Implementing Scrollbars: Step 4

Modify the Color.H file to add some global variables to support scrolling.

int nScrollInc; /* Scrolling increment */
int ClientWidth, ClientHeight, BottomBarThickness, RightBarThickness; /* Client area metrics */
int DisplayWidth, DisplayHeight;
RECT ScrollRect; /* Used in WM_HSCROLL and WM_VSCROLL to make scrolling smoother */
RECT rLeadDest, rLeadSource;
RECT rClientSize;