The visibility of an edit control's text is governed by the dimensions of its window rectangle and its formatting rectangle. The window rectangle is the client area of the window containing the edit control. The formatting rectangle is a construct maintained by the system for formatting the text displayed in the window rectangle. When an edit control is first displayed, the two rectangles are identical on the screen. An application can make the formatting rectangle larger than the window rectangle (thereby limiting the visibility of the edit control's text) or smaller than the window rectangle (thereby creating extra white space around the text).
An application can set the coordinates of an edit control's formatting rectangle by sending it an EM_SETRECT message. The EM_SETRECT message also automatically redraws the edit control's text. To establish the coordinates of the formatting rectangle without redrawing the control's text, an application can send the control an EM_SETRECTNP message. To retrieve the coordinates of the formatting rectangle, an application can send the control an EM_GETRECT message. These messages apply to multiline edit controls only.