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canvas_test.html
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<html>
<head>
<title>Graphs</title>
<!-- https://developer.mozilla.org/en/Canvas_tutorial/Drawing_shapes#Rectangular_shape_example -->
<script type="text/javascript" src="convert.js"></script>
<script type="text/javascript" src="tree.js"></script>
<script type="text/javascript" src="math.js"></script>
<script type="text/javascript">
blocks = [];
var ctx = null;
var WIDTH = 0;
var HEIGHT = 0;
var MINX = 0;
var MINY = 0;
var MAXX = 0;
var MAXY = 0;
var is_dragging = -1;
var prevX = -1;
var prevY = -1;
var origX=0, origY=0;
var tree_mode=0;
function Block(text) {
this.x = 0;
this.y = 0;
this.width = 50;
this.height = 50;
this.node = new node();
this.node.value = text;
}
function node_to_block(n)
{
for(i = 0; i < blocks.length; i++){
if(blocks[i].node == n)
return blocks[i];
}
return null;
}
function clear() {
ctx.fillStyle = 'white';
ctx.fillRect(0, 0, WIDTH, HEIGHT);
}
function g2log(val)
{
var x = 2;
while(val >= x){
x *= 2;
}
return x;
}
function tree_align(node, value) {
if(!node) return 0;
block = node_to_block(node);
block.x = block.width*value*0.7;
block.y = block.height*(g2log(value))*0.2;
lefties = tree_align(node.left, value*2);
righties = tree_align(node.right, value*2+1);
/* if(node.value == "c" || node.value == "d"){
alert(depth + " " + lefties + " " + righties + " " + value);
}
*/
return lefties+righties+1;
}
function align_blocks() {
var nextX = WIDTH/2 - (blocks.length/2+1)*50;
var nextY = HEIGHT/2 - 50;
if(tree_mode){
root = tree.root;
tree_align(root, 1);
} else {
for (var i = 0; i < blocks.length; i++) {
blocks[i].y = nextY;
blocks[i].x = nextX;
nextX += blocks[i].width + 10;
}
}
}
function draw()
{
clear();
ctx.strokeStyle = '#11e57f';
ctx.lineWidth = 1;
ctx.font = "20pt Verdana";
ctx.fillStyle = 'black';
for (var i = 0; i < blocks.length; i++) {
ctx.strokeRect(blocks[i].x, blocks[i].y,
blocks[i].width,
blocks[i].height);
//print the text
code = [blocks[i].node.value];
for (var j = 0; j < code.length; j++) {
ctx.fillText(code[j], blocks[i].x+15, blocks[i].y+j*(blocks[i].height/2)+blocks[i].height/2);
}
}
}
function distance(x1,y1,x2,y2){
return (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);
}
function find_near_block(x,y,excl)
{
var mini = Number.MAX_VALUE;
var best = -1;
for(var i = 0; i < blocks.length; i++){
if(i == excl) continue;
var d = distance(blocks[i].x, blocks[i].y, x, y);
if(d < mini){
mini = d;
best = i;
}
}
return best;
}
function drag_finish(b){
if(b < 0) return;
block = blocks[b];
/* did a block just hop onto the other side
of the '='? */
n = block.node;
// walk up block b's tree until the = sign
while(n && n.par != null){
if(n.par.value == "="){
eq_block = node_to_block(n.par);
//compare coordinates
if(eq_block.x > block.x ) {
//block is now to the right
//console.log("= is left; " + eq_block.x + " vs " + (block.x+block.width));
if(origX > eq_block.x){
//console.log("moved right to left");
doswap(n.par, block.node, 0);
}
} else if(eq_block.x < block.x) {
//block is now to the left
//console.log("= is right; " + eq_block.x + " vs " + (block.x+block.width));
if(origX < eq_block.x){
//console.log("moved left to right");
doswap(n.par, block.node, 1);
}
}
break;
}
n = n.par;
}
render_from_tree();
if(!tree_mode){
if(b != -1){
//align block i to the nearest one
var near = find_near_block(block.x, block.y, b);
if(near != -1){
block.y = blocks[near].y;
}
}
fix_x_overlaps();
}
}
function is_overlapping(block_idx) {
b = blocks[block_idx];
for(var i = 0; i < blocks.length; i++){
a = blocks[i];
if( (a.x + a.width > b.x && a.x < b.x+b.width)
|| (b.x + b.width > a.x && b.x < a.x+a.width)){
return 1;
}
}
return 0;
}
function fix_x_overlaps(){
for(var i = 0; i < blocks.length; i++){
for(var j = 0; j < blocks.length; j++){
if(j == i) continue;
if( blocks[i].x > blocks[j].x ){
b = blocks[i];
a = blocks[j];
} else {
a = blocks[i];
b = blocks[j];
}
if(a.x+a.width+5 > b.x && a.x+5 < b.x+b.width){
overlap = a.x+a.width - b.x;
a.x -= overlap/2+10;
b.x += overlap/2+10;
fix_x_overlaps();
}
}
}
}
//in: x,y coordinates
//out: first block at those coordinates
function find_block(x,y) {
x -= MINX;
y -= MINY;
for (var i = 0; i < blocks.length; i++) {
lx = blocks[i].x;
rx = blocks[i].width + lx;
uy = blocks[i].y;
dy = (2)*blocks[i].height + uy;
