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PICTURETHIS(TM) "SHAREWARE" VERSION RELEASE 4.00 DECEMBER 31, 1991 TUTORIAL, PART 1 OF 2 PARTS Copyright 1988, 1989, 1990, 1991 by Patricia Y. Williams and Gregory Williams, All Rights Reserved. HortIdeas Publishing, 460 Black Lick Road, Gravel Switch, KY 40328 U.S.A. Trademarks/Owners: CaptureThis and PictureThis/Patricia Y. Williams and Gregory Williams; Hercules/Hercules Computer Technology, Inc.; IBM and PC-DOS/International Business Machines Corp.; MS-DOS/Microsoft Corp.; PostScript/Adobe Systems Inc. NOTE: Carefully read all of the terms and conditions of the License Agreement (near the beginning of the READTHIS.1ST file on distribution disk #1) PRIOR to using the PictureThis and/or CaptureThis programs. USE OF THE PROGRAM(S) INDICATES YOUR ACCEPTANCE OF THOSE TERMS AND CONDITIONS. GETTING STARTED This file and TUTOR2.TXT provide a "hands-on" tutorial to introduce beginners to PictureThis and CaptureThis. Print out copies of this file, TUTOR2.TXT, and KEYS.TXT (so you can quickly look up the functions of various keys if you forget them), and you'll be ready to try PictureThis and CaptureThis. Happy drawing! EXERCISE 1. RUNNING PictureThis 1. Install PictureThis as per the READTHIS.1ST file on distribution disk #1, if you haven't already. The following files are needed for this tutorial: PICTHIS4.EXE PICTHIS4.OVL PTS4D.OVR LEAFCGA.TMP or LEAFEGA.TMP or LEAFVGA.TMP LEAF.DRW PIVY.DRW CAPTHIS.COM or ACAPTHIS.COM TEST1.DAT GRAPHBOX.CLP SCALE.CLP AXIS.CLP FONT91.* FONT93.* STANDARD.SFT 34DIFF.TXT STANDARD.CVT TWOCOL.DRW *.FAC !*.* (part files for Kartoons, such as !NOSE.1 and !CHIN.5) To use the DOS shell feature of PictureThis, you might need to copy COMMAND.COM to your "RUN" floppy disk or hard- disk directory for PictureThis. 2. You MUST have a video board and monitor compatible with CGA, EGA, or VGA graphics; a monochrome (TTL) monitor with a Hercules-compatible graphics board should work IF it has software or hardware CGA emulation (several inexpensive CGA emulation programs are available, some marketed as "shareware"). At the DOS prompt for the \PICTHIS4 hard-disk directory or for the floppy disk drive containing PICTHIS4.EXE, key in "PICTHIS4"; then press Enter. If PICTHIS4.OVL is not in the default directory, you will be prompted for a path to it; enter this path (if you have two 360K floppy drives, place the RUN disk in the B drive and type "B:"; for one 360K floppy drive, replace the STARTUP disk with the RUN disk and type "A:"). Immediately press Tab IF you have a Hercules- compatible graphics board with CGA emulation. Some CGA emulators cannot handle direct-to-screen writing in text mode, which is the default mode of PictureThis. Pressing Tab (ONLY while the program is loading) switches to (slightly slower) through-the-BIOS writing of text characters. Otherwise, your computer might hang up. The title screen should appear for a few seconds, and then a copyright and ordering information screen should appear. Please read it! When you press a key to continue, a blank screen with a dotted frame and an X-shaped cursor at its center should appear. This is the PictureThis drawing screen. If you see "OUT OF MEMORY" when PictureThis tries to load, you need to free up some memory by removing memory-resident programs. If you still see "OUT OF MEMORY" after freeing up as much memory as possible, you'll need to install more RAM to run PictureThis. 640 KB RAM is recommended, though you may be able to make simple drawings with less. See the user manual for information on changing the memory needs of PictureThis. 3. Knowing how to exit from a program is just as important as knowing how to run it! To return to DOS from PictureThis, no matter where you are in the program, press Esc (repeatedly if necessary) until you see the prompt "Quit PictureThis? (Y/N)" Then press Y if you really want to quit; press any other key (including, but not limited to N) if you don't. Note: Usually, PictureThis is INSENSITIVE TO CASE (here, Y is treated the same as y). Try it: press Esc. When you see the exit prompt, press any key OTHER THAN Y. The prompt vanishes and you're still in PictureThis. Press Esc again, then Y -- you're back at the DOS command prompt. 4. Press R and you should hear a beep, meaning that R is an invalid key, currently (but not always) inappropriate. Don't worry about pressing invalid keys: nothing else happens except the beep. If you get tired of hearing beeps, you can turn them off by pressing H. Try it: press H, then R: no beep. Press H again, then R again: the beep is back, AND an error message appears. Press a key to make the error message go away. When you press H and then R a third time, you're back to only a beep. The H (for "Hear") key toggles among three responses to invalid key inputs: beeping with no error messages, no beeping and no error messages, and beeping with error messages. Note: Not all invalid keys have associated error messages (a complete list of error messages can be found in ERRORS.TXT). When error messages are toggled on, special prompts appear during some infrequently used and/or possibly confusing operations. We recommend that beginners toggle on beeping AND error messages and prompts, so, if you just pressed H three times, as directed above, press it twice more. To make sure beeping with error messages and prompts are now toggled on, press W. This ("What's Happening") key turns a status box on and off at the bottom of the drawing screen. Press W a few times to see the box appear and disappear, ending with it toggled on. For now, you can disregard most of contents of the status box, but there should be an "H+" in it to denote that