Direct2D (18) : 图层之 TD2D1LayerParameters.contentBounds (图层的有效范围)
{相关方法} TDirect2DCanvas.RenderTarget.CreateLayer(); //建立层 TDirect2DCanvas.RenderTarget.PushLayer(); //开始层;层的功能及效果取决于它的 TD2D1LayerParameters 结构参数 TDirect2DCanvas.RenderTarget.PopLayer(); //结束层 {相关结构} TD2D1LayerParameters = record contentBounds: TD2D1RectF; //层的有效范围 geometricMask: ID2D1Geometry; //用于剪裁的几何图形 maskAntialiasMode: TD2D1AntiAliasMode; //抗锯齿模式 maskTransform: TD2D1Matrix3x2F; //2D 变换 opacity: Single; //层的透明度 opacityBrush: ID2D1Brush; //蒙版画刷 layerOptions: TD2D1LayerOptions; //文本抗锯齿模式 end;
测试图层范围(用不同的透明度绘制了两次图片,第二次通过层指定了有效范围):
uses Direct2D, D2D1; procedure TForm1.FormPaint(Sender: TObject); var cvs: TDirect2DCanvas; iLayer: ID2D1Layer; rLayerParameters: TD2D1LayerParameters; wic: TWICImage; R: TRect; begin wic := TWICImage.Create; wic.LoadFromFile('C:\Temp\Test.png'); R := Rect(0, 0, wic.Width, wic.Height); cvs := TDirect2DCanvas.Create(Canvas, ClientRect); cvs.RenderTarget.SetTransform(TD2DMatrix3x2F.Translation((ClientWidth-wic.width)/2, (ClientHeight-wic.height)/2)); cvs.BeginDraw; cvs.StretchDraw(R, wic, 128); {建立层} cvs.RenderTarget.CreateLayer(nil, iLayer); //参数1是初始大小,一般无需指定 {为 PushLayer() 方法准备参数} InflateRect(R, -50, -40); rLayerParameters.contentBounds := R; //指定层的有效范围 // rLayerParameters.geometricMask := nil; rLayerParameters.maskAntialiasMode := D2D1_ANTIALIAS_MODE_PER_PRIMITIVE; // rLayerParameters.maskTransform := TD2DMatrix3x2F.Identity; rLayerParameters.opacity := 1.0; // rLayerParameters.opacityBrush := nil; rLayerParameters.layerOptions := D2D1_LAYER_OPTIONS_NONE; {开始层} cvs.RenderTarget.PushLayer(rLayerParameters, iLayer); cvs.Draw(0, 0, wic); {结束层} cvs.RenderTarget.PopLayer; cvs.EndDraw; cvs.Free; wic.Free; end; procedure TForm1.FormResize(Sender: TObject); begin Repaint; end;
效果图:
posted on 2011-04-05 15:34 万一 阅读(1598) 评论(0) 编辑 收藏