Grids, Guides AND Snapping by Xhris (of TalkGraphics)

Introduction

Use of the grid, guidelines, and snapping is essential if you are trying to ensure precise positioning of objects. This tutorial will discuss the grid, guidelines, and magnetic snapping in detail and highlight how their use is affected by the Scale Line Widths feature.

To activate the grid, go to the Window menu, and select Show Grid, or just press the # key to toggle. The default grid is shown below.

Grid Options

There are many grid options, and there is a dedicated tab in the options dialogue that deals with them. There are two ways to access this:

1. Go to the Utilities menu, and select Options (or just press Ctrl+Shift+O), and select the Grid and Rulers tab.

2. With the rulers visible in the document (Ctrl+L, or Ctrl+Shift+R), right click on a ruler, and select Grid and Ruler Options from the context menu.

Major Spacing

This determines the main spacing between major gridlines, i.e. the general scale of the grid. The major gridline intersections are visually represented with crosses (+).

Number of Subdivions

This determines how many smaller gridlines fit in-between the main gridlines discussed earlier. The minor gridline intersections are visually represented with dots (�.�). For example, for the default grid, a Major spacing of �50pix� and Number of subdivisions of �50� will produce a grid with gridlines at every 1 pixel from the grid origin. There is a major gridline every 50 pixels, and 49 minor gridlines in-between, each 1 pixel apart. If you are zoomed-out sufficiently such that the minor grid spacing reduces and is less than a few screen-pixels, enough minor gridlines are not drawn to ensure the visible grid spacing is reasonable and neat. If Snap to Grid is active (see section 4.3), snapping still occurs on gridlines too narrowly-spaced to be drawn; snapping thus may not be noticeable however.

Tip: When setting up scale drawings (not covered in this tutorial�see Scaling tab in options dialogue), it is helpful to reset the grid divisions to use the new scaled units. For example, if your scale factor is 1 mm : 100 mm, setting Major spacing: 600 mm, Number of subdivisions: 6 will display updated rulers, and will show sensible scaled units (the rulers reflect the grid settings).

Grid Types

There are two different grid types: Rectangular and Isometric. The Rectangular grid is the default and is used to draw in a parallel orientation. The Isometric grid is used to draw perspective-oriented diagrams that allow vanishing points. Both grid types are shown below.

Origin (0,0) Point

The origin (0,0) point represents the point at which all measurements are taken relative to, and by default is located in the lower left corner of the page in the document. The selector tool infobar shows (x,y) coordinates (of the shape), as does the status line in the bottom right of the screen (which shows mouse coordinates), and these are both defined relative to the document origin point. The local origin of the shape is determined by the Coordinate direction (see section 2.2.4). In general, all coordinate measurements in Xara documents are made relative to the document origin. The origin point can be changed by either manually typing in values into the options dialogue, or by simply clicking and dragging on the origin marker located in the top left and in-between the rulers, as shown below.

Coordinate Direction

This option allows you to define whether the x-coordinate increases in value as the measurement point (local origin of the cursor or shape) moves either to the right or to the left of the origin. Similarly for whether the y-coordinate increases in value as the measurement point moves either above or below the origin. The default setting is that increasing coordinates occur as the measurement point moves to the right and above the origin point, in line with standard mathematical coordinate space. However, there are times when this is not useful and it is more useful to define downwards and/or to the left of the origin as increasing the coordinate measure. An example of this is when designing graphics for web pages; the origin for design is typically defined as being in the top left of the page, with positive being defined as moving downwards and to the right from the origin. It is useful in this instance to set Xara to be the same by using these options, as it allows accurate measuring of object sizes. In changing the default coordinate direction, as you might expect, you also change the local origin of shapes. For example, if you set positive being defined as moving downwards and to the right from the origin point, then the local origin of a shape (say a square) is in the top-left instead of the bottom-left; thereby the shape�s size increases to the right and downwards. When selecting one of these options other than the default, the global coordinates displayed anywhere in Xara will update to reflect the new relative measure (i.e. will negate in value).

Guidleine

Guidelines can be manually positioned anywhere on the page, and can be used to help align objects in a similar fashion to using the grid. You would use guides instead of the grid if you were aligning to just a few specific locations; however, you may use the grid to align guidelines.

Guides Layer

Any guidelines that are created are put onto a special layer called the Guides layer. It is located in the Layer gallery once created, and the contents of that layer are non-printable. The simplest way to create a Guides layer is to create a guideline (see section 1.1). Alternatively, open the Layer gallery (press F10 in the document), right-click anywhere in the gallery, and select Create guide layer as shown below.



Any objects can be put onto the Guides layer but they will all be displayed as outlines, as shown in Figure 3.2. Only the guidelines created using the ruler (see section 1.1) will generate leading-edge-snapping (see section 4.3) when Snap to guides is on; other custom shapes will only cause hard- and soft-snapping (see section 4.3.3.1). This is discussed again in Note 3 in section 4.3.3.1.

Creating Guides

The easiest way to create a guideline is to click and hold on the ruler, and drag into the document. A new guideline follows your mouse curser, and is placed at the point where you release the mouse button. You can drag like this from both the horizontal and vertical rulers. An alternative, equally easy way to generate a guideline is to double-click at a point on either ruler. A guideline appears at the double-click point. Creating a guideline automatically creates a Guides layer if one doesn�t already exist. For completeness: a more convoluted way to create guidelines is to right-click the ruler, and select New Guideline from the context menu that appears (below), and fill in the information in the dialogue box that is displayed, and accept it to place the guideline.



Alternatively, right-click the rulers and select Guide layer properties (also shown in Figure 3.3) to bring up a dialogue box (Figure 3.4); click on the New button to bring up the same dialogue as is produced by the method shown in Figure 3.3 to create a guideline. The dialogue in Figure 3.4 can also be used to change the colour of the guideline.