Making a simple drawing tool, help appreciated

Question

hi, i'm trying to make a simple drawing program, but the graphics line are quite dotted if i'm not taking it really slow. FPS is set at 120 (max), but this doesn't seem to help me. I have a button to erase, and one to draw, all I need is template for one of them. down below are the code necessary for executing the operation:
stage.addEventListener(MouseEvent.MOUSE_MOVE, moveLine);
drawButton.addEventListener(MouseEvent.CLICK, clickPencil);
graphics.lineStyle(2, 0x000000, 1);//linecolor = black
function moveLine(evt:MouseEvent) {
    if (mouseX<670) {//this will make it stop functioning before hitting sidepanel
        graphics.moveTo(mouseX, mouseY);
        graphics.lineTo(mouseX-1, mouseY+1);//makes the lines appear
function clickPencil(evt:MouseEvent) {
    graphics.lineStyle(2, 0x000000, 1);
But the second problem is that it keeps drawing when I go to the eraser. Tried using MouseEvent.MOUSE_DOWN, to make it only draw when I held down the mousebutton, either that, or I want it to draw only when combined with some KeyboardEvent...is this possible?
I also wonder if it'd be possible to make smoother lines, almost like the ones drawing in Flash itself....

Answer 1

Looks like you heed to change it to something like this:
drawButton.addEventListener(MouseEvent.MOUSE_DOWN, clickPencil);
graphics.lineStyle(2, 0x000000, 1);
function moveLine(evt:MouseEvent):void {
    if (mouseX < 670) {
        graphics.lineTo(mouseX-1, mouseY+1);
function clickPencil(evt:MouseEvent):void {
     graphics.moveTo(mouseX, mouseY);
     stage.addEventListener(MouseEvent.MOUSE_UP, stopDrawing);
     stage.addEventListener(MouseEvent.MOUSE_MOVE, moveLine);
function stopDrawing(evt:MouseEvent):void{ 
     stage.removeEventListener(MouseEvent.MOUSE_MOVE, moveLine);
     stage.removeEventListener(MouseEvent.MOUSE_UP, stopDrawing);
As for smoothness, you probably need to come up with some trigonometric algorithm that takes into account mouse move direction and make curveTo() call. I am not sure it is worth it though.