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Using Morph: Tutorial Excerpt Preliminary. For use with Morph Created: Sun Oct 1 19:39:12 1989 Copyright 1989 by Garry R. Osgood. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the copyright notice and title of the manual and its date of publication appear, and notice is given that copying is by prermission of Garry R. Osgood. To otherwise republish this material requires a fee and/or specific permission from Garry R. Osgood. Contents: 1. About This Manual 2. Tutorial 1.0 About This Manual 1.1 Background 1.2 Organization 1.1 Background A series of structured drawing objects that depict the transformation of one key object into another is called blending, or morphing, and is a feature of advanced structured drawing programs such as Adobe System's Illustrator 88. Artists employ blending for a variety of purposes: giving rounded objects a three dimensional effect, making in-between objects for animation, or obtaining subtle variations between objects quickly and without tedious manipulation of control points (to name a few). As of this writing, no version of Illustrator 88 has been ported to the Amiga Personal Computer, and Professional Draw Version 1.0, by Gold Disk Inc., the preminent structured drawing program in the Amiga community, has no blending tool. Morph, a utility program by Garry R. Osgood, employs clip files created by Professional Draw to emulate Illustrator 88's blend tool. This manual teaches you how to use Professional Draw in concert with Morph so you can enhance your drawing with blending effects. To use this manual, you need: An Amiga 500/1000/2000 Personal Computer A copy of Gold Disk's Professional Draw, version 1.0 A Morph Distribution Kit, a set of files that include the Morph program, a set of Professional Draw clip files to be employed in the tutorial, installation command files, a clip printout utility, and a copy of this manual. 1.2 Organization This is a preliminary manual containing the tutorial excerpt from the Morph user manual. That manual is currently being written. (Oct 1, 1989). Tutorial The tutorial gives you lessons for using Morph with Professional Draw. Once you have taken the tutorial, you will know how to prepare Professional Draw clip files for blending, how to start the Morph program, and how to incorporate the product of the Morph program into your Professional Draw artwork. 2.0 Tutorial 2.1 Key Concepts 2.2 First Blend 2.3 Blending Summary 2.4 Color Blending - Preliminary Remarks 2.1 Key Concepts What do blend tools do? Starting with a ``departure'' and ``destination'' pair of ``key'' objects, a blend tool adds a series of ``inbetween'' objects. On ``step'' one, the blend tool first copies the departure object then transforms the new copy so that it begins to resemble the destination object. the blend tool continues copying and transforming objects through the remaining steps so that in the end, the last inbetween object almost resembles the destination object. For example, if the departure object is a black-filled rectangle and the destination object is circular and filled with white, an inbetween object in some middle step would be grey- filled and look somewhat like a rectangle with rounded corners. What is Morph? Morph emulates Adobe Illustrator's blend tool. Unlike Illustrator's blend tool, which is an integral part of that program's drawing desktop, Morph is a separate program that operates in an AmigaDOS Command Line Interpreter (CLI) window. Morph operates on clip files produced by Gold Disk's Professional Draw Version 1.0. What does using Morph Entail? As a user of Morph, you would typically go through three steps: 1. Within Professional Draw, creation of at least one pair1 of key objects, turning it into a clip, saving the clip as file. 2. Within a CLI, starting Morph, first naming the clip file created in step one for input to Morph, then naming a new file to hold Morph's output, finally specifying the number of inbetween objects to use in blending from one key object to the next. Your CLI command may look something like this: 1 Advanced users need not restrict themselves to pairs of key objects. see the Theory chapter. 3 Using Morph - Tutorial, Reference and Theory 1> morph input.clips output.clips 40 input.clips -- the name of your input file (created by Professional Draw) output.clips -- the name of your output file (to be created by Morph and used by Professional Draw) 40 -- the number of inbetween objects to use in blending from one key object to the next. 3. Within Professional Draw, load the output file created by Morph. Select the clips created by Morph to incorporate the blended objects into your drawing. 