex(0xFFFEFF),lv_color_hex(0xD7FFFE),LV_GRAD_DIR_HOR);map[PerfectWhite] = std::make_tuple(lv_color_hex(0xE3FDF5),lv_color_hex(0xFFE6FA),LV_GRAD_DIR_HOR);map[FreshOasis] = std::make_tuple(lv_color_hex(0x7DE2FC),lv_color_hex(0xB9B6E5),LV_GRAD_DIR_HOR);map[StrictNovember] = std::make_tuple(lv_color_hex(0xCBBACC),lv_color_hex(0x2580B3),LV_GRAD_DIR_HOR);map[MorningSalad] = std::make_tuple(lv_color_hex(0xB7F8DB),lv_color_hex(0x50A7C2),LV_GRAD_DIR_HOR);map[DeepRelief] = std::make_tuple(lv_color_hex(0x7085B6),lv_color_hex(0xDEF3F8),LV_GRAD_DIR_HOR);// map[SeaStrike] =map[NightCall] = std::make_tuple(lv_color_hex(0xAC32E4),lv_color_hex(0x4801FF),LV_GRAD_DIR_HOR);map[SupremeSky] = std::make_tuple(lv_color_hex(0xD4FFEC),lv_color_hex(0x4596FB),LV_GRAD_DIR_HOR);map[LightBlue] = std::make_tuple(lv_color_hex(0x9EFBD3),lv_color_hex(0x45D4FB),LV_GRAD_DIR_HOR);map[MindCrawl] = std::make_tuple(lv_color_hex(0x473B7B),lv_color_hex(0x30D2BE),LV_GRAD_DIR_HOR);map[LilyMeadow] = std::make_tuple(lv_color_hex(0x65379B),lv_color_hex(0x6457C6),LV_GRAD_DIR_HOR);map[SugarLollipop] = std::make_tuple(lv_color_hex(0xA445B2),lv_color_hex(0xFF0066),LV_GRAD_DIR_HOR);map[SweetDessert] = std::make_tuple(lv_color_hex(0x7742B2),lv_color_hex(0xFD8BD9),LV_GRAD_DIR_HOR);map[MagicRay] = std::make_tuple(lv_color_hex(0xFF3CAC),lv_color_hex(0x2B86C5),LV_GRAD_DIR_HOR);map[TeenParty] = std::make_tuple(lv_color_hex(0xFF057C),lv_color_hex(0x321575),LV_GRAD_DIR_HOR);map[FrozenHeat] = std::make_tuple(lv_color_hex(0xFF057C),lv_color_hex(0x4CC3FF),LV_GRAD_DIR_HOR);// map[GagarinView] =// map[FabledSunset] =map[PerfectBlue] = std::make_tuple(lv_color_hex(0x3D4E81),lv_color_hex(0x6E7FF3),LV_GRAD_DIR_HOR);auto it = map.find(gradient);if (it == map.end()){rect_dsc->bg_color = lv_color_hex(0xFFFFFF);rect_dsc->bg_grad_color = lv_color_hex(0xFFFFFF);rect_dsc->bg_grad_dir = LV_GRAD_DIR_HOR;}else{auto tuple = map[gradient];rect_dsc->bg_color = std::get<0>(tuple);rect_dsc->bg_grad_color = std::get<1>(tuple);rect_dsc->bg_grad_dir = std::get<2>(tuple);}
}

使用示例：

int main(int argc, char **argv)
{lv_init();hal_init();lv_log_register_print_cb(esp32_log_cb);lv_obj_t * page = lv_canvas_create(lv_scr_act());lv_obj_set_size(page, LV_HOR_RES, LV_VER_RES);       //设置为屏幕大小lv_coord_t canvas_width = LV_HOR_RES;lv_coord_t canvas_height = LV_VER_RES;lv_img_cf_t color_format = LV_IMG_CF_TRUE_COLOR ; // ARGB8888格式size_t buffer_size = lv_img_cf_get_px_size(color_format) * canvas_width / 8 * canvas_height;std::unique_ptr<unsigned char[]> buffer = std::make_unique<unsigned char[]>(buffer_size);lv_canvas_set_buffer(page, buffer.get(), canvas_width, canvas_height, color_format);lv_draw_rect_dsc_t rect_dsc;lv_draw_rect_dsc_init(&rect_dsc);// 初始化矩形样式描述符Gradient::Preset set = Gradient::SoftLipstick;Gradient::setGradient(set,&rect_dsc);lv_canvas_draw_rect(page, 0, 0, LV_HOR_RES, LV_VER_RES, &rect_dsc);// 在Canvas上绘制一个矩形while (1){lv_timer_handler();usleep(5 * 1000);}return 0;
}