Beginning Expression 3

Lesson 4

Strokes 101

This lesson is all about making and using strokes. We'll start by looking at how strokes are applied to a path and what you can do to a stroke once it's applied. Then we'll go into the mechanics of creating strokes. Let's get started.

Applying Strokes

In the last lesson we learn about the direction of a path and that the arrow at the end of a path indicates in which direction the path was drawn. It is important to consider the direction of a stroke as well. Let's take another look at the Strokes palette:

In many cases, you need not be concerned about the direction of a stroke. In the last lesson we applied some strokes from the Dry stroke folder. The strokes in that folder consist of natural media type strokes and direction with this type of stroke really doesn't matter because the stroke looks the same on both ends. But consider the strokes in the palette on the left. These strokes are graphic style strokes and with this type of stroke, direction matters.

Strokes are applied to a path in the direction they appear in the Strokes palette. The left end of the stroke is always applied to the beginning of a path and the right end of the stroke is always applied to the end of a path. Try this: choose the Pen tool from the ToolBox and click to place the beginning point of a path. Double click about 3 inches to the right of your first click to end the path. Click the Skeletal Stroke button on the Paint Style palette. Open the Graphics folder in the Strokes palette and scroll down to the 'dry fish' stroke and click on it to apply it to your path. (You may want to increase the stroke width if your fish seems distorted.) Notice that while the fish seems to be pointing in the opposite direction as the path, it is applied to the path as it appears in the Strokes palette.

Take a look at the leaf stroke; the fourth stroke in the list on the screen shot above. Because the stem is on the left side of the palette, we know that it will attach to the beginning of a path. If I want the leaf to stand upright, I would have to end a path above the point where I started the path, like this:

Remember, the arrow at the end of a path tells you in which direction the path was drawn. In the leaf example, you can see that I drew my path from bottom to top. Create a path as I did and click on the leaf stroke in the list of strokes to apply it to the path. Now click on the stroke above the leaf stroke, named 'flowerframe' and notice that it's upside down when applied to the same path.

You are not limited to single segment paths with graphic strokes. (Remember that a segment is the section between two nodes.) Here's the leaf stroke applied to a two segment path created with the B-Spline tool:

As you can see, you can use the same stroke and make it look different just by applying it to a curved path. You can also change the look of a stroke by "shearing" the stroke. Remember our discussion on the stroke width handle? That's the funny little gadget next to the arrow on the end of a path. Pulling it away from the path makes the stroke wider and pulling it toward the path makes the stroke slimmer. Moving it in any other direction will "shear" the stroke. Compare the leaf above with the one below and notice the difference in the angle of the stroke width handle:

Shearing can be done by adjusting the stroke width handle, as you just witnessed, or it can be done using the Attributes palette. We looked at this palette briefly in lesson 3. Let's take another look at it. Open this palette, if it isn't opened already, by choosing Window > Attributes from the menu bar or by using the F4 shortcut key.

Mouse over the second slider from the top and the tool tip should say "Shear." Create a path and apply the leaf stroke. Move the stroke width handle on the path and notice how the slider on the Attributes palette moves. Move the slider on the palette and notice how the stroke width handles on the path moves. Either way you choose to shear a stroke, the results are the same. You'll need to remember to set the slider to the 0 degree mark (center of the slider) when you're done because the setting on this slider will apply to all subsequent strokes you make.

We'll learn more about stroke behavior as we learn to make our own stroke. First, it's important to learn the difference in the types of strokes available in Expression.

Skeletal vs. Bitmap Strokes

You've heard me talk about skeletal strokes and bitmap strokes. Strokes can be made from one or more vector paths and this is what you normally think of when you hear the term skeletal strokes. The strokes we've looked at today are of this type. Bitmap strokes are made from a bitmap image, such as .gif or .jpg images, but bitmap strokes are still skeletal strokes. Strokes made up of vector paths behave differently than strokes made up of bitmap images and that, in my opinion, is why you hear Expression users refer to strokes as either bitmap or skeletal. It saves them from otherwise lengthy explanations because users know that other users know the difference.

The term 'skeletal stroke' is actually a technology which means to attach an image to a path, so to speak. The 'picture' can be either a bitmap or an image created by one or more vector paths. Let's get to this business of making different kinds of strokes so you too can speak the user lingo.

