IOS图像处理（2）绘制文本

- (void)drawRect:(CGRect)rect
{
    //获取图像上下文对象
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetRGBStrokeColor(context, 250/255.0, 250/255.0, 250/255.0, 1);
    CGContextSetFillColorWithColor(context, [UIColor greenColor].CGColor);
    CGContextSetShadowWithColor(context, CGSizeMake(1, 1), 3, [UIColor yellowColor].CGColor);
    
    
    //使用填充模式绘制文字
    CGContextSetTextDrawingMode(context,kCGTextFill);
    NSString *str = @"this is a jock";
    [str drawAtPoint:CGPointMake(20, 20) withAttributes:@{NSFontAttributeName:[
                                                              UIFont fontWithName:@"Arial" size:30],NSForegroundColorAttributeName:[UIColor greenColor]}];
    
    //使用描边模式绘制文字
    CGContextSetTextDrawingMode(context, kCGTextStroke);
    [str drawAtPoint:CGPointMake(20, 70) withAttributes:@{NSFontAttributeName:[
                                                                               UIFont fontWithName:@"Arial" size:30],NSForegroundColorAttributeName:[UIColor magentaColor]}];
    
    CGContextSetTextDrawingMode(context, kCGTextFillStroke);
    [str drawInRect:CGRectMake(20, 120, 100, 100) withAttributes:@{NSFontAttributeName:[UIFont fontWithName:@"Arial" size:30],NSForegroundColorAttributeName:[UIColor redColor]}];
   
}