VectorDraw Developer Framework（VDF）是一个用于应用程序可视化的图形引擎库。有了VDF提供的功能，您可以轻松地创建、编辑、管理、输出、输入和打印2D和3D图形文件。
VectorDraw web library (javascript)不仅能打开CAD图纸，而且能显示任何支持HTML5标准平台上的通用矢量对象，如Windows，安卓，iOS和Linux。无需任何安装，VectorDraw web library (javascript)就可以运行在任何支持canvas标签和Javascript的主流浏览器（Chrome, Firefox, Safari, Opera, Dolphin, Boat等等）中。这意味着可以用DXF，DWG，DGN，SKP（Google的Sketchup），VDML等多种格式在任何台式、平板电脑，智能手机和便携式笔记本上展现出你的业务。
问：
透明度如何在VDF中发挥作用？
答：
在版本6023中，我们为vdFigure对象添加了一个名为TransparencyMethod的新属性。此属性从vdFigure.TransparencyMethodEnum获取值，如下所示：
| TransparencyMethodEnum.ByLayer | 该对象采用透明度（AlphaBlending值）的颜色为图层pencolor AlphaBlending。 |
| TransparencyMethodEnum.ByBlock | 该对象获取所有者的颜色透明度（AlphaBlending值）。所有者是一个带有AlphaBlending笔颜的vdInsert。 |
| TransparencyMethodEnum.Default默认值 | 如果对象是真彩色，则对象将获得自己的透明度值。如果笔触是索引，则使用调色板的颜色透明度值。 |
| TransparencyMethodEnum.KeepOwn | 该对象总是采用它自己的pencolor透明度（AlphaBlending值）。 |
除此属性外，还有Solid2dTransparency属性，该属性仅应用于阴影线/填充对象，并且仅应用于2D（线）模式，而不应用于3D（Wire3d / Shade / Hide / ShadeOn / Render）模式。因此，如果您希望填充的对象仅在2D而不是3D中透明，则可以使用此属性。
另一方面，如果您希望对象在3D和2D模式下透明，则需要使用TransparencyMethod属性并将AlphaBlending值设置为vdFigure （KeepOwn，Default）或vdLayer（ByLayer）或parent（vdBlock）。AlphaBlending将值从0（完全透明，如不可见）取值到255（根本不透明）。
本方法适用于版本6.6023.x及更高版本，因为以前的6023版本中不存在用于vdFigure的TransparencyMethod。
下面的代码将向您演示对象的透明度如何在VDF中工作：
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
vdDocument doc;
private void Form1_Load(object sender, EventArgs e)
{
doc = vdFramedControl1.BaseControl.ActiveDocument;
}
private void button1_Click(object sender, EventArgs e)
{
//Transparency of vdCurves (line, polyline etc).
// For better display of this transparency a thicker line type is used in the code
doc.New();
vdRect rect = new vdRect(doc, new gPoint(0, 0, -0.1), 10, 2, 0);
rect.HatchProperties = new vdHatchProperties(VdConstFill.VdFillModeSolid);
doc.Model.Entities.AddItem(rect); // this is added just for better transparency display
// Using the transparency in the object by setting the AlphaBlending
vdCircle cir1 = new vdCircle(doc, new gPoint(2, 2), 1.0d);
cir1.LineWeight = VdConstLineWeight.LW_211;
cir1.PenColor.ColorIndex = 2;
cir1.PenColor.AlphaBlending = 120;
// the PenColor.AlphaBlending will be applied
cir1.TransparencyMethod = vdFigure.TransparencyMethodEnum.KeepOwn;
doc.Model.Entities.AddItem(cir1);
// Using the transparency in the Layer
vdLayer lay = new vdLayer(doc, "Transparent");
lay.PenColor.FromSystemColor(Color.Red); // layer is red !!!
lay.PenColor.AlphaBlending = 120; // setting layer's transparency
doc.Layers.AddItem(lay);
vdCircle cir2 = new vdCircle(doc, new gPoint(4.7, 2), 1.2d);
cir2.LineWeight = VdConstLineWeight.LW_200;
cir2.Layer = lay;
cir2.PenColor.ColorIndex = 2;
// but object is not colored by layer, only transparency is by layer here
// Layer's alpha blending wil be applied
cir2.TransparencyMethod = vdFigure.TransparencyMethodEnum.ByLayer;
doc.Model.Entities.AddItem(cir2);
// Using the transparency inside blocks/inserts
vdBlock blk = new vdBlock(doc, "Transparecy");
vdCircle cir3 = new vdCircle(doc, new gPoint(8, 2, 0), 1.5); // bigger circle
cir3.PenColor.ColorIndex = 2;
cir3.LineWeight = VdConstLineWeight.LW_158;
// the insert's Aplha blending will be applied
cir3.TransparencyMethod = vdFigure.TransparencyMethodEnum.ByBlock;
blk.Entities.AddItem(cir3);
cir3 = new vdCircle(doc, new gPoint(8, 2, 0), 0.7); //smaller circle
cir3.PenColor.ByBlock = true;
cir3.LineWeight = VdConstLineWeight.LW_158;
// the layer's Aplha blending will be applied which isn't transparent
cir3.TransparencyMethod = vdFigure.TransparencyMethodEnum.ByLayer;
blk.Entities.AddItem(cir3);
doc.Blocks.AddItem(blk);
vdInsert ins = new vdInsert(doc, blk, new gPoint(0, 0, 0), 0, 1, 1, 1);
// setting the inserts draw to use the Alpha Blending
ins.TransparencyMethod = vdFigure.TransparencyMethodEnum.Default;
ins.PenColor.FromSystemColor(Color.Yellow);
ins.PenColor.AlphaBlending = 120; // setting transparency to 120
doc.Model.Entities.AddItem(ins);
doc.Model.ZoomExtents(); doc.Redraw(true);
}
private void button2_Click(object sender, EventArgs e)
{
// Hatches/Filled objects and Transparency
doc.New();
vdRect rect = new vdRect(doc, new gPoint(0, 0, -0.1), 10, 2, 0);
rect.HatchProperties = new vdHatchProperties(VdConstFill.VdFillModeSolid);
doc.Model.Entities.AddItem(rect); // this is added just for better transparency display
// 2D Transparency Does NOT work in 3D modes (hide/shade/render/wire3D)
vdCircle cir1 = new vdCircle(doc, new gPoint(2, 2), 1.0d);
cir1.HatchProperties = new vdHatchProperties(VdConstFill.VdFillModeSolid);
cir1.HatchProperties.Solid2dTransparency = 80; // values 0 (invisible) to 255 (no transparency)
cir1.PenColor.FromSystemColor(Color.Red);
cir1.HatchProperties.FillColor.FromSystemColor(Color.Green);
doc.Model.Entities.AddItem(cir1);
// Transparency in PenColor work ALSO in 3D modes (hide/shade/render/wire3D)
vdCircle cir2 = new vdCircle(doc, new gPoint(4.7, 2), 1.2d);
cir2.HatchProperties = new vdHatchProperties(VdConstFill.VdFillModeSolid);
cir2.PenColor.FromSystemColor(Color.Green);
cir2.HatchProperties.FillColor.FromSystemColor(Color.Red);
cir2.HatchProperties.FillColor.AlphaBlending = 80;// values 0 (invisible) to 255 (no transparency)
doc.Model.Entities.AddItem(cir2);
// the above modes can be compbined with TransparencyMethod of vdfigure (that work in 3D modes), like
vdCircle cir3 = new vdCircle(doc, new gPoint(8, 2, 0), 1.5);
cir3.PenColor.ColorIndex = 4;
cir3.LineWeight = VdConstLineWeight.LW_200;
cir3.PenColor.AlphaBlending = 80;
cir3.HatchProperties = new vdHatchProperties(VdConstFill.VdFillModeSolid);
cir3.HatchProperties.FillColor.FromSystemColor(Color.Green);
cir3.HatchProperties.FillColor.AlphaBlending = 80;
cir3.TransparencyMethod = vdFigure.TransparencyMethodEnum.KeepOwn;
doc.Model.Entities.AddItem(cir3);
doc.Model.ZoomExtents(); doc.Redraw(true);
}
}