2.2 First Blend Let's walk through a morphing session to get a feel for this new tool. In this session, we'll take a pre-made clip file, make a new version of the clip file, load the new clip file into Professional Draw and observe some blending effects. to follow this procedure, you will need a copy of Professional Draw, Morph, and the file squarecircle.clip that came with the preliminary distribution. 1. Start a CLI window if you don't have one running already. Change your directory to where Morph is stored. 2. Start Professional Draw (optionally, create a page). Let's ensure that we have the proper tutorial file handy: 3. Within Professional Draw, select from the menu ``Clip: Load'' Using the device gadgets and directory window, direct Professional Draw to the where Morph is stored. 4. Select and load ``squarecircle.clip'' 5. From Professional Draw's menu, select ``Clip: Draw. Pick ``squaretocircle'' and draw it. You should see a square on your left and a circle on your right. Lets try blending from the square to the circle. For this first blend we'll work with the squarecircle.clip file already on the disk. 6. Bring the Workbench screen to front. Bring your CLI window to front and make it the active window. 7. Start the Morph program by typing at the CLI prompt: 4 Using Morph - Tutorial, Reference and Theory 1>morph squarecircle.clip newsquarecircle.clip 5 Explanation: morph -- the name of the blending program. squarecircle.clip -- the Professional Draw clip file we'd loaded and drawn with during steps 4-6. Now we are using this as an input file to Morph. newsquarecircle.clip -- a new clip file that will contain blended objects based on the clip stored in squarecircle.clip. We need not name this output file ``newsquarecircle.clip'', but it will suffice as a reference for this procedure. 5 -- the number of steps we want to have in our blend. In creating a blended clip, Morph will create this many objects to ``insert in between'' the two key objects. 9. Hit Return. In response, Morph should type words like this in the CLI window: This is Morph for Professional Draw. v 1.0. Copyright 1989 by Garry R. Osgood. Created: Sun Oct 1 19:39:12 1989 Morphing clip squaretocircle with 2 key objects...Done. Inserted 5 inbetween objects between keys. Finished Morphing. Writing newsquarecircle.clip Morph's startup banner consists of three lines, its name, a copyright notice, and a compilation date. You should check the compilation date you actually get when you run your copy of Morph against the date cited in this manual. If there is a difference of greater than six months, check for a revision announcement or updated documentation -- Morph may have acquired features or obtained bug fixes not covered in this manual. Morph reports its processing efforts in the three following lines. In this example, Morph found a clip named ``squaretocircle'' that held two key objects -- the square and circle. ``...Done'' means Morph had no trouble deciding how to blend from one key object to the next. Morph created five new ``inbetween'' objects to express the transition from one key object to the next. This is in line with our request. Finally Morph wrote a new clip file, newsquarecircle.clip, to store the 5 Using Morph - Tutorial, Reference and Theory newly-blended clip. Errors can happen. When errors occur, Morph reports ``...Problem'' instead of ``...Done''. For example, had we created the clip squaretocircle with only the square object, Morph would have reported: Morphing clip squaretocircle with 1 key objects...Problem. I can't morph if I only have one key object. Sorry, Morph failed. In rule format: Rule 1: Rule of Keys: Morph needs at least two key objects to make a blend. Morph sometimes can't decide how to blend between two objects, another source of error messages. This indecision stems from certain limitations in this release of Morph: it cannot blend between structually distinct objects. In Professional Draw's domain, Bezier objects, Grids and Ellipses are all structurally distinct from one another. Professional Draw uses different procedures to draw each type of object and, as a consequence, each type of object has different internal representations. For example, a center point, a minimum axis, a maximum axis, and a rotation about the center point comprise the items of information that go into the description of an elliptic object. To make a drawing, Professional Draw ``plugs'' these data into the formula for an ellipse. On the other hand, Bezier objects consist of arrays of control point locations and are ``plugged'' into cubic parametric equations. This array of control points does not compare with elliptic objects' center points, minimum and maximum axes, or rotation angles. A similiar mis-match in representation prevails between Ellipses and Grids. Thus, attempting to blend from an Ellipse to a Grid (stored in a clip called ovaltogrid) will cause Morph to report: Morphing clip ovaltogrid with 2 key objects...Problem. I don't know how to morph between different object types. Sorry, Morph failed. Beziers made with differing numbers of control points are also structurally distinct and, in this release of Morph, unblendable. These so-called mis-matched Bezier objects cause Morph to report: Morphing clip mismatch with 2 key objects...Problem. I don't know how to morph between Beziers with differing numbers of control points. Sorry, Morph failed. 