View - Panes - Selections

The View - Panes - Selections pane is used to save selections for later use. If we select a particular region of pixels in an image, for example, we can save that region so that later, if desired, we can select exactly the same pixels once more. The Selections pane is enabled when the focus is on any component (image, drawing, chart or table) in which selections can be made.

Each component has its own set of saved selections. We can save up to seven selections for each drawing and up to six selections for each image (one saved selection in images is reserved for showing any regions of invisible pixels leaving only six available slots for selections saved by the user). Maps can have as many saved selections as exist within the various drawing and image layers that comprise the map.

When the Selections pane is open, switching focus to a different window will switch the contents of the Selections pane to the saved selections for the component(s) shown in that window. The selections pane will not be enabled if a window from which selections can be made and saved does not have the focus (is the active window or layer).

To Save a Selection

1. Make a selection.

2. Open the Selections pane and press the New Selection button. The selection will be added to the saved selections list as "Selection1"

3. Double click onto the saved selection name to rename it, if desired.

To Use a Saved Selection

1. Click on the target component to make it active. Open the Selections pane.

2. Click on the desired saved selection to highlight it. Checking the Preview box will show that saved selection in blue color in the component so you can see how it relates to any selection currently made.

3. Click on one of the selection command buttons to combine the saved selection with any selection that is currently made. For example, clicking on the Subtract from Selection button will take the highlighted saved selection and will subtract the pixels or objects it contains from the current selection.

To Delete a Saved Selection

1. Click on the desired saved selection to highlight it.

2. Press the Delete Selection button.

Selection Commands

Five selection command buttons are arrayed at the top of the Selections pane. These commands apply to whatever saved selection has been highlighted in the Selections pane. If we click on a saved selection to highlight it and then press one of these buttons, it will be combined with whatever is the current selection in the image. The selection commands allow us to use the saved selection to replace the selection, to add to the selection, to subtract from the selection, to invert with the selection and to intersect the selection.

$images\btn_selcmd_rep.gif$	Replace Selection - Replace the existing selection with the highlighted saved selection.
$images\btn_selcmd_add.gif$	Add to Selection - Add the highlighted saved selection to the existing selection.
$images\btn_selcmd_sub.gif$	Subtract from Selection - Subtract the highlighted saved selection from the existing selection.
$images\btn_selcmd_inv.gif$	Invert with Selection - Deselect what is in the highlighted saved selection that was already in the existing selection and otherwise add the highlighted saved selection.
$images\btn_selcmd_int.gif$	Intersect Selection - Select only the region of overlap between the highlighted saved selection and what is in the existing selection. If there is no overlap, nothing will be selected.
$images\btn_newsavedsel.gif$	New Selection - Save the current selection as a new entry in the Selections pane list.
$images\btn_delsavedsel.gif$	Delete Selection - Delete the highlighted saved selection from the Selections pane list.
$images\btn_preview.gif$	Preview - Press to see a preview (in blue color) in the drawing or image window of the highlighted saved selection.

See the Selection topic for examples.

Invisible Pixels

Images in Manifold can have invisible pixels that do not appear in the image. They are simply "placeholders" for empty regions of the image. When images containing invisible pixels are stacked above one another in a map, items in layers below the invisible pixels will be visible.

Invisible pixels are very frequently used when composing advanced images (that is, maps) that consist of stacks of many constituent image components. When working with many different image components that contain transparent regions, especially when combined with images that have white pixels or drawings with "white space" in them, it is easy to forget which parts are transparent and which regions are simply "white space" or white pixels seen through the layer stack.

In addition, we often would like to use the region of invisible pixels in selection combinations with selections made in other parts of the image. To support this usage and to make it easy to always rapidly see the region of invisible pixels, Manifold devotes one of the seven saved selections in images to a saved selection that always shows the region of invisible pixels. This saved selection will appear in the Selections pane if any invisible pixels occur in the image. It cannot be removed from the Selections pane nor can it be renamed.

To see the region of transparency, simply click on this saved selection to highlight it and check the Preview box. It will appear in blue preview color.

See the Invisible Pixels and Selection topic for information on selecting invisible pixels and on using the Invisible Pixels selection in the Selections pane.

Saved Selections and the Transform Toolbar

Saved selections will appear in transform toolbar boxes that can work with selection sets. For example, if a drawing has two saved selections called South West States and Mountain West then these will appear as choices in the transform toolbar when that drawing has the focus.

When drawings appear together in a map, if any drawing layer has the focus the transform toolbar for the map will list all saved selections in all drawings. This is a great convenience, but it also leads to a slight complication in that all saved selections using the same name are treated alike. Saved selections in the same drawing are required to have different names, but saved selections in different drawings might use the same name.

The transform toolbar for the map will treat all drawing saved selections using the same name as one, combined saved selection. For example, if we have two drawing layers in a map, one called East and the other called West and they both have a saved selection called Cities, then using the transform toolbar to create a convex hull using the saved selection choice called Cities will use the objects from both the East and West drawings that appear in their respective Cities saved selection.

Therefore, it is a good idea to use unique names for saved selections in drawings that might appear together in the same map. For example, we could name the saved selection in one drawing East - Cities and that in the other drawing West - Cities.