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Download QCChart3D 3D Charting Tools for .Net - Quinn
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4. Scaling and Coordinate Systems ChartScale LinearScale LogScale TimeScale Transform3D UserCoordinates WorldCoordinates WorkingCoordinates PhysicalCoordinates CartesianCoordinates TimeCoordinates The starting point for all drawing in a window is the .Net 2D device coordinate system. The coordinate system uses a default device resolution of the underlying .Net window. A .Net window maintains a viewport for the client area of the window, controlling the position and size of the drawing area in the window. Graphics output is clipped to the viewport, preventing graphics output in one window from over-writing graphics in another window. The user coordinate system for the window starts at (0,0) in the upper left corner and extends in the positive direction down and to the right. This software maps a 3D physical coordinate system on the .Net 2D device coordinate system. The 3D transformation pipeline looks something like this: 3D Physical Coordinates ->3D User/Device Coordinates -> 2D Screen Coordinates The position and size of all 3D chart objects are defined using one of the 3D physical coordinate systems (CartesianCoordinates or TimeCoordinates). A chart object is broken into component lines and polygons, the 3D coordinates of which are transformed through scaling operations into 3D user coordinates. User coordinates are based on the device coordinate dimensions of the window the chart is displayed in. The 3D user coordinates are then processed using standard 3D transformation techniques (4x4 homogeneous matrix conversions), rotating and translating the coordinates into a flat 2D projection of the 3D image. The resulting screen coordinates match the .Net device coordinates of the underlying .Net window. Plot area volume and the graph area volume The plot area volume of a graph is the 3D volume where the plot data objects (line plots, bar plots, etc.) are drawn. The graph area volume is the entire volume of the chart window. The graph area volume includes the plot area volume as a subset. Usually, the plot area volume is smaller than the graph area volume and resides roughly centered in
