ObjectC&&Swift 渐变色算法实现

来源：互联网发布：windows文档加密编辑：程序博客网时间：2024/05/16 05:45
-(NSArray *)getGradientColorWithStartColor:(UIColor *)startColor endColor:(UIColor *)endColor step:(NSInteger)step inverse:(BOOL)inverse {    //1 get start color rgb    CGFloat startR = 0.0, startG = 0.0, startB = 0.0;    CGColorRef startColorRGB = [startColor CGColor];    NSInteger startNumComponents = CGColorGetNumberOfComponents(startColorRGB);    if (startNumComponents == 4)    {        const CGFloat *components = CGColorGetComponents(startColorRGB);        startR = components[0];        startG = components[1];        startB = components[2];    }    //2 get end color rgb    CGFloat endR = 0.0, endG = 0.0, endB = 0.0;    CGColorRef endColorRGB = [endColor CGColor];    NSInteger endNumComponents = CGColorGetNumberOfComponents(endColorRGB);    if (endNumComponents == 4)    {        const CGFloat *components = CGColorGetComponents(endColorRGB);        endR = components[0];        endG = components[1];        endB = components[2];    }    //3 calculate total threshold by step    CGFloat stepR = 0.0, stepG = 0.0, stepB = 0.0;    stepR = step == 1 ? 0 : (endR-startR) / (step - 1);    stepG = step == 1 ? 0 : (endG-startG) / (step - 1);    stepB = step == 1 ? 0 : (endB-startB) / (step - 1);    //calculate uicolor by step    CGFloat green = startG;    CGFloat red   = startR;    CGFloat blue  = startB;    NSMutableArray *stepColorArray = [[NSMutableArray alloc] initWithCapacity:step];    for (NSInteger i = 0; i < step - 1; i++) {        red   = red + stepR;        green = green + stepG;        blue  = green + stepB;        UIColor *color = [UIColor colorWithRed:red green:green blue:blue alpha:0];        [stepColorArray addObject:color];    }    return stepColorArray;}
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