Volume 7A: XView Programming Manual

Example 19-1. Sourcing a drag (continued)

if (dragging && drag_pixels++ == 5) {

xv_set(frame, FRAME_LEFT_FOOTER, "Drag and Drop:", 0);

switch (dnd_send_drop(dnd)) {

case XV_OK:

xv_set(frame, FRAME_LEFT_FOOTER,

"Drag and Drop: Began", 0);

break;

case DND_TIMEOUT:

xv_set(frame, FRAME_LEFT_FOOTER,

"Drag and Drop: Timed Out",0);

break;

case DND_ILLEGAL_TARGET:

xv_set(frame, FRAME_LEFT_FOOTER,

"Drag and Drop: Illegal Target",0);

break;

case DND_SELECTION:

xv_set(frame, FRAME_LEFT_FOOTER,

"Drag and Drop: Bad Selection",0);

break;

case DND_ROOT:

xv_set(frame, FRAME_LEFT_FOOTER,

"Drag and Drop: Root Window",0);

break;

case XV_ERROR:

xv_set(frame, FRAME_LEFT_FOOTER,

"Drag and Drop: Failed",0);

break;

}

drag_pixels = 0;

}

}

break;

}

}

PaintObject(object, win, dpy)

DragObject object;

Window win;

Display *dpy;

{

static GC gc;

static int gcCreated = False;

if (!gcCreated) {

XGCValues gcv;

gcv.stipple = (Pixmap) xv_get(object.image, XV_XID);

gcv.fill_style = FillStippled;

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

GCFillStyle, &gcv);

XSetForeground(dpy, gc, BlackPixel(dpy, XDefaultScreen(dpy)));

XSetBackground(dpy, gc, WhitePixel(dpy, XDefaultScreen(dpy)));

}

if (object.inverted) {

XSetFillStyle(dpy, gc, FillSolid);

448 XView Programming Manual

Example 19-1. Sourcing a drag (continued)

XDrawRectangle(dpy, win, gc, object.x-1, object.y-1, 66, 66);

XSetFillStyle(dpy, gc, FillStippled);

} else

XClearWindow(dpy, win);

XSetTSOrigin(dpy, gc, object.x, object.y);

XFillRectangle(dpy, win, gc, object.x, object.y, 65, 65);

}

void

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

Canvas canvas; /* unused */

Xv_Window paint_window; /* unused */

Display *dpy;

Window xwin;

Xv_xrectlist *xrects; /* unused */

{

unsigned width, height;

int x, y;

width = xv_get(paint_window, XV_WIDTH);

height = xv_get(paint_window, XV_HEIGHT);

x = (width/2)-(dO.w/2);

y = (height/2)-(dO.h/2);

dO.x = x;

dO.y = y;

PaintObject(dO, xwin, dpy);

}

/* The convert proc is called whenever someone makes a request

* to the dnd selection. Two cases we handle within the convert

* proc: DELETE and _SUN_SELECTION_END. Everything else we pass

* on to the default convert proc which knows about our selection

* items.

*/

int

SelectionConvert(seln, type, data, length, format)

Selection_owner seln;

Atom *type;

Xv_opaque *data;

long *length;

int *format;

{

Xv_Server server = XV_SERVER_FROM_WINDOW(xv_get(seln,

XV_OWNER));

if (*type == (Atom)xv_get(server,

SERVER_ATOM, "_SUN_SELECTION_END")) {

/* Destination has told us it has completed the drag

* and drop transaction. We should respond with a

* zero-length NULL reply.

*/

xv_set(dnd, SEL_OWN, False, 0);

xv_set(frame, FRAME_LEFT_FOOTER, "Drag and Drop: Completed",0);

Drag and Drop

Drag and Drop 449

Example 19-1. Sourcing a drag (continued)

*format = 32;

*length = 0;

*data = NULL;

*type = (Atom)xv_get(server, SERVER_ATOM, "NULL");

return(True);

} else if (*type == (Atom)xv_get(server,

SERVER_ATOM, "DELETE")) {

/* Destination asked us to delete the selection.

* If it is appropriate to do so, we should.

*/

*format = 32;

*length = 0;

*data = NULL;

*type = (Atom)xv_get(server, SERVER_ATOM, "NULL");

return(True);

} else

/* Let the default convert procedure deal with the

* request.

*/

return(sel_convert_proc(seln, type, data, length, format));

}

/* When we lose the primary selection, this procedure is called.