beeping and error messages/prompts are on. If there is just an "H " in it, only beeping is toggled on, and if there is an "H-" in it, neither beeping nor error messages/prompts are toggled on. Press the H key a few times to watch the symbols cycle among the three possibilities, and stop with "H+" showing. Then press W to toggle the status box off. Currently valid keys are listed in contextual help screens which can be accessed (except when a menu is showing) by pressing ?. Try it. Then press a key to return to the drawing screen. EXERCISE 2. ABOUT FILES 1. The "ultimate products" of PictureThis are files written in the PostScript page description language, which contain all of the information about your drawings needed by PostScript-compatible printers and imagesetters to generate hard copies. Seven other kinds of files can be involved in the production process: template files, drawing files, clip art files, ASCII text files, data files, Kartoon face files, and Kartoon part files. (Also, font files are used when you place text on drawings.) CGA, EGA, and VGA graphics screens can be captured in TEMPLATE FILES by using the CaptureThis (or Alternate CaptureThis) program; these files then can be imported into PictureThis to provide background screens for tracing. DRAWING FILES are used to store and retrieve information about your drawings in a format usable by PictureThis; you can save a drawing-in-progress in a drawing file for later recall. CLIP ART FILES save parts of drawings for use in other drawings. ASCII TEXT FILES can be created in other editors and word processors and imported into the PictureThis editor for use as text on a PictureThis drawing. DATA FILES provide numerical data for plotting two- dimensional graphs. Kartoon FACE and PART FILES are used to store faces and face parts used in Kartoons mode. Following the instructions in this tutorial, you will work with sample template, drawing, clip art, ASCII text, and data files, and you will create a template file, two drawing files, two clip art files, a face file, two face part files, and two encapsulated PostScript (EPS) files. The recommended extensions for names of PictureThis template, drawing, clip art, data, face, and PostScript files are, respectively, .TMP, .DRW, .CLP, .DAT, .FAC, and .EPS. All face part file names start with an exclamation mark (!) and have numbers as their extensions (example: !NOSE.3); face part files are named and accessed automatically. Font file names have extensions .FNM, .FIN, .FKN, or .SFT. ASCII text files can be named whatever is convenient for you and your editor/word processor. Access the file operations menu by pressing F10. In response to the menu, press R (for "ReadTMP"). A prompt for a template file specification appears, with a "wild card" file specification in the second line. This file specification consists of your current directory (see your DOS manual) and "*.TMP." Press Enter and a directory page appears with all files listed which match this file specification, with a (reverse-color) block cursor on the first file name. Move the block cursor to LEAFCGA.TMP, LEAFEGA.TMP, or LEAFVGA.TMP (depending on which mode you started PictureThis in) using the cursor keys (if necessary) and press Enter. The drawing screen reappears and you should see a representation of a leaf, which can be used as a tracing template for your drawing. Note: Importing a template file erases a template already on the screen. In Exercise 15, you'll learn how to capture graphics screens for use as templates. 2. Press F10 to access the file operations menu a second time. In response to the menu, press G. A prompt for a drawing file specification appears with a "wild card" file specification on the second line (your current directory and *.DRW). Press Enter; a directory page appears. Move the block cursor to LEAF.DRW using the cursor keys (if necessary) and press Enter. The drawing screen will reappear with the same template, plus curves (with a color different from the template colors) along the leaf's edges and stem. These curves comprise a drawing previously made with PictureThis. Note: Importing a drawing file erases a drawing already on the screen. In Exercise 7, you'll learn how to save a drawing file. 3. Encapsulated PostScript files are ASCII text files which can be written, but not read, by PictureThis. To write such a file for the leaf drawing, again access the file operations menu by pressing F10, then, in response to the menu, key in W. Respond to the next prompt ("Use current settings? (Y/N)") by pressing Y to accept the defaults (see the PictureThis user manual for more information). In response to the prompt for a filespec, key in "LEAF.EPS" and then press Enter. The file is written to disk, in the current directory. If there is any problem, such as an open drive door, you'll see an error message and have a change to correct the problem before attempting the procedure again. If you want to take a look at the PostScript file just saved, you can shell to DOS. (Note: COMMAND.COM must be accessible; see your DOS manual.) To shell, access the file operations menu again by pressing F10. In response to the menu, press D. The DOS prompt appears. At the DOS prompt, key in "TYPE LEAF.EPS" and then press Enter. You can stop the scrolling temporarily, by pressing Ctrl S; press any key to begin scrolling again. At the DOS prompt, return to where you were in PictureThis by keying in "EXIT" and pressing Enter. EXERCISE 3. THE SCREEN 1. For CGA mode only: To access the miscellaneous menu, press F9. In response to the menu, press P to select a different palette. There are six palettes (three normal and three intense) available, although your video card and/or monitor might not show each palette differently. Press 2 or 3 on the main keyboard (not on the numeric keypad) to respond to the next prompt. For an intense palette (not available with some video cards and monitors), press Shift simultaneously with the number key. Try this (F9, then P, then a number key, with Shift or not) several more times to see which palette choices are available with your video card and monitor. Stop at the palette you find most pleasing. 2. Press T. This ("Template") key toggles the template off, so you see only the drawing. It does NOT erase the template permanently. Press T again to toggle the template back on. Press R. This ("Remove and Restore") key toggles the drawing off, so you see only the template. It does NOT erase the drawing permanently. Press R again to toggle the drawing back on. Press D. This ("reDraw") key erases both the template and the drawing, and then immediately draws them again -- useful for removing "garbage" (extra and/or missing parts of curves) which appears occasionally on the screen (especially when erasing or manipulating objects, as explained later in this tutorial). Such "garbage" may not be aesthetically pleasing, but it ISN'T included in drawing or PostScript files made with PictureThis, and preventing it would have slowed the program's operation. The D key also has another function, described in step 5 of this Exercise. Press C. This ("Clear") key accesses a prompt to erase the drawing PERMANENTLY! The drawing will be lost IRRETRIEVABLY unless you saved it previously in a drawing file. In response to the "Clear current drawing? (Y/N)" prompt, press any key other than Y to make the prompt disappear; the drawing remains. Press C again; since you can easily get LEAF.DRW again, press Y. Only the template remains. To get LEAF.DRW again, press F10 and then G; press Enter and use the cursor keys (if necessary) to move the block cursor to LEAF.DRW. Press Enter, and the leaf drawing appears again. 3. Note that the curves comprising the drawing have small boxes at their ends. To see the drawing without these boxes (and with no screen border), press V. This ("Viewscreen") key is useful when you want to find out how much of the available curve space a drawing has used. Press U to toggle on the "curve space Used" box (the viewscreen must be on); press U again to toggle the box off). For more information on memory limits, see the user manual. No drawing can take place while the viewscreen is on (the cursor is gone!). Press Esc to return to the drawing screen. 4. To see an approximation of the drawing as it will appear when output on a PostScript printer, press Q. The "Quickshow" screen shows approximately correct line widths, fills, etc. (see Exercises 6 and 9). By using the Print Screen function (see your operating system manual for more information), you can "dump" the Quickshow screen to a dot matrix printer for a low-resolution print of the drawing, assuming that you previously installed a memory-resident graphics printer driver program appropriate for the CGA, EGA, or VGA graphics mode (such as GRAPHICS.COM, supplied with PC-DOS, or a more sophisticated program such as Pizazz). Press Esc to return to the drawing screen. 5. Six screen magnifications are possible: 50%, 100%, 300%, 600%, 1200%, and 2400%. You see the 100% screen currently. Switch to the 50% screen by pressing - (on the numeric keypad). Now switch back to the 100% screen by pressing + (on the numeric keypad). Press + four more times to switch successively to the 300%, 600%, 1200%, and 2400% screens. Notice that the template is NOT shown on the 600%, 1200%, or 2400% screens (the template at these magnifications is too coarse to be of much use). Switch back to the 100% screen by pressing - four times. So: Press + to magnify, - to demagnify. When the magnification is "zoomed" to any screen except the 50% screen, the screen centers on the cursor. (The 50% screen always shows the entire available drawing area.) When working on the 100%, 300%, 600%, 1200%, or 2400% screen, you can center the screen on the cursor without "zooming" by pressing X. The T, R, and C keys work the same way at all screen magnifications, but at the 50% screen, the D key also switches among four algorithms for compressing the template (the practical significance is that some template lines might be visible only when some of the algorithms are used). Press the numeric keypad - to switch to the 50% screen, then press D repeatedly as you watch for subtle changes in the template. (It might help to toggle the drawing off by pressing R, for a better view.) If you zoom and then return to the 50% screen, the template looks as it did when you left the 50% screen. Test this if you want. The viewscreen and the Quickshow screen also can be "zoomed," using the + and - keys on the numeric keypad. 