Marquee tool

Draw a pixel selection as a rectangle, ellipse, polygon or lasso, or paint it with a brush, then combine, reshape, move and copy it.

The Marquee (M) makes a pixel selection: a mask that limits where painting, erasing and filling can land. The selection belongs to the project rather than to a layer, so it stays put while you switch layers, and it survives until you clear it.

A live selection is drawn as marching ants. Everything the tool can do to an existing selection is on the right of the options bar, and those buttons are greyed out until there is one.

The shapes#

Rectangle and Ellipse also have a style on the bar: Normal, Fixed Ratio or Fixed Size. Normal follows the drag. Fixed Ratio keeps the width to height ratio typed into the W and H fields. Fixed Size draws a box of exactly W by H pixels, from 1 to 16384, centred on the cursor, so a click is enough.

With Rectangle or Ellipse, a box smaller than one document unit clears the selection, but only in Replace mode, so a stray click cannot wipe a selection you are adding to.

Combining selections#

The Mode dropdown decides what a new marquee does to the selection you already have.

• Replace: the new marquee becomes the selection. The default.
• Add: the new area is added to it.
• Subtract: the new area is removed from it.
• Intersect: only the overlap survives.

Any mode other than Replace draws an accent line under the dropdown. One word in a menu is easy to read past, and a latched Subtract or Intersect makes the tool look broken: both leave an empty selection, so dragging appears to do nothing at all.

The modifiers override the dropdown for one drag: Shift adds, Alt subtracts, Shift+Alt intersects. The dropdown still decides what a plain drag does. What counts is what you hold when you press: Shift or Alt pressed after the drag has started shapes the box instead, making it square or drawing it from the centre.

The Mode dropdown is shared with the Magic Wand: the combine mode belongs to the selection rather than to one tool, so setting Add here keeps applying when you switch to the wand, and the two tools build up one mask together.

Reshaping a selection#

Pixel ▸ Selection holds the rest: Border turns the selection into a band along its edge, Smooth rounds off its corners, Fill Selection and Stroke Selection paint it or its outline onto the selected layer, Selection from Layer selects what a layer draws, Selection to Shape turns the outline into a Shape layer, and Crop Canvas to Selection makes the canvas the size of the selection. See The Layer, Vector and Pixel menus.

Expand and Inset flank the number they share, one on each side, so the amount can only belong to them; Feather has one direction, so its amount follows its button. All three are worked out at a cost that does not grow with the number, so a 64 px expand is as immediate as a 1 px one.

Moving the outline#

A drag that starts inside the marching ants moves the selection itself, not the pixels under it, in whole pixels so its edge stays crisp. It works in every shape, Polygon included, and whatever the Mode dropdown says. Only Shift or Alt held at the press keep their Add and Subtract meaning, so you can still add a region that starts inside. With Polygon, a click inside that does not move starts a new polygon as usual, and the selection Brush always paints.

Hold Ctrl as you start the drag to move the selected pixels along with the outline, or Ctrl+Alt to leave them where they are and move a copy of them on a new Pixel layer. The whole move is one undo step.

What a selection constrains#

While a selection is live it masks every painting operation, on every layer type. A brush or eraser stroke is clipped to it, on a Raster Cells or Pixel layer and on the vector blob brush alike, so you can work straight over the boundary and only the selected area changes. That holds for the tools that paint straight onto the layer as well: the eraser, Smudge, Deform, and any textured or blend-mode brush. The Fill tool flood is clipped the same way on a vector layer as on a raster one, and Delete clears the pixels inside it.

The clipping is live, not just applied at the end: paint stops at the marching ants while you are still drawing, rather than spilling over and snapping back when you lift the pen. On the vector blob brush the on-canvas preview is clipped to the selection's bounding box, which is exact for a rectangular marquee and generous for an ellipse, lasso or wand region; the committed shape is cut exactly in every case.

A feathered edge softens a raster stroke pixel by pixel. Where the selection has to become a vector outline, which is what happens when the blob brush is clipped, the soft edge has to harden somewhere: the cut is made at 50% coverage.

With the Move or Transform tool active, the selection itself is what you transform, not the layer under it: the marching ants are the subject, and they carry the pixels with them. Four corner handles scale, the dots at the middle of the edges scale in one direction, a knob above the top edge rotates, and a drag inside moves. Hold Shift for uniform scaling and 15 degree rotation steps. Hold Alt and drag inside the selection to leave the original behind and move a copy. Clicking outside commits the move; Esc cancels the transform and leaves the selection where it was, rather than throwing the selection away with it. Arrow keys nudge the selected pixels rather than the whole layer. The Transform tool's Skew, Perspective, Distort and Warp modes work on the selection too, and the selection follows the pixels when they are dropped. See Transform tool.

While a selection is up on a Raster Cells or Pixel layer, Copy, Cut and Paste work on pixels rather than layers. Copy takes the selected layer's pixels inside the marching ants, soft edge included, and also puts them on the system clipboard as a picture. Paste brings them back at the same place as floating pixels, ready to move, onto the selected bitmap layer, and switches to the Transform tool if you were using another tool. When the selected layer cannot hold pixels, the paste becomes a new Pixel layer instead.

Undoing a selection#

Every change to the mask is a history step of its own: drawing a marquee, adding to it, clearing it, and each Expand, Inset, Feather or Invert. Ctrl+Z brings the previous mask back intact, including its feathered edge, and History names the step Select pixels, Modify selection or Deselect pixels so it is distinguishable from a layer selection.

Practical notes#

• The marquee needs no layer and creates none. On an empty project it still draws a selection, it just has nothing to constrain yet.
• The mask covers paint that lies outside the canvas as well, so a selection over an oversized pixel layer works out to the edge of the artwork.
• The marquee does not snap to the grid or to vertices.