Women in Technology

Article:		Bitmap Image Filters
Subject:		Centering the view.
Date:		2002-08-12 05:02:38
From:		infallible
Response to: Centering the view.
I am looking for a solution for that problem also. 1. Fixing lower-left corner problem is easy, just overwrite one method: - (BOOL)isFlipped { return YES; } now about centering the view :/.... I have 1 idea: 1. make a new subclass from NSView called MyPositioningView or something. 2. add a MyImageView subview to MyPositioningView 3. then check if the clipview is larger than the image * scaleFactor. If it is set MyPositioningView's frame as big as clipView's frame, but if not then make it as big as your image * scaleFactor. 4. change MyImageView's frame origin. I am gonna try it this week[when i got time], but maybe somebody knows a better way... Oh easiest way would be just make a subclass of NSScrollView and overwrite the (void)tile method, but its not a good solution[ euw ugly!] :( ]. btw. sorry about my poor english. And good luck with your book Mike :).

Showing messages 1 through 2 of 2.

• Solution here:
  2002-08-12 07:30:31  infallible [View]
  
  
  Ok this is how you can do it:
  
  1. Make a subclass of NSScrollView
  2. overwrite drawRect, its not needed, but i wanted to make gray background for the image :]. If you won't overwrite it then it will be white
  
  - (void)drawRect:(NSRect)rect
  {
  [[NSColor whiteColor] set];
  NSRectFill(rect);
  [[NSColor grayColor] set];
  NSRectFill(NSMakeRect(0,0,rect.size.width - 15,rect.size.height - 15));
  [self tile];
  }
  
  hmm 15 pixels is scroller's width ofcourse, you can make the code sigtly better ofcourse. Like: float scrollerWidth = NSHeight([[self horizontalScroller] frame]);
  
  3. overwrite (void)tile
  
  - (void)tile
  {
  NSRect newContentRect = [self frame];
  NSRect documentRect = [[self documentView] frame];
  float scrollerWidth = NSHeight([[self horizontalScroller] frame]); // 15 pixels for normal scrollers
  
  // assuming that both scrollers are always visible! Modify if needed :]
  newContentRect = NSMakeRect(0,0,newContentRect.size.width - scrollerWidth, newContentRect.size.height - scrollerWidth);
  
  // use if([self hasHorizontalScroller])/if([self hasVerticalScroller]) also if you need to check if the scrollView has to draw the scrollers
  
  [[self horizontalScroller] setFrame:NSMakeRect(0,newContentRect.size.height,newContentRect.size.width,scrollerWidth)];
  [[self verticalScroller] setFrame:NSMakeRect(newContentRect.size.width,0,scrollerWidth,newContentRect.size.height)];
  
  // Now check if centering is needed at all
  
  if( newContentRect.size.width >= documentRect.size.width )
  {
  newContentRect.origin.x = (newContentRect.size.width - documentRect.size.width) / 2;
  newContentRect.size.width = documentRect.size.width;
  }
  
  if( newContentRect.size.height >= documentRect.size.height )
  {
  newContentRect.origin.y = (newContentRect.size.height - documentRect.size.height) / 2;
  newContentRect.size.height = documentRect.size.height;
  }
  
  // draw the content view
  [[self contentView] setFrame:newContentRect];
  }
  
  /Infallible da n00b coder
• Oh almost forgot
  2002-08-12 07:53:03  infallible [View]
  
  
  This how it should look(without that popup button ofcourse)
  http://www.hot.ee/priiware/shot0001.gif
  
  and there may be some bugs when the image width or height isn't a whole number, i fixed that problem with the round() command.
  
  /Infallible da n00b coder