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我试图用CGContext
更改我的UIImage
区域的颜色,然后从当前状态创建一个新图像。原始图像具有正确的方向,但在此之后,图像变成侧向。为什么CGContextDrawImage旋转我的图像
CGRect imageRect = CGRectMake(0, 0, originalImage.size.width, originalImage.size.height);
UIGraphicsBeginImageContextWithOptions(originalImage.size, false, originalImage.scale);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGContextDrawImage(context, imageRect, originalImage.CGImage);
CGContextSetRGBFillColor(context, 255.0f, 255.0f, 255.0f, 1.0f);
CGContextFillRect(context, CGRectMake(5,5,100,100));
CGContextRotateCTM (context, radians(270));
CGContextRestoreGState(context);
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();