GIMP User Manual
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# Gfig

## Overview

The Gfig plug-in is a versatile plug-in that is used to create geometric shapes. It makes use of definable paths and the currently selected brush. The Gfig dialog window is neatly divided into three areas.

## Gfig Options

- Ops contains the shape creation tools. These are the tools that are used to control the shapes that are created with Gfig.

- Preview contains the shape preview area, the Object Details, and the Collection Details. The main preview window is where the creation of shapes will occur.

- Settings shows many control options. This area includes save and delete tools for shapes. Also a mini-preview can be seen. Grid settings are found here, as well as the rendering options.

## Object Settings

The Object section, inside Settings, offers the loading, creation, and saving features of the plug-in.

Rescan

  This allows the rescanning of the list of available shapes from the file system. Any shapes that are saved to the file system can be loaded into the list via this button. Clicking the Rescan button will display a dialog that shows the currently loaded shape paths. New paths can be added by clicking the icon in the top left. A browse button is provided in the top right of the dialog.

Load

  The Load button is used for loading individual shapes into the editor. If there is a Gfig file located somewhere on the file system, this button is used to load the shape.

New

  Clicking this button will remove all of the current shape settings and create a new shape file. After clicking the New button, a dialog will request a filename for the new shape.

Delete

  Delete is the button used to delete a saved shape.

Edit

  The Edit button is used to transfer the currently displayed small preview into the main preview window.

Merge

  The Merge button is used to merge the current shape with the shape in the main preview window. This function adds the new shape to the current one.

Upon editing an existing shape or creating a new shape, a disk icon will appear next to the name of the shape. This icon indicates that the shape has not yet been written to disk. A red cross indicates that the file is read-only and cannot be saved.

## Grid Options

The Grid settings located below the Object settings control the editing grid layout and behavior.

Snap to Grid

  This checkbox toggles grid snaps. When grid snaps are active, drawing nodes are forced to the nearest grid intersection.

Display Grid

  This toggles the visibility of the editing grid.

Grid Spacing

  Grid Spacing adjusts the density of the grid. A higher setting here will space the grid further apart. A lower setting will make the grid spacing smaller.

The tab section located below Grid settings controls the rendering settings.

## Tabs

The first tab, Paint, contains basic brush options.

Draw on

  These options control the layer that will be used for the shape render.

  - Original will render the shapes onto the existing layer.

  - New will force the creation of a new layer for the shape.

  - Multiple option will render each of the individual, unjoined shape components to a separate layer.

Using

  This dropdown list allows the selection of the method by which the shape will be rendered.

  - Brush will render the shape using the currently selected brush. The Brush tab contains the options that affect this choice.

  - Selection will render the shape as a selection area.

  - Selection+Fill will render the shape as a filled selection area.

  Choosing either of the selection render methods will change the Brush tab to a Select tab. The Select tab controls settings that affect the selection render methods.

With BG of

  This dropdown is available only if the Draw on dropdown has either New or Multiple selected. The available options here change the background setting for the rendered shape.

  - The Transparent setting renders the shape onto a transparent background.

  - Background uses the currently selected background color for the shape background.

  - Foreground uses the currently selected foreground color to render the the background for the shape.

  - White will render the shape onto a white background.

  - Copy will use a copy of the current layer for the background.

Scale to Image

  Selecting the Scale to Image toggle will scale the rendered shape to the size of the image where rendering will take place. If this option is not checked, then the Scale to Image slider will become active allowing controlled resizing of the shape at render time. A setting of "1.00" will render the shape at 1:1 scale.

Reverse Line

  This option will render the shapes in reverse. When creating shapes there is at least a start node and an end node. By this logic, these nodes, and consequently all encapsulated between them, can be rendered in reverse order. Rendering nodes in reverse can be useful for those choosing to use a brush that fades out, for example.

Approx. Circles/Ellipses

  This option, when activated, will create an anti-aliasing effect when rendering the arcs of circles.

## Brushes

Brush Selection

  The Brush dropdown allows selection of the brush type.

  - Brush, pencil, and airbrush correspond to the GIMP equivalents that are found in the Toolbox.

