图

// 尺寸变换

• (UIImage *)reSizeImage:(UIImage *)image toSize:(CGSize)reSize {

  // 创建图形要变化的大小的上下文
  UIGraphicsBeginImageContext(CGSizeMake(reSize.width, reSize.height));
  // 绘制图形的位置和大小
  [image drawInRect:CGRectMake(0, 0, reSize.width, reSize.height)];
  // 图形获取图片从当前图片的上下文
  UIImage *reSizeImage = UIGraphicsGetImageFromCurrentImageContext();
  // 结束图形绘制
  UIGraphicsEndImageContext();

  return reSizeImage;
  }

// 等比率缩放

• (UIImage *)scaleImage:(UIImage *)image toScale:(float)scaleSize{
  UIGraphicsBeginImageContext(CGSizeMake(image.size.width * scaleSize, image.size.height * scaleSize));
  [image drawInRect:CGRectMake(0, 0, image.size.width * scaleSize, image.size.height * scaleSize)];
  UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return scaledImage;
  }

// 截图

• (UIImage *)captureView:(UIView *)view {
  // 获得截图view的fram
  CGRect rect = view.frame;
  // 图形开始图片的上下文
  UIGraphicsBeginImageContext(rect.size);
  // 获得当前上下文
  CGContextRef context = UIGraphicsGetCurrentContext();
  // 呈现图形当前的上下文到目标view的layer层中
  [view.layer renderInContext:context];

  UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return img;
  }

// 储存图片， 这里分为储存在app的文件里和储存到手机的图库里

// 1.储存到app的文件里

• (void)saveImageToAppFileWithImage:(UIImage *)image path:(NSString *)path{
  //把要处理的图片, 以image.png名称存到app home下的Documents目录里
  // NSString *pathStr = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]stringByAppendingPathComponent:@"image.png"];
  [UIImagePNGRepresentation(image) writeToFile:path atomically:YES];
  }

// 2.储存图片到手机相册中（必须真机使用，模拟器无法使用）

• (void)saveImageToPhotoAlbum:(UIImage*)savedImage {

  UIImageWriteToSavedPhotosAlbum(savedImage, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
  }
  // 保存图片成功与否的提示

• (void)image: (UIImage *) image didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo

{
NSString *msg = nil ;
if(error != NULL){
msg = @"保存图片失败" ;
}else{
msg = @"保存图片成功" ;
}
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"保存图片结果提示"
message:msg
delegate:self
cancelButtonTitle:@"确定"
otherButtonTitles:nil];
[alert show];
}