/* Edouard.Thiel@lif.univ-mrs.fr */
#include <helium.h>
#include <math.h>

He_node *princ, *panel1, *panel2, *canvas, *tmp, *mess, *text1, *b_quit,
        *b_plus, *b_minus;

XImage *xi = NULL;

int recalc_xi = TRUE;

double theV = 1.0;


int min (int a, int b)
{
    return (a < b) ? a : b;
}

void CalcDisque (double V, int width, int height)
{
    int x, y, t,
        xo = width/2, yo = height/2, r = min(xo,yo) - 10, l;
    int R, G, B;
    double H, S;
    double du1, du2;
    char bla[200];
    
    HeSetMessageLabel (mess, "Calcul ...");
    HeFlushDisplay ();
     
    /* Fond blanc */
    du1 = HeGetTime();
    HeSetXiBg (xi, 255, 255, 255);
    du1 = HeGetTime() - du1;
    
    du2 = HeGetTime();
    for (y = -r; y <= 0; y++) {
    
        l = sqrt ((double)(r*r - y*y));
        
        for (x = -l; x <= l; x++) {

            S = sqrt ((double)(x*x + y*y));
 
            /* acos() renvoie angle entre 0 et +PI */
            H = (S == 0) ? 0 : acos (x / S) * HE_COLOR_MAXH / (M_PI*2);

            HeHsvToRgb (H, HE_COLOR_MAXSV * S/r,
                HE_COLOR_MAXSV * V, &R, &G, &B);
            t = (yo + y) * width + xo + x;
            HeSetXiPixel (xi, t, R, G, B);
            
            HeHsvToRgb (H+(HE_COLOR_MAXH/2), HE_COLOR_MAXSV * S/r,
                HE_COLOR_MAXSV * V, &R, &G, &B);
            t = (yo - y) * width + xo - x;
            HeSetXiPixel (xi, t, R, G, B);
        }
    }   
    du2 = HeGetTime() - du2;
    
    sprintf (bla, "Fond %.4f s  Calcul %.4f s", du1, du2);
    HeSetMessageLabel (mess, bla);
}

void TrouveValeurs (int x, int y, double V, int width, int height)
{
    int R, G, B;
    double H, S;
    int xo = width/2, yo = height/2, r = min(xo,yo) - 10, l;
    char bla[200];
     
    HeSetMessageLabel (mess, "");
    
    x -= xo; y -= yo;
    if (abs(y) > r) return;
    l = sqrt ((double)(r*r - y*y));
    if (abs(x) > l) return;
    
    S = sqrt ((double)(x*x + y*y));
    H = (S == 0) ? 0 : acos (x / S) * HE_COLOR_MAXH / (M_PI*2);
    if (y > 0) H = HE_COLOR_MAXH - H;
    HeHsvToRgb (H, HE_COLOR_MAXSV * S/r, HE_COLOR_MAXSV * V, &R, &G, &B);
    
    sprintf (bla, "RGB = (%d,%d,%d)  H = %.1f  S = %.3f",
	R, G, B, H, S/r);
    HeSetMessageLabel (mess, bla);
}

void princ_resize (He_node *hn, int width, int height)
{
    /* printf ("princ resizeproc  width = %d  height = %d\n", width, height); */
    
    HeSetWidth (panel1, width);
    HeJustify (b_quit, NULL, HE_RIGHT);
    
    HeSetWidth (panel2, width);
    HeJustify (panel2, NULL, HE_BOTTOM);

    HeExpand (canvas, NULL, HE_RIGHT);
    HeExpand (canvas, panel2, HE_BOTTOM);
}

void canvas_resize (He_node *hn, int width, int height)
{
    /* printf ("resize %d %d\n", width, height); */
    recalc_xi = TRUE;
}

void canvas_repaint (He_node *hn, Window win)
{
    /* printf ("repaint %d %d\n", HeGetWidth(canvas), HeGetHeight(canvas)); */
    
    if (recalc_xi == TRUE || xi == NULL) {
	/* printf ("   calcul\n"); */
	if (xi != NULL) HeDestroyXi (xi);
	xi = HeCreateXi (HeGetWidth(hn), HeGetHeight(hn));
	CalcDisque (theV, xi->width, xi->height);
	recalc_xi = FALSE;
    }    
    HePutXi (win, he_gc, xi, 0, 0);
}

void canvas_event (He_node_ptr hn, He_event_ptr hev)
{
    switch (hev->type) {
        case ButtonPress :
        case MotionNotify :
            if (hev->sb == 1)
		TrouveValeurs (hev->sx, hev->sy, theV, xi->width, xi->height);
	    break;
    }
}

void grise ()
{
    HeSetActive (b_plus,  theV<1 );
    HeSetActive (b_minus, theV>0 );
}

void butt_proc (He_node *hn)
{
    char *name = HeGetButtonLabel (hn);
    char bla[200];
    
    if (strcmp (name, "Quit") == 0) {
	HeQuit(0);
    } else if (strcmp (name, "-") == 0) {
	if (theV > 0) {
            theV -= 0.05; if (theV < 0) theV = 0;
            grise();
	    sprintf (bla, "%.3f", theV); HeSetTextValue (text1, bla);
	    recalc_xi = TRUE;
	    HePostRepaint(canvas);
        }
    } else if (strcmp (name, "+") == 0) {
	if (theV < 1) {
            theV += 0.05; if (theV > 1) theV = 1;
            grise();
	    sprintf (bla, "%.3f", theV); HeSetTextValue (text1, bla);
	    recalc_xi = TRUE;
	    HePostRepaint(canvas);
        }
    } 
}

void text1_proc (He_node *hn)
{
    double tmp = atof (HeGetTextValue(hn));
    if (tmp >= 0 && tmp <= 1) {
	theV = tmp; grise();
	recalc_xi = TRUE;
	HePostRepaint(canvas);
    } else XBell(he_display, 80);
}

int main (int argc, char *argv[])
{
    HeInit (&argc, &argv);

    princ = HeCreateFrame();
    HeSetFrameLabel (princ, "Palette de couleurs HSV");
    HeSetFrameResizeProc (princ, princ_resize);
    
    panel1 = HeCreatePanel (princ);
    
    HeCreateMessageP (panel1, "V:", TRUE);
    text1 = HeCreateText (panel1);
    HeSetTextValue (text1, "1.000");  
    HeSetTextVisibleLen (text1, 6);  
    HeSetTextNotifyProc (text1, text1_proc);
    HeSetTip (text1, "Value entre 0 et 1");
     
    b_plus  = HeCreateButtonP (panel1, "+", butt_proc, NULL);
    b_minus = HeCreateButtonP (panel1, "-", butt_proc, NULL);
    grise();
    b_quit  = HeCreateButtonP (panel1, "Quit", butt_proc, NULL);

    HeFit(panel1);
    
    canvas = HeCreateCanvas (princ);
    HeSetCanvasRepaintProc (canvas, canvas_repaint);
    HeSetCanvasResizeProc (canvas, canvas_resize);
    HeSetCanvasEventProc (canvas, canvas_event);
    HeJustify (canvas, panel1, HE_TOP);
    HeSetWidth (canvas, 400);
    HeSetHeight (canvas, 400);
    
    HeSetTip (canvas, "Bouton 1 : affiche les paramètres\n"
                      "R,G,B et H,S du point cliqué.");
    
    panel2 = HeCreatePanel (princ);
    HeJustify (panel2, canvas, HE_TOP);
    
    mess = HeCreateMessage (panel2);
    HeFit(panel2);
    
    HeFit (princ);
    
    return HeMainLoop (princ);
}