Compte Formes de pagament Les meves subscripcions Bescanvia Compra una targeta regal La meva llista de desitjos La meva activitat Play Guia per a pares. Afegeix a la llista de desitjos. GIMP is a multi-platform photo manipulation tool. The GIMP is suitable for a variety of image manipulation tasks, including photo retouching, image composition, and image construction. The Gimp Manual provides beginners with a simple introduction to the basics, and experts will find advanced details they need. In this you will see the following things below.

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Gimp, the Gnu Image Manipulation Program, is a free and open-source program that has many of the capabilities of the better-known commercial program, Adobe Photoshop. Gimp can be used both for creating images from scratch and for modifying existing images. This appendix is based on Gimp 2. Note that when you start Gimp 2. You will then see a window with a central area where you can work on images, with dialogs along the left and right edges.

The central editing area uses tabs when multiple images are open. There are also tabs on the dialog window to the right that allow you to access several different dialogs. If you ever mess up the original window layout, it can be difficult to figure out how to get it back.

You will be able to set the size of the image and other properties, such as background color. Saving is a little more problematic. An xcf file is not an image, and it can only be opened with Gimp. It saves the full Gimp editing environment, which you need for more complex projects if you want to be able to return to editing them later.

These commands let you save images in a wide variety of formats. I strongly suggest that you get Gimp and experiment with it as you read about it here! As you experiment, remember that you can always use Control-Z to undo any action.

My discussion here assumes that you are working in single-window mode, with the window in its original configuration.

You can hover your mouse over a tool button to find out what the tool is for. Click a button to select a tool. Click or drag the mouse on an image window to apply the selected tool. The Toolbox also has buttons for controlling the foreground and background color.

Here is an illustration of the Toolbox with a few annotations:. The contents of the dialog change when you select a new tool. Here, for example, are the options for the Brush tool, which is used for painting on an image in the usual sense.

The Brush is probably the most basic and useful tool:. However, it is possible to draw such shapes using selections. The selection tools—at the top of the Toolbox—can be used to select regions in the image. For example, click the Rectangle tool, and drag the mouse on the image to select a rectangular region. The Ellipse Select tool can be used to select oval-shaped regions. The Free Select or Lasso tool, which is next to the Ellipse, can be used to select polygonal regions: Just click a sequence of points to select the vertices of the polygon, and click back on the initial point to close the polygon.

You can also drag the Lasso tool to draw the outline of a region freehand. Once you have a selection, there are many things that you can do with it.

One important fact is that when there is a selection, you can only draw inside the selection— the area outside the selection is completely unaffected by painting tools, or by anything else that you try to do the image! If you forget about this, you can be very confused when you try to apply a painting tool outside the selection and it has no effect at all.

The Bucket Fill Tool, which looks like a spilling paint bucket, is especially useful with selections. With that setting, clicking inside the selected area will fill that area with color. Drawing straight lines in Gimp is a little strange. To draw a line, click the image and immediately release the mouse button. Then press the shift key. Move the mouse while holding down the shift key without holding down any button on the mouse. Then click the mouse again. A line is drawn from the original click to the final click.

You can apply this technique to the Brush tool as well as to other tools, such as the Eraser. The Gradient tool allows you to paint with gradients. A gradient is a smoothly-changing sequence of colors, arranged in some pattern.

Many different gradients are available in Gimp. After selecting the Gradient tool, click the image of the gradient in the Tool Options dialog to select the gradient that you would like to use. Note that some of the more interesting gradients include transparent colors, which create regions where the gradient is transparent or translucent. To apply a gradient to an image, press the left mouse button at the point where you want the color sequence to start, drag the mouse while holding down the button, and release the button at the point where you want the color sequence to end.

Remember that you can limit the area affected by the gradient by making a selection; that is, you can fill a shape with a gradient by creating the shape as a selection and then applying the gradient tool. Here is an image that was created entirely with a few applications of the gradient tool:. The frame was made by dragging the mouse from the center of the image to the edge, but the only opaque part of the gradient was near the edges.

Without the selection, the rainbow would have been a full circle. However, only part of that circle was inside the selection, so only that part was drawn.

You will want to try some of the other tools as well, such as the Smudge tool, the Eraser, and the Clone tool. For help on using any tool, look at the message in the bottom of the image window while using the tool. Consult the user manual if you want to learn more. In addition to its painting tools, Gimp has a wide variety of color manipulation tools that apply to an entire image at once.

These tools are often used to modify the colors in photographs or to apply effects to images. Remember that if there is a selection, then the change will apply only to the pixels in the selected area. This image is in the public domain.

Note that only the colors of the flowers have been modified, not the leaves or branches. To make that possible, I had to select the flowers before changing the color, so that the color change would be limited to the selection. If you click on an image using that tool, all pixels that have a similar color to the clicked pixel will be selected.

By holding down the shift key as you click, you can add new pixels to the pixels that were already selected. I had to click many times, using Control-Z whenever I accidently added too much to the selection. Another way to modify an image is with a filter. Filters in Gimp can be very general. Some filters in Gimp generate images from nothing, and some do even more complicated things. Selections are very important in Gimp, and there is a lot more to learn about them.

For example, the Cut command Control-X deletes the content of a selection. It sets a fully selected pixel to transparent if the image has an alpha component or to the background color if there is no alpha component. However, a partially selected pixel will only be partially cut. If there is an alpha component, the pixel becomes translucent; if not, the current color of the pixel is blended with the background color.

Similarly, when you fill a selection, the current color of a partially selected pixel is blended with the fill color. This is very much like alpha blending, with the degree of selectedness playing the role of the alpha component. See Subsection 2. When a selection is feathered by, say, 10 pixels, the sharp boundary around the selection is replaced by a pixel-wide border, with the degree of selectedness decreasing from one to zero across the width of the border.

Alternatively, selection tools, such as the Rectangle Select tool, have a Tool Option that will automatically feather the border of any selection that you create with the tool. As an example, a feathered elliptical selection was used to make the image on the right, starting from the image on the left:. The original image is, again, a public-domain image from Wikimedia Commons. I started with an elliptical selection around the flowers in the original image.

Gimp users often put a great deal of work into creating a selection. One way to get more control over selections is with the Path tool, which is discussed below. When the Quick Mask is on, the current selection is represented as a translucent pink overlay on the image.

The degree of transparency of the overlay corresponds to the degree of selectedness of the pixel. The overlay is completely transparent for fully selected pixels. When the Quick Mask is on, all painting tools affect the mask rather than the image. For example, drawing with black will add to the mask and therefore subtract from the selection , and drawing with white—or erasing—will subtract from the mask and therefore add to the selection. When editing the Quick Mask, consider using the pencil tool instead of the brush tool.

The pencil tool is the same as the brush tool, except that it does not do any transparency or antialiasing. Paths are not selections, but they are closely related. You can convert a path into a selection, or a selection into a path. Paths are created using the Path Tool the eighth tool in the Toolbox.

To create a path, click a sequence of points with the Path Tool. Optionally, you can make a closed path by control-clicking back on the first point. This gives a polygonal path. You can then drag on one of the sides of the polygon to change it from a straight line into a curve. When you do that, the usual Bezier control handles will appear at the endpoints of the curve. You can drag the ends of the control handles for finer control of the shape.


GIMP Documentation

There are two problems that affect GIMP if you're working on a picture with an alpha layer e. When you save the image to a format that supports alpha e. PNG , any "removed" picture information isn't actually removed. GIMP simply adjusts the alpha channel to make a hole through the picture. From a UI perspective, the above picture sure seems that it has content removed.




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