The Basics And Characteristics Of Gimp Selection Toolss

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GIMP Selection Tools Overview

There are seven separate selection tools in GIMP. All offer the options of feathering and antialiasing, and all can be used for cropping by making the selection, then going to Image > Crop to Selection. When doing this, selections that are not rectangular are simply cropped to the nearest possible rectangular shape.

Rectangle Select and Ellipse Select:
This tools are identical save for one creating rectangles and squares, and the other creating ellipses and circles.

The Fixed option allows selecting to predetermined dimensions. Selection can be restrained to fixed size (width and height), fixed height, fixed width or a fixed width to height ratio. Enter the fixed values you want to use in the text box below.
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An important characteristic of this tool, and one that differentiates it from the Select by Color Tool, is that the selection process spreads out from the first pixel, and areas are selected only if there is a path that apart from gaps of a few pixels, is contiguous right back to the start point. This tool is best used to select an object of multiple shades of a single colour. This colour must be dissimilar to the surrounding colours.

If, after the first click, the full object is not selected, then the tool’s options mode should be set to “Add to the current selection”. Further, clicks on unselected areas will now cause the resulting selections to be added to the total selected area. Each click can be undone with Ctrl + Z, and the Quick Mask can be used to check the results at any time.

The Threshhold option allows the range of tone values selected to be controlled. If the threshold is set to 50 for example, then colour values ranging from 50 below to 50 above the pixel clicked on will be selected. Setting the threshold value to 255 results in every colour from pure black to pure white being selected through a click on a pixel of any
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If the line is not correctly placed between two nodes, you cannot undo it. Instead, you must click the line between the nodes to add a third node, then use the to realign the selection line. In working your way around the object you can either position the cursor first and then click to add a node, or click first anywhere then drag the new node to the object edge. The Interactive Boundary option should be ticked if using the second method, as you will then see the tool’s line being aligned with the object edge as you drag it into place, This option needs to be turned off only if you are using a computer with limited resources.

The tool’s cursor will show a small “+” sign as you work around the object, unless you happen to be readjusting an existing node. Once you reach the starting node the sign will turn into a chain-like “link” symbol. Once you click to close the selection, you need only press Enter to convert the path into a standard selection.

This tool appears to attract mixed views on its worth. Even for objects that contrast starkly with their surrounds, it appears to do a poor job of consistently finding the edges. It is easy enough to use Quick Mask and clean up the selection with a paint brush, but there are many times when some another tool, like the Free Select Tool used at high magnification, would likely do a better and faster job.

My Recommended Method for Selecting a Complex

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