Vector Type Skeletal Strokes

Transparent style: The first stroke we will make uses transparency. Strokes containing transparency build up in color as they cross over themselves or other strokes. In the process of creating this type of stroke, we'll learn about blending paths. Ok, let's do it.

Open a new document and draw an oval shape with the Ellipse tool. Choose the No Stroke button and a black color fill. Choose Menu > Objects > Convert to Path. Convert two opposite nodes to corner points so you have something that looks like this:

Using the opacity slider on the Paint Style palette (between the Stroke Preview and the Fill Preview), reduce the opacity to 10%. Duplicate the shape and reduce it in length to about half the length of the original shape. Now place the second shape on top of the first one so that it looks like this:

Notice that although the transparency of the second shape was not changed, the second shape appears darker than the first. This is what I mean about colors building up. The transparency of the second shape allows color from the first shape to show through, giving the second shape a darker appearance.

Select both objects and choose Menu > Objects > Blend Paths. Type 8 in the resulting dialog box and make sure the Linear Interpolate radio button is selected. Click OK to close the dialog box. You should now have something like this:

The blending path feature creates a number of additional paths from two or more source paths. The number of paths it creates, of course, is determined by the value entered in the resulting dialog box. If you want fewer blends, type in a lower number. The blends between the source paths are grouped together but the two source paths are not included in the group. Notice, from the screen shot above that only the two source paths are selected. So click away from the paths and then select all of the paths with the Object Select tool.

We are now ready to define our stroke and one way to do that is to choose Menu > Stroke > New Stroke Definition from the menu bar. Go ahead and do that now. This brings up the Stroke Definition box which looks much like the Pattern Definition box in lesson 2. Notice the red box around the stroke with an arrow running through it.

We'll get to the red box later. But notice the arrow. This is the direction arrow. This tells you how your stroke will appear in the Stroke palette and how it will apply to a stroke. This will become more significant when we get to graphic style strokes, as we discussed earlier. Everything looks good so click the Define Stroke button at the bottom of the definition box and now you get a dialog box asking for the name of this new stroke, the folder where you want to store the stroke and the default stroke width. Enter your information, accepting the default width value, and click the OK button to dismiss both the definition box and information box. Your new stroke is added to the folder you designated and it should be the active stroke.

Have you noticed that most of the strokes in the Strokes palette are black? It really doesn't matter what color you used to create the stroke because strokes can be colored, as you already know. Choose the drawing tool of your choice, draw a path and apply your new stroke to it and let's give the stroke some color. (Note: If your stroke appears pale in color, check the transparency slider and make sure you didn't move it (the top slider) along with the fill transparency slider (the bottom slider) when we first created the paths from which to make the stroke. Now would be a good time to set both sliders all the way to the right for full opacity.)

Notice in the Paint Style palette that the Color Preview has two boxes instead of one and that both boxes appear empty. The top box is considered the foreground color and the bottom one is the background color. Click on a color in the color triangle and your stroke takes on the new color. In the color preview, notice that the top box reflects your color selection and the color in the bottom box is white. The reason for this will become apparent when we make our next stroke. For now, make another stroke that crosses over the first one and notice how the color builds up where the strokes cross, like this:

Textured style: Another type of vector skeletal stroke is referred to as a textured stroke and it's this type of stroke where the bottom half of our color preview comes into play. Create a path and apply the stroke named S14 in the General folder in the Strokes palette. This is what the stroke looks like with our color settings:

Click on the bottom box of the color preview and choose a color in the color triangle. I'm going to make my stroke real ugly and choose green:

To see what's happening here, set the stroke back to it's original colors, which are various shades of gray. To do this, click on the little colored button to the right of the transparency sliders on the Paint Style palette. This is what your stroke should look like:

From these three images you can see that the foreground color in the color preview applies from the darkest color in the stroke (black in this case) to the midrange color (medium gray here) and that the bottom box in the color preview applies to where the midrange color left off in the foreground color all the way to white. Any vector style skeletal stroke can have color applied this way, regardless of whether it was created in various shades of gray. You might test this by downloading some of the leaf strokes on Alan's Expression Strokes page and applying different colors to them.

