Class MoleculeSetRenderer

All Implemented Interfaces:

public class MoleculeSetRenderer extends AbstractRenderer<IAtomContainerSet> implements IRenderer<IAtomContainerSet>
A general renderer for IChemModels, IReactions, and IAtomContainers. The chem object is converted into a 'diagram' made up of IRenderingElements. It takes an IDrawVisitor to do the drawing of the generated diagram. Various display properties can be set using the RendererModel.

This class has several usage patterns. For just painting fit-to-screen do:

   renderer.paintMolecule(molecule, visitor, drawArea)
for painting at a scale determined by the bond length in the RendererModel:
   if (moleculeIsNew) {
     renderer.setup(molecule, drawArea);
   Rectangle diagramSize = renderer.paintMolecule(molecule, visitor);
   // ...update scroll bars here
to paint at full screen size, but not resize with each change:
   if (moleculeIsNew) {
     Rectangle diagramBounds = renderer.calculateDiagramBounds(molecule);
     renderer.setZoomToFit(diagramBounds, drawArea);
     renderer.paintMolecule(molecule, visitor);
   } else {
     Rectangle diagramSize = renderer.paintMolecule(molecule, visitor);
   // ...update scroll bars here
finally, if you are scrolling, and have not changed the diagram:
will just repaint the previously generated diagram, at the same scale.

There are two sets of methods for painting IChemObjects - those that take a Rectangle that represents the desired draw area, and those that return a Rectangle that represents the actual draw area. The first are intended for drawing molecules fitted to the screen (where 'screen' means any drawing area) while the second type of method are for drawing bonds at the length defined by the RendererModel parameter bondLength.

There are two numbers used to transform the model so that it fits on screen. The first is scale, which is used to map model coordinates to screen coordinates. The second is zoom which is used to, well, zoom the on screen coordinates. If the diagram is fit-to-screen, then the ratio of the bounds when drawn using bondLength and the bounds of the screen is used as the zoom.

So, if the bond length on screen is set to 40, and the average bond length of the model is 2 (unitless, but roughly Ångstrom scale) then the scale will be 20. If the model is 10 units wide, then the diagram drawn at 100% zoom will be 10 * 20 = 200 in width on screen. If the screen is 400 pixels wide, then fitting it to the screen will make the zoom 200%. Since the zoom is just a floating point number, 100% = 1 and 200% = 2.

Source code:
Belongs to CDK module: