iOS绘制效果界面

iOS绘制效果界面

 

我们除了平时来扩展单色背景图方式来减小图片，还可以用iOS自带的类库同样能做出好的背景，可以大大缩小软件的大小。下面是做出的效果

以3.5寸屏为例，大小可以自己控制

直接贴代码吧：

①底部上下渐变效果背景

    CGRect frame = _entranceFunViewController.view.frame;

    

    backgroundImageView = [[UIImageViewalloc]initWithFrame:frame];

    UIGraphicsBeginImageContext(backgroundImageView.frame.size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGColorSpaceRef rgb = CGColorSpaceCreateDeviceRGB();

    CGContextScaleCTM(context, frame.size.width , frame.size.height);

    CGFloat colors[] =

    {

        253.0/255.0, 163.0/255.0, 87.0/255.0, 1.0,

        253.0/255.0, 163.0/255.0, 87.0/255.0, 0.0,

    };

    CGGradientRef backGradient = CGGradientCreateWithColorComponents

    (rgb, colors, NULL, sizeof(colors)/(sizeof(colors[0])*4));

    CGColorSpaceRelease(rgb);

    CGContextDrawLinearGradient(context,

                                backGradient,

                                CGPointMake(0.5, 0), CGPointMake(0.5, 1),

                                kCGGradientDrawsBeforeStartLocation);

    backgroundImageView.image = UIGraphicsGetImageFromCurrentImageContext();

②上部发散球效果

 //球形扩散图

    clearCircleImageView = [[UIImageViewalloc]initWithFrame:CGRectMake(0, 0, frame.size.width, frame.size.height)];

    UIGraphicsBeginImageContext(clearCircleImageView.frame.size);

    CGContextRef clearCircleContext = UIGraphicsGetCurrentContext();

    CGColorSpaceRef clearCircleRGB = CGColorSpaceCreateDeviceRGB();

    CGContextRotateCTM(context, -360.0 * M_PI/180.0);

    CGFloat clearCircleColors[] =

    {

        253.0/255.0, 163.0/255.0, 87.0/255.0, 1.0,

        253.0/255.0, 163.0/255.0, 87.0/255.0, 0.0,

    };

    CGGradientRef clearCircleGradient =CGGradientCreateWithColorComponents

    (clearCircleRGB, clearCircleColors, NULL,sizeof(colors)/(sizeof(colors[0])*4));

    CGColorSpaceRelease(rgb);

    CGContextDrawRadialGradient(clearCircleContext,

                                clearCircleGradient, CGPointMake(160, 160), 0,

                                CGPointMake(160, 160), 160,kCGGradientDrawsBeforeStartLocation);

    clearCircleImageView.image = UIGraphicsGetImageFromCurrentImageContext();

    [backgroundImageView addSubview:clearCircleImageView];

    CGGradientRelease(clearCircleGradient);

简单说，底部绘制一矩形，上端绘制已透明度变化的黄球。