highlight-range

This function highlights a region of text in the buffer.

• (send a-text:basic highlight-range start end color bitmap caret-space priority) -> (-> void)
      start : exact-integer
      end : exact-integer
      color : (instance color%)
      bitmap : (union #f (instance bitmap%))
      caret-space = #f : boolean
      priority = 'low : (union 'high 'low)

  The range between start and end will be highlighted with the color in color, and bitmap will be painted over the range of text in black and white. If bitmap is #f, the range will be inverted, using the platform specific xor. This method is not reccommend, because the selection is also displayed using xor.

  If caret-space? is not #f, the left edge of the range will be one pixel short, to leave space for the caret. The caret does not interfere with the right hand side of the range. Note that under X windows the caret is drawn with XOR, which means almost anything can happen. So if the caret is in the middle of the range it may be hard to see, or if it is on the left of the range and caret-space? is #f it may also be hard to see.

  The priority argument indicates the relative priority for drawing overlapping regions. If two regions overlap and have different priorities, the region with 'high priority will be drawn second and only it will be visible in the overlapping region.

  This method returns a thunk, which, when invoked, will turn off the highlighting from this range.