Volume 7A: XView Programming Manual

F

Example Programs

This appendix contains nine example programs that supplement the programs in the chapters:

• item_move.c

• scroll_cells2.c

• menu_dir2.c

• type_font.c

• fonts.c

• x_draw.c

• Logo.c

• Bitmap.c

• panel_dnd.c

Some of these programs are extensions to programs presented earlier in this book; they are

listed here to demonstrate extended usage. Other programs in this appendix attempt to inte-

grate features from unrelated XView packages that exceeded the scope of a particular chap-

ter.

F.1 item_move.c

The first program demonstrates how you can use an event handler within a panel to allow the

user to create panel items, move them around within the panel, and delete them. Chapter 7,

Panels, discusses specifics about how panels work. Chapter 5, Canvases and Openwin, dis-

cusses the canvas and openwin issues, since the panel is subclassed from those packages.

Example F-1. The item_move.c program

/*

* item_move.c

* Move items around in a panel using an interpose event handler

* specific to the panel. Two panels are created -- the left panel

* contains panel buttons that allow you to create certain types of

* items that are put in the second panel. Use the MENU (right)

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Example Programs 713

Example F-1. The item_move.c program (continued)

* mouse button to move items around in the second panel.

*/

#include <stdio.h>

#include <xview/xview.h>

#include <xview/panel.h>

/* We need handles to the base frame and a panel -- instead of

* using global variables, we’re going to attach the objects to

* the objects which need to reference them. Attach using

* XV_KEY_DATA -- here are the keys.

*/

#define PACKAGE_KEY 100

#define FRAME_KEY 101

#define PANEL_KEY 102

main(argc, argv)

int argc;

char *argv[ ];

{

Frame frame;

Panel panel;

Xv_Window window;

Panel_item create_text, item;

Notify_value my_event_proc();

int create_item();

char buf[64];

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

sprintf(buf, "%s: Use MENU (Right) Button To Move Items", argv[0]);

frame = (Frame)xv_create(XV_NULL, FRAME,

FRAME_LABEL, buf,

FRAME_SHOW_FOOTER, TRUE,

NULL);

/*

* Create panel for known panel items. Layout panel vertically.

*/

panel = (Panel)xv_create(frame, PANEL,

PANEL_LAYOUT, PANEL_VERTICAL,

NULL);

/*

* Create text panel item, attach the frame as client data for

* use by the notify procedure create_item(). Text items inherit

* the layout of "label" and "value" from its parent panel.

* override for the text item by setting PANEL_LAYOUT explicitly.

*/

create_text = (Panel_item)xv_create(panel, PANEL_TEXT,

XV_X, 0,

XV_Y, 20,

PANEL_LABEL_STRING, "Create Button:",

PANEL_NOTIFY_PROC, create_item,

PANEL_LAYOUT, PANEL_HORIZONTAL,

PANEL_VALUE_DISPLAY_LENGTH, 10,

NULL);

/*

* Create panel button to determine which type of button to create --

714 XView Programming Manual

Example F-1. The item_move.c program (continued)

* a button, message, or text item. See create_item().

*/

item = (Panel_item)xv_create(panel, PANEL_CHOICE,

XV_X, 0,

XV_Y, 50,

PANEL_DISPLAY_LEVEL, PANEL_CURRENT,

PANEL_LAYOUT, PANEL_HORIZONTAL,

PANEL_LABEL_STRING, "Item type",

PANEL_CHOICE_STRINGS, "Button", "Message", "Text", NULL,

NULL);

window_fit(panel);

/* Create a new panel to be used for panel creation. The panel

* from above is no longer referenced. The panel created here

* is the panel used throughout the rest of this program. To

* add confusion, "panel" is used as the handle of this panel, too.

* The panel referenced in WIN_RIGHT_OF and XV_HEIGHT is the old

* one since the new one hasn’t been created yet.

*/

panel = (Panel)xv_create(frame, PANEL,

WIN_RIGHT_OF, canvas_paint_window(panel),

XV_WIDTH, 300,

XV_HEIGHT, xv_get(panel, XV_HEIGHT),

WIN_BORDER, TRUE,

XV_KEY_DATA, PANEL_KEY, panel,

NULL);

/* Install event handling routine for the panel. This must be done

* by an interpose function to make sure that the ACTION_MENU

* event is not consumed by the first panel before it has a chance

* to get to the second panel’s event proc: my_event_proc.

