roar/js/undo.js

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JavaScript
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2018-10-24 15:14:46 +00:00
var undo = (function(){
var max_states = 200;
// undotimetotal = 0;
var stack = {undo: [], redo: []};
var current_undo = null;
var dom = {undo: undo_el, redo: redo_el};
dom.undo.is_visible = dom.redo.is_visible = false
var LexState = function(lex){
this.fg = lex.fg;
this.bg = lex.bg;
this.char = lex.char;
this.opacity = lex.opacity;
};
var update_dom_visibility = function(type){
var el = dom[type]
if (el.is_visible){
if (stack[type].length === 0) {
el.classList.add('hidden')
el.is_visible = false
}
} else if (stack[type].length > 0){
el.classList.remove('hidden')
el.is_visible = true
}
}
var update_dom = function(){
update_dom_visibility('undo')
update_dom_visibility('redo')
}
// state is an undo or redo state that might contain these props
// { lexs: {'0,0': LexState, ...}, // for sparse lex changes (eg brush, fill)
// focus: {x:, y: },
// size: {w:, h: },
// rects: [{x:, y:, w:, h:, lexs: [LexState, ...]}, ...]
// }
var new_state = function(){
var state = {lexs:{}};
save_focus(canvas.focus_x, canvas.focus_y, state)
return state
}
var new_redo = function(){
return new_state()
}
var new_undo = function(){
current_undo = new_state()
stack.redo = []
stack.undo.push(current_undo)
if (stack.undo.length > max_states) stack.undo.shift();
update_dom()
return current_undo
}
var save_focus = function(x, y, state){
state = state || current_undo
state.focus = {x:x, y:y}
}
var save_size = function(w, h, state){
state = state || current_undo
state.size = {w:w, h:h};
}
// the reason for stringifying the x y coords is so that each
// coordinate is saved only once in an undo state.
// otherwise there would be problems with, eg, a brush stroke
// that passed over the same grid cell twice.
var save_lex = function(x, y, lex, state){
// var start = Date.now()
state = state || current_undo
var lexs = state.lexs;
var xy = x + "," + y;
if (xy in lexs) return;
lexs[xy] = new LexState(lex)
// undotimetotal += Date.now() - start
}
var save_focused_lex = function(state){
state = state || current_undo
var x = canvas.focus_x
var y = canvas.focus_y
save_lex(x, y, canvas.aa[y][x], state)
}
var save_rect = function(xpos, ypos, w, h, state){
if (w === 0 || h === 0) return;
state = state || current_undo;
state.rects = state.rects || []
var aa = canvas.aa;
var rect = {x: xpos, y: ypos, w: w, h: h, lexs: []}
var lexs = rect.lexs
var xlen = xpos + w
var ylen = ypos + h
for (var y = ypos; y < ylen; y++){
var aay = aa[y]
for (var x = xpos; x < xlen; x++){
lexs.push(new LexState(aay[x]))
}
}
state.rects.push(rect)
}
var save_resize = function(w, h, old_w, old_h, state){
state = state || current_undo
save_size(old_w, old_h, state)
if (old_w > w){
// .---XX
// | XX
// |___XX
save_rect(w, 0, old_w - w, old_h, state)
if (old_h > h){
// .----.
// | |
// XXXX_|
save_rect(0, h, w, old_h - h, state)
}
} else if (old_h > h){
// .----.
// | |
// XXXXXX
save_rect(0, h, old_w, old_h - h, state)
}
}
var restore_state = function(state){
// all redo states will have a cached undo state on them
// an undo state might have a cached redo state
// if it doesn't have one, generate one
var make_redo = ! ('redo' in state || 'undo' in state);
var aa = canvas.aa
var lex, lexs;
if (make_redo){
state.redo = new_redo()
// copy saved rects that intersect with current canvas size
// important to do this before resizing canvas
if ('rects' in state){
for (var ri=0, rect; rect=state.rects[ri]; ri++){
if (rect.x >= canvas.w ||
rect.y >= canvas.h) continue;
var w = Math.min(rect.w, canvas.w - rect.x)
var h = Math.min(rect.h, canvas.h - rect.y)
save_rect(rect.x, rect.y, w, h, state.redo)
}
}
if ('size' in state){
save_resize(state.size.w, state.size.h, canvas.w, canvas.h, state.redo)
}
}
if ('size' in state){
canvas.resize(state.size.w, state.size.h, true);
}
if ('rects' in state){
for (var ri=0, rect; rect=state.rects[ri]; ri++){
lexs = rect.lexs
for (var li=0; lex=lexs[li]; li++){
var x = (li % rect.w) + rect.x
var y = ((li / rect.w)|0) + rect.y
aa[y][x].assign(lex)
}
}
}
lexs = state.lexs
for (var key in lexs){
var xy = key.split(',');
lex = aa[xy[1]][xy[0]]
if (make_redo)
save_lex(xy[0], xy[1], lex, state.redo)
lex.assign(lexs[key])
}
if ('focus' in state){
canvas.focus_x = state.focus.x
canvas.focus_y = state.focus.y
if (current_canvas === canvas){
canvas.focus()
}
}
}
var undo = function(){
var state = stack.undo.pop();
if (!state) return;
restore_state(state)
// now take the applied undo state and store it on the redo state
// and push the redo state to the redo stack
state.redo.undo = state
stack.redo.push(state.redo)
delete state.redo
update_dom()
}
var redo = function(){
var state = stack.redo.pop();
if (!state) return;
restore_state(state)
state.undo.redo = state
stack.undo.push(state.undo)
delete state.undo
update_dom()
}
return {
stack: stack,
new: new_undo,
// new_redo: new_redo,
save_focus: save_focus,
save_size: save_size,
save_lex: save_lex,
save_focused_lex: save_focused_lex,
save_rect: save_rect,
save_resize: save_resize,
undo: undo,
redo: redo
}
})()