Gimp - 2.4 Guía Del Usuario
GNU Image Manipulation Program
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Tip
If you Shift-click on the eye symbol, this will cause all layers except the one you click on to be hidden.
If you Shift-click on the eye symbol, this will cause all layers except the one you click on to be hidden.
Linkage to other layers If you click between the eye icon and the layer thumbnail, you get a chain icon (
), which
enables you to group layers for operations on multiple layers (for example with the Move tool or a transform tool).
Size In GIMP, the boundaries of a layer do not necessarily match the boundaries of the image that contains it. When you create
text, for example, each text item goes into its own separate layer, and the layer is precisely sized to contain the text and
nothing more. Also, when you create a new layer using cut-and-paste, the new layer is sized just large enough to contain the
pasted item. In the image window, the boundaries of the currently active layer are shown outlined with a black-and-yellow
dashed line.
nothing more. Also, when you create a new layer using cut-and-paste, the new layer is sized just large enough to contain the
pasted item. In the image window, the boundaries of the currently active layer are shown outlined with a black-and-yellow
dashed line.
The main reason why this matters is that you cannot do anything to a layer outside of its boundaries: you can’t act on what
doesn’t exist. If this causes you problems, you can alter the dimensions of the layer using any of several commands that
you can find near the bottom of the Layer menu.
doesn’t exist. If this causes you problems, you can alter the dimensions of the layer using any of several commands that
you can find near the bottom of the Layer menu.
Note
The amount of memory that a layer consumes is determined by its dimensions, not its contents. So, if you are
working with large images or images that contain many layers, it might pay off to trim layers to the minimum
possible size.
The amount of memory that a layer consumes is determined by its dimensions, not its contents. So, if you are
working with large images or images that contain many layers, it might pay off to trim layers to the minimum
possible size.
Opacity The opacity of a layer determines the extent to which it lets colors from layers beneath it in the stack show through.
Opacity ranges from 0 to 100, with 0 meaning complete transparency, and 100 meaning complete opacity.
Mode The Mode of a layer determines how colors from the layer are combined with colors from the underlying layers to produce
a visible result. This is a sufficiently complex, and sufficiently important, concept to deserve a section of its own, which
follows. See Section
follows. See Section
Layer mask In addition to the alpha channel, there is another way to control the transparency of a layer: by adding a layer mask,
which is an extra grayscale drawable associated with the layer. A layer does not have a layer mask by default: it must
be added specifically. Layer masks, and how to work with them, are described much more extensively in the
be added specifically. Layer masks, and how to work with them, are described much more extensively in the
section.
‘Keep transparency’ setting In the upper right corner of the Layers dialog appears a small checkbox that controls the ‘keep
transparency’ setting for the layer. If this is checked, then the alpha channel for the layer is locked, and no manipulation
has any effect on it. In particular, nothing that you do to a transparent part of the layer will have any effect.
has any effect on it. In particular, nothing that you do to a transparent part of the layer will have any effect.
8.2
Layer Modes
GIMP has twenty-one layer modes. Layer modes are also sometimes called ‘blending modes’. Selecting a layer mode changes
the appearance of the layer or image, based on the layer or layers beneath it. If there is only one layer, the layer mode has no
effect. There must therefore be at least two layers in the image to be able to use layer modes.
the appearance of the layer or image, based on the layer or layers beneath it. If there is only one layer, the layer mode has no
effect. There must therefore be at least two layers in the image to be able to use layer modes.
You can set the layer mode in the Mode menu in the Layers dialog. GIMP uses the layer mode to determine how to combine
each pixel in the top layer with the pixel in the same location in the layer below it.
each pixel in the top layer with the pixel in the same location in the layer below it.
Note
There is a drop-down list in the Toolbox options box which contains modes that affect the painting tools in a similar
way to the layer modes. You can use all of the same modes for painting that are available for layers, and there are two
additional modes just for the painting tools, which are described here at the end of the list of layer modes.
There is a drop-down list in the Toolbox options box which contains modes that affect the painting tools in a similar
way to the layer modes. You can use all of the same modes for painting that are available for layers, and there are two
additional modes just for the painting tools, which are described here at the end of the list of layer modes.