Function msRotateVectorSymbol

mapsymbol.c:887–943

** msRotateSymbol - Clockwise rotation of a symbol definition. Contributed ** by MapMedia, with clean up by SDL. Currently only type VECTOR and PIXMAP ** symbols are handled. */

 ** symbols are handled.
 */
symbolObj *msRotateVectorSymbol(symbolObj *symbol, double angle)
{
    double angle_rad=0.0;
    double cos_a, sin_a;
    double minx=0.0, miny=0.0, maxx=0.0, maxy=0.0;
    symbolObj *newSymbol = NULL;
   double dp_x, dp_y, xcor, ycor;
    double TOL=0.00000000001;
    int i;

    //assert(symbol->type == MS_SYMBOL_VECTOR);

    newSymbol = (symbolObj *) malloc(sizeof(symbolObj));
    msCopySymbol(newSymbol, symbol, NULL); /* TODO: do we really want to do this for all symbol types? */

    angle_rad = (MS_DEG_TO_RAD*angle);

 
    sin_a = sin(angle_rad);
    cos_a = cos(angle_rad);

    dp_x = symbol->sizex * .5; /* get the shift vector at 0,0 */
    dp_y = symbol->sizey * .5;

    /* center at 0,0 and rotate; then move back */
    for( i=0;i < symbol->numpoints;i++) {
        /* don't rotate PENUP commands (TODO: should use a constant here) */
        if ((symbol->points[i].x == -99.0) || (symbol->points[i].x == -99.0) ) {
            newSymbol->points[i].x = -99.0;
            newSymbol->points[i].y = -99.0;
            continue;
        }

        newSymbol->points[i].x = dp_x + ((symbol->points[i].x-dp_x)*cos_a - (symbol->points[i].y-dp_y)*sin_a);
        newSymbol->points[i].y = dp_y + ((symbol->points[i].x-dp_x)*sin_a + (symbol->points[i].y-dp_y)*cos_a);
    }

    /* get the new bbox of the symbol, because we need it to get the new dimensions of the new symbol */
    get_bbox(newSymbol->points, newSymbol->numpoints, &minx, &miny, &maxx, &maxy);
    if ( (fabs(minx)>TOL) || (fabs(miny)>TOL) ) {
        xcor = minx*-1.0; /* symbols always start at 0,0 so get the shift vector */
        ycor = miny*-1.0;
        for( i=0;i < newSymbol->numpoints;i++) {
            if ((newSymbol->points[i].x == -99.0) || (newSymbol->points[i].x == -99.0))
                continue;
            newSymbol->points[i].x = newSymbol->points[i].x + xcor;
            newSymbol->points[i].y = newSymbol->points[i].y + ycor;
        }

        /* update the bbox to get the final dimension values for the symbol */
        get_bbox(newSymbol->points, newSymbol->numpoints, &minx, &miny, &maxx, &maxy);
    }

    newSymbol->sizex = maxx;
    newSymbol->sizey = maxy;
    return newSymbol;
}