Paint Shop Pro Vector Basics: Path Anatomy

Paint Shop Pro Vector Basics

Paint Shop Pro Vector Basics

When you draw with the Draw tool or lay down a shape with the Preset Shape tool in Create as vector mode, you make a vector path. Paint Shop Pro hides the real nuts and bolts of the vector path from you, so to really appreciate the power of vector graphics it's essential to have access to the raw vector elements. We can do this in PSP by going into node editing mode.

Simply selecting a vector object with the Vector Selection tool (single selections only, you can't node edit multiple vector selections), right-clicking, and choosing Node Edit from the drop down menu will get you there. (Alternatively, clicking Node Edit in the Selection Tool Options palette while an object is selected will accomplish the same thing). When an object is being node edited, its fill and stroke attributes disappear, leaving you with the vector essentials of the shape. Those essentials consist of the anchor points and the segments that join them. A single set of anchor points and segments is a contour and an individual vector object may consist of one or more contours and is called a path on the node editing level.

Segments can be either straight or curved, and anchor points or nodes, as they're called in PSP, define segment ends. Paint Shop Pro uses Bézier curves, a compact way of mathematically describing a curved segment, which is based on the location of the nodes that define the segment's ends and on direction lines that describe the angle and length of the curve, called curve handles.

Types of Nodes

Types of Nodes

A few cautions about Paint Shop Pro 7's node editing may be in order. In version 7 you need to select a path with the Object Selector the choose Node Edit from the Tool Options palette. Node editing puts you into a whole different environment in 7. While in node editing, no other PSP tools, palettes, scroll bars, or menus can be accessed. The very act of clicking outside the image window will kick you out of node editing. You can, scroll around an image by using the arrow keys, and zoom in and out using the numeric keypad + and - keys respectively.

In Paint Shop Pro 8 and 9 simply selecting the Pen tool in Edit mode will allow you to node edit. Scroll bars, menus and palettes can still be accessed.

Nodes come in two basic types, those with curves and those without curves. You can tell if a node has a curve or not by selecting it in node editing and checking if it has curve control handles. Selecting a node is just a matter of clicking on it. Once selected, a node turns black and its curve handles, if any, appear.

Node Editing Mode

Node Editing Mode

Once you turn on node editing, you can manipulate the various nodes and curve handles. A selected a node can be dragged and dropped anywhere on the canvas and, in fact, outside the canvas. Multiple nodes can be selected to be dragged in unison by either drag-selecting or selecting individual nodes while holding down the Shift key. Note that curve handles can't be addressed in multiple node selections.

You can adjust the curve handles in a similar fashion by dragging them in or out to shorten or lengthen them, or in a new direction to change the angle of the curve, or both. One end of the curve handle on a given node controls the portion of the segment on that side of the node, the other side of the segment is controlled by the end on the other side of the node.

Node with No Curves

Node with No Curves

Nodes come in different flavors. A node can have no curves, as our friend here...

Node with Curves on both Sides

Node with Curves on both Sides

Or it can have a curve on both sides...

Node with a Curve on One Side and a Line on the Other

Node with a Curve on One Side and a Line

Or it can have a curve on one side and a line on the other...

Exploring the Node Types in Paint Shop Pro

Exploring the Node Types in Paint Shop P

Let's take a closer look at the different types of nodes. Open up PSP and create a new image file, then lay down an ellipse with the

Preset Shapes

tool in PSP7 or 8. In PSP9 select the Ellipse tool, lay down an ellipse then in the Object Menu select Convert to Path. Now select the ellipse with the Object selector and choose Node edit in the Tool Options palette in PSP7 or in PSP 8-9 select the Pen tool in Edit Mode. If you select the top node, right-click again and select

Node Type

you'll be presented with the menu.

As you can see, Cusp, Curve Before, and Curve After are greyed out. This is because the ellipse preset shape comes complete with four Cusp nodes that already have curves on both sides. A cusp or corner node's curve handles can be manipulated totally independent of each other; that is, moving one has no effect on the other. Try moving the handles around to get a feel for what sort of changes you can make to an object by manipulating the curve control handles. Notice that when you pass the cursor over one of the control handles, it changes the cursor to indicate that you can drag the control handle to adjust the curve.

Cusp Node, Asymmetric Node, and Symmetric Node

Cusp Node, Asymmetric Node, and Symmetri

A cusp node makes a sharp corner. The




nodes are called

Smooth curves

. In the case of the


node, the control handles can be lengthened or shortened independent of each other, but if you try to change the direction of one, the other follows, keeping both handles in a straight line. Change your node to an


one and see what I mean. It's not possible to make the same pointy shape you could with the



With a Symmetric node, the curve handles behave similar to Newton's Third Law of Motion: "For every action, there is an equal and opposite reaction". Neither curve handle can be moved without the other moving in an equal and opposite direction, maintaining handles of equal length and opposite direction. Change your node to Symmetric to get a feel for what you can do with a Symmetric node.

Smooth/Tangent Node Type

Smooth/Tangent Node Type



is a different sort of an animal. If you use it on a


node with two curves, it simply changes it to an


node; and if you use it on a node with

Lines Before and After

, it does nothing. But when you use it on a node that has a


on one side and a


on the other, it does its thing, giving a smooth transition from a curve to a line by constraining the curve handle to the same direction as the line. To make a


node, lay down a rectangle, node edit and select one of the nodes. Right-click, choose

Node Type

, and select

Curve After

. Move the curve handle up, and then right-click, choose

Node Type > Smooth/Tangent

. Notice how the control handle snaps back so that it's in line with the line before the curve? If you try changing its direction, you'll find you can't.

Convert to Line, Line Before, and Line After

The next three items on the menu,

Convert to Line


Line Before

, and

Line After

, pretty much do what they say and are only available when the selected node has curves.

Convert to Line

will convert both sides of the node to lines, making it a tangent node.

Line Before


Line After

simply changes the curve on one side or the other to a line. "Before" refers to the portion of the contour behind the node where the round curve handle is and "after" refers to the portion of the contour ahead of the node where the pointy handle is.

That pretty well covers the node type options in Paint Shop Pro. Armed with this knowledge, you can become master of your nodes. Take some time getting familiar with node types. Lay down some shapes and see what you can do by adding curves or lines and changing to different node types. Once you've mastered node editing, you'll be able to fine tune your drawings and shapes with great precision.