/*
-----------------------------------------------
HDR HTML Viewer ver. 1.0
Author: Rafal Mantiuk
URL:    http://www.cs.ubc.ca/~mantiuk/hdrhtml.html
----------------------------------------------- */

function set_opacity( obj, opacity ) {
    // for IE8
    obj.style.filter="progid:DXImageTransform.Microsoft.Alpha(Opacity=" + opacity*100 + ")";
    // for IE5-7
    obj.style.filter = "alpha(opacity=" + opacity*100 + ")";
    // for all other browsers
    obj.style.opacity = opacity;
}

function update_exp_text( hdr_image, new_exp ) {
    document.getElementById(hdr_image.base_name + "_exp_text").innerHTML = "EV: " + Math.round( (hdr_image.best_exp-new_exp)*10 )/10 + " f";
}

function change_exp( hdr_image, exp_change ) {

    hdr_active_image = hdr_image;
    hdr_image.exposure = hdr_image.exposure + exp_change;

    if( hdr_image.exposure > hdr_image.f8_stops*8 ) {
        hdr_image.exposure = hdr_image.f8_stops*8;
    }
    else if( hdr_image.exposure < 0 ) {
        hdr_image.exposure = 0;
    }

    exp_cur = Math.floor(hdr_image.exposure / 8);
    exp_shar = exp_cur + 1;

    exp_blend = Math.round((hdr_image.exposure - exp_cur*8)*hdr_image.f_step_res);

    var i;
    for( i = 0; i < hdr_image.basis; i++ ) {
        var img_obj = document.getElementById(hdr_image.base_name+"_"+i);
        img_obj.src = hdr_image.image_dir + hdr_image.base_name + "_"+exp_cur+"_" + (i+1) + ".jpg";
        set_opacity( img_obj, cf[exp_blend][i] );
    }

    for( i = 0; i < hdr_image.shared_basis; i++ ) {
        var img_obj = document.getElementById(hdr_image.base_name+"_"+(i+hdr_image.basis));
        img_obj.src = hdr_image.image_dir + hdr_image.base_name + "_"+exp_shar+"_" + (i+1) + ".jpg";
        set_opacity( img_obj, cf[exp_blend][i+hdr_image.basis] );
    }

    var hist_left = (hdr_image.exposure-hdr_image.hist_start)*hdr_image.pix_per_fstop;

    hist = document.getElementById(hdr_image.base_name+"_dr_wind");
    hist.style.left = Math.round(hist_left) + "px";
    hist.style.width = hdr_image.pix_per_fstop*8 + "px";
    set_opacity( hist, 0.7 );

    update_exp_text( hdr_image, hdr_image.exposure );
}

function insert_hdr_image( hdr_image ) {

    for( i = 0; i < hdr_image.basis + hdr_image.shared_basis; i++ ) {
        document.write("<img id=\"" + hdr_image.base_name + "_" + i +
                     "\" style=\"margin: 0px; padding: 0px; opacity: 1; width: " +
                     hdr_image.width + "px; height: " + hdr_image.height +
                     "px; position: absolute; top: 0px; left: 0px\"" +
                     " />\n");
    }
}

function getAbsX (obj) {
    var abs_x=0;
    while(obj) {
        abs_x+= obj.offsetLeft;
        obj= obj.offsetParent;
    }
    return abs_x;
}

function dr_wind_clicked( event, hdr_image ) {

    var hist = document.getElementById(hdr_image.base_name+"_dr_wind");
    var drw_left = hist.offsetLeft;
    var drw_right = hist.offsetLeft + hist.offsetWidth;

    var hist_obj = document.getElementById(hdr_image.base_name + "_hist");
    var rel_x = event.clientX - getAbsX(hist_obj) - 5;

    var small_step_marg = 20;

    if( rel_x < drw_left ) {
        change_exp( hdr_image, (drw_left-rel_x) < small_step_marg ? -1/3 : -1 );
    } else if( rel_x > drw_right ) {
        change_exp( hdr_image, (rel_x-drw_right) < small_step_marg ? 1/3 : 1 );
    }

}

function dr_wind_mousedown( event, hdr_image ) {

    if(event.preventDefault) {
        event.preventDefault();
    }

    var ctrl_obj = document.getElementById(hdr_image.base_name + "_dr_ctrl");
    var drw_obj = document.getElementById(hdr_image.base_name+"_dr_wind");
    set_opacity( drw_obj, 0.5 );

    hdr_mousedrag.hdr_image = hdr_image;
    hdr_mousedrag.start_mouse_x = event.clientX;
    hdr_mousedrag.start_win_x = drw_obj.offsetLeft + 2;
    ctrl_obj.onmousemove = dr_wind_move;
    ctrl_obj.onmouseup = dr_wind_mouseup;
}

function dr_wind_mouseup( event ) {
    event = event || window.event;

    hdr_image = hdr_mousedrag.hdr_image;

    var ctrl_obj = document.getElementById(hdr_image.base_name + "_dr_ctrl");
    var drw_obj = document.getElementById(hdr_image.base_name+"_dr_wind");
    var drw_left = drw_obj.offsetLeft;

