File size: 3,459 Bytes
36064ef | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 | import { writable } from "svelte/store";
import type { ImageEditorContext } from "./editor";
/**
* Base command interface that is added to the command_managers history
*/
export interface Command {
/**
* The name of the command
*/
name: string;
/**
* Optionally called when the command is first executed for multi-step commands
* @param args arguments to pass to the command
*/
start?: (...args: any) => any | Promise<any>;
/**
* Optionally called when the command is continued for multi-step commands
* @param args arguments to pass to the command
*/
continue?: (...args: any) => any | Promise<any>;
/**
* Optionally called when the command is stopped for multi-step commands
* @param args arguments to pass to the command
*/
stop?: (...args: any) => any | Promise<any>;
/**
* Called by the command manager to execute the command, can act as a no-op if the work has already been done
* This function must be able to recreate the command if the command is undone and redone (`stop`/`start`/`continue` will not be called again)
*/
execute(context?: ImageEditorContext): any | Promise<any>;
/**
* Called by the command manager to undo the command
* This function must be able to undo the work done by the execute function
*/
undo(): any | Promise<any>;
}
/**
* Creates a command node
* @param command command to add to the node
* @returns a command node
*/
export class CommandNode {
command: Command | null;
next: CommandNode | null;
previous: CommandNode | null;
constructor(command?: Command) {
this.command = command || null;
this.next = null;
this.previous = null;
}
push(command: Command): void {
this.next = null;
const node = new CommandNode(command);
node.previous = this;
this.next = node;
}
}
/**
* Creates a command manager
* @returns a command manager
*/
export class CommandManager {
history: CommandNode = new CommandNode();
current_history = writable(this.history);
undo(): void {
if (this.history.previous) {
this.history.command?.undo();
this.history = this.history.previous;
this.current_history.update(() => this.history);
}
}
redo(context?: ImageEditorContext): void {
if (this.history.next) {
this.history = this.history.next;
this.history.command?.execute(context);
this.current_history.update(() => this.history);
}
}
async execute(command: Command, context: ImageEditorContext): Promise<void> {
await command.execute(context);
this.history.push(command);
this.history = this.history.next!;
this.current_history.update(() => this.history);
}
async wait_for_next_frame(): Promise<void> {
return new Promise((resolve) => {
requestAnimationFrame(() => {
resolve();
});
});
}
async replay(
full_history: CommandNode,
context: ImageEditorContext
): Promise<void> {
while (full_history.previous) {
full_history = full_history.previous;
}
while (full_history.next) {
await full_history.next.command!.execute(context);
full_history = full_history.next;
}
this.history = full_history;
this.current_history.update(() => this.history);
}
contains(command_name: string): boolean {
let current: CommandNode | null = this.history;
while (current) {
if (current.command?.name === command_name) return true;
current = current.next;
}
return false;
}
reset(): void {
this.history = new CommandNode();
this.current_history.update(() => this.history);
}
}
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