图片强制解压缩优化技巧

gistfile1.txt

图片优化技巧
- (void)decompressImage:(UIImage *)image
{
  UIGraphicsBeginImageContext(CGSizeMake(1, 1));
  [image drawAtPoint:CGPointZero];
  UIGraphicsEndImageContext();
}
This causes the image to decompress


同样的，这个函数也完成了image data的解压

- (UIImage *)compressImage:(UIImage *)image
{
  CGSize size = {36.0f, 36.0f};
  UIGraphicsBeginImageContextWithOptions(size, NO, [[UIScreen mainScreen] scale]);
  [image drawInRect:CGRectMake(0, 0, size.width, size.height)];
  image = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return image;
}


我猜测，UIImage对象初始化，只是持有了data数据，真正要显示的时候才开始解压数据--》CGContext纹理--》复制到显存---》GPU display
所以这里提前调用 draw 方法解压数据，在主线程中只 display image