ref: 2360b77812e184902e44c7f4ea2f6fc79729e370
dir: /emccpre.js/
/*
* emccpre.js: one of the Javascript components of an Emscripten-based
* web/Javascript front end for Puzzles.
*
* The other parts of this system live in emcc.c and emcclib.js. It
* also depends on being run in the context of a web page containing
* an appropriate collection of bits and pieces (a canvas, some
* buttons and links etc), which is generated for each puzzle by the
* script html/jspage.pl.
*
* This file contains the Javascript code which is prefixed unmodified
* to Emscripten's output via the --pre-js option. It declares all our
* global variables, and provides the puzzle init function and a
* couple of other helper functions.
*/
// To avoid flicker while doing complicated drawing, we use two
// canvases, the same size. One is actually on the web page, and the
// other is off-screen. We do all our drawing on the off-screen one
// first, and then copy rectangles of it to the on-screen canvas in
// response to draw_update() calls by the game backend.
var onscreen_canvas, offscreen_canvas;
// A persistent drawing context for the offscreen canvas, to save
// constructing one per individual graphics operation.
var ctx;
// Bounding rectangle for the copy to the onscreen canvas that will be
// done at drawing end time. Updated by js_canvas_draw_update and used
// by js_canvas_end_draw.
var update_xmin, update_xmax, update_ymin, update_ymax;
// Module object for Emscripten. We fill in these parameters to ensure
// that Module.run() won't be called until we're ready (we want to do
// our own init stuff first), and that when main() returns nothing
// will get cleaned up so we remain able to call the puzzle's various
// callbacks.
var Module = {
'noInitialRun': true,
'noExitRuntime': true
};
// Variables used by js_canvas_find_font_midpoint().
var midpoint_test_str = "ABCDEFGHIKLMNOPRSTUVWXYZ0123456789";
var midpoint_cache = [];
// Variables used by js_activate_timer() and js_deactivate_timer().
var timer = null;
var timer_reference_date;
// void timer_callback(double tplus);
//
// Called every 20ms while timing is active.
var timer_callback;
// The status bar object, if we create one.
var statusbar = null;
// Currently live blitters. We keep an integer id for each one on the
// JS side; the C side, which expects a blitter to look like a struct,
// simply defines the struct to contain that integer id.
var blittercount = 0;
var blitters = [];
// State for the dialog-box mechanism. dlg_dimmer and dlg_form are the
// page-darkening overlay and the actual dialog box respectively;
// dlg_next_id is used to allocate each checkbox a unique id to use
// for linking its label to it (see js_dialog_boolean);
// dlg_return_funcs is a list of JS functions to be called when the OK
// button is pressed, to pass the results back to C.
var dlg_dimmer = null, dlg_form = null;
var dlg_next_id = 0;
var dlg_return_funcs = null;
// void dlg_return_sval(int index, const char *val);
// void dlg_return_ival(int index, int val);
//
// C-side entry points called by functions in dlg_return_funcs, to
// pass back the final value in each dialog control.
var dlg_return_sval, dlg_return_ival;
// The <select> object implementing the game-type drop-down, and a
// list of the <option> objects inside it. Used by js_add_preset(),
// js_get_selected_preset() and js_select_preset().
//
// gametypehiddencustom is a second copy of the 'Custom' dropdown
// element, set to display:none. This is used by a bodge in emcclib.js
// (see comment in js_add_preset) to arrange that if the Custom
// element is (apparently) already selected, we still find out if the
// user selects it again.
var gametypeselector = null, gametypeoptions = [];
var gametypehiddencustom = null;
// The two anchors used to give permalinks to the current puzzle. Used
// by js_update_permalinks().
var permalink_seed, permalink_desc;
// The undo and redo buttons. Used by js_enable_undo_redo().
var undo_button, redo_button;
// Helper function which is passed a mouse event object and a DOM
// element, and returns the coordinates of the mouse event relative to
// the top left corner of the element by iterating upwards through the
// DOM finding each element's offset from its parent, and thus
// calculating the page-relative position of the target element so
// that we can subtract that from event.page{X,Y}.
function relative_mouse_coords(event, element) {
var ex = 0, ey = 0;
while (element.offsetParent) {
ex += element.offsetLeft;
ey += element.offsetTop;
element = element.offsetParent;
}
return {x: event.pageX - ex,
y: event.pageY - ey};
}
// Init function called from body.onload.
function initPuzzle() {
// Construct the off-screen canvas used for double buffering.
onscreen_canvas = document.getElementById("puzzlecanvas");
offscreen_canvas = document.createElement("canvas");
offscreen_canvas.width = onscreen_canvas.width;
offscreen_canvas.height = onscreen_canvas.height;
// Stop right-clicks on the puzzle from popping up a context menu.
