Abstract

In the past we did usually have only text to show for user. Today we have more media types: pagespans and images at least. The View framework has been designed too much for text only. Although text is the most common view media we should easily be able to show any content in nodes.

Issues

• Should getsize return float[2] or Dimension?

Changes

We need an abstract layer where we can just place a node and where we shouldn't need to know what kind of types of spans are in the node's enfilade.

CellView was abstract class:

   public abstract void place(Cell c, VobScene vs, int box,
                              ViewContext context);
   public void getSize(Cell c, float scale, ViewContext context,
                       float[] out) {
       getSize(c, context, out);
   }
}

I suggest that we abstract ViewContext away and let someone else to handle the view context['3)']. Now, make a new interface from the rest:

public interface NodeContent {
    void place(RDFNode node, VobScene vs, int box);
    void getSize(RDFNode node, float[] size, float scale=1);
}

We want to be able just to say nodeview.place(...); and know nothing about view context nor node's content.

Note:

• Very important thing is that we don't know anything about the content. We can only assume what an enfilade includes. That's why I like to suggest additional methods to the interface which would then be:

public interface NodeContent {
     void place(RDFNode node, VobScene vs, int box);
     void getSize(RDFNode node, float[] size, float scale=1);

     // has methods - ask from enfilade if it contains specified span.
     boolean hasText(RDFNode node);
     boolean hasImage(RDFNode node);
     boolean hasPageSpan(RDFNode node);
}

NodeContent interface should be implemented by NodeView.

Abstract

It hasn't been very easy to say: "Write this text with red color" or "draw pagespan without the background texture". As I previously said about node content we don't even know if we have text and/or pagespan but if we have we want to change it's state to this or that.

Issues

None

Changes

I suggest several interfaces to be implemented by suitable content state handler:

public interface TextState {
   // color
   void setColor(Color c);
   Color getColor();

   // font
   void setFont(Style style);
   Style getFont();
}

public interface PageState {
   void setBackgroundTexVisible(boolean b);
   boolean isBackgroundTexVisible();
}      

These would be easily called from NodeView public attributes, i.e., nodeview.text.setColor(Color.red); or nodeview.page.setBackgroundTexVisible(false);

Abstract

View context isn't very easy task. When you place a node it's correct time to ask from view context if it has plans for current node. View context might want to set cursor offset, pagespan view coordinates or it might want to set text's color more important by reddishing it for example.

Issues

None

Changes

When NodeView has a new node to be placed it should mention it to ViewContext.

So ViewContext should implement the following interface:

public interface NodeViewContext {
   nodeIsToBePlaced(RDFNode current, NodeView nv);
}

And now ViewContext is able to do it's job if we define new interfaces:

public interface TextContext {
    void setCursorOffset(int off);
    int getCursorOffset();
}

public interface PageContext {
    void setViewCoords(float x, float y);
    float[] getViewCoords();
}

Of course ViewContext can change also states, i.e., text color and font, defined in the '2)'.