ICADDemo is a demonstration version of IntroCAD 2.1. Copyright (C) 1987, 1988 Tim Mooney ICADDemo and the accompanying files IntroCAD.txt and ICADDemo.doc are freely distributable, but are nevertheless protected by copyright. They are not to be sold, although you may charge a nominal copying/hassle fee for distributing them. -------------------------------------------------------------------------- The following text is taken from the IntroCAD Owner's Manual. -------------------------------------------------------------------------- *********************** OBJECT-ORIENTED DRAWING IntroCAD is an OBJECT-ORIENTED drawing program. It might be easiest to explain what that means by comparing IntroCAD to the PIXEL-ORIENTED drawing programs (e.g., GraphiCraft and Deluxe Paint) with which you may be more familiar. The major difference, as you will see, is in the way information is stored. Pixel-oriented programs store essentially all of the information which describes the picture you are drawing right on the screen in front of you. Each little dot on the screen--each pixel--has a color; your job, as drawer, is to change the colors of selected pixels. Now, for some purposes, the screen is not an ideal place to store picture information. A computer screen is a relatively low-resolution device when compared to most printers and plotters; you normally can't use the higher resolution of these output devices if the picture information is stored on the screen. Some numbers: the highest resolution achievable on the Amiga is approximately 75 dots per inch (DPI) horizontally, by 60 dpi vertically (with the standard Amiga monitor.) In contrast, the best resolution of one medium-priced dot matrix printer is 240 by 216 dpi. Laser printers routinely achieve 300 by 300 dpi. Object-oriented programs, on the other hand, store information in a drawing list--kept in memory which is separate from the screen's memory--and use the screen only to exchange information with you. The screen is optimized for quick transmission of information to your monitor, while the drawing list is optimized for faithful recording of your drawing. Your job, in using an object-oriented program, is to tell the program where the lines which make up your drawing begin and end, what color the lines are, whether they are solid or dashed, etc. You tell IntroCAD these things by drawing the objects, just as if you were using a pixel-oriented program. IntroCAD responds by showing you a picture of what you're drawing. In IntroCAD, what actually is stored are the coordinates of the *POINTS* of the objects you draw. A line segment, for example, is stored simply as two points--two pairs of coordinates. IntroCAD can use the full resolution of any output device it knows how to talk to because the picture information is stored--as floating-point numbers--in a drawing list rather than on a screen. IntroCAD could effectively use an output device with a resolution of well over one million dots per inch, (although no such device exists, nor is one likely to become generally available in the near future.) This ability is one major advantage enjoyed by object-oriented drawing programs. A second difference between object-oriented and pixel-oriented programs is the way they behave when you draw one object on top of another. In pixel-oriented drawing, the covered object is gone forever; all memory of it has been erased and replaced by the new object. (But most pixel-oriented programs provide a means of recovering the obscured object by "undoing" the drawing motion which erased it.) In object-oriented drawing, nothing is ever erased by drawing on top of it; objects are remembered unless they are explicitly erased. The biggest difference becomes clear when you begin to modify a drawing. Let's say you have drawn a box on the screen and then, later, drawn a circle overlapping it. An object-oriented program allows you to move the box, or modify its shape without changing the circle in any way. Normally, you can also group the box and circle together and move or modify them as a unit. A pixel-oriented program normally doesn't allow you to move or modify overlapping objects separately. Instead, you modify sections of the screen--with whatever objects, or parts of objects happen to lie on those sections. In pointing out some of the advantages of object-oriented drawing, I don't mean at all to represent it as "better" in any absolute sense than pixel-oriented drawing. It simply is different, with different advantages and disadvantages. A major disadvantage of object- oriented drawing, for example, is that the drawing list grows, consuming more memory, as more objects are drawn. A very complex drawing may not fit in your computer's memory space. In contrast, a pixel-oriented drawing always takes up the same amount of memory--regardless of the drawing's complexity. **************** INVOKING IntroCAD ------------- From the WorkBench: There are three methods: 1) Double-click on the IntroCAD icon. 2) Press and hold the shift key. Click on the icon of an IntroCAD Drawing. Double-click on the IntroCAD icon. Release the shift key. This will open IntroCAD and cause it to also open the Drawing you selected. 