// We need those right-clicks!
onscreen_canvas.oncontextmenu = function(event) { return false; }
// Set up mouse handlers. We do a bit of tracking of the currently
// pressed mouse buttons, to avoid sending mousemoves with no
// button down (our puzzles don't want those events).
mousedown = Module.cwrap('mousedown', 'void',
['number', 'number', 'number']);
buttons_down = 0;
onscreen_canvas.onmousedown = function(event) {
var xy = relative_mouse_coords(event, onscreen_canvas);
mousedown(xy.x, xy.y, event.button);
buttons_down |= 1 << event.button;
onscreen_canvas.setCapture(true);
};
mousemove = Module.cwrap('mousemove', 'void',
['number', 'number', 'number']);
onscreen_canvas.onmousemove = function(event) {
if (buttons_down) {
var xy = relative_mouse_coords(event, onscreen_canvas);
mousemove(xy.x, xy.y, buttons_down);
}
};
mouseup = Module.cwrap('mouseup', 'void',
['number', 'number', 'number']);
onscreen_canvas.onmouseup = function(event) {
if (buttons_down & (1 << event.button)) {
buttons_down ^= 1 << event.button;
var xy = relative_mouse_coords(event, onscreen_canvas);
mouseup(xy.x, xy.y, event.button);
}
};
// Set up keyboard handlers. We do all the actual keyboard
// handling in onkeydown; but we also call event.preventDefault()
// in both the keydown and keypress handlers. This means that
// while the canvas itself has focus, _all_ keypresses go only to
// the puzzle - so users of this puzzle collection in other media
// can indulge their instinct to press ^R for redo, for example,
// without accidentally reloading the page.
key = Module.cwrap('key', 'void', ['number', 'number', 'string',
'string', 'number', 'number']);
onscreen_canvas.onkeydown = function(event) {
key(event.keyCode, event.charCode, event.key, event.char,
event.shiftKey ? 1 : 0, event.ctrlKey ? 1 : 0);
event.preventDefault();
};
onscreen_canvas.onkeypress = function(event) {
event.preventDefault();
};
// command() is a C function called to pass back events which
// don't fall into other categories like mouse and key events.
// Mostly those are button presses, but there's also one for the
// game-type dropdown having been changed.
command = Module.cwrap('command', 'void', ['number']);
// Event handlers for buttons and things, which call command().
document.getElementById("specific").onclick = function(event) {
// Ensure we don't accidentally process these events when a
// dialog is actually active, e.g. because the button still
// has keyboard focus
if (dlg_dimmer === null)
command(0);
};
document.getElementById("random").onclick = function(event) {
if (dlg_dimmer === null)
command(1);
};
document.getElementById("new").onclick = function(event) {
if (dlg_dimmer === null)
command(5);
};
document.getElementById("restart").onclick = function(event) {
if (dlg_dimmer === null)
command(6);
};
undo_button = document.getElementById("undo");
undo_button.onclick = function(event) {
if (dlg_dimmer === null)
command(7);
};
redo_button = document.getElementById("redo");
redo_button.onclick = function(event) {
if (dlg_dimmer === null)
command(8);
};
document.getElementById("solve").onclick = function(event) {
if (dlg_dimmer === null)
command(9);
};
gametypeselector = document.getElementById("gametype");
gametypeselector.onchange = function(event) {
if (dlg_dimmer === null)
command(2);
};
// In IE, the canvas doesn't automatically gain focus on a mouse
// click, so make sure it does
onscreen_canvas.addEventListener("mousedown", function(event) {
onscreen_canvas.focus();
});
// In our dialog boxes, Return and Escape should be like pressing
// OK and Cancel respectively
document.addEventListener("keydown", function(event) {
if (dlg_dimmer !== null && event.keyCode == 13) {
for (var i in dlg_return_funcs)
dlg_return_funcs[i]();
command(3);
}
if (dlg_dimmer !== null && event.keyCode == 27)
command(4);
});
// Set up the function pointers we haven't already grabbed.
dlg_return_sval = Module.cwrap('dlg_return_sval', 'void',
['number','string']);
dlg_return_ival = Module.cwrap('dlg_return_ival', 'void',
['number','number']);
timer_callback = Module.cwrap('timer_callback', 'void', ['number']);
// Save references to the two permalinks.
permalink_desc = document.getElementById("permalink-desc");
permalink_seed = document.getElementById("permalink-seed");
// Default to giving keyboard focus to the puzzle.
onscreen_canvas.focus();
// Run the C setup function, passing argv[1] as the fragment
// identifier (so that permalinks of the form puzzle.html#game-id
// can launch the specified id).
Module.arguments = [location.hash];
Module.run();
// And if we get here with everything having gone smoothly, i.e.
// we haven't crashed for one reason or another during setup, then
// it's probably safe to hide the 'sorry, no puzzle here' div and
// show the div containing the actual puzzle.
document.getElementById("apology").style.display = "none";
document.getElementById("puzzle").style.display = "inline";
}