How to covert alpha Image into 8 bit depth in iOS

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• Load remaining rows once you reached the bottom of the page - objective-c

  I'm having a problem with my code. Initially i want to show only 5 rows for my table and I'd like to show the remaining data once I scroll down to the bottom. What is happening now is it's giving me a next page with the next results. I want it to just append the remaining results with the first results.

  i.e:

  | first data
  | second data
  | third
  | fourth
  | fifth
  

  and once I scroll down I want it to show the remaining data with the first results.

  i.e

  | first data
  | second data
  | third
  | fourth
  | fifth
  | sixth
  | seventh
  | etc...
  

  Here are my codes:

  This is the part if the request is success

  -(void)IGRequestManagerEmailAlertHistorySuccess:(NSMutableArray *)EmailAlertsHistory{
      if ([EmailAlertsHistory count] > 0) {
          [self._arrayEmailAlertsHistory removeAllObjects];
          self._arrayEmailAlertsHistory = [[NSMutableArray alloc] initWithArray:EmailAlertsHistory];
          [self._tblView reloadData];
          [self._lblNavTitle setText:[NSString stringWithFormat:@"Email Alerts"]];
          [self._tblView setHidden:NO];
      }else{
          [self._fieldValidation alertMessage:@"CodeNinja" Message:@"No search result"];
          [self Back];
  
      }
  }
  

  once I scroll it will go here

  -(void)queryData{
      [self._igRequestManager SearchEmailAlerts:[__dictAccountInformation objectForKey:@"username"] withCountry:[self._fieldValidation getSelectedCountry] withToken:[__dictAccountInformation objectForKey:@"stoken"] withPageNumber:(int)self._pageNumber];
  }
  
  
  - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
      return [self._arrayEmailAlertsHistory count];
  }
  
  
  - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
  
  static NSString *cellIdentifier = @"Cell";
  
  SWTableViewCell *cell = (SWTableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
  
      cell = [[[SWTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier] autorelease];
      cell.delegate = self;
  
      UILabel *lblTitle = [[[UILabel alloc] initWithFrame:CGRectMake(18, 10 , [[UIScreen mainScreen ] bounds ].size.width - 70, 14)] autorelease];
      [lblTitle setText:[NSString stringWithFormat:@"%@",[[[self._arrayEmailAlertsHistory objectAtIndex:indexPath.row] objectForKey:@"cell"] objectAtIndex:1]]];
      [lblTitle setBackgroundColor:[UIColor clearColor]];
      [lblTitle setTextColor:[UIColor blackColor]];
      [lblTitle setNumberOfLines:1];
      [lblTitle setFont:[UIFont fontWithName:@"HelveticaNeue-Bold" size:14]];
      [cell.contentView addSubview:lblTitle];
  
      if ([[UIScreen mainScreen] bounds].size.width == 375 || [[UIScreen mainScreen] bounds].size.width == 414){
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          UIView *bottomLineView = [[UIView alloc] initWithFrame:CGRectMake(0, cell.bounds.size.height +22, self.view.bounds.size.width, 1)];
          bottomLineView.backgroundColor = [UIColor colorWithRed:0.91 green:0.91 blue:0.91 alpha:1.0];
  
          [cell.contentView addSubview:bottomLineView];
      }
  
  
      return cell;
  }
  

  and if ever you scroll

  - (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset{
  
      targetContentOffset->y = 0;
      if (targetContentOffset->y < scrollView.contentOffset.y) {
          if (self._pageNumber == 1) {
              self._pageNumber = self._pageNumber + 1;
              [self queryData];
          } else if (self._pageNumber == 2) {
              self._pageNumber = self._pageNumber;
              [self queryData];
          }
  
          if (self._pageNumber >= 3) {
              self._pageNumber = self._pageNumber - 1;
          }
  
      } else {
          if (self._pageNumber == 1) {
  
          } else if (self._pageNumber == 2) {
              self._pageNumber = self._pageNumber - 1;
              [self queryData];
          }
      }
  }
  
• Swift 4: Deleting an object in Core Data

  I am trying to delete an object from my tableView using commitEditingStyle. When I delete the object and create another one with the same name, the old values come up for this object too. I don't understand what the problem is here. I think I cannot delete the object properly.

  Here is the code:

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      let appDel:AppDelegate = (UIApplication.shared.delegate as! AppDelegate)
      let habitContext:NSManagedObjectContext = appDel.managedObjectContext
  
      if editingStyle == UITableViewCellEditingStyle.delete{
          habitContext.delete(self.habitArray![indexPath.row] as! NSManagedObject)
          self.habitArray!.removeObject(at: indexPath.row)
          do{try habitContext.save()}catch{print("no save")}
      }
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• How to use opencv copyTo() function?

  I have read through the documentation for copyTo() but am still confused on how this function would be applied to the following code. This anwer states that we can use the copyTo function instead of 255-x. How would this function be applied in this case? I would appreciate a code snippet.

  #   Compute the gradient map of the image
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      # YOU SHOULD TUNE THESE VALUES TO SUIT YOUR NEEDS
      kernel_size = 5         # Size of the laplacian window
      blur_size = 5           # How big of a kernal to use for the gaussian blur
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  This is the filter derivatives that I want to apply Robert cross operator

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• How to set bit depth in Magick.NET Read

  How can I specify the bit depth for the MagickImage.Read() function when reading binary files?

  I have a 1024x1024 image represented by 8-bit grayscale values (total file length = 1024x1024 = 1048576 bytes). Using ImageMagick v.7.0.8-7 Q16 x64, I can convert the file using

  magick.exe -depth 8 -size 1024x1024 -format Gray Gray:filepath.bin convertedfile.png
  

  When I try to convert the file using Magick.NET Q16-AnyCPU v7.5.0.1,

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      MagickReadSettings settings = new MagickReadSettings();
  
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      settings.Format = MagickFormat.Gray;
  
      MagickImage newImage = new MagickImage();
      newImage.Depth = 8; //this appears to be ignored once the Read function is called
      newImage.Read(fileName, settings);
  
      return newImage;
  }
  

  I get the error

  Message: ImageMagick.MagickCorruptImageErrorException : unexpected end-of-file '': No such file or directory @ error/gray.c/ReadGRAYImage/241

  Indicating that the program has read past the end of the file. I've confirmed that Magick.NET is reverting to a 16-bit depth instead of the 8-bit depth I want. I can read the file using settings.Height = 512 instead of 1024, which gives me a squashed version of my grayscale image.

  I learned from Memory consumption in Magick.NET that Magick.NET Q16 stores pixels in memory with 16-bit precision; I'm fine with that but it doesn't seem that should preclude 8-bit reading capabilities.

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