3) Double-click on a Drawing's icon. This will do the same thing as method #2, and is a nice short-cut. But this method requires that: a) IntroCAD hasn't been renamed. b) IntroCAD is located in the top drawer of a disk (also) named IntroCAD. In other words, IntroCAD's FULL name must be "IntroCAD:IntroCAD". Experienced users sometimes call the part up to and including the colon the "path", while the rest is the "name". If you've copied IntroCAD to a hard-disk or ram disk, you can't cause the path to be "IntroCAD:", but you can do the next best thing: Say, for example, you've copied IntroCAD to the directory "DH0:cad". You can open a CLI window and type: Assign IntroCAD: DH0:cad From now until you reboot the machine or turn it off, the WorkBench will act as though IntroCAD were located on a disk named "IntroCAD". ------------- From the CLI: Type IntroCAD or IntroCAD filename where "filename" is the name of a drawing or part file that you want to create or edit. ************************** DRAWING WITH IntroCAD Here's how to draw some simple objects with IntroCAD: -------------------------- BOX: Select "Box" from the "Draw" menu. Position the mouse pointer where you want one corner of the box to be. Click the left mouse button once. Move the mouse pointer until the box you see is the box you want. Click the left mouse button once. So you see what's going on here: Your first mouse click puts an imaginary pen down on the page; your second one picks it back up and makes the box part of your drawing. (All that hideous stuff--about coordinates of points being somehow entered into a drawing list--you might have imagined while reading the "Object-Oriented Drawing" section has just been done for you. You can think about the box; IntroCAD will take care of the drawing list.) -------------------------- CIRCLE: Much like drawing a box. Select "Circle" from the "Draw" menu. Position the mouse pointer where you want the center of the circle to be. Click the left mouse button once. Move the mouse pointer until the circle you see is the circle you want. Click the left mouse button once. -------------------------- LINE: This one's a little different. Select "Line" from the "Draw" menu. Position the mouse pointer where you want the line to begin. Click the left mouse button once. Move the mouse pointer until the line you see is the line you want. Click the left mouse button *twice* (don't move the mouse between clicks.) Why do you have to click twice to end a line? Because the "Line" tool is also used to draw a set of connected lines. A single click with this tool means "end this line and start another." There's a limit to the number of connected lines you can draw at once, but you'll probably never reach it. For concreteness, here's an example of two connected lines: SET OF TWO CONNECTED LINES: Select "Line" from the "Draw" menu. Position the mouse pointer where you want the line to begin. Click the left mouse button once. Move the mouse pointer until the line you see is the line you want. Click the left mouse button once. Move the mouse pointer until the line you see is the line you want. Click the left mouse button *twice* (don't move the mouse between clicks.) -------------------------- FREEHAND: Different from all the others in that you hold the mouse button down while you draw. Select "FreeHand" from the "Draw" menu. Position the mouse pointer where you want the freehand figure to begin. Press and hold the left mouse button. Move the mouse pointer to draw the figure. Release the left mouse button. -------------------------- ARC: Like a circle, but with one extra click. Select "Arc" from the "Draw" menu. Position the mouse pointer where you want the center of the arc to be. Click the left mouse button once. Move the mouse pointer to set the radius and starting angle of the arc. Click the left mouse button once. Move the mouse pointer until the arc you see is the arc you want. Click the left mouse button once. -------------------------- TEXT: Just as you might expect. Type a letter at the keyboard. That's it. (You can do this at any time. You never need to make a menu selection before typing text into your drawing.) You can set the text size very simply: Select "TextSize" from the "Draw" menu. Draw a box. (It doesn't matter where you draw the box; only its size matters.) You can set the text location very simply as well: Select "Cursor" from the "Draw" menu. Position the mouse pointer where you want the lower left hand corner of the next letter to begin. Click the left mouse button once. ************************** IntroCAD'S SCREEN There are a number of features IntroCAD can put on the screen on top of your drawing. All of these are intended to give you information of one sort or another. All are controlled by