  - Pattern fills the brush area with the currently selected pattern. Pattern is only applicable to circles and ellipses if Approx. Circles/Ellipses is active in the Paint tab.

Set Brush...

  The Set Brush... button can be clicked to set up the brush in more detail. Clicking this button will bring forth the brush selection dialog.

Fade Out

  This option is only available if Brush is the selected brush type. The slider sets the number of pixels over which the stroke should be faded. A low setting is recommended to begin with until more skill is gained judging the lengths of the strokes.

Gradient

  This option is only available if Brush is the selected brush type. The gradient slider selects the number of pixels along a stroke to render the current gradient. For example, a setting of fifty would render the gradient every fifty pixels.

Pressure

  This option is only available if Airbrush is the selected brush type. Pressure is a slider that sets the amount of ink allowed into the brush shape. A low setting will produce a faint brush, whereas a higher setting will result in a more solid one.

## Selections

The Select Tab is only made available if Selection is the active option in the Paint tab.

Selection Type

  The Selection Type can be set to one of four things.

  - Add will merge any existing selection with the shape that will be rendered. If no selection exists, Gfig will create one.

  - Subtract will take the existing selection area and remove the shape from that area. If no existing selection is present, Gfig will do nothing.

  - Replace will remove existing selections and replace them with the current shape.

  - Intersect will change the current selection to an intersection with the shape. Any area that that the shape overlaps will be kept. Any other areas will be discarded. If no selection exists, nothing will occur.

Fill Type

  Fill Type is only applicable if Selection+fill is the active selection in the Paint tab. There are three options.

  - Foreground will fill the selection with the current foreground color from the Toolbox.

  - Background will fill the selection with the current background color from the Toolbox.

  - Pattern will fill the selection with the current pattern fill from the Toolbox.

Fill after

  The Fill after settings control how selection areas are painted with a pattern. This option is only available if Selection+Fill is the active Paint option.

  - Each Selection ensures that selections are painted after each segment of the shape is rendered.

  - All Selections fills the selected areas only after all shape segments have been rendered.

Antialiasing

  Checking the Antialiasing option will turn on the anti-aliasing features of the renderer. Anti-aliasing can give the effect of smoothness between two areas of differing color.

  See also: Anti-aliasing glossary entry

Fill Opacity

  This slider sets the level of opacity that the rendered shape will have. A high setting here will result in more opacity and a lower one in less. Opacity is defined as "The quality or state of being opaque". A layer or shape with less opacity will allow color information from underneath it to be visible to some extent through it. The extent is based on the level of opacity.

Feather

  The Feather toggle allows specification of feathering of the selection area. If Feather is checked, the selection will be feathered to the amount set by the Radius slider. Feathering produces a faded edge on a selection. This can help to smooth a layer or shape into a background that may not quite match the shape in color weight.

Radius

  The Radius slider is a subset of the Feather option. The slider sets the amount of feathering that will be created against the selection. A high setting here will result in more feathering.

## Options

The Options Tab sets many of the Gfig options.

Show Image

  The Show Image checkbox toggles whether the current image or layer is shown in the main Preview window.

Reload Image

  Reload Image reloads the active image or layer into the main Preview window. This option can be used to update the window contents in the event that the image has been changed or modified while Gfig is in use.

Grid Type

  - Rectangular shows the grid as a standard 90o line grid. This is the default for most grid based applications.

  - Polar displays the grid as a polar grid. Polar grids are circular, as if looking at a wireframe sphere from above.

  - Isometric grids are common to technical drawing fields. Isometric layouts are also frequently seen in reference to three dimensional work.

Grid Color

  The Grid Color settings control the color of the displayed grid. It can be useful to change these settings if an image has been loaded into the main Preview window which might obscure the normal grid.

Max Undo

  This slider adjusts the number of possible undo operations for the drawing. Any change made to the drawing can be reverted or undone by using the Undo button. The Max Undo slider controls the exact number of operations that can be undone.

Show Position

  The Show Position checkbox toggles the display of the current X,Y co-ordinates in the Object Details area, underneath the main Preview window. The coordinates represent the mouse cursor position within the drawing window.

Hide Control Points

  This option toggles the display of the control points. The control points are the squares that are displayed on the start and end points of the shape lines.

