Volume 7A: XView Programming Manual

Example 19-2. A drop-site item example (continued)

window_fit(frame);

xv_main_loop(frame);

exit(0);

}

void

EventProc(window, event)

Xv_Window window;

Event *event;

{

switch (event_action(event)) {

/* When drop previewing is available, if

* the drop site has selected for previewing

* events (DROP_SITE_EVENT_MASK) then it will

* receive ACTION_DRAG_PREVIEW events from

* the source as requested.

*/

case ACTION_DRAG_PREVIEW:

switch(event_id(event)) {

case LOC_WINENTER:

inverted = True;

break;

case LOC_WINEXIT:

inverted = False;

break;

case LOC_DRAG:

break;

}

PaintCanvas(NULL, window, XV_DISPLAY_FROM_WINDOW(window),

xv_get(window, XV_XID), NULL);

break;

case ACTION_DRAG_COPY:

case ACTION_DRAG_MOVE: {

Xv_drop_site ds;

Xv_Server server = XV_SERVER_FROM_WINDOW(event_window(event));

/* If the user dropped over an acceptable

* drop site, the owner of the drop site will

* be sent an ACTION_DROP_{COPY, MOVE} event.

*/

/* To acknowledge the drop and to associate the

* rank of the source’s selection to our

* requestor selection object, we call

* dnd_decode_drop().

*/

if ((ds = dnd_decode_drop(sel, event)) != XV_ERROR) {

if (xv_get(ds, DROP_SITE_ID) == BULLSEYE_SITE)

UpdatePanel(server, sel);

/* If this is a move operation, we must ask

* the source to delete the selection object.

* We should only do this if the transfer of

* data was successful.

*/

Drag and Drop

Drag and Drop 453

Example 19-2. A drop-site item example (continued)

if (event_action(event) == ACTION_DRAG_MOVE) {

int length, format;

xv_set(sel, SEL_TYPE_NAME, "DELETE", NULL);

(void)xv_get(sel, SEL_DATA, &length, &format);

}

/* To complete the drag and drop operation,

* we tell the source that we are all done.

*/

dnd_done(sel);

inverted = False;

PaintCanvas(NULL, window, XV_DISPLAY_FROM_WINDOW(window),

xv_get(window, XV_XID), NULL);

} else

printf ("drop error\n");

break;

}

default:

break;

}

}

UpdatePanel(server, sel)

Xv_Server server;

Selection_requestor sel;

{

int length,

format,

*string_length;

char buf[7],

*string,

*hostname;

xv_set(sel, SEL_TYPE, XA_STRING, NULL);

string = (char *)xv_get(sel, SEL_DATA, &length, &format);

if (length != SEL_ERROR) {

xv_set(p_string, PANEL_VALUE, string, NULL);

free (string);

}

xv_set(sel,

SEL_TYPE, xv_get(server, SERVER_ATOM, "LENGTH"), NULL);

string_length = (int *)xv_get(sel, SEL_DATA, &length, &format);

if (length != SEL_ERROR) {

sprintf(buf, "%d", *string_length);

xv_set(p_length, PANEL_VALUE, buf, NULL);

free ((char *)string_length);

}

xv_set(sel, SEL_TYPE, xv_get(server, SERVER_ATOM, "HOST_NAME"), NULL);

hostname = (char *)xv_get(sel, SEL_DATA, &length, &format);

if (length != SEL_ERROR) {

xv_set(p_host, PANEL_VALUE, hostname, NULL);

454 XView Programming Manual

Example 19-2. A drop-site item example (continued)

free (hostname);

}

xv_set(sel, SEL_TYPE_NAME, "_SUN_SELECTION_END", NULL);

(void)xv_get(sel, SEL_DATA, &length, &format);

}

void

PaintCanvas(canvas, paint_window, dpy, xwin, xrects)

Canvas canvas; /* unused */

Xv_Window paint_window; /* unused */

Display *dpy;

Window xwin;

Xv_xrectlist *xrects; /* unused */

{

static GC gc;

static int gcCreated = False;

static int lastMode = False;

int width, height;

int x, y;

Rect *r;

if (!gcCreated) {

XGCValues gcv;

gcv.stipple = (Pixmap) xv_get(drop_image, XV_XID);

gcv.foreground = BlackPixel(dpy, XDefaultScreen(dpy));

gcv.background = WhitePixel(dpy, XDefaultScreen(dpy));

gcv.fill_style = FillStippled;

gc = XCreateGC(dpy, xwin, GCStipple|GCForeground|GCBackground|

GCFillStyle, &gcv);

}

if (lastMode != inverted) {

if (!inverted)

XSetStipple(dpy, gc, (Pixmap) xv_get(drop_image, XV_XID));

else

XSetStipple(dpy, gc, (Pixmap) xv_get(drop_image_inv,

XV_XID));

lastMode = inverted;

}

width = xv_get(paint_window, XV_WIDTH);

height = xv_get(paint_window, XV_HEIGHT);

x = (width/2)-(DROP_WIDTH/2);

y = (height/2)-(DROP_HEIGHT/2);

XClearArea(dpy, xwin, x, y, DROP_WIDTH, DROP_HEIGHT, False);

XSetTSOrigin(dpy, gc, x, y);

XFillRectangle(dpy, xwin, gc, x, y, DROP_WIDTH, DROP_HEIGHT);

}

void

ResizeCanvas(canvas, width, height)

Canvas canvas;

int width;

int height;

Drag and Drop

Drag and Drop 455

Example 19-2. A drop-site item example (continued)

{

int x, y;

Rect rect;

x = (width/2)-(DROP_WIDTH/2);

y = (height/2)-(DROP_HEIGHT/2);

rect.r_left = x;

rect.r_top = y;

rect.r_width = DROP_WIDTH;

rect.r_height = DROP_HEIGHT;

/* Update the drop site information. */

xv_set(drop_site, DROP_SITE_DELETE_REGION_PTR, NULL,

DROP_SITE_REGION, &rect,

NULL);

}

19.7 Drag and Drop Package Summary

Table 19-3 lists the procedures and macros used for dragging and dropping. Table 19-4 lists

the DROP_SITE_ITEM and DRAGDROP package attributes. These attributes, procedures, and

macros are described fully in the XView Reference Manual.

Table 19-3. DROP_SITE_ITEM and DRAGDROP Procedures and Macros

dnd_decode_drop()

dnd_done()

dnd_is_forwarded()

dnd_is_local()

dnd_send_drop()

Table 19-4. DROP_SITE_ITEM and DRAGDROP Attributes

DROP_SITE_ITEM Attributes DRAGDROP Attributes

DROP_SITE_DEFAULT DND_ACCEPT_CURSOR

DROP_SITE_DELETE_REGION DND_ACCEPT_X_CURSOR

DROP_SITE_DELETE_REGION_PTR DND_CURSOR

DROP_SITE_EVENT_MASK DND_TIMEOUT_VALUE

DROP_SITE_ID DND_TYPE

DROP_SITE_REGION DND_X_CURSOR

DROP_SITE_REGION_PTR

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