6. You can scroll around any screen EXCEPT the 50% screen. Use the number keys (except 5) on the numeric keypad with Shift pressed or NumLock toggled on. Try it. Note that the scrolling increment is about one-quarter of the screen, horizontally or vertically (or both, for diagonal scrolling). Also note that when the cursor reaches the edge of the screen during scrolling, it is "dragged along" by the scrolling, so it remains at the edge of the screen. The viewscreen and the Quickshow screen also be scrolled, using the same keys. 7. You can center the frame (the rectangular dotted box) on the screen (at 100% to 2400% magnifications) by pressing Shift 5. You can center the frame on the screen and simultaneously center the cursor in the frame (called "zeroing" the screen) by pressing Z. The viewscreen and the Quickshow screen also can be centered and zeroed (even though the cursor doesn't show!), using the same keys. 8. Whenever a screen (drawing, Quickshow, or view) is being redrawn and a key is pressed which redraws the screen (+, -, D, scrolling keys, and Q or V while at the drawing screen), the drawing process stops immediately, and the newly specified screen starts to draw. This speeds magnification and scrolling of complicated drawings. EXERCISE 4. CURSOR MOVEMENTS 1. Note: For cursor control via a mouse, refer to the file PTMOUSE.TXT on one of the distribution disks. To move the cursor anywhere on the screen, use the number keys (except 5) on the numeric keypad (with Shift not pressed and NumLock toggled off). Initially (if you have brought in LEAF.DRW), the cursor moves one pixel horizontally or vertically (or both, for diagonal movements) each time a number key is pressed. Practice moving the cursor around, and then press Ins, with Shift not pressed and NumLock toggled off. Use the numeric keypad number keys again to move the cursor. Now the cursor moves 10 pixels each time a number key is pressed. The Ins key toggles between cursor movement increments (you can think of these as cursor "speeds") of one and 10 pixels. (The cursor also can be moved in "real" units: inches, millimeters, centimeters, points, or picas & points. For "real" units, both the "slow" and "fast" cursor "speeds" can be changed; see the user manual on how to do this.) 2. To move the cursor to a corner of the frame, press Ctrl Home, Ctrl End, Ctrl PgUp, or Ctrl PgDn. The cursor jumps to the appropriate corner of the frame. 3. Another way to move the cursor around a drawing is to use the endpoint selection operation, which you initiate by pressing Del, with Shift not pressed and NumLock toggled off. The cursor moves to the closest curve endpoint, all of the curves having that endpoint are dashed, and (if "H+" is toggled) a prompt to press +, -, Space, or Enter appears. Now press + several times, so the cursor moves to each endpoint in turn. Next, press Esc. The cursor returns to where it was before Del was pressed. Again press Del; press + a few times, then press - a few times to return to the endpoint where the cursor went when you pressed Del. If you press - immediately after pressing Del, the cursor jumps to the most distant endpoint. Try it. In general, + (or Space) takes the cursor FORWARD through the sequence of endpoints arranged (approximately) by closeness to the original cursor position, and - takes the cursor BACKWARD through the same sequence. To select an endpoint at which to leave the cursor, press Enter when the cursor is on the desired endpoint. The cursor remains at the endpoint, and the dashing of the curves having that endpoint goes away. 4. Press P. This ("Position box") key toggles the cursor position box (at the bottom right corner of the screen) and the relative cursor position box (at the top of the screen) on and off in a three-way toggle (try it, and stop with only the position box on). The number on the left in the position box is the horizontal distance of the cursor from the left of the frame in INTERNAL UNITS; the number on the right is the vertical distance of the cursor from the top of the frame in INTERNAL UNITS. Watch the numbers as you move the cursor around the screen. Try this at various screen magnifications. What are internal units? PictureThis saves the positions of the cursor and elements of drawings in internal units (ius). These are integer values allowing extremely fine resolution. (On the 50% screen there are 48 ius per pixel; on the 100% screen there are 24 ius per pixel; on the 300% screen there are 8 ius per pixel; on the 600% screen there are 4 ius per pixel; on the 1200% screen there are 2 ius per pixel; and on the 2400% there is 1 iu per pixel. For the default settings, 1 iu is approximately 1/1000 inch in CGA mode and 1/2000 inch in EGA and VGA modes.) You can move the cursor in internal unit increments as well as in pixel increments. To switch to internal units, press I. Now move the cursor around the screen again. Try it at various screen magnifications. Ins still toggles between 1 and 10 units per cursor movement increment, but now the units are internal units, not pixels. Press W to see the status box. The fifth character from the right in the status box is "I" (for internal units) Press I again. The "I" changes to "E" (for external units). ("G" (for grid) is a third possibility, as described in the user manual). The number following this indicator is the cursor speed. The two characters following the cursor speed abbreviate the current units ("PX" for pixels). For the drawing that you will be doing in the following exercises, the positions are given in inches. To change the units to inches, press F9, then U, then I, then Enter. The units in the Position box are now in inches measured from the top left corner of the frame. Notice that the unit indicator in the status box now reads "IN" for inches. If the fifth character in the box still reads "I" press I to change it to "E". Now each time the cursor moves, it will move in either .01 or .1 inch increments in relation to the drawing (depending on the Ins key). Try moving the cursor at various screen magnifications. Notice that one press moves the cursor twice as far on the 200% screen than on the 100% screen. EXERCISE 5. DRAWING CURVES 1. By following the instructions in the remainder of this tutorial, you'll draw a leaf with three leaflets, using the template already on the screen as a guide for the first leaflet. But first, you need to erase the already completed leaf drawing. Press C and then Y to do this. Make sure you are at the 100% drawing screen (see Exercise 3.5), and that it is centered (see Exercise 3.7). 2. Curves drawn in PictureThis are cubic Bezier curves, which means that they are each completely determined by two endpoints and by two "control points" (one associated with each endpoint) which specify curve shape. To draw a curve, you first set (specify the location of) its first endpoint, then you set its second endpoint, then you position its control points, and finally you set the curve. Before you begin drawing, remember what was said earlier about using Esc to cancel the current operation. If you become confused or frustrated at any point, just press Esc to restore the program to its state just before you began the current operation. Also, we recommend that you press W to toggle the status box on (if it is not already showing) while learning to draw; in the status box is an indicator of the current operation or state (before you begin drawing, it says "FREE"). Start with the leaf's stem. Move the cursor to the tip of the template leaf, at the upper left. The coordinates in inches of the tip (shown in the position box) used when making the drawing saved in LEAF.DRW are 1.020 (horizontal), 1.210 (vertical), but you don't necessarily have to duplicate that drawing exactly. Press Ins and I as necessary to alter cursor speed. When the cursor is where you want it, press F1. This key sets the endpoints of curves. Now it says "LINE" in the status box. Move the cursor to the other end of the stem, at the top of the small oval. The coordinates used when making the drawing are, 6.830, 4.680, but, again, you needn't duplicate the drawing exactly. When the cursor is where you want it, press F1 again to set the curve's second endpoint. The curve is actually a line at this stage, but the status box says "CURVE" because you now are able to alter the curve's shape. Move the cursor away from the second endpoint, up and to the left, and the line becomes curved. You are moving the control point associated with the second endpoint (which we'll call the "second control point") away from the second endpoint. Press F2. This key switches the cursor between control points after both endpoints of a curve have been defined. The cursor now is at the first endpoint, which is where the "first control point" is located initially (control points are always at their associated endpoints until you move them). A dot marks the position of the second control point. Now move the cursor away from the first endpoint, down and to the right, and you can make the curve have an S-shape. You are moving the first control point away from the first endpoint. Press F2 again. The cursor jumps back to the second control point, leaving a dot to mark the position of the first control point. Now you can move the second control point again. You can keep pressing F2 and moving the cursor, in turn, positioning both control points so as to shape the curve the way you want it. The LEAF.DRW drawing has 1.720, 2.010 for the first control point's coordinates, and 5.780, 3.200 for the second control point's coordinates. Now you need to set the curve. Press F3. This key sets a curve after its two endpoints have been set and its two control points have been positioned. The status box says "FREE" again. You've just drawn your first curve in PictureThis. Note that the cursor ends up at the second endpoint; this makes it easy to draw a succession of connected curves. Now for the end of the stem. The cursor is already where the first endpoint of the next curve should be. There is an important rule for drawing with PictureThis which is exemplified here: IF YOU WANT CURVES TO CONNECT PRECISELY, MAKE SURE THAT THEY HAVE A COMMON ENDPOINT. If you simply move the cursor by eye, it can LOOK as if the cursor is positioned exactly at an endpoint, yet it can be off by many internal units. The ways to be SURE that you are at a previously set endpoint are either to end up there after setting a curve (as you just did), or to use the endpoint selection operation, as described in Exercise 4.3. Now switch to the 300% screen for a better view of what you're doing. Without moving the cursor, press F1 to set the first endpoint of the right side of the oval. Now move the cursor, set the second point, move the two control points (switching between them by pressing F2 when necessary), and finally set the curve with F3. In LEAF.DRW, the coordinates of the second endpoint are 6.750, 4.830; it also has 6.860, 4.770 for the coordinates of its first control point, and 6.810, 4.830 for the coordinates of its second control point. Switch back to the 100% screen and press Shift 5 (on the numerical keypad) to center the frame on the screen. Next, draw the bottom curve of the stem, starting at the endpoint at the bottom of the stem end you just completed (the cursor should already be there), and ending at the leaf tip endpoint. Remember to use the endpoint selection operation to make sure that you are at the previously defined tip endpoint. The LEAF.DRW bottom stem curve uses first control point coordinates 5.940, 3.400, and second control point coordinates 1.520, 2.210. EXERCISE 6. MODIFYING CURVES 1. If you happen to make a mistake when drawing a curve, or decide later that a curve should be altered, you can erase or change the curve. To try this, press F4. The cursor moves to the nearest endpoint, just as if you had pressed Del. Right now, the cursor should already be on the tip endpoint. Select that endpoint by pressing Enter. One of the curves having the endpoint where the cursor is located becomes dashed, and a prompt appears. You can switch the dashing between each of the curves having the selected endpoint by pressing Space, +, or - (try it). Dash the LOWER of the curves, then press Enter. The curve modification menu appears. Press E (for "Erase"). A prompt appears asking if you're sure you want to erase the curve. If you answer Y, the curve is erased IRRETRIEVABLY. Go ahead and press Y. (If you answer with N (or any character except Y or y), the curve is not erased, and the curve modification menu will reappear.) 2. You'll need to redraw the curve you just erased, but this time, press F1 to define the curve's first (upper left) endpoint, then use the endpoint selection operation (Del, then +, -, and/or Space, repeatedly if required) to move the cursor to where the curve's other endpoint should be (at the bottom of the stem oval), and press F3. This sets a straight line between the two endpoints, since neither control point was moved away from its associated endpoint. Press F4, then press Enter to choose the current endpoint (at the bottom of the stem oval), then Space to choose the straight line, and finally Enter to see the curve modification menu. You want to "Change" the line to a curve, so press C. The menu and the dashing go away; A CURVE WHICH CAN BE SHAPED IS NOW ON TOP OF THE ORIGINAL LINE. The status box says "CHANGE." Move the cursor with the numeric keypad number keys to shape the new curve; notice the dashed line still in place to show you what the original curve looks like. When you are changing a curve, you can use the F2 key to switch between control points, as usual. When the new curve's shape is acceptable to you, press F3 to define the new curve. The old curve (represented by the dashed line) is erased. 3. Press F4, choose the long curve again, then (at the curve modification menu) press L (for "Line"). A line parameter menu appears which allows you to change the chosen curve's line weight (thickness), line gray, linecap (the way the line ends), and line dash pattern. The top line of the menu lists the parameters which you can change. The second line lists the current values of those parameters. Press W. Now you can key in a new line weight value in PostScript points (1 point = 1/72"). Key in "20" and press Enter. Now press K (for "Keep") or Enter to save the new line weight, followed by Q to see the Quickshow screen. Notice that one of the long curves is now MUCH thicker than the other. Press Esc to return to the drawing screen. Press F4 again; choose the thick curve again. Press L; then press G. Now you can change the gray percentage of the curve. The gray values range from 0% (white) to 100% (black). Key in "50" and press Enter, then press K or Enter to save the new line gray. Now look at the Quickshow screen (Q). Press Esc to return to the drawing screen. Press F4 again and choose the thick curve. Press L twice. Now you can change the linecap (the way the line ends). The default linecap is "Round," and you can see on the Quickshow screen that the current thick curve has rounded ends. The other two choices are "Butt" (the cap ends at the curve end and is squared off) and "Square" (the linecap projects half the width of the curve beyond the end and is squared off). Try these and check the results on the Quickshow screen. For details on changing the dash pattern, see the user manual. You can experiment by altering the line parameters and checking the results with the Quickshow screen. It is possible to change any combination of the line parameters at one time before you press K for keep. If you press Esc while at the line parameter menu, NONE of the changed values are saved. Note that a white (0% line gray) curve doesn't show at all on the white background, but does show where it crosses another darker curve. While you are experimenting, change a line weight to -1. This changes the curve to a "construction" curve which shows on the drawing screen as a dotted curve, but doesn't show at all on the Quickshow screen or the PostScript output. When you are done experimenting, change all curves back to a line weight of 1, a line gray of 100 (black), and round linecaps. EXERCISE 7. CUTTING CURVES 1. All that remains to complete your drawing's outline is adding the leaf edge curves. There is a potential problem here: each of the (two) edge curves which you will draw share the leaf tip endpoint, but they also need to intersect the stem curves (near the stem oval) where there AREN'T any endpoints currently. Recall that precise intersections of curves occur ONLY at shared endpoints. We need to ADD an endpoint "in the middle" (actually, nearer to the right end) of each of the stem curves. This can be done by "cutting" each of the curves into two curves which are very similar to the parts of the original curves on both sides of the newly added "middle" endpoint. To begin the cutting operation, press F5. The cursor jumps to the nearest endpoint, just as if you had pressed Del. Select the rightmost endpoint of the upper stem side; next select the upper stem side by pressing + until it is dashed and then pressing Enter. Now you can move the cursor ALONG the curve with the cursor keys until the cursor reaches the point at which the leaf edge meets the stem (LEAF.DRW uses 6.495, 4.288). You might want to press Ins to slow the cursor speed. Press F3 and PictureThis automatically cuts the original curve into two curves at the newly chosen "middle" endpoint. Now do the same operation for the lower stem side (in this case, LEAF.DRW uses coordinates 6.370, 4.376 for the new "middle" endpoint). 2. Now complete the leaf by drawing the upper and lower leaf edges using the newly established endpoints. First draw the lower leaf curve, starting at the lower endpoint. For the lower leaf edge, LEAF.DRW uses 1.320, 3.430 and 4.570, 4.954 for the control point coordinates. Next draw the upper leaf edge, starting at the leaf tip. For the upper leaf edge, LEAF.DRW uses 6.495, 1.784 and 4.020, 1.450 for the control point coordinates. 3. At this point you should save your drawing! Press F10 to access the file operations menu, then press S. A prompt appears asking if you want to save the drawing as LEAF.DRW. Answer with N. In response to the next prompt, key in: "MYLEAF.DRW" and press Enter. It should only require a few seconds for your drawing to be saved. EXERCISE 10. DRAWING BOXES AND OVALS 1. Turn the template off by pressing T, and erase your drawing by pressing C followed by Y. 2. To draw a box, move the cursor to where you want a corner of the box and press B (for "Box"). Now move the cursor away from the first corner. A box follows. When you are satisfied with the size of the box, press F3. The box is set, and the cursor returns to the initial corner. Each box made this way has four straight lines connected at four corner endpoints. You can treat each of the four straight lines as you would treat any other curve. 3. To draw a square, press B at one corner of the square, then press S (for "Square"). Two guidelines appear, running through the cursor position at 45-degree angles. Move the cursor along one of the guidelines by pressing one of the "diagonal" cursor keys (7, 9, 3, or 1 on the numeric keypad). A square follows. You can press the cursor key diagonally opposite to the first one you pressed to go in the other direction along the same guideline. If you now want to move the cursor along the other guideline, you must first press F2. Try it. The square disappears, and the cursor moves back to the original corner. Now you can move along the other guideline with the other two diagonally opposite cursor keys. When you are satisfied, press F3 to set the square. If the squares which you draw using this method don't appear to be true squares, you need to adjust your screen's aspect ratio (see the user manual). 4. To draw a circle, press O (for "Oval") with the cursor positioned where you want the center of the circle. Two guidelines appear through the cursor position, one horizontal and the other vertical. Move the cursor along the horizontal guideline with the 4 and 6 numeric keypad keys. A circle is drawn, centered on the guideline cross, passing through the cursor. When you are satisfied with the circle, press F3, and the circle is set. It consists of four Bezier curves, each of which can each be treated as any other curve drawn in PictureThis. The cursor is positioned at the center of the circle to facilitate drawing concentric circles. If the circles you draw don't look like true circles, you need to adjust your screen's aspect ratio (see the user manual). 5. To draw an oval (ellipse), press O with the cursor where you want the center of the oval, and start by drawing a circle as above. When the circle is a reasonable size, press F2. The cursor jumps to the top or bottom of the circle, where the circle crosses the vertical guideline. Now you can change the circle to an oval by moving the cursor up and down (with the 8 and 2 numeric keypad keys). You can move the cursor back to its previous position on the horizontal guideline (to change the horizontal dimension again) by pressing F2, and so on. When you are satisfied with the oval, press F3. The oval is set as four Bezier curves, and the cursor is positioned at the center of the oval. 6. Draw several boxes, squares, circles, and ovals, making some of them overlap. Try pressing Esc at various points while drawing, to see what happens. (Remember that, in general, Esc backs out of an operation one step at a time.) EXERCISE 9. MODIFYING TRAILS 1. A "trail" in PictureThis consists of one or more curves which are treated as associated with each other. Usually, trails are composed of curves continuously connected endpoint to endpoint. Trails can be filled with gray shades and combined to form "objects" which can be manipulated in other ways. Whenever you draw a curve it is automatically put in a trail. If the NEXT curve you draw has its FIRST endpoint in the SAME place as the previous curve's SECOND endpoint, the second curve is put in the same trail, and so on. When you drew the leaf edges in Exercise 7.2, you drew them so they would form a continuous trail (of two curves). The curves which form an oval or a box are also automatically placed in a trail. 2. Now you will fill some of the boxes, circles, and ovals that are on your screen. To access the trail menu, press F6. Then press F to fill a trail. The cursor jumps to the initial point of one of the trails on screen (the initial point is the first endpoint drawn in a trail), and the trail is dashed. Press +, Space, and - repeatedly until the trail you want to fill is dashed (in this case just pick any box or oval), and then press Enter. A prompt appears, showing the current gray fill percentage and asking for a new one. The current fill should be -1%, meaning that the selected trail is NOT filled (that is, it is transparent -- not the same as white, which is opaque to parts of the drawing beneath it; see below). Enter a number between 0 (white) and 100 (black). The screen is unchanged (since fills do not show on the drawing screen), so press Q to see the Quickshow screen. The trail you have chosen is filled with a pattern representing the shade of gray you have chosen. Now press Esc to return to the drawing screen. Fill other ovals and boxes with different gray percentages, and check the results on the Quickshow screen. If you fill some overlapping trails you will notice an important property about PictureThis (and PostScript) fills: they are "opaque." If a trail overlaps another trail, and the trail "in front" is filled, the portions of the other trail that are "behind" the first trail are NOT visible on the Quickshow screen or on the PostScript output. Watch overlapping trails being drawn on the Quickshow screen. First the "behind" trail is drawn completely; then the "in front" trail is drawn, obscuring part of the "behind" trail. It is as if the "in front" trail is pasted over the "behind" trail. The order in which trails are "pasted" on the Quickshow screen (and on the PostScript output) initially is determined by the order in which they are drawn (the earliest drawn are "pasted" on first), but this layering can be changed easily (see Exercise 11.5). 