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From: steve@cad0.arch.unsw.oz.au (Stephen Peter)
Newsgroups: comp.windows.open-look
Subject: Problems using Dynamic colours with XView
Message-ID: <1330@usage.csd.unsw.oz.au>
Date: 4 Apr 91 07:06:08 GMT
Sender: news@usage.csd.unsw.oz.au
Organization: Faculty of Architecture, UNSW, Australia
Lines: 166


G'Day all,

I'm having some problems trying to write an Xview based program
that creates and then alters a dynamic colour-map-segment.  If the
colour map has two entries (0=back, 1=fore) everytime is fine, BUT
if I try to have more colours it doesnot seem to work.

Included below is a small program that demonstrates the problem.

If anyone has any comments or suggestions, I would really appreciate
hearing them (post or mail)!

Thanks,
Stephen.

--------------included program starts here ------------------
/*
 *   XView based program:
 *      testing creation of a dynamic colour-map-segment.
 *
 *   The program should change the RGB of the displayed line pattern
 *   every time a Canvas Event occurs (mouse button presses).
 *
 *   The program works fine if COLOUR_NUM (defined below) is 2,
 *   but does NOT work if COLOUR_NUM is greater than 2.
 *
 *   If anybody can shed some light on this, I would appreciate it!
 *
 *   My compile line is as follows ("col.c" is the source filename):
 *       cc -I/usr/openwin/include col.c -L/usr/openwin/lib -lxview -lX
 *
 *------------------------------------------------------------
 *   Stephen Peter,  internet:  steve@cad0.arch.unsw.oz.au
 *   April 1991.
 *------------------------------------------------------------
 */
#include <stdio.h>
#include <X11/Xlib.h>
#include <X11/X.h>
#include <X11/Xutil.h>
#include <xview/xview.h>
#include <xview/notify.h>
#include <xview/canvas.h>
#include <xview/cms.h>
#include <xview/xv_xrect.h>

#define COLOUR_NUM   2      /* <------- if this number is changed
					(eg: to 4) then nothing is drawn */
Frame             frame;
Canvas            canvas;
Cms               cms;

void		canvas_repaint_proc();
void		set_colour();
void		event_proc ();

static  Xv_singlecolor   colour_map_seg[COLOUR_NUM];

unsigned char 	red, green, blue;

/**************************************************************************/
main(argc, argv)
int     argc;
char    *argv[];
{
    extern void exit();
    int a;

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

    /*----- initialise the colours (to white) */
    for (a = 0; a < COLOUR_NUM; a++)   {
	colour_map_seg[a].red   =  255;
	colour_map_seg[a].green =  255;
	colour_map_seg[a].blue  =  255;    }

    cms = (Cms)xv_create(NULL, CMS, 
			CMS_TYPE, XV_DYNAMIC_CMS,
			CMS_SIZE, 2,
			CMS_COLORS, colour_map_seg, NULL);

    frame = (Frame)xv_create(XV_NULL, FRAME,
        FRAME_LABEL,            argv[0],
        FRAME_SHOW_FOOTER,      TRUE,
        NULL);

    canvas = (Canvas)xv_create(frame, CANVAS,
        CANVAS_REPAINT_PROC,    canvas_repaint_proc,
        /*XV_WIDTH,               250,
        XV_HEIGHT,              260,*/
        WIN_CMS,                cms,
        CANVAS_X_PAINT_WINDOW,  TRUE,
        CANVAS_RETAINED,        FALSE,
        NULL);

    xv_set (canvas_paint_window(canvas),
		WIN_EVENT_PROC,	set_colour,
		NULL);

    red   = 120;
    green = 120;
    blue  = 120;

    xv_main_loop(frame);
}

/**************************************************************************/
/* this routine gets called after the app-window is resized/covered etc,
   the size of the window is requested and then the line pattern is drawn.*/
/**************************************************************************/
void
canvas_repaint_proc(canvas, paint_window, dpy, xwin, xrects)
Canvas        canvas;         /* unused */
Xv_Window     paint_window;
Display      *dpy;
Window        xwin;
Xv_xrectlist *xrects;         /* unused */
{
	GC gc;
	int width, height, x,y, space;

	set_colour(); 

	gc = DefaultGC(dpy, DefaultScreen(dpy));
	XSetForeground (dpy, gc, xv_get(cms, CMS_FOREGROUND_PIXEL));

	width  = (int)xv_get(paint_window, XV_WIDTH);
	height = (int)xv_get(paint_window, XV_HEIGHT);
 	space = 3;
	for (x = 0; x <= (width/space); x++) {
	    XDrawLine(dpy, xwin, gc, x*space,0, width-(x*space),height);
	}

	for (y = 0; y <= (height/space); y++) {
	    XDrawLine(dpy, xwin, gc, width,y*space, 0,height-(y*space));
	}
}

/**************************************************************************/
/* event-proc (I'm not using the arguements) */
void
set_colour  ()
{
	int i;

	red   = (red + 10) % 255;
	blue  = (blue + 20) % 255;
	green = (green + 30) % 255;

	colour_map_seg[COLOUR_NUM-1].red   = red;
	colour_map_seg[COLOUR_NUM-1].green = green;
	colour_map_seg[COLOUR_NUM-1].blue  = blue;

	(void)  xv_set (cms, CMS,
			CMS_SIZE, 	COLOUR_NUM, 
			CMS_INDEX, 	0,
			CMS_COLORS, 	colour_map_seg, 
			NULL);
}
-------------- end included program ------------------
--
 _--_|\                                           steve@cad0.arch.unsw.oz.au
/      \    Stephen Peter                 or  steve@keystone.arch.unsw.oz.au
\_.--._/<-------------------------------------------------------------------
      v     School of Architecture, University of New South Wales, Australia