QT-常用函数参数详解之painter-＞fillRect()，预设值的颜色展示

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项目场景：

在使用qt中的painter直接进行绘制时，有时会用到fillrect进行填充矩形的展示，此函数预设了很多的颜色，在网上我暂时没找到直接能够查看的颜色展示，在此我写一个程序用于直接展示出来，截图在此，方便自己以及有一样需求的人直接查看

代码描述：

通过生成pdf以及保存pdf的方式，直接调用QPdfWriter，QPrinter这两种库，进行编程展示。需要提前引入printsupport的插件（和gui，charts差不多的东西）。最终代码以及展示结果见正文，不想看的也可以直接看结果。（QT5.12.5以上版本才有）

1.fillRect代码和预设值有关的函数

inline void fillRect(int x, int y, int w, int h, QGradient::Preset preset); inline void fillRect(const QRect &r, QGradient::Preset preset); inline void fillRect(const QRectF &r, QGradient::Preset preset); 

2.展示代码

 //设置pdf保存的路径 QString file_path = pdfSaveAs(QString::fromLocal8Bit("展示QGradient预设值")); if(file_path.isEmpty()) return; QFile pdfFile(file_path); pdfFile.open(QIODevice::WriteOnly); QPdfWriter* pWriter = new QPdfWriter(&pdfFile); //Init Page pWriter->setPageSize(QPagedPaintDevice::A4); pWriter->setResolution(300); //设置dpi 每个平方英寸像素为300 pWriter->setPageMargins(QMarginsF(30, 30, 30, 30)); QPainter* pPainter = new QPainter(pWriter); //Painter PDF qDebug() << pPainter->viewport(); int nPDFWidth = pPainter->viewport().width(); int nPDFHeight = pPainter->viewport().height(); //test start int realcolor = 0; int realheight = 0; while (realcolor < 180) { 
     realcolor++; QGradient::Preset a = QGradient::Preset(realcolor); pPainter->fillRect(QRect(0, realheight, nPDFWidth, 100), a); pPainter->setFont(QFont("黑体", 26, 60)); pPainter->drawText(QRect(0, realheight, nPDFWidth, 100), Qt::AlignCenter, QString::fromLocal8Bit("测试预设颜色%1").arg(realcolor)); realheight += 100; if (realheight >= nPDFHeight) { 
     pWriter->newPage(); realheight = 0; } } //test end //绘制完毕 delete pPainter; delete pWriter; pdfFile.close(); //通过其它PDF阅读器来打开PDF QDesktopServices::openUrl(QUrl::fromLocalFile(file_path)); 

结果图展示：

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 };