3. On the drawing screen, scroll your drawing so that an edge of the frame runs across your computer's screen (see Exercise 3.6). Now draw a circle so it is partially within the frame and partially outside the frame. Fill the circle and press Q. Notice that only the part of the circle WITHIN the frame appears on the Quickshow screen. That is because the frame "clips" your drawing: only portions of a drawing WITHIN the frame show on the Quickshow screen and on the PostScript output. It is easy to change the size and location of the frame (see the user's manual). 4. If you have many elements in a drawing, the Quickshow screen may take a long time to finish drawing. To stop it before it completes drawing, press Esc. When you press Esc a second time, the drawing screen reappears. Try it. 5. Try erasing one or more trails. To do this, press F6 to bring up the trails menu, then press E (for "Erase"). A trail is dashed. Choose a trail by pressing +, -, and/or Space repeatedly, then press Enter. A prompt appears, asking if you want to erase the chosen trail. Answer Y and the entire trail is erased. 6. Now you will change the line parameters of some trails. First press F6 to access the trails menu again; then press L. Choose a trail in the normal mannner. When you press Enter, a line menu appears. This menu is the same as the line menu for a single curve (see Exercise 6.3), except with an added parameter: the "join" of the trail, which refers to how two curves of a trail are joined where they connect at their endpoints. If the second line for any of the parameters says "Mixed," then the curves in the chosen trail don't all have the same value for that parameter. You can change the line weight, line gray, and linecap of ALL the curves in the trail, just as you changed them for an INDIVIDUAL curve in Exercise 6.3. Try it and check your results with the Quickshow screen. Try changing a filled trail's line weight to -1 and check the Quickshow screen; you should see a filled area with no boundary. Also try changing the join for a box with thick black lines (say, 40 points). The three possibilities are "Mitered" (the default for boxes), "Rounded," and "Beveled." Look at the joins on the 300% screen. You also can change the dash pattern of ALL curves in a trail; see the user manual for instructions. 7. Now return to your leaf drawing by pressing F10 and G, then keying in "MYLEAF.DRW" and pressing Enter. Notice that the current drawing is cleared before the new drawing is brought in. Center the frame (if it isn't centered already) by pressing Shift 5. Fill the trail made of the two edges of the leaf with some reasonable gray value (say 50%). (It was drawn as a continuous trail in Exercise 7.2.) If you look closely, you will notice that the two leaf edges do not form a CLOSED trail -- there is a small gap at the stem. When a trail that is not closed is filled, PictureThis automatically closes the trail by drawing a straight line of line weight -1 (a construction line) from the last endpoint in the trail to the first one, and filling the resulting closed trail. In this case, it doesn't matter, but you usually will want to fill only closed trails. After you have filled the trail, change all the curves of this trail to a line weight of -1. Check your results on the Quickshow screen. Notice that the stem is mostly covered by the leaf fill pattern now; you will correct that in the next step. EXERCISE 10. DEFINING A TRAIL Many trails are defined automatically as you draw them, but sometimes you need to define a new trail of already existing curves. The stem of the leaf was drawn as a continuous trail, but since you erased one of its curves and redrew it, it is no longer a single trail. This gives you the opportunity to learn how to define trails. Press F6, then press D to start defining a new trail. The cursor jumps to the nearest endpoint (just as if you pressed Del). Move the cursor using +, Space, and/or - repeatedly until it is on one of the endpoints of the stem; press Enter. One of the curves emanating from the chosen endpoint is now dashed. If it is a stem curve, press Enter. Otherwise, press +, Space, and/or - repeatedly until a stem curve is dashed and then press Enter. The chosen curve becomes dashed-and-dotted, and the cursor jumps to the other end of the curve. In the same manner, choose the next stem curve, etc., until the cursor is back to the original endpoint, then press D (for "Done"). The new trail is now defined. A prompt appears asking for a fill value for the new trail; enter some reasonable value (say, 75%) CONSIDERABLY DIFFERENT from the fill value of the leaf. Now a prompt appears asking if you want to change the line parameters of all the curves in the new trail. Press Y and change the line weights of all the curves to -1. View your drawing on the Quickshow screen. Now the stem is again "in front of" the leaf, because the stem trail was defined more recently than the leaf edge trail.