org.havi.ui

Interface HTextLayoutManager

All Known Implementing Classes:

DVBTextLayoutManager, HDefaultTextLayoutManager

public interface HTextLayoutManager

The HTextLayoutManager class manages the layout and rendering on-screen of a "marked-up" string.

Possible implementations of HTextLayoutManager could enable the following behaviors:

• Interpreting basic markup, such as changing color or font, and forced line breaks.
• Providing text alignment, as in the HDefaultTextLayoutManager.
• Providing text wrapping policies, such as word-wrap.
• Providing text orientations, such as right-to-left, or top-to-bottom rendering.
• Providing specialized support for missing characters, or fonts.
• Providing specific language support.
• Additional text styles, such as drop capitals or "shadow" characters.

HTextLayoutManager supports passing a java.awt.Insets object as argument to the render method to restrict the area in which text may be rendered. If the insets are zero, the text is rendered into the area defined by the bounds of the HVisible passed to the render method.

The clipping rectangle of the Graphics object passed to the render method is not used to determine the area in which text is rendered, as its size and position is not guaranteed to cover the entire HVisible - for example, when partial repainting of an HVisible is performed. The diagram below shows a possible scenario:

The gray area shows the bounds of the HVisible. The green area shows the clipping rectangle of the Graphics context, and the dashed lines show the insets passed to the render method. The text is laid out into the rectangle defined by the HVisible bounds after subtracting the insets. However, only the part of the text covered by the clipping rectangle is actually drawn to the screen, as shown in the diagram below:

The behavior of the render method when the text to be rendered does not fit in the current area specified is implementation-specific.

See Also:

HDefaultTextLayoutManager

Method Summary

Methods

Modifier and Type	Method and Description
void	render(String markedUpString, Graphics g, HVisible v, Insets insets) Render the string.

Method Detail

render

void render(String markedUpString,
          Graphics g,
          HVisible v,
          Insets insets)

Render the string. The HTextLayoutManager should use the passed HVisible object to determine any additional information required to render the string, e.g. Font, Color etc.

The text should be laid out in the layout area, which is defined by the bounds of the specified HVisible, after subtracting the insets. If the insets are null the full bounding rectangle is used as the area to render text into.

The HTextLayoutManager should not modify the clipping rectangle of the Graphics object.

Parameters:

markedUpString - the string to render.

g - the graphics context, including a clipping rectangle which encapsulates the area within which rendering is permitted. If a valid insets value is passed to this method then text must only be rendered into the bounds of the widget after the insets are subtracted. If the insets value is null then text is rendered into the entire bounding area of the HVisible. It is implementation specific whether or not the renderer takes into account the intersection of the clipping rectangle in each case for optimization purposes.

v - the HVisible into which to render.

insets - the insets to determine the area in which to layout the text, or null.