2. Creating and Using Selections

2. Creating and Using Selections
	第 7 章 Painting with GIMP

2.1. Moving a Selection

Rectangular and elliptical selections have two modes. The default mode has handles on the selection. If you click the selection or press the Enter key,the handles disappear leaving only the dotted outline (marching ants). The other selection tools have different behaviour.

2.1.1. Moving rectangular and elliptical selections

If you click-and drag a selection with handles, you move the selection outline, and you don't move the contents of rectangular or elliptic selections.

Select the Move tool and set the options to move the selection; the tool supports moving the selection, path, or layer.

图 7.5. Moving selection outline

Most systems support moving the selection using the arrow keys. The precise behavior is system dependent. If the arrow keys do not cause the selection to move, try hovering the mouse cursor over the selection first. Press and hold the Alt (or Ctrl+Alt, Shift+Alt, or Alt). One combination may move the selection by one pixel, and another by 25 pixels each step. Hover the mouse cursor over a side or corner handle, and the arrow keys and combinations can change the size of the selection.

If you click-and-drag the selection without handles, you create a new selection! To move the selection contents, you have to

hold down Ctrl+Alt keys and click-and-drag the selection. This makes the original place empty. A floating selection is created. The required key commands may differ on your system, look in the status bar to see if another combination is specified; for example, Shift+Ctrl+Alt.

图 7.6. Moving a selection and its content, emptying the original place
hold down Shift+Alt keys and click-and-drag the selection to move without emptying the original place. A floating selection is created.

图 7.7. Moving a selection and its content without emptying the original place

	注意
	On some systems, you must push Alt before Shift or Ctrl. On these systems, pressing Shift or Ctrl first, causes GIMP to enter a mode that adds or subtract from the current selection — after that, the Alt key is ineffective!

2.1.2. Moving the other selections

The other selections (Lasso, Magic wand, By Color) have no handle. Click-and dragging them doesn't move them. To move their contents, as with rectangular and elliptical selections, you have to hold down Ctrl+Alt keys or Shift+Alt and click-and-drag.

If you use keyboard arrow keys instead of click-and-drag, you move the outline.

2.1.3. Other method

	注意
	You can also use a more roundabout method to move a selection. Make it floating. Then you can move its content, emptying the origin, by click-and-dragging or keyboard arrow keys. To move without emptying, use copy-paste.


第 7 章 Painting with GIMP		2.2. Adding or subtracting selections