The Magic Wand Tool allows areas of similar color to be selected. The region to be selected may be a single continuous shape or multiple separate areas.
It is easiest to think of the Magic Wand Tools behavior as similar to the Paint Bucket, except that instead of filling an area with color the Magic Wand Tool selects it.
In most situations, to select a single continuous area with the Magic Wand Tool, simply click on it.
Of course there are several options which expand and alter the default behavior. These can be found in the Tool Bar.
There are five selection modes. These dictate how subsequent selections interact with an existing selection. Each mode has an associated keyboard shortcut for ease of access. The default mode is Replace.
The Magic Wand Tool shares the same two flood modes as the Paint Bucket Tool: Contiguous and Global.
Flood Mode: Contiguous - the selection will continue to bleed outwards from the click point until neighboring pixels fail to satisfy the Tolerance setting.
Flood Mode: Global - the selection will extend to all the pixels in the layer which satisfy the Tolerance setting.
The keyboard shortcut to enable Global selection mode is the Shift key.
Holding the Shift key down while clicking to make a selection temporarily enables the Global selection mode.
This complex selection was made by first selecting the entire image ( or Ctrl + A).
Next the black areas were excluded by holding down both the Shift key (Global mode) and Alt key (Subtractive mode) while clicking on any black area.
Note how all the disconnected areas of black have been deselected. This technique is particularly useful for selecting text characters.
Another way of achieving the same selection is to select all the black areas ( Shift click on any black pixel ) then
inverting the selection with Ctrl + I. This technique works particularly well to select text.
Similar to the Paint Bucket Tool, Magic Wand's selection can be adjusted by tuning the Tolerance.
New to paint.net is the ability to adjust the Tolerance of an active selection.
Altering the Tolerance reinterprets the selection using the original click point with the new Tolerance parameter.
Click the Finish button in the Tool Bar or press Enter to finish editing the selection.
The effect of adjusting the Tolerance value is shown below:
Example - Magic Wand Tolerance
Magic WandTolerance: 25%. The selection captures most of the sky, but not all. The tolerance is too low.
Magic WandTolerance: 50%. The selection captures all of the sky, but also some of the water and other elements in the photo.
The tolerance is too high.
Magic WandTolerance: 31%. The selection properly captures the area of interest (the sky), no more, no less.
The Magic Wand Tool has two sampling modes, Image and Layer.
These modes are shared by the Magic Wand, Paint Bucket and Color Picker tools (shown below).
The two sampling modes dictate which pixels will be sampled or tested to determine how far the selection extends.
Image - pixels are polled from the composite image to determine their suitability to be included in the selection.
This mode will operate in the same way as if a multi-layered image was flattened prior to using the Magic Wand Tool.
Layer - pixels only within the active layer are polled to determine their suitability to be included in the selection.
This is the sampling mode which was used by the Magic Wand in previous versions of paint.net.
Dragging the click point
New to paint.net 4 is the ability to adjust the click point of the Magic Wand Tool while a selection is still active.
This replaces the need to undo and reapply a Magic Wand selection if it did not cover the desired region.
The Control Nub looks like a white square with four arrows inside it (see image below).
Click and drag this icon to relocate the click point.
The selection will be reinterpreted as if the user had undone the original and reapplied it using the new source point.
In the image above, Image A is the original object.
Image B shows the initial selection based on the first click with the Magic Wand. The click point is the tiny dark square near the sphere's bright spot.
The larger square with the four arrows is the Control Nub.
Image C shows the reinterpreted selection following relocation of the click point much closer to the center of the sphere.
The action of dragging the click point is shown in the animation below.
Advanced Use - Selection Building
Often it is not possible to make a completely accurate selection with one click, regardless of the Tolerance setting.
An example might be the subtle skin tones in a facial portrait.
To make complex selections like this, try building a selection using the Magic Wand with a low Tolerance and the Additive selection mode.
The Additive mode allows multiple selections to be chained together, extending the selection each time to capture slightly more of the desired region.
The keyboard shortcut to enable Additive selection mode is the Ctrl key.
Holding down the Ctrl key while clicking adds the new selection region to the existing one.
The selection can be extended with each click while the Ctrl key remains down.
Initial Magic Wand selection with low Tolerance.
Continuing to add to the original selection by clicking new areas while holding the Ctrl key down.
Advanced Use - Selection By Exclusion
Complex selections can also be made by over-selecting then removing areas not required.
This method is particularly effective when the subject is surrounded by a background relatively low in detail.
An initial selection can be made with any of the Selection Tools, then the Magic Wand Tool in Subtractive selection mode is used to remove areas not required.
The keyboard shortcut to enable Subtractive selection mode is the Alt key.
Hold the Alt key down while clicking to temporarily enable Subtractive mode, reducing the selection with each new click.
Lasso Tool used to make initial selection.
Using Magic Wand in Subtractive mode to successively refine the selection.