Graphic style: I call vector paths that make up an image and defined as a stroke a 'graphic style' stroke. Let's create one of these. Let's make life easy and use a font. Use any font you want; I'm using a leaf font from a freeware font set. Here's my leaf in fall colors:

Now this is where it's important to know how to position your stroke so that it will attach to a path in the manner you want. You can make it go in any direction you want, but just remember that the left most point on the leaf will attach to the beginning of the path and the right most point will attach to the end of the path. When your image is in position (use the rotation handles on the bounding box for this), choose the Stroke Definition tool (last button in the top row of the ToolBox). If it will help you, turn on the grid lines for guidance. You will want to define the image as close to the left and right edges of the image as possible. When you are ready to define the stroke, drag a marquee around the image with the Stroke Definition box. When you release the mouse, the same Stroke Definition box will appear as when we defined a stroke using the Define Stroke menu item. I'm going to leave a lot of space on the right and left sides of my stroke so you can see the effect it has:

The red box around the image shows how close I got with the Stroke Definition tool. When we defined our first stroke, using the Define Stroke menu item, Expression used the bounding box as the defining area. In other words, the menu item method of defining is fine if you aren't particular about how much white space is between the left and right edge of the image and the red box. Any white space there will show up on the stroke. What attaches to the beginning of a path is the area at the very left edge of the definition box (the red box in the image above), not the edge of the stroke itself. I'll demonstrate by defining the stroke in the image above and applying it to a path:

Notice all the white space at both ends of the path? To avoid this, define your strokes as close to the left and right edges as possible. The red line with the arrow in the center of the Stroke Definition box represents a path to show you how your stroke will attach to paths you draw in Expression. Compare the last two images above.

Our font stroke was a simple example. You can also create complex images and turn them into strokea. Instead of creating one, let's take an existing stroke apart and re-define it. Create a path and apply the 'longfish' stroke from the Graphics folder in the Strokes palette. With the path selected, choose Objects > Unstructure and then Arrange > Ungroup from the menu bar.

What we did here was de-construct the stroke to bring it back to the paths use to create the stroke. Click away from the fish to deselect all the paths and then click on a few individual paths. The stroke used to outline the main body of the fish is a stroke found in the Water folder of the Strokes palette. How do I know that? With the path selected, the stroke used on the path will appear in the Stroke Preview in the Paint Style palette. Hold your mouse over the preview window and a tool tip will appear containing the stroke type followed by the name of the stroke. (At this point you could choose a different stroke from the Strokes palette to replace the original stroke used.)

Let's change the colors in the fish and re-define it. As we do we'll learn some new selection tricks. I'm partial to salmon colored fish so these are the colors I've chosen for my fish.

Follow along using my color choices; you can change them later if you want. If the HSL color picker is not your active color picker, change it so we can take advantage of the 'Lightness' meter. Click on the fish body and then click on either the Fill Preview or the Fill button to change the fill color. Enter the following values in the color meters: H 10: S 100: L 76.

We want to remember this color so choose the Eyedropper from the Toolbox (shown in the image on the left). Notice the two color buttons at the end of the ToolBox. We want the second button which says 'Screen Color' when you mouse over it. With the Eyedropper tool, click on the new fill color in the fish body and notice that a little box appears next to the eyedropper icon on Paint Style palette (below the Color Preview) filled with the color you chose with the Eyedropper tool. Switch back to your Object Select tool and click on the face of the fish. The color in the Paint Style palette changed to the current fill color and we want to change it so click on the little box next to the eyedropper icon filled with the body color. Now the fish face is filled with the new body color, but of course we don't want it quite that dark. Change the value in the Lightness meter to 92. The face should now be a much lighter shade of salmon. We really should change the mouth color now so click on it to make it active and then click on the eyedropper color box again to change the mouth to the color stored in the eye dropper.

Choose the Eyedropper tool and click on the fish face to place the lighter shade of salmon in the eyedropper color box. Switch back to the Object Select tool (see why I urged you to learn the shortcuts?) and click on the top fin on the fish. From the menu bar, choose Edit > Select By, put a check mark in the box labeled 'Same Fill' and click OK to close the dialog box. Ah ha! Another way of selecting paths! (Investigate this further to see what other selection options you have). In addition to the top fin, the two bottom fins should also be selected because they contain the same fill color. Click on the eyedropper color box to change the fill color of all selected objects to the lighter salmon color.