selections from the "Options" menu. RULERS These are the numbered bars which occur at the left and bottom edges of the screen. The rulers are marked out in inches. You can toggle display of the rulers with the menu item "Rulers". There is nothing special about the screen regions occupied by the rulers. You can (and should not hesitate to) draw right on top of them. IntroCAD normally doesn't bother to refresh the screen when the rulers are scribbled on because this can happen frequently and, for a complex drawing, a screen refresh can take several seconds. You can, however, cause IntroCAD to refresh the screen each time the drawing changes by selecting the menu item "ReDraw/Auto" ("Auto" is a sub-item of "ReDraw") from the "Options" menu. GRID These lines are drawn behind your drawing. You can choose from several different kinds of grid. You can also make the grid invisible. The menu item "Grid" is used for these selections. You can make the grid mesh finer or coarser with the menu item "Grid Mesh". CURRENT TOOL At the upper left-hand corner of the screen, IntroCAD prints the abbreviated name of the *tool* you are currently using. (Examples of tools are the "Line" tool, with which you draw lines; the "Erase" tool, with which you erase objects; and the "Group" tool, with which you group objects together.) Display of this feature is controlled with the menu item "ShowTool". COORDINATE READOUT When the menu item "ShowXY" is active, IntroCAD prints four numbers at the lower left-hand corner of the screen. The display might look like: 00.00:2.00 0.00:5.00 L:3.00 A:0.00 The first two numbers in the display are the current X (horizontal) and Y (vertical) coordinates of the mouse pointer. The next two numbers are the X and Y distances from the pointer to the position of the most recent SELECT click. The number which follows "L:" is the length of the line connecting the point of the most recent SELECT click and the current position of the mouse. The number following the "A:" is the angle of that line. FREE MEMORY When the menu item "ShowMem" is active, IntroCAD prints the total amount of computer memory which has not been allocated by any process. The display occurs near the middle bottom of the screen. The number is in kilobytes. GRID SPACING While a "Plain" or "Projection" grid is selected, IntroCAD prints the spacing between grid lines at the lower right-hand corner of the screen. ************************** IntroCAD OBJECTS & GROUPS In this manual, the words OBJECT, GROUP, and PRIMITIVE will occur frequently. These words have special meanings here; they refer to parts of your drawing. To IntroCAD, an *OBJECT* is either of: 1) The result of a single complete drawing motion. A box, for example, is an object. So is a set of connected line segments all drawn "at the same time." So are circles, letters, etc. These objects are also called *PRIMITIVE*s. 2) A grouped set of primitives. Such an object is also be called a *GROUP*. There is no limit to the number of primitives in a group, or to the number of groups in a drawing. A few notes about groups: The grouping of objects need not be permanent. You can dismember ("UnGroup") a group into primitives at any time. IntroCAD doesn't ever change the group structure of a drawing on it's own, however. When a drawing is saved to disk, the group structure is saved with it. No object can be in more than one group at a time. If you try to group objects which are already members of different groups, IntroCAD will assume you want the entire *groups* grouped together. Although you can group groups together, groups are not hierarchical. In other words, IntroCAD does not keep track of groups within groups. When a group is "UnGrouped", the result is always a collection of primitives. It is not an error to attempt to ungroup a primitive. (It doesn't work, though.) ********* THE MOUSE In IntroCAD, the mouse does mostly what you're accustomed to from drawing programs like "Deluxe Paint". There are a few differences, however. (Here, and throughout this manual, the *SELECT* button is the left mouse button; the *MENU* button is the right mouse button.) 1) In IntroCAD, you are called on to select objects, e. g., for treatment with one of the editing tools. Since IntroCAD can't know for which of two or more overlapping objects your *SELECT* click was intended, it runs through a list of all the possibilities, highlighting each in turn. In this context, a *MENU* click means "No, not that one", a *SELECT* click means "Yes, the highlighted object is the one I want". (See "Selecting Objects" for more detail.) 2) While drawing an object (exception: text) or editing (exceptions: coloring, setting line type, rotating by 90 degrees), IntroCAD gives you a chance to abort the whole operation. In this context, a *MENU* click means "Abort", a *SELECT* click means "The highlighted object is drawn as I want it, make it permanent." 