/* examples/canvas/echelle.c */

#include <helium.h>

He_node *princ, *canvas;
int old_width = 1, old_height = 1;

#define SMAX 1000
int Sx[SMAX], Sy[SMAX], Sn = 0;

void dessin_segment (Window win, int i)
{
    if (i == 0)
         XDrawPoint (he_display, win, he_gc,
            Sx[0], Sy[0]);
    else XDrawLine (he_display, win, he_gc,
            Sx[i-1], Sy[i-1], Sx[i], Sy[i]);
}

void princ_resize_proc (He_node *hn, int width, int height)
{
    HeExpand (canvas, NULL, HE_BOTTOM_RIGHT);
}

void canvas_resize_proc (He_node *hn, int width, int height)
{
    int i;
    for (i = 0; i < Sn; i++) {
        Sx[i] = Sx[i] * width / old_width;
        Sy[i] = Sy[i] * height / old_height;
    }
    old_width = width; old_height = height;
}

void canvas_repaint_proc (He_node *hn, Window win)
{
    int i;
    XSetForeground (he_display, he_gc, he_black);
    for (i = 0; i < Sn; i++)
        dessin_segment (win, i);
}

void canvas_event_proc (He_node *hn, He_event *hev)
{
    switch (hev->type) {
        case ButtonPress :
            HeDrawBg (hn, he_white);
            Sn = 0;
            Sx[Sn] = hev->sx; Sy[Sn] = hev->sy; 
            dessin_segment (hev->win, Sn++);
            break;
        case MotionNotify :
            if (hev->sb > 0 && Sn < SMAX) {
                Sx[Sn] = hev->sx; Sy[Sn] = hev->sy;
                dessin_segment (hev->win, Sn++);
            }
            break;
    }
}

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

    princ = HeCreateFrame();
    HeSetFrameLabel (princ, "Mise ŕ l'échelle");
    HeSetFrameResizeProc (princ, princ_resize_proc);

    canvas = HeCreateCanvas (princ);
    HeSetWidth (canvas, 300);
    HeSetHeight (canvas, 300);
    HeSetCanvasResizeProc  (canvas, canvas_resize_proc);
    HeSetCanvasRepaintProc (canvas, canvas_repaint_proc);
    HeSetCanvasEventProc   (canvas, canvas_event_proc);

    HeFit (princ);

    return HeMainLoop (princ);
}