Obviously the person who created this stroke used a different shade of yellow for the fish tail fins because they weren't selected when we selected all objects containing the same fill color. You might keep this in mind when you create your own strokes. So go ahead and select the tail fins and once again click on the eyedropper color box to apply the lighter salmon color. Now we're ready to define the fish stroke. Do this now, using the method we used earlier, and create a very long path. Apply your new fish stroke and notice how it stretches to fill the full length of the path.

In some cases we don't want a stroke to stretch like this. Fortunately, Expression has anchoring and repeating features to modify a stroke's behavior. Let's create a new stroke and test these features. Move your group of fish objects off to the side as we will use them again when we work with bitmap strokes.

Anchoring Strokes:

Using the Pen tool, create a stroke 5 inches long. Choose the 'train' stroke in the Repeating folder in the Stroke palette. Set stroke width to 70 pixels and you should have 4 train cars, like this:

First, look closely at the train stroke and notice that the beginning and end of the stroke extends beyond the beginning and end of the path. You don't need to enclose an entire object to make it part of the stroke. In this case, the author of this stroke enclosed only part of the caboose and engine. When you enclose an object with the Stroke Definition tool, enclosing only part of an object will cause the entire object to be included in the stroke.

Choose Objects > Unstructure and then Arrange > Ungroup from the menu bar to deconstruct the train into separate objects. Deselect all objects and then select the caboose. Fill the caboose with a red color. Instead of using the Eyedropper tool, select the Attributes tool under the Eyedropper tool. With the Attributes tool, click on the caboose and drag to the train's engine and release the mouse. The Attributes tool allows you to drag an object's stroke and fill attributes to another object. Your train objects should now look like this:

Select the train car to the right of the caboose and give it a green fill color. Choose the remaining train car and give it a yellow fill color. We are now ready to define our rather colorful train as a stroke. We don't want this stroke to stretch the full length of the path like our fish stroke did so we will anchor the caboose to the starting point of the path and the engine to the ending point on the path.

The Anchor tool is the first button in the third row of the ToolBox but you can only access this tool after you drag a marquee around the object(s) you want to define as a stroke with the Stroke Definition tool. Choose the Stroke Definition tool and drag around the train objects to display the Stroke Definition box. Try dragging inward to capture only part of the caboose and engine like the original author did. Once the definition box appears, choose the Anchor tool (Shift-A shortcut key) on the ToolBox (below the Object Select tool).

When you choose the Anchor tool, two new buttons appear on the right side of the ToolBox, as shown on the left. These button are, from left to right, the Anchor to Start and Anchor to End buttons. With the Anchor tool, click on the caboose to select it. Then, hold down the Shift key and click on the two wheels below the caboose, the wheel bar between the wheels, and the bar that connects the caboose to the next train car to add them to the caboose selection. (If you need to, enlarge the definition box by dragging the edges of the definition box outward and use the zoom tool to enlarge your view of the train. You can also use the hand tool to move around inside the definition box.) Click on the Anchor to Start button and you'll see an anchor button at the beginning of the stroke in the definition box. This causes all of the selected objects to be anchored to the starting point of a path so they won't stretch.

With the Anchor tool still active, click on the engine, the wheels and wheel bar, and the connector between the engine and the train car behind it. Click on the Anchor to End button and once again an Anchor button appears, but this time at the end of the stroke. Define your stroke and give it the name 'color train' and save it to the folder of your choice. Make a nice long path and apply the new stroke to it. Here's what it should look like:

Well cool! Our caboose and engine didn't stretch, but the other train cars did. What we want to do with the other cars is to have them repeat. Let's fix that now. Double click on the train in the Stroke Preview on the Paint Style palette, or on the name of the stroke in the list of strokes in the Strokes palette to bring up the stroke in the Stroke Definition box for editing. This time choose the Repeat tool which lives under the Anchor tool. When you choose this tool, notice the new buttons on the right end of the ToolBox (shown on the left). These are the Repeat and Do Not Repeat buttons. Drag a marquee around the two cars in the center with the Repeat tool. It's ok if the two connectors are also selected, even though we anchored them originally. Then click on the Repeat button on the right end of the ToolBox.