Show Tooltips

  This option toggles the display of the floating tip windows that are displayed if the mouse cursor is hovered over a button or slider for a set period of time.

About

  This button displays the Gfig About dialog window. This window provides information about the authors.

## Operations

The Ops panel is located on the far left side of the Gfig window. This panel is used for the actual creation of shapes.

Line Tool

  The line tool is located at the top of the Ops panel. This is the tool used to draw straight lines. Lines are created by clicking and dragging the mouse cursor. The initial click point is the start of the line, and the drop point is the end of the line.

Tool

  The circle tool is the second tool in the Ops panel. The circle tool is used to create perfect circles. Circles are created by clicking and dragging the mouse cursor. The initial click point becomes the center of the circle and the drop point sets the radius of the circle.

Ellipse Tool

  The ellipse tool is used to create non-symmetrical circles. The ellipses have either a horizontal or a vertical alignment. Ellipses are created by dragging the mouse cursor. The initial click point becomes the center of the ellipse and the drop point sets the X and Y extremities of the ellipse.

Curve Tool

  The curve tool draws part of a circle. To create a curve, click the start point of the arc, click the radius of the arc, and finally click the endpoint of the arc.

Polygon Tool

  The polygon tool draws equilateral polygons between three sided and two hundred sided. To set the number of sides, double click the tool button. To create the polygon, click and drag a line. The initial click point becomes the center of the polygon, and the drop point becomes the radius.

Star Tool

  The star tool creates star shapes between three points and two hundred points. To set the number of points simply double click the tool button. To create the star shape, click and drag the mouse cursor. The initial click sets the center of the star, and the drop point sets the maximum radius.

Spiral Tool

  The spiral tool, like the Polygon and Star tools, can be double clicked. This will display the tool options associated with the spiral tool. Both the direction of the spiral and the number of turns can be set. The creation of a spiral is similar to that of a circle. Simply click and drag a line to set the center and the radius and endpoint of the spiral.

Bezier Tool

  The bezier tool can create abstract curves. The tool can be double clicked to display the tool specific options. Within those options are two settings.

  - Closed toggles whether to close the bezier curve upon completion.

  - Show Line Frame toggles the display of the control lines between nodes during curve creation.

  Creation of a bezier curve requires at least three clicks. The first click sets the start point. All consecutive clicks set the controls for the curve. To complete the curve, shift-leftclick. If Closed has been toggled, the curve will close automatically.

Move Tool

  This tool allows the movement of a shape. In order to move a shape, click one of the control points that belong to the image and drag it. If Hide Control Points is toggled, the control points will still be able to be clicked for movement, but will not be visible. This will make it rather difficult to move the shape.

Move Single Point

  This tool is used to move control points without moving the entire shape. This can be useful when changing the actual shape, and not just the position of the shape. Each of the primitives is affected differently by this tool. Of particular note are the following:

  - Circles and Ellipses can be moved with the center control point. This will however relocate the center control point, but not the radius control point.

  - The Star shape, when created, contains a third control point located between the center and the radius. This point controls the length of the spokes.

Copy Tool

  The copy tool is used to copy shapes. Click any control point that belongs to the shape that is to be moved and drag the point to a new location.

Delete Tool

  This tool deletes shapes. Clicking on a control point will remove the shape that owns the control point.

"<" , ">" , and "=="

  These three tools control what shapes are displayed in the main Preview window.

  - The "<" and ">" tools cycle through each shape individually. These tools can be useful for painting shapes by themselves.

  - The "==" button redisplays all the shapes that may be hidden after using the "<" and ">" tools.

## Rendering the figure

The list of buttons located at the bottom of the Gfig dialog window produce, clear, and undo the work in the main Preview window.

Done

  Clicking will end the current Gfig session.

Paint

  Paint will render the visible shape with the current settings.

Save

  This button saves the current shape. If the shape has never been saved to disk before, Gfig will ask for a filename and location.

Clear

  This will clear the active Preview and any changes will be lost.

Undo

  As discussed earlier, this button will revoke the last change made to the shape or drawing.

Cancel

  This button will close Gfig.

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