Selection Area


Selection Area
◇ In the most basic form, Selection Area act as containers that isolate parts of an image for editing
◇ Each pixel has a value between 0 and 255
▪ Fully selected: 255
▪ Not selected: 0
▪ Partially selected: 0 - 255
Contour Line
◇ Solid lines that draws the boundary of a shape like ellipse
◇ Pixel value >= 128, inside contour line
◇ Pixel value < 128, outside contour line

Marching Ants: dashed lines around the Contour Line. It tells you what area has been selected


Make a Selection

• You can make a selection / shape using the following methods
Selection Tools
◇ Path Tools (enable you to draw curve)
◇ Text Tools
Keyboard Shortcuts


Expand / Compress the Selection

• If you hover over the corners or sides of the Contour Line, a box / square will be shown. You can then drag along the box / squrare to expand or compress the shape


Move the Selection

• You can move the shape by dragging within the Marching Ants


Inverted Selection

• You can invert the selection using shortcut key ctrl-i or

# Inverted Selection
Select > Invert

• The Marching Ants will be shown along the layer boundary
• You can't expand / compress the shape, the original composition will be truncated


Fill Selection with Color / Pattern

• When an area is selected, you can fill that area with the color you've selected using any Paint Tools like Bucket Fill Tool, Paint Brush etc.
• You can also fill that area with a Pattern selected from the Pattern dockable dialog box (located at the lower right corner)

# Fill Selection with Color / Pattern
Edit > Fill with FG Color
Edit > Fill with BG Color
Edit > Fill with Pattern


Remove Contents Inside a Selection

• You can remove the whatever is inside the selection area by hitting the shortcut key Delete (Edit > Clear)
• If no Alpha Channel is set, the Background color will be shown on the deleted area


Filter and Image Adjustment

• You can add Filter or apply image adjustment inside a Selection Area
• Use the Color and Filter pulldown menus


Create Selection Area with Text

• Apply Text Tool first
• Right click the corresponding layer in Layer Panel and select Alpha to Selection
• Text will be outlined by Marching Ants


Create Area of Partial Transparency

• Drag and drop one image to another image
• Use the Unified Transform Tool to scale the image down in order to fit inside another image
• Use Lasso Tool to outline, connect the ends and hit the Enter key
• Now we have our Selection Area. You can use either of the below 2 methods to create partial transparency

1. Select Float Method

Select > Float to put the Selection Area on its own floating selection layer or
• Add the floating selection layer to its own layer
• You can use the Opacity Slider to adjust the opacity of this layer. The Opacity Slider is located at the top of the Dockable Dialogs
• You may want to add Alpha Channel on the image if the image is at the bottom of the layer

2. Add Layer Mask Method

Less destructive than Select Float method as you can disabled it or delete the layer mask entirely to revert back to the original image
• Right click the layer and select Add Layer Mask > Selection > Add


Adjust the Size of the Selection

Select > Grow or Select > Shrink


Add Border around Selection Area

• Select all (ctrl-a)
Select > Border
• Use the Bucket Fill Tool to fill the border with color


Selection Editor

• Select > Selection Editor to open the Selection Editor
• Display in the Dockable Dialog to show you what is selected relative to the size of the composition
• Selection Area is indicated by background color (default=white)
• Options available at the bottom
• If you click on the Selection Filter, it's going to be Select All


Tools Option



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