BricsCAD'S rendering

Steven Langhammer

Hello there,

I'm currently working on a program, that uses BricsCAD to read information from a .dwg file and export it to a formated .txt file via LISP.

Now the export to the .txt works perfectly.

The program loads the information in a decent time.

Now there's a problem: it can take rather long to render the view and it also tends to lag, when it's being moved around. The problem appears, when there are a lot of lines in the view. Since I break down all Polylines and alike objects in BricsCAD to lines and we are talking about architectural drawings here, there will always be many lines.

Does anyone know how BricsCAD handles it's rendering, that it works so fast?

I can't expect a customer to wait 30 seconds or more for a drawing to reload, only because he/she deactivated a layer in the view.

Daniel Eiszele

Hi Stephen,

I assume you are trying to render these objects to a Delphi canvas? The way most drawing engines speed up the rendering process is to buffer/draw your objects to an offscreen bitmap which is the same size as your screen canvas and then copy this bitmap to your screen. In your canvas's OnPaint event copy the TBitmap to the TCanvas.  Only redraw the TBitmap when you make a change to the objects or pan/zoom your canvas.

If this isn't what you're doing you may need to provide more detail in your question.

Regards

Daniel