HTML5 canvas 在线画笔绘图工具（三）

组装画板（TDrawBuilder）

在这一小节中我们要把工具条和画板组装起来，让他们可以协同进行工作。

画板通过一个命名为TDrawBuilder来进行组装。在详细讲解TDrawBuilder对象之前我们来看一下程序的HTML代码。

画布由三个Canvas组成

toolbar用于绘制工具条，drawCanvas 用于画图的画布，openCanvas 用于在打开保存的图片时显示小图片。

通过建立一个新的TDrawBuilder对象 new TDrawBuilder(toolbar,drawcanvas,opencanvas),将工具条、画布、小图片显示画布组装起来。

<div id="mainForm" class="mainForm" align="center" >   <canvas id="toolbar" width="780" height="105"   >你的浏览器不支持HTML Canvas</canvas>    <canvas id="drawCanvas" width="760" height="440" style="margin-top: 10px;margin-left: 2px;border:2px solid black; background-color: white" >你的浏览器不支持HTML Canvas</canvas>    <canvas id="openCanvas"  width="760" height="440" style="margin-top: 10px;margin-left: 2px;border:2px solid black; background-color: white" >你的浏览器不支持HTML Canvas</canvas>  <script type="text/javascript"> var toolbar=document.getElementById('toolbar');    var drawcanvas=document.getElementById('drawCanvas');    var opencanvas=document.getElementById('openCanvas');    opencanvas.style.visibility="hidden";    <span style="color:#ff0000;">var drawBuilder=new TDrawBuilder(toolbar,drawcanvas,opencanvas);</span><span style="color:#ff0000;">    var drawHandler=new TDrawHandler(drawcanvas,drawBuilder.getToolbarIns());     drawBuilder.setDrawHandler(drawHandler);</span>    </script>

function BuildToolbar() {BuildCommandButton();BuildLineStyle();BuildColor();BuildNewFunction();BuildSaveFunction();BuildOpenFunction();Toolbar.InstallEvents();}

function BuildCommandButton() {//直线按钮btnList[0] = new TImageButton(1, "Images/lineNormal.png", "Images/lineMoveOn.png", "Images/lineMouseDown.png", CurrentLeft, 8, 32, 32, Toolbar, 1);Toolbar.AddButton(btnList[0]);CurrentLeft = CurrentLeft + 32 + 10;//直线按钮btnList[1] = new TImageButton(2, "Images/rectNormal.png", "Images/rectMoveOn.png", "Images/rectMouseDown.png", CurrentLeft, 8, 32, 32, Toolbar, 1);Toolbar.AddButton(btnList[1]);//直线按钮CurrentLeft = CurrentLeft + 32 + 10;btnList[2] = new TImageButton(3, "Images/arcNormal.png", "Images/arcMoveOn.png", "Images/arcMouseDown.png", CurrentLeft, 8, 32, 32, Toolbar, 1);Toolbar.AddButton(btnList[2]);}

function BuildLineStyle() {var Top = 2;CurrentLeft = CurrentLeft + 50;LineStyles[0] = new TImageButton(1, "Images/W1N.png", "Images/W1M.png", "Images/w1d.png", CurrentLeft, Top, 128, 16, Toolbar, 2);Toolbar.AddButton(LineStyles[0]);Top = Top + 14;LineStyles[1] = new TImageButton(2, "Images/W2N.png", "Images/W2M.png", "Images/w2d.png", CurrentLeft, Top, 128, 16, Toolbar, 2);Toolbar.AddButton(LineStyles[1]);Top = Top + 14;LineStyles[2] = new TImageButton(3, "Images/W3N.png", "Images/W3M.png", "Images/w3d.png", CurrentLeft, Top, 128, 16, Toolbar, 2);Toolbar.AddButton(LineStyles[2]);Top = Top + 14;LineStyles[3] = new TImageButton(4, "Images/W4N.png", "Images/W4M.png", "Images/w4d.png", CurrentLeft, Top, 128, 16, Toolbar, 2);Toolbar.AddButton(LineStyles[3]);Top = Top + 14;LineStyles[4] = new TImageButton(5, "Images/W5N.png", "Images/W5M.png", "Images/w5d.png", CurrentLeft, Top, 128, 16, Toolbar, 2);Toolbar.AddButton(LineStyles[4]);Top = Top + 14;LineStyles[5] = new TImageButton(6, "Images/W6N.png", "Images/W6M.png", "Images/w6d.png", CurrentLeft, Top, 128, 16, Toolbar, 2);Toolbar.AddButton(LineStyles[5]);Top = Top + 14;CurrentLeft = CurrentLeft + 140;}

function BuildColor() {var Top = 2;var Left = CurrentLeft;var ColorArray = ["#000000", "#333333", "#666666", "#999999", "#CCCCCC", "#FFFFFF", "#FF0000", "#00FF00", "#0000FF", "#FFFF00", "#00FFFF", "#FF00FF"];var ColorButtons = new Array();for (var i = 0; i < ColorArray.length; i++) {if ((i % 4) == 0) {Left = CurrentLeft;Top = 2 + (Math.floor(i / 4)) * 26;} elseLeft = CurrentLeft + (i % 4) * 26;ColorButtons[i] = new TColorButton(ColorArray[i], Left, Top, 24, 24, Toolbar, 3);Toolbar.AddButton(ColorButtons[i]);}var CurrentBorderColor = new TColorButton("black", CurrentLeft + 4 * 26 + 10, 8, 64, 64, Toolbar, 4);Toolbar.AddButton(CurrentBorderColor);Toolbar.setBorderColorButton(CurrentBorderColor);CurrentLeft = CurrentLeft + 4 * 26 + 74;}

function BuildNewFunction() {CurrentLeft = CurrentLeft + 10;NewButton = new TImageButton(1, "Images/newNormal.png", "Images/newNormal.png", "Images/newMove.png", CurrentLeft, 8, 64, 64, Toolbar, 5);NewButton.OnClick = function() {DoNewDrawing();};Toolbar.AddButton(NewButton);CurrentLeft = CurrentLeft + 64;}

function DoNewDrawing() {Drawhandler.NewDrawing();Drawhandler.setId(NewGuid(true));}