6 Using Morph - Tutorial, Reference and Theory Let's establish rules stating these limitations succinctly: Rule 2: Law of Types: Morph only blends objects with like types. Rule 2a: Law of Bezier Control Points: Morph only blends Bezier objects comprised of equal numbers of control points. Astute readers may wonder how the square and circle in our sample clip file squarecircle.clip can be morphed without violating Rule 2; in Professional Draw, aren't squares Bezier objects and circles specialized ellipses? Circles usually are made with elliptic objects, but they can be emulated with Bezier objects2. In squaretocircle.clip, the absense of a central control point in the ``circle'' gives away the fact that the circle is a Bezier object constructed out of the same number of control points as the square (four). Once Morph has made `newsquarecircle.clip' we return to Professional Draw to inspect how the blend between the two key objects in the clip turned out. 10. Bring the Professional Draw screen to front. Within Professional Draw, select Clip: Load. Change to the tutorial directory, if necessary, and load `newsquarecircle.clip'. 11. Select Clip: Draw. In the clip directory, you should see a new clip %-squaretocircle in addition to squaretocircle. the ``%-'' prefix reminds us that squaretocircle is a ``parent'' of this clip. Select it; position the clip and draw it. We now should have a series of objects. Going from left to right, the objects go from square to round, corners disappearing, sides bulging out. Congratulations, you have now blended two objects. 2In the author's opinion, ``Bezier'' circles are a good deal more useful than native ellipses. They may be disassembled into arcs, they may be distorted in ways far more interesting than what prevails with native ellipses, and so forth. True, Bezier circles (and ellipses) may never be exactly circles or ellipses, but they can be made to approximate the conic sections to an arbitrarily close degree of precision. Similar reasoning is in force with grids; the author rarely uses them in his work. Agreed, making Bezier imitations are tricky. The artist ``constructs'' a Bezier on top of an ellipse (or grid), serving as a template. Conversion is possible, and the presence of such conversion routines in future creations of Morph would eliminate the restrictive Law of Types and (with some more work) Law of Bezier Control Points. 7 Using Morph - Tutorial, Reference and Theory From this point onward, you can do anything you wish with this clip: ungroup it, move the components around, change the individual objects. Morph generated clips are the same as any other clips made with Professional Draw. Assuming that we've been successful so far, lets make an important observation about the square and circle: First, if we check the front-to-back relationship between the initial square and the final circle, we'll see that the square is ``layered behind'' the circle. Front to back relationships are important to Morph because this program always picks the rearmost object to start blending from, and blends toward the frontmost object. Let's state this as a third rule: Rule 3: Blending order: Morph blends from the rearmost key object to the frontmost key object. 2.3 Blending summary Our first blend was untypical in that we started with a canned clip and blended it -- a useful experience in that we were able to walk through the mechanics of operating Morph, deriving three working rules in the process, but not like a typical working session. In a typical Professional Draw/Morph working session you might set up a pair of key objects by duplicating some object already in your drawing, then modifying the copy object in some way. Finally, you would employ Morph to blend between the two, using the new clip to achieve some step-like effect in your work. In detail, you would: Select an object, and Make a duplicate of it by hitting the TAB key. Then Modify the duplicate. Include the original object in an aggregate with the modified object by shift-selecting it. Define the aggregate as a clip. Save the clip file. Blend the clip file using the procedure in ``First Blend.'' Load the blended version of the clip file and use the blended version in your drawing. Morph has other features that come in handy after you've had some practice. Morph accepts clips with more than two key objects -- middle key objects act like key objects just as key frames act in animation, Morph accepts clip files with more than one clip. It processes all clips independently of one another. This serves 8 Using Morph - Tutorial, Reference and Theory as a way to batch blends together. 