public function drag(e:MouseEvent)
{
lineDraw(mouseX, mouseY);
e.updateAfterEvent();
}
public function lineDraw(X:int, Y:int):void
{
currentX = X;
currentY = Y;
graphics.lineStyle(size, color)
graphics.moveTo(previousX, previousY)
graphics.lineTo(currentX, currentY)
previousX = currentX;
previousY = currentY;
}
我制作的非常简单的代码,允许我用鼠标画线。函数拖动在MOUSE_DOWN
后MOUSE_MOVE
触发。
我的问题是:我将如何清除绘制的最后一条线?基本上,一个ctrl+z/undo
函数,可以根据需要重复多次。
我是否必须完全重写我的代码并将绘制的每一行推送到数组中,然后在数组中向后工作,在单击"撤消"时删除行?还是有其他更好、更简单的解决方案?
谢谢! :)
下面是一个示例: 有关说明,请参阅代码注释
private var undoStates:Vector.<Shape> = new Vector.<Shape>(); //holds all your undo states (HAS TO BE SHAPE SINCE AS3 DOESN"T LET YOU ISNTANTIATE A GRAPHICS OBJECT DIRECTLY)
private var redoStates:Vector.<Shape> = new Vector.<Shape>(); //holds all your redo states
private var undoLevels:int = 1; //how many undo levels you'd like to have
private var redoLevels:int = 1;
public function undo() {
if (undoStates.length > 0) { //make sure there is an undo state before preceeding
//add redo state
redoStates.push(getState());
//if redo states are more than redoLevels, remove the oldest one
if (redoStates.length > redoLevels) redoStates.splice(0, 1);
//make the the last undo state the current graphics
graphics.clear(); //not sure if this line is required, can't recall if copyFrom clears first
graphics.copyFrom(undoStates.pop().graphics); //pop removes the last item from the array and returns it
}
}
public function redo() {
if (redoStates.length > 0) {
//add undo state
addUndo();
//make the the last undo state the current graphics
graphics.clear(); //not sure if copy from (the next line) clears or not
graphics.copyFrom(redoStates.pop().graphics);
}
}
private function getState():Shape{
var state:Shape = new Shape();
state.graphics.copyFrom(graphics); //copy the current graphics into a new Graphics object
return state;
}
private function addUndo():void {
undoStates.push(getState()); //add the current state to the undo array
//if more undo states than undoLevels, remove the oldest one
if (undoStates.length > undoLevels) undoStates.splice(0, 1);
}
public function lineDraw(X:int, Y:int):void {
currentX = X;
currentY = Y;
//create undo state before we draw more
addUndo();
graphics.lineStyle(size, color)
graphics.moveTo(previousX, previousY)
graphics.lineTo(currentX, currentY)
previousX = currentX;
previousY = currentY;
}