*/

notify_interpose_event_func(panel, my_event_proc, NOTIFY_SAFE);

/* attach various items to the text item for text_select() */

xv_set(create_text,

XV_KEY_DATA, FRAME_KEY, frame,

XV_KEY_DATA, PACKAGE_KEY, item,

XV_KEY_DATA, PANEL_KEY, panel,

NULL);

window_fit(frame);

xv_main_loop(frame);

}

/*

* Process events for panel’s subwindow. This routine gets -all-

* events that occur in the panel subwindow but passes them on to

* the normal event dispatcher when the interposed function has been

* completed. The notify function, my_event_proc, is only

* interested in MENU button events that happen on top of panel items.

* When the user clicks and _drags_ the MENU button on a panel item,

* the item is moved to where the mouse moves to.

*/

Notify_value

my_event_proc(panel, event, arg, type)

Panel panel;

Example Programs

Example Programs 715

Example F-1. The item_move.c program (continued)

Event *event;

Notify_arg arg;

Notify_event_type type;

{

static Panel_item item;

static int x_offset, y_offset;

Frame frame = (Frame)xv_get(panel, XV_OWNER);

Rect *rect, *item_rect;

char buf[64];

/*

* If the mouse is dragging an item, reset its new location.

*/

if (event_action(event) == LOC_DRAG && item) {

Panel_item pi;

Rect r;

/*

* Get the rect of item, then *copy* it -- never change data

* returned by xv_get(). Modify the copied rect reflecting

* new X,Y position of panel item and check to see if it

* intersects with any existing panel items.

*/

rect = (Rect *)xv_get(item, XV_RECT);

rect_construct(&r, /* see <xview/rect.h> for macros */

rect->r_left, rect->r_top, rect->r_width, rect->r_height);

r.r_left = event->ie_locx - x_offset;

r.r_top = event->ie_locy - y_offset;

PANEL_EACH_ITEM(panel, pi)

if (pi == item)

continue;

/* don’t let panel items overlap */

item_rect = (Rect *)xv_get(pi, XV_RECT);

if (rect_intersectsrect(item_rect, &r))

return;

PANEL_END_EACH

/* no overlap -- move panel item. */

xv_set(item,

PANEL_ITEM_X, r.r_left,

PANEL_ITEM_Y, r.r_top,

NULL);

}

/* If it’s not the MENU button, we’re not interested,

* so allow the event to be passed on to the notifier

* for normal event handling.

*/

if (event_action(event) != ACTION_MENU) {

notify_next_event_func(panel, (Notify_event) event, arg, type);

return;

}

/*

* next two cases is MENU button just-down or just-released

*/

if (event_is_down(event)) {

/* Right (MENU) button down on an item -- determine panel item */

716 XView Programming Manual

Example F-1. The item_move.c program (continued)

if ( (xv_get((panel), PANEL_FIRST_ITEM) ) == NULL ) {

sprintf(buf, "No panel items are currently in the panel.");

xv_set(frame, FRAME_RIGHT_FOOTER, buf, NULL);

}

PANEL_EACH_ITEM(panel, item)

rect = (Rect *)xv_get(item, XV_RECT);

if (rect_includespoint(rect,

event->ie_locx, event->ie_locy)) {

x_offset = event->ie_locx - rect->r_left;

y_offset = event->ie_locy - rect->r_top;

sprintf(buf, "Panel item found.");

xv_set(frame, FRAME_RIGHT_FOOTER, buf, NULL);

break;

}

else {

sprintf(buf, "The cursor is not over any panel item.");

xv_set(frame, FRAME_RIGHT_FOOTER, buf, NULL);

}

PANEL_END_EACH

if (item)

sprintf(buf, "Moving item: ’%s’",

(char *)xv_get(item, PANEL_LABEL_STRING));

else

buf[0 ] = 0;

} else if (item) {

char *name = (char *)xv_get(item, PANEL_LABEL_STRING);

/* test if item is inside panel by comparing XV_RECTs */

rect = (Rect *)xv_get(panel, XV_RECT);

if (!rect_includespoint(rect,

event->ie_locx + rect->r_left,

event->ie_locy + rect->r_top)) {

/* item is outside the panel -- remove item */

xv_destroy(item);

sprintf(buf, "Removed ’%s’ from panel", name);

} else

sprintf(buf, "’%s’ moved to %d %d", name,

(int)xv_get(item, XV_X), (int)xv_get(item, XV_Y));

/* set "item" to null so that new drag

* events don’t attempt to move old item.

*/

item = NULL;

}

xv_set(frame, FRAME_LEFT_FOOTER, buf, NULL);

}

/*

* Callback routine for all panel buttons.

* If the panel item is the text item, determine the name of the new

* panel button the user wishes to create. Loop through all the

* existing panel items looking for one with the same label. If so,

* return PANEL_NONE and set the frame’s footer with an error message.

* Otherwise, create a new panel item with the label, reset the text

* item value and return PANEL_NEXT.

*/

int

Example Programs

Example Programs 717