    var new_exp = Math.round((drw_obj.offsetLeft/hdr_image.pix_per_fstop + hdr_image.hist_start)*3)/3;

    ctrl_obj.onmousemove = null;
    ctrl_obj.onmouseup = null;
    hdr_mousedrag.hdr_image = null;

    change_exp( hdr_image, new_exp - hdr_image.exposure );
}


function dr_wind_move(event){
    event = event || window.event;

    hdr_image = hdr_mousedrag.hdr_image;
    var drw_obj = document.getElementById(hdr_image.base_name+"_dr_wind");

    var new_pos = (event.clientX-hdr_mousedrag.start_mouse_x) + hdr_mousedrag.start_win_x;
    drw_obj.style.left = new_pos + "px";

    var new_exp = Math.round((drw_obj.offsetLeft/hdr_image.pix_per_fstop + hdr_image.hist_start)*3)/3;
    update_exp_text( hdr_image, new_exp );
}

function hdr_show_help() {
    newwindow=window.open('','name','height=400,width=300');
    var tmp = newwindow.document;
    tmp.write('<html><head><title>HDR HTML viewer help</title>');
    tmp.write('</head><body>');
    tmp.write('<a href="http://pfstools.sourceforge.net/hdrhtml/" target="_blank">HDR HTML viewer</a> <div style="font-size: small">ver. 1.0</div>');
    tmp.write('<div style="font-size: small">(C) 2008 Rafal Mantiuk</div>');
    tmp.write('<ul style="font-size: small">');
    tmp.write('<li>Change exposure by scrolling the blue dynamic range window left and right.</li>');
    tmp.write('<li>Click on the left or right side of the dynamic range window to change exposure by either 1 or 1/3 of an f-stop depending on how far from the window you click.</li>');
    tmp.write('<li>Press "-" and "=" keys to change exposure by 1 f-stop.</li>');
    tmp.write('<li>The green plot represents image histogram. Each tick represent one f-stop. EV value is given in f-stops (log<sub>2</sub> units) relative to the inital exposure.</li>');
    tmp.write('</ul>');
    tmp.write('</body></html>');
    tmp.close();
}

function hdr_onkeydown(e) {
    var hdr_image = hdr_active_image;
    var keynum;
    if( hdr_image == null )
        return;

    if(window.event) { // IE
        keynum = window.event.keyCode;
        if( keynum == 189 )
            change_exp( hdr_image, +1 );
        if( keynum == 187 )
            change_exp( hdr_image, -1 );
    } else if(e.which) { // Netscape/Firefox/Opera
        keynum = e.which;
        if( keynum == 109 )
            change_exp( hdr_image, +1 );
        if( keynum == 61 || keynum == 107)
            change_exp( hdr_image, -1 );
    }

    //var ev = document.getElementById(hdr_image.base_name + "_exp_text");
    //ev.innerHTML = ev.innerHTML + " (" + keynum + ")";
}

function dr_wind_mousewheel( event ) {
    if (!event) /* For IE. */
        event = window.event;

    var hdr_image = hdr_active_image;

    var posx = 0;
    var posy = 0;
    if (event.pageX || event.pageY) {
        posx = event.pageX;
        posy = event.pageY;
    } else if (event.clientX || event.clientY) {
        posx = event.clientX;
        posy = event.clientY;
    }
    if (posx || posy) {
        var ctrl = document.getElementById(hdr_image.base_name+"_dr_ctrl");
        if (posx < ctrl.offsetLeft || posx >= ctrl.offsetLeft + ctrl.offsetWidth
            || posy < ctrl.offsetTop || posy >= ctrl.offsetTop + ctrl.offsetHeight) {
            //var ev = document.getElementById(hdr_image.base_name + "_exp_text");
            //ev.innerHTML = "(" + posx + "," + posy + "; " + ctrl.offsetLeft + "," + ctrl.offsetTop + "; " + ctrl.offsetWidth + "," + ctrl.offsetHeight + ")";
            return;
        }
    }

    var delta = 0;
    if (event.wheelDelta) { /* IE/Opera. */
        delta = event.wheelDelta/120;
        /** In Opera 9, delta differs in sign as compared to IE.
         */
        if (window.opera)
            delta = -delta;
    } else if (event.detail) { /** Mozilla case. */
        /** In Mozilla, sign of delta is different than in IE.
         * Also, delta is multiple of 3.
         */
        delta = -event.detail/3;
    }
    /** If delta is nonzero, handle it.
     * Basically, delta is now positive if wheel was scrolled up,
     * and negative, if wheel was scrolled down.
     */
    if (delta)
        change_exp( hdr_image, (delta > 0) ? -1/3 : 1/3 );
    /** Prevent default actions caused by mouse wheel.
     * That might be ugly, but we handle scrolls somehow
     * anyway, so don't bother here..
     */
    if (event.preventDefault)
        event.preventDefault();
    event.returnValue = false;
}