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。