Week 4 Part 10: Selections
Selections
Selections allow you to confine your adjustments or edits to a certain area. They can be defined in many ways with many tools. A Selection is displayed by a moving dashed line. I refer to them as the little marching ants. By defining a selection it is important to remember that whatever you do after that selection is made, you are only affecting the area inside the selection. That is, at least until you de-select that area. Also note that you can have a selection in place, make an adjustment on the currently selected layer, then switch layers and use that same exact selection to modify another layer. Selections are not tied to layers.
The most common is to use the marquee tool. The marquee tool will draw rectangles or be constrained to a square if you hold the [shift] key while drawing your selection.There is also the ellipse tool for ovals, or circles if you hold the [shift] key while drawing the selection. There is also the single row marquee and the single column marquee tool that will select only a single row of pixels horizontally or vertically respectively.
There is also the lasso and the polygonal lasso tools. The lasso tool will allow you to draw selections in free hand shapes. Just click and drag the mouse around to draw your shape. The polygonal lasso is also for free hand shapes with straight lines. Click for each point and make your last click over the first to join the ends.
All of these tools have 4 different modes that can be chosen in the top options bar. They are as follows:
New selection - Defines a new selection removing an already established one.
Add to selection - Adds new selection area to existing one.
Subtract from selection - Removes a new selection area to an existing one.
Intersect with selection - Overlaps a new selection area to an existing one.
There is also the magic wand tool which selects pixels with the same color values. You can set a tolerance level to choose how close to the selected value it chooses similar pixels. If you have the "contiguous" checkbox selected, your selection will only expand to pixels that are touching the chosen pixel that are within the setting of the tolerance level. With the "contiguous" checkbox unchecked, the selection will include all pixels within the tolerance level across the whole canvas. Not only pixels that are touching.
If you have the "Sample all layers" checkbox checked, it will do exactly that. Your selection will only be the pixels within that tolerance on that layer only. With it unchecked, it will include all pixels within the tolerance level throughout all layers.
If you make a selection and then move your cursor over top of that selection, you'll notice the cursor changes. This puts the tool in 'move mode'. If you click and drag while hovering over the selection, you can move the selection. NOTE: It only moves the selection and not the contents of the selection. To do that you would use the actual MOVE Tool.