* We dehigh-light our selection.

*/

void

SelectionLose(seln)

Selection_owner seln;

{

Xv_Window owner = xv_get(seln, XV_OWNER);

if (xv_get(seln, SEL_RANK) == XA_PRIMARY) {

dO.inverted = False;

PaintObject(dO, xv_get(owner,

XV_XID), XV_DISPLAY_FROM_WINDOW(owner));

}

}

19.6 Sample Program—Drop Site Item and Destination

Example 19-2 provides a example of a program that creates a drop-site item and sets up to

receive a drop.

Example 19-2. A drop-site item example

/*

* dest.c - Example of how to register interest in receiving

* drag and drop events and how to complete a drag

* and drop operation.

*

*/

#include <stdio.h>

450 XView Programming Manual

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

#include <xview/xview.h>

#include <xview/frame.h>

#include <xview/canvas.h>

#include <xview/panel.h>

#include <xview/font.h>

#include <xview/dragdrop.h>

#include <xview/xv_xrect.h>

#include <X11/Xlib.h>

#define DROP_WIDTH 65

#define DROP_HEIGHT 65

#define BULLSEYE_SITE 1

Frame frame;

Canvas canvas;

Panel panel;

Xv_drop_site drop_site;

Server_image drop_image;

Server_image drop_image_inv;

Panel_item p_string,

p_length,

p_host;

Selection_requestor sel;

int inverted;

main(argc, argv)

int argc;

char **argv;

{

void EventProc(),

PaintCanvas(),

ResizeCanvas();

Xv_Font font;

xv_init(XV_INIT_ARGC_PTR_ARGV, &argc, argv, NULL);

frame = xv_create((Window)NULL, FRAME,

XV_X, 330,

XV_Y, 10,

XV_WIDTH, 10,

XV_LABEL, "Drag & Drop Destination",

NULL);

panel = xv_create(frame, PANEL,

PANEL_LAYOUT, PANEL_VERTICAL,

NULL);

p_string = xv_create(panel, PANEL_TEXT,

PANEL_LABEL_STRING, "Dropped Text:",

PANEL_VALUE_DISPLAY_LENGTH, 50,

NULL);

p_host = xv_create(panel, PANEL_TEXT,

Drag and Drop

Drag and Drop 451

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

PANEL_LABEL_STRING, "From host:",

PANEL_VALUE_DISPLAY_LENGTH, 15,

NULL);

p_length = xv_create(panel, PANEL_TEXT,

PANEL_LABEL_STRING, "Length:",

PANEL_VALUE_DISPLAY_LENGTH, 6,

NULL);

window_fit(panel);

canvas = xv_create(frame, CANVAS,

XV_HEIGHT, 100,

XV_WIDTH, WIN_EXTEND_TO_EDGE,

XV_X, 0,

WIN_BELOW, panel,

CANVAS_REPAINT_PROC, PaintCanvas,

CANVAS_RESIZE_PROC, ResizeCanvas,

CANVAS_X_PAINT_WINDOW, TRUE,

NULL );

xv_set(canvas_paint_window(canvas),

WIN_BIT_GRAVITY, ForgetGravity,

WIN_CONSUME_EVENTS,

WIN_RESIZE,

NULL,

WIN_EVENT_PROC, EventProc,

NULL);

drop_image = xv_create(NULL, SERVER_IMAGE,

SERVER_IMAGE_BITMAP_FILE, "./bullseye.bm",

NULL);

drop_image_inv = xv_create(NULL, SERVER_IMAGE,

SERVER_IMAGE_BITMAP_FILE, "./bullseyeI.bm",

NULL);

/* Selection requestor object that will be

* passed into dnd_decode_drop() and later used

* to make requests to the source of the

* drop.

*/

sel = xv_create(canvas, SELECTION_REQUESTOR, NULL);

/* This application has one drop site with

* site id BULLSEYE_SITE and whose shape will

* be described by a rectangle. If

* animation is supported, it would like to

* receive LOC_DRAG, LOC_WINENTER and

* LOC_WINEXIT events.

*/

drop_site = xv_create(canvas_paint_window(canvas), DROP_SITE_ITEM,

DROP_SITE_ID, BULLSEYE_SITE,

DROP_SITE_EVENT_MASK, DND_ENTERLEAVE,

NULL);

inverted = False;

452 XView Programming Manual