5) Grouping, Line Width, and Color

Today's post will cover how to group objects, edit line width, and change color. I'll be using the trefoil from my previous post to create the following image:

Grouping:

Grouping is a feature that is used to combine objects so that they can be edited as one unified whole. Grouping comes in handy in a number of situations. We might group a trefoil so that we don't have to edit each ring separately. We might create a diagram with all rings in one group and all chains in another. With a few clicks we could change all of the rings to red and the chains to blue. Grouping can also be used to rotate entire sections of a diagram to create images such as snowflakes.

To group: Drag the cursor over all of the objects that you want to combine.

The individual boxes show you which items have been selected:

To group these items, press Ctrl+G on your keyboard. You can also group and ungroup by clicking on the following icons on your screen:

If you can't find the grouping icons, you can go to the menu at the top of the screen, and go to Object > Group:

 
After we have grouped our selection, notice the border has increased to include all three rings in the trefoil:

We can now duplicate, resize, and rotate the trefoil without having to edit each ring separately:

(For more about duplicating, resizing, and rotating click here)

If, at any time, you'd like to Ungroup: Select the object and press Shift+Ctrl+G. You can also click on the Ungroup icon on your screen, or go to Object > Ungroup on the menu.


Line Width:

In Inkscape, "Stroke" refers to the lines that form our images. We can adjust the thickness of our lines by editing Stroke Width.

It is much easier to edit Stroke Width in groups, however, to get an idea of the original width, I am going to briefly Ungroup my trefoil. I am doing this because Grouped items have a tendency to display Stroke Width as "Unset," which doesn't help me at all in figuring out what values to work with.

With my trefoil Ungrouped, I can click on one of the rings to see Stroke value in the lower left corner of the screen:

I can also see this value by opening up the Fill and Stroke menu. To open up the menu, double click on the area to the right of the word Stroke:

I can also access the Fill and Stroke menu from the top of the screen, by selecting Object > Fill and Stroke:

After the Fill and Stroke menu opens, click on the tab that says "Stroke Style." Make note of the width that is displayed, in this case, 1 pixel (px).

Now I am going to group my trefoil again, so that I don't have to change the width of each ring individually. With a grouped object, the Stroke may display as Unset. In the lower left corner of the screen, double clicking on "Unset" will bring up the Fill and Stroke menu again:

I want to make the lines in my trefoil thicker, so I am going to increase the Stroke value to 2 pixels. After typing in a new value, press Enter on the keyboard to get the change to take effect. Make sure that you are working in the correct units on the drop down menu (in this case "px" for pixels).

Now my trefoil looks like this:

Color:

There are two types of color changes: Fill and Stroke. Fill refers to the inside of the object, while Stroke refers to the outline of the object. For tatting diagrams, we usually only need to change the outline color. To do so, select your object and hold Shift down on your keyboard while you select a color from the palette at the bottom of the screen:

If you want to create a custom color, open up the Fill and Stroke menu and click on the tab for "Stroke Paint." Then choose a style (in this case I've chosen "flat color") and slide the Red, Green, and Blue dials (R, G, B) to create a color of your own:

For tatting diagrams, we typically want to set Fill to "X" so that the shapes are not colored in. Fill should be set to "X" by default, but if you need to you can select your object and click on the "X" in the lower left part of the screen to eliminate Fill. (Holding Shift down is NOT required to change Fill)

If you'd like to fill in your shape with a color, simply click on a color from the palette at the bottom of the screen. You can also open up the Fill and Stroke menu and click on the tab that says "Fill" to make custom edits to color.

I like to diagram my rings in red, so my final trefoil looks like this: