I am building an application where I have a ruler (that is a UIImage) that I use to scroll a UITableView. My UITableView has UILabels on each cell that display text. When the user leaves the ruler over a cell, the ruler has on it a UILabel that displays the contents of the UITableViewCell that it is over top of. All of this functionality is in place, and is working fine.
What I would like to do is when I scroll the ruler up or down, is to be able to view the contents of the table rows behind it dynamically while "the ruler is moving", so that the user can see right through the ruler. As a concept, I realize that this technique is called "masking", but normally "masking" is done using two images. What I'm trying to do is use a UIImage that has a UILabel on top of it, to display the contents of the rows behind it while it is moving. Can anyone show me how to do this, or point me in the right direction?
Here is an image of what it is I am trying to implement:
If you look at the image that I am using, the ruler image is partially hiding the bottom of the text in the third row, and partially hiding the top of the text in the fourth row. I would like the ruler to display the bottom of the text in row 3, and the top of the text in row 4 rather than hiding it when it is in this transition state.