3) Certain editing functions, "Point" for example, require additional information and indicate this by drawing highlighted objects. You are asked to click on (*SELECT* button) e. g., one of the objects. 4) In certain circumstances, IntroCAD prompts you for a mouse motion by making a suggestive little pictogram with the mouse pointer. The meanings of the pictograms are as follows: A) CIRCLE WITH A SLASH THROUGH IT: Wait. IntroCAD is busy with some calculations and is not looking for input from you. However, Intuition--the Amiga's user interface--is *always* attentive to the mouse and keyboard and will "stack up" mouse clicks and key presses for later handling by IntroCAD. You should not assume, then, that the mouse and keyboard are ignored while the "Wait" pointer is displayed. B) ARROW WITH A QUESTION MARK: This is a "Select Something" mouse pointer. Point at something and click the *SELECT* button. Typically, you will position the mouse pointer over some object on the screen and click to direct IntroCAD's attention to the object. C) ARROW WITH A BOX: This is a "Draw Region" mouse pointer. Draw a box. (For "Zooming" only, clicking twice in the same spot is equivalent to drawing a box twice the size of the screen. See "Zoom" in the section which describes the "Options" menu.) D) QUESTION MARK WITH A "Y" ON THE LEFT AND A "N" ON THE RIGHT: This is a "Yes/No" mouse pointer. Say "Yes" by clicking the *SELECT* button, or "No" by clicking the *MENU* button. So, generally, when the mouse buttons don't have their Intuition meanings, the *SELECT* button means "Yes/THAT one/Do it", and the *MENU* button means "No/Not THAT one/Get me out of this!". This follows the generally accepted convention that "left" breaks new ground while "right" is conservative and safe. If you get lost in, or called away in the middle of, a sequence of mouse clicks, some number of *MENU* button clicks will ALWAYS get you out of it. One last thing about mouse buttons: Since IntroCAD appropriates the *MENU* button for things like selecting objects and aborting, there are times when you can't (immediately) make menu selections with this button. If you truly DO want to make a menu selection, and IntroCAD seems uncooperative, just click the *MENU* button repeatedly until the menu bar flashes at the top of the screen, and then make your menu selection. ************************** SELECTING OBJECTS To edit, clone, or save an object to disk, you must first specify the object by selecting it. (This is true even if there is only one possible object.) There is no explicit tool--no menu item--for this purpose since IntroCAD always knows when a selection is required. At the appropriate time, IntroCAD will ask you to specify an object by giving you the "Select Something" mouse pointer (an arrow with a question mark above it.) When IntroCAD gives you the "Select Something" mouse pointer, you should point to the object of your choice and click the *SELECT* button. IntroCAD will make a list of all the objects you might possibly be referring to (let's call this list the *SELECT LIST*), and highlight the first one in the list by re-drawing it in the highlight color. (The highlight color is color #15. IntroCAD causes this color to change continuously whenever it's waiting for input from you.) After highlighting an object, IntroCAD will give you the "Yes/No" mouse pointer. If the highlighted object is the one you want, say "Yes" by clicking the *SELECT* button; if not, say "No" by clicking the *MENU* button and IntroCAD will "unhighlight" the object and highlight the next object in the list. If you get all the way through the Select List without saying "Yes" to any of the objects, IntroCAD will invite you to make another selection by again giving you the "Select Something" mouse pointer. You can, of course, ignore the invitation and make a menu selection instead. It may help you to know how IntroCAD infers, from the position of the mouse pointer at the time of your *SELECT* click, which object you are specifying. For each primitive, IntroCAD maintains a *REGION-RECTANGLE*. This is the smallest rectangle, having horizontal and vertical sides, which completely encloses all points of the primitive. (A vertical line, then, has a region-rectangle one pixel wide. You can't be that precise? Well, actually, IntroCAD allows a little slop here.) If your click lands in an object's region-rectangle, that object goes into the Select List because it might be the one you have in mind. If the object is part of a group, the whole group goes into the list as a single object. There is a potential problem with this method of selecting objects: What if you draw, for example, a circle with some objects inside it, and then zoom inside the circle so that none of it is visible on the screen? If you now try to select one of the objects inside the circle, you're *SELECT* click can't help but be inside the circle's region- rectangle. IntroCAD will dutifully include the circle in the Select List, and highlight it in its turn. You won't be able to see the highlighted circle