Volume 7A: XView Programming Manual

In the first form of the repaint procedure, the only other parameter is the repaint_area.

This is a linked list of rectangular areas in the paint window that have been exposed and need

to be repainted. The Rectlist type is a linked list of Rect’s as shown in <xview/rect.h>.

The declaration for the Rect type is:

typedef struct rect {

coord r_left, r_top;

short r_width, r_height;

} Rect;

The type coord is #define’d as type short. The Rectlist is declared in

<xview/rectlist.h> as:

typedef struct rectnode {

struct rectnode *rn_next; /* Pointer to next rectnode */

struct rect rn_rect;

} Rectnode;

typedef struct rectlist {

coord rl_x, rl_y; /* Offset to apply to each rect

* in list including bound */

struct rectnode *rl_head; /* Pointer to first rectnode */

struct rectnode *rl_tail; /* Pointer to last rectnode */

struct rect rl_bound; /* Describes bounding rect of

* all rects in list */

} Rectlist;

The repaint_area parameter is of type Rectlist, so the application has several ways it

can approach repainting the window. It could just ignore the parameter and repaint the entire

window, or it could repaint the entire area described by the rl_bound field of the

rectlist structure or it could loop through all the Rectnode’s and repaint those areas

individually. Deciding which method to choose should be based on how complicated the

redrawing is.

When CANVAS_X_PAINT_WINDOW is set to FALSE, the internal clipping for the ...