Using Views: Border

The Mosaic class Views::Border implements a primitive graphical object specialized to stroke a rectangular border. This so-called Border view can be used to compose the appearance of a GUI component, in particular to add any decoration frames to it. The following screenshot demonstrates few examples of how Border views appear in the canvas area of Composer (and accordingly on the screen in your target device):

The following sections are intended to provide you an introduction and useful tips of how to work with the Border view. For the complete reference please see the documentation of the Views::Border class.

Add new Border view

To add a new Border view just at the design time of a GUI component do following:

First ensure that the Templates window is visible.

In Templates window switch to the folder Views.

In the folder locate the template Border.

Drag & Drop the template into the canvas area of the Composer window:

Eventually name the new added Border view.

Inspect the Border view

As long as the Border view is selected you can inspect and modify its properties conveniently in the Inspector window as demonstrated with the property Bounds in the screenshot below:

This is in so far worth mentioning as all following sections describe diverse features of the Border view by explicitly referring to its corresponding properties. If you are not familiar with the concept of a property and the usage of Inspector window, please read first the preceding chapter Compositing component appearance.

Arrange the Border view

Once added, you can freely move the Border view, or you simply grab one of its corners and resize it in this way. You can control the position and the size of the view also by directly modifying its property Bounds. If you want the Border view to appear behind other views you can reorder it explicitly.

Specify the color of the Border view

To specify the color of the Border view you change its property Color. Alternatively you can configure the border to be stroked with a color gradient. For this purpose you specify the colors for the four corners (top-left, top-right, bottom-right and bottom-left) individually by using the corresponding properties ColorTL, ColorTR, ColorBR and ColorBL. The gradient colors are interpolated linearly between the specified values. Using color values with alpha < 255 causes the border to appear semi- or even transparent. For example:

Specify the width of the Border

Per default borders are stroked with 1 pixel thickness. This setting can be controlled by the property Width. For example:

Control the visibility of the Border view

The visibility of the Border view is controlled primarily by the property Visible and the specified color values. Per default the views appear alpha-blended over the contents lying behind them unless you explicitly disable this mode by setting the property AlphaBlended to the value false. In such case, the border will overwrite the contents in the background. For example:


In the complete GUI application an individual view is visible on the screen only when all of its superior Owner components are visible too, the view itself does lie within the visible area of the superior components and the view is not covered by other sibling views nor components.