GIMP Image Editor – Part 2 (Selection tools explained)

By | 21/01/2013

GIMP image editor provides a complete set of basic editing tools that let you perform variety of tasks. Broadly, these tools fall under five major categories known as Selection tools, Paint tools, Transform tools, Color tools and Other tools. In part-I of this series we presented an overview of these tools.

GIMP Image editor (Selection tools)

GIMP has a tool box containing tool icons. For activating most of the tools, you just need to click on their respective tool icon. Color tools are accessible via menu option “Colors” and not by toolbox. All of these tools are accessible through “Tools” option in the menu.

first

 

 

In this article, we will discuss the functioning of each selection tool in detail and learn how it works.

 

Selection tools explained

Before you start editing an image, it is very important to select the areas or regions of editing. Selection tools are designed to select a particular area or region to be edited in the active layer. You can select and work on the region to be edited without affecting rest of areas in the active layer.

The seven selection tools are:

  • Rectangle select
  • Ellipse select
  • Free select
  • Fuzzy select
  • By Color select
  • Intelligent Scissors select
  • Foreground select

 

For an even better clarity, all these tools are represented (order wise) in form of icons in the image below :

 

selection tools

 

 

 

We will refer to each icon in the relevant section while explaining the corresponding tool that the icon represents.

 

Original Image

The image shown below is the original or the base image that we have chosen to explain selection tools in this article. Now we will perform set of operations over this image with each selection tool and you can easily compare how the tool works. However, a different image is used for some operations in order to present more functional clarity of the tool.

 

original image

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Let’s now understand each select tool one by one.

 

1. Rectangle Select

The Rectangle Selection tool enables you to select rectangular regions on the active layer. You can use drag and drop feature to get a rectangular or square shape over the image. In the icon image (presented in the beginning of this article), the first icon highlighted in the purple colored rectangle represents this tool.

 

rectangle select

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

As soon as you activate rectangle selection tool and click on the active layer, the mouse cursor gets transformed into a small square icon while on the image. Drag the cursor on image to create a rectangular region. By dragging and dropping, you can manipulate the length and the width of the rectangular region. If you want to select multiple rectangular regions, you need to press shift key before starting the selection. When you press shift, a ” +” sign will appear on the image along with the small square icon as soon as you click on the region of selection and this will add the new selection to the existing one. Once you are done with the selections, press enter and you can perform various set of tasks in the selected area. For example, we have changed the hue and saturation in the selection.

 

2. Ellipse Select

The Ellipse Selection tool enables you to select the circular and elliptical regions on the active layer. In the icon image (presented in the beginning of this article), the second icon highlighted in the red colored oval shaped figure represents this tool.

 

elipse select

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

As soon as you activate this tool, the mouse cursor icon gets transformed into a circle icon while on the image. Drag the cursor on image to create an elliptical region. Initially the ellipse appears inside a rectangular box. You can adjust the ellipse or circle by drag and drop within a rectangular box. Once done with the settings, if you click again inside the elliptical selection, the outer rectangular box disappears and elliptical region becomes permanent on the image. You need to follow the same procedure as described in rectangular selection (in the point above) if you want to make multiple elliptic selections over the image.

 

3. Free Select

The Free Selection tool is designed for selecting a hand-drawn region with free and polygonal segments on the active layer. In the icon image (presented in the beginning of this article), the third icon highlighted in the blue colored rounded rectangle represents this tool.

 

free select

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Now, when you activate this tool and click on the region of the image to be selected, its icon will appear there. Now you can move it in whichever direction you want. This tool is mainly for rough drawing and not for precise selection. When you start drawing, just click once on the starting point to create an anchor point at the start, similarly while drawing you can create more anchor points by clicking in between which will help in creating more precise drawing. When you are done with the selection, click once more on the starting anchor point to complete the selection.

 

4. Fuzzy Select

The Fuzzy Selection tool is for selecting a contiguous region on the basis of color similarity on the active layer. This tool is also called Magic Wand tool. In the icon image (presented in the beginning of this article), the fourth icon highlighted in the brown colored rectangle represents this tool.

 

fuzzy

 

 

 

 

 

 

 

 

 

Once you activate this tool, you need to click at the correct spot in the image and it starts selecting. It expands outwards like its spreading, selecting contiguous pixels with color similar to the starting pixel. Now you can compare the two pictures, flower with black outline is the original picture. Once you click on the black outline, all the contiguous area with same color got selected, then press enter to keep the region selected and perform whatever operations are required to be performed.

 

5. By Color Select

The Select by Color tool is designed for selecting the regions with similar color. It may work like the “Magic Wand” tool but the only difference is that it selects all the pixels of the same color regardless of where they are located whereas the other tool selects only contiguous regions. Once you activate this tool and select the reference pixel, it will select all the regions of same pixel automatically on the active layer. In the icon image (presented in the beginning of this article), the fifth icon highlighted in the green rectangle represents this tool.

 

by color

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You can compare the modified picture with the original picture and observe that all the regions with nearly similar pixel got selected once I selected the reference pixel irrespective of the fact whether they are adjacent or not.

 

6. Intelligent Scissors

Intelligent Scissors tool is designed for selecting shapes using intelligent edge fitting on the active layer. Once you activate this tool, you need to click to create a set of  control points at the edges of a region which you are trying to select. Scissors will make a curve in continuation which is passing through these points following the edges. Once you are done with your selection, click anywhere inside the curve to stop. In the icon image (presented in the beginning of this article), the sixth icon highlighted in the grey colored oval shaped figure represents this tool.

 

scissors

 

 

 

 

 

 

 

 

 

 

 

 

 

You can very well see that we have selected the flower using scissors tool. You need to go from one edge to another by clicking at the edges using nodes and this tool will find out the rough lines in between and mark them precisely as per their shape. Once you are done with the selection, click on the entry node and then click anywhere in between the selection to mark the end of the selection.

 

7. Foreground Select

Foreground Select tool is for selecting a region containing foreground objects. It enables you to extract the foreground from the active layer. Once you activate this tool, select the foreground you want to extract and draw a line through the foreground. When you release the mouse, non selected area will be in dark color, then press enter to get the required selection. In the icon image (presented in the beginning of this article), the seventh icon highlighted in black hexagon represents this tool.

 

foreground

 

 

 

 

 

 

 

 

 

 

You can compare the two pictures and easily analyze how the foreground picture is extracted from the background. Once you have extracted it, perform any set of tasks over the selection and press enter to keep them.

So, this was all about GIMP selection tools. You are welcome to provide your comments and share your experiences related to selection tools. Also, stay tuned for more on GIMP image editor.

One thought on “GIMP Image Editor – Part 2 (Selection tools explained)

  1. venkatesh

    Sir,
    i am not able to copy the area of interest after i have clearly demarcated the area using intelligent scissors.

    Suppose i want to copy the image of the person alone leaving behind the background how do i accomplish this using the intelligent scissor tool?
    Can you help me?

    Regards,
    Venkatesh.

    Reply

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