//alert( MINX + " " + MINY + " :: " + lx + " " + x + " " + rx + "::" + uy + " " + y + " " + dy )
if ((lx <= x && rx >= x) && (uy <= y && dy >= y)) {
return i;
}
}
return -1;
}
function ev_canvas(ev) {
if (ev.type == "mousemove") {
if (is_dragging != -1) {
deltaX = ev.layerX - prevX;
deltaY = ev.layerY - prevY;
blocks[is_dragging].x = deltaX + origX;
blocks[is_dragging].y = deltaY + origY;
//alert((deltaX+origY) + " " + (deltaY+origY))
} else {
}
} else if (ev.type == "mousedown") {
//check through and see if the click collides with a code block
//if it does, turnon dragging
is_dragging = find_block(ev.layerX, ev.layerY)
if (is_dragging != -1) {
//mouse down on block i, enable dragging
prevX = ev.layerX;
prevY = ev.layerY;
origX = blocks[is_dragging].x;
origY = blocks[is_dragging].y;
}
} else if (ev.type == "mouseup") {
drag_finish(is_dragging);
is_dragging = -1;
}
/* multitouch events */
else if (ev.type == "touchmove") {
if (is_dragging != -1) {
deltaX = ev.touches[0].pageX - prevX;
deltaY = ev.touches[0].pageY - prevY;
blocks[is_dragging].x = deltaX + origX;
blocks[is_dragging].y = deltaY + origY;
//alert((deltaX+origY) + " " + (deltaY+origY))
}
} else if (ev.type == "touchstart") {
//check through and see if the click collides with a code block
//if it does, turnon dragging
is_dragging = find_block(ev.touches[0].pageX, ev.touches[0].pageY);
if (is_dragging != -1) {
ev.preventDefault();
//mouse down on block i, enable dragging
prevX = ev.touches[0].pageX;
prevY = ev.touches[0].pageY;
origX = blocks[is_dragging].x;
origY = blocks[is_dragging].y;
}
} else if (ev.type == "touchend") {
drag_finish(is_dragging);
is_dragging = -1;
}
}
function init() {
var canvas = document.getElementById('tutorial');
WIDTH = canvas.width;
HEIGHT = canvas.height;
MINX = canvas.offsetLeft;
MINY = canvas.offsetTop;
MAXX = MINX+WIDTH;
MAXY = MINY+HEIGHT;
align_blocks();
canvas.ontouchstart = ev_canvas;
canvas.ontouchend = ev_canvas;
canvas.ontouchmove = ev_canvas;
canvas.onmousedown = ev_canvas;
canvas.onmousemove = ev_canvas;
canvas.onmouseup = ev_canvas;
if (canvas.getContext) {
ctx = canvas.getContext('2d');
intervalId = setInterval(draw, 20);
return intervalId;
}
}
var tree = new mathTree();
/*
This function updates the infix notation
to match any updates to the tree.
*/
function render_from_tree()
{
var newnodes = tree.printTree();
blocks = [];
for(var idx = 0; idx < newnodes.length; idx++){
var b = new Block(null);
b.node = newnodes[idx];
blocks.push(b);
}
align_blocks();
}
function go_tree_mode()
{
render_from_tree();
var root = tree.root;
print_as_tree(root, -1, -2);
}
function print_as_tree(root, over, up)
{
var root2 = root;
while(root2.left)
{
root2 = root2.left;
over++;
}
var newblock = node_to_block(root);
newblock.x += 3*over;
newblock.y += 50*up;
if(root.left)
print_as_tree(root.left, 0, up+1);
if(root.right)
print_as_tree(root.right, over+1, up+1);
}
function i_to_p(input) {
//convert input into an array of blocks
blocks = []
for(var idx = 0; idx < input.length; idx++){
if(input[idx] == " ") { idx++; }
if( isalnum(input[idx]) ) {
var token = "";
while(idx < input.length){
if(!isalnum(input[idx])) break;
token += input[idx++];
}
blocks.push(new Block(token));
}
op = operators.indexOf(input[idx]);
if(op != -1 || input[idx] == '(' || input[idx] == ')'){
blocks.push(new Block(input[idx]));
}
}
var post = infix_to_postfix(blocks);
var str = "";
for(var i = 0; i < post.length; i++){
str += post[i].value + " ";
}
document.getElementById("ret1").innerHTML = str;
tree = new mathTree();
tree.buildTree(post, post.length-1);
render_from_tree();
}
</script>
<style type="text/css">
body { margin: 20px;
font-family:
arial,verdana,helvetica;
background: #fff;}
h1 { font-size: 140%;
font-weight:
normal;
color: #036; border-bottom: 1px solid #ccc;
}
canvas { border: 2px solid #000; float: left; margin-right: 20px; margin-bottom: 20px; }
pre { float: left;
display: block;
background: rgb(238,238,238);
border: 1px dashed #666; padding: 15px 20px; margin: 0 0 10px 0;
}
</style>
</head>
<body onload="init();">
<div>
<form action="" name="text">
<h3>Infix->Postfix</h3>
<textarea name="input1"></textarea><br />
<input type="button" value="Submit" onclick="javascript:i_to_p(document.text.input1.value);" />
<input type="button" value="Treemode" onclick="javascript:go_tree_mode();" />
<div>
<canvas id="tutorial" width="640" height="512"></canvas>
</div>
<div id="ret1"></div>
</div>
</body>
</html>