2.4 Color Morphing - Preliminary Remarks Morph blends colors as well as line attributes and shapes. Theoretically, you can work with the 1.6 million colors Professional Draw ``supports'', but the limitation of Amiga's high resolution color palette certainly compromises our ability to make informed judgements when drawing with more than the seven additional colors beyond the nine-step grey scale built into Professional Draw. This tutorial investigates the possibilities and limitations of color morphing. 1. Load the clipfile squarecircle.clip; draw it. 2. Ungroup the objects. 3. Set line weights for both objects to zero; 4. Fill the square and circle with different colors. Do not use gray scale colors for at least one of the objects; in this tutorial, we are stretching Professional Draw/Amiga's display capabilities to the limit. 5. Morph what you've got using five steps. You should have a pretty rainbow effect, especially if you had picked both colors from the list. Morph ascribes to the R-G-B Color Cube model when blending colors; it decomposes source and destination colors into red, green, and blue components and then adds the components. Thus, blending complements (i.e. red to cyan, green to magenta, blue to yellow, or white to black and vice versa) ``brings us through'' the center of the color cube; colors tend to grey, then to the complement. More colorful blends may be obtained by avoiding the middle of the cube, i.e. morphing from red to magenta, yellow to green. Since Morph creates colors, we should visit the Fill Color List. Select Color: Fill Color. Note that new patches have appeared. While vaugely mathematical in appearance, the patch names follow this convention: C<cccc>-M<mmmm>-Y<yyyy> <cccc> an up-to-four digit number expressing the amount of cyan pigment. <mmmm> a up-to-four digit number expressing the amount of magenta pigment. <yyyy> a up-to-four digit number expressing the amount of yellow pigment. 9 Using Morph - Tutorial, Reference and Theory This naming style follows subtractive color conventions, appropriate for laying ink on paper. This convention is appropriate since most Professional Draw renderings will employ subtractive pigments to modify white light. Professional Draw scales pigment from 0 (no pigment) to 1023 (maximum pigment). Thus C1023-M1023-Y1023 is another way to express black; C1023-M1023-Y0 represents blue, and C511-M511-Y511 represents middle grey. This scheme supports 1024 * 1024 * 1024, or 1,073,741,824 colors. The full expression of this palette is far beyond Amiga's high resolution mode color capability; Of the sixteen color Amiga high resolution palette, Professional Draw lends you seven ``spares'' beyond the nine gray scale colors it allocates at the outset. But if your drawing technique depends on the expression of many different colors, Professional Draw and Morph can only support your style internally; the ``WYSISWYG'' preview mode of Professional Draw cannot, because of hardware limitations, lend you much visual support.3 To get a sense of the limitation, morph your colored version of squaretocircle again, but use thirty or forty steps. As you may see, starting from the eight new color, Professional Draw substitutes black for new colors. If you have blended several times using different color octaves, the majority of them will be poorly represented in the ``WYSIWYG'' mode. In some cases, switching to a black-and-white WYSISYG mode will give you 3There are few remedies for artists wishing to have TRUELY representative displays. In terms of expense they run from: 1. Placing Professional Draw into black-and-white mode; the mezzotinting effect at least reflects a gray scale 2. Print a proof on a black-and-white PostScript printer. As above, but at a higher resolution and somewhat wider latitude 3. Proof on a Color PostScript printer, an expensive purchace or an inconvenient wait while your local output service delivers 4. Color separate and have proofs made 5. Migrate to a Mac II. 6. Migrate to a UNIX workstation The author presents the last two alternatives only somewhat in jest. 10 Using Morph - Tutorial, Reference and Theory a more telling representation of your drawing.