When you clicked on the Repeat button, two bars appeared at the beginning and end of the stroke in the definition box. Where these handles are determines the point on a path where the repeat takes place. If we leave the bars where they are, the two cars will repeat from the beginning and end of the path, on top of the caboose and engine. To avoid this, drag the first bar to the beginning of the connector between the caboose and car to the right of it and release the mouse. Do the same with the other bar, dragging it to the end of the connector just before the engine. These bars determine where the repeat starts and ends, but we still need to anchor these cars to their starting and ending points. To do this, look at the center of each bar and notice a small pointy retangular button. This is the repeat anchor. Hold down the Shift key and click on the button in the center of the first bar. You'll see the button turn into a button with an anchor icon on it. Do the same thing with the ending repeat bar. Your repeat bars should now look like this:

Finally, define the stroke by clicking on the Define Stroke button. The original name of the stroke will appear in the information box. Leave the original name and accept the other defaults and click the OK button. You will be prompted to overwrite the original. Choose Yes. You will see the new version of the stroke attached to the path you made earlier. If all went well, your stroke should now look like this:

As you can see, we have the caboose and engine anchored at the beginning and end of the path, respectively, and our center cars repeated, giving us two green cars and two yellow cars. This process might have seemed complicated, but once you create a few strokes like this, you'll discover how easy it really is. Of course this is not to say that you won't come upon objects that aren't complicated to define. The more complex the objects, the more complicated the definition process will be. Start with easy objects and work towards more complicated ones when you're ready. You'll find two tutorials in your user manual that will help you; See Tutorials 3 and 4 beginning on page 171 of the user manual for additional information.

Bitmap Strokes

Bitmap stroke are created a little differently than vector style strokes. First, there is no bitmap definition tool on the toolbox. Instead, you select the bitmap image you want to create a stroke from and choose Stroke > Define Bitmap Stroke from the menu bar. This results in the following dialog box:

The top half of the dialog box asks for a stroke name, the folder where you want to save the stroke, and a default stroke width. The next section gives you three options which determine how transparency in an image should be treated, if the image has transparency. The first option is to use no alpha channel. With this option, the stroke is created from the image exactly as the image appears. This option is supposed to ignore any transparency in an image, but it doesn't on my Windows XP system (sometimes features work differently on different operating systems).

The second option is to use the image's original alpha channel (transparent areas). If the image you're defining has transparency, this option is active by default but you can change it by selecting one of the other options. If the image has no transparency, this option is grayed out and unavailable.

The third option is to define the stroke as a grayscale image. With this option, the image is converted to grayscale with transparency applied to the white and lighter shades of gray in the image. White parts of an image will be totally transparent, with diminishing degrees of transparency applied to shades of gray until they reach black, which will be totally opaque.

The next section on the dialog box is used for anchoring parts of the stroke and repeating other parts. We'll discuss this section a little later. Let's create our first bitmap stroke using the grayscale option.

Copy the following image and import it into Expression.

Select the image and choose Stroke > Define Bitmap Stroke from the menu bar. Notice that Expression detected this image as a grayscale image as the grayscale option is selected. Give your stroke a name. Choose a folder to save the stroke in, or create a new folder by typing in the name of a folder that doesn't currently exist. Expression will create the directory. Before you use your stroke, create a big rectangle shape and fill it with a dark color. Choose any drawing tool, draw a path anywhere inside the dark rectangle and, with the Skeletal Stroke button active in the Paint Style palette, choose the name of your new bitmap stroke to attach it to the path. The purpose of the dark colored rectangle is to show you that the bitmap stroke is transparent in all the right places. Change your stroke to a lighter color, or white. (Tip: To easily obtain a pure white color, click and drag inside the color triangle all the way to, and even beyond, the upper left corner and release the mouse.) All the white parts in the original bitmap image were treated as transparent to create a totally natural brush stroke.

There's just one problem with this stroke. Choose the Freehand tool and draw a very long path and apply the new stroke. Notice how the stroke stretches and no longer looks 'crayon' like. Let's redefine the stroke and change this default behavior. Select the original bitmap image and choose Stroke > Define Bitmap Stroke to display the Define Bitmap Stroke dialog box. Give your stroke the same name to write over the original stroke with this new version, or a new name to create a new stroke. The Grayscale option should be selected; select it if it isn't. Notice the bottom section of the dialog box and that the image size is stated there. Below that it tells you that there is no head section or tail section and that the body section of your new stroke will be the entire length of the image. We want to change that.

