System.Drawing.Managed and Cross-Platform Rendering

Drawing & Painting in Wisej.NETModule 6The samples are ready before the course is: the module outline is on learnwisej.com, and the lessons, the knowledge checks and the hands-on labs follow when it launches — free, with an AI tutor in every lesson.

See the outline

A TopologyImageRenderer turns the same topology model into PNG bytes with no Wisej control and no session involved: a Bitmap, a Graphics over it, pens, brushes and a GraphicsPath, a font resolved through a fallback chain, and Application.Download handing the bytes to the browser. The three remaining Module 1 surfaces - Label + ProgressBar, a Wisej.Web.Canvas and an off-screen Bitmap in a PictureBox - stay on the operations page under the gauges, so the same reading can still be compared across surfaces. Surface 2, the inline Paint handler, is now the TelemetryGauge control itself.

This folder is the complete application at this point in the course, with its own solution and port.

The source of this sample

iceteagroup/LearnWisej-SamplesDrawing and Painting Course/Module 6

Browse this folder on GitHub

Or clone it: git clone https://github.com/iceteagroup/LearnWisej-Samples.git — then open VisualOperationsStudio.slnx in Visual Studio and press F5.

Run it

cd "Drawing and Painting Course/Module 6/VisualOperationsStudio"
dotnet run -f net10.0 --urls http://localhost:6006

Open http://localhost:6006, press Plant topology, then Export PNG.

What to try

Action	Expected result
Export PNG	The browser downloads plant-topology.png. The status line reports the size, the time, how many objects were drawn and which font family was actually resolved.
Export twice	The first call is slower (JIT and the font probe); after that it settles. Both numbers are recorded in CrossPlatform.md.
Drag a node, then export	The image follows the model, because the export renders the model again — it never screenshots the Canvas.
Empty the scene (TopologyScene.CreatePlant returning no nodes)	A readable image saying "No nodes to display", not a blank file.
Drop a .ttf into a Fonts/ folder beside the application and export	The status line names that family instead of the runtime fallback.
Ask for 4000 × 3000 in btnExport_Click	The renderer clamps each side to 200–2000 rather than allocating ~48 MB.
Open VisualOperationsStudio.csproj	One drawing implementation: Wisej-4 brings Managed.System.Drawing, and there is no direct System.Drawing.Common reference.