In the "Body Section" drop down box, choose Simple repeat. This will cause the entire mid section of the stroke to repeat as many times as it needs to, depending on the length of the path it is applied to. In the "Anchored head section Length" box, type 70, which represents 70 pixels from the left, or "head" section of the stroke. Notice that the head, tail and body dimensions listed above change dynamically to reflect the new values entered in the text boxes. Set the Anchored tail section Length to 70 and click on the OK button to dismiss the dialog box. Drag out a very long stroke again and notice that the stroke no longer stretches to fit the path. Rather, the stroke is anchored at the beginning and end of the path while the mid section repeats.

What's great about the grayscale option is that you can scan natural media paint, pencil or other strokes to files, bring them into Expression and turn them into strokes easily. This is what Jessica did with her watercolor paints. You can download Jessica's stroke here. You'll find more information on making bitmap strokes in Tutorial 9, beginning on page 187 of your user manual.

Let's create one more stroke before we move on to discuss the advantages and disadvantages of bitmap and vector skeletal strokes. This next stroke will be defined using the Use Original Alpha option. When you have a bitmap image that contains many colors, the grayscale option isn't suitable as that option converts an image to grayscale if it isn't grayscale already. Let's go back to our salmon colored fish paths, rasterize the paths and then turn the resulting bitmap into a bitmap stroke.

Place your fish paths within easy reach in the view area and choose Objects > Bitmap > Create Bitmap from the menu bar. Your cursor will turn into a bitmap cusor. Drag a marquee around your paths, staying as close to the edges as possible (again, grid lines work well here), and release the mouse. In the resulting dialog box, check the 'Rasterize region' option and click the OK button to dismiss the dialog box and create the bitmap. A copy of the paths now appears on your view area as a selected bitmap image.

Define this bitmap image as a bitmap stroke just like you did before, except use the 'Use Original Alpha' option this time. (Leave the bitmap image in place on your view area when you're done; we will get back to it shortly.) With this option, you have the best of all possible worlds. You retain all the colors in the stroke, the background is transparent, and you can anchor the head and tail and repeat the body portion just as you would with the other options. When you're done defining your stroke, test it against a dark colored background to make sure the transparency is in place. You will find that you can't change the color of this type of bitmap stroke when applying the stroke to a path. What you will get is an outline of your stroke filled with the solid color. Very unattractive.

Advantages and Disadvantages of Bitmap v. Vector Strokes

Bitmap images do not retain clarity when rasterized or imported into Expression. Move your bitmap image and notice that the original paths are below the bitmap image. Comparing the paths to the bitmap image, you can see the loss of clarity. You can, in some cases, use Photoshop filters to sharpen the image a little but many people have problems using Photoshop filters, and many people can't get them to work at all. (This is the main reason filters are not covered in this course).

File size isn't much of a factor between the two different types of strokes. The vector longfish skeletal stroke is 25 kb in size, the bitmap version is only 23 kb. Not much of an advantage. But the file size of an Expression document can be drastically different depending one which type of strokes are used. Consider the following vector stroke, and notice the amount of nodes it contains:

If this stroke is applied to a path that isn't perfectly straight, look how many more nodes are needed to compensate for the curve, despite how slight the curve is:

Imagine how many nodes it would take if the curve was more than just a slight curve:

Every one of those nodes adds to the overall size of the finished image. Multiply those nodes with many strokes and the image size can get rather large, and you can even cause Expression to labor if you really get carried away with vector style strokes.

One thing you can do to reduce the number of nodes on a path is to use the Smooth Path feature. Here, I've taken the stroke shown in the image above, which has been unstructured to return the stroke to it's original path, and chosen Objects > Smooth Path from the menu bar. In the resulting dialog box, which asks for a tightness of fit value, I left the default value at 1. Here's the result:

You've already seen how a vector stroke can be dissected and changed. If you spend a lot of time making strokes and sharing them with friends, but don't want your work changed, distribute bitmap versions of the strokes. You can't unstructure a bitmap stroke.