because it's off-screen, BUT IntroCAD WILL NOT REALIZE THIS. Your job is to say "No" whenever you get the "Yes/No" mouse pointer, but don't see a highlighted object. ************************ RESPONDING TO REQUESTERS When IntroCAD has a message for you that does not require a reply, it normally doesn't make you reply just to get the requester off of your screen. You can go on about your business; the requester will go away the next time you click a mouse button. (But the mouse click which removes a requester will not be used again for anything else.) Further, if pressing the *SELECT* button brought the requester up, releasing the *SELECT* button will remove it. **************************************************************************** FIRST TIME THROUGH This section is an introduction to some IntroCAD features. Not all features are covered here. Neither are the covered features described in glorious detail. The idea here is to give "The Big Picture" very quickly and painlessly to users who dislike formal tutorials. Some users like detailed move-by-move instructions and some don't. If you're one who does, go through the section of this manual called "Drawing with IntroCAD". The basic drawing motions are described in that section. Another place to go for more detail is the section called "Menus".) 1) Set up check. Make a copy of the IntroCAD disk and put the master copy in a safe place. (If you use the Workbench, the copied disk should, ideally, be named "IntroCAD", just as the master copy was. If you use the CLI, the disk name is irrelevant.) If you use IntroCAD from the CLI, set your stack size to 10000 or more. (You may know from experience with other programs that to set your stack size to anything less than 10000 is to live dangerously. Some folks recommend an even larger stack.) If you use IntroCAD from the WorkBench, the stack size will be set to 10000 for you when you open IntroCAD. 2) Get comfortable with your drawing environment: Play around with the tools from the "Draw" menu until you have some "stuff" on the screen (forget "TextSize", "Cursor", and "Clone" for now.) You might have a hard time guessing that the only way to "end" a line is to click twice in the same spot. The other Draw menu items are more intuitive. Just bang away at those mouse buttons until your *fingers* know how to draw the primitives. Make a few selections from the "Options" menu and see what they do. ("Zoom", "Slide", and "Snap to" will be explained presently. You can wait or not, as you like.) 3) Learn how to "drive" around in your drawing: Select "Slide" from the "Options" menu act like you're drawing a line with the mouse. When you've finished the line the picture will move in the direction of your drawing motion. Select "Zoom" from the same menu. The mouse pointer should now be an arrow with a box above it. IntroCAD is asking you to draw a box. When you do, the picture will expand to show you the region inside the box. You can "zoom out" by clicking twice in the same spot instead of drawing a box. Notice that you can't "squash" your drawing horizontally or vertically with this tool. Select "FullPict". IntroCAD immediately zooms out so that the entire drawing is displayed. Select "ReDraw/Now". IntroCAD refreshes the screen without zooming. 4) Be aware that the keyboard is active: Type a couple of letters. (If no letters appear on the screen, do a "FullPict".) You can choose the location of the next character with the "Cursor" tool from the "Draw" menu: select that item and click somewhere on the screen. You can choose the character size with the "TextSize" tool, also from the "Draw" menu: select that item and draw a box. Notice that "Cursor" and "TextSize" do not affect text already drawn. You can use the "Edit" menu for that. Try the DEL key. Notice that this key deletes the primitive most recently drawn (whether or not that primitive was text.) 5) Editing Select "Erase" from the "Edit" menu. The mouse pointer should now be an arrow with a question mark above it. IntroCAD is asking you to select an object by "pointing at it" and clicking the left mouse button. Once you've selected an object, IntroCAD will "highlight" it and ask, by changing the shape of the mouse pointer (to a question mark flanked by "Y" and "N"), whether this is the object you had in mind. Click the left mouse button for "Yes" and the object will be erased. If you click the right button instead, IntroCAD will highlight another object if there is one nearby. If not, the menu bar will flash at the top of the screen, telling you that menu selections can now be made. At this point, you can also select another object for treatment with the editing tool you are using. All of the editing tools begin work in the same way: you first select an object, then confirm your selection. But with some of the editing tools, there is more. Try the "Move" tool. Maybe you can guess how to use this one. (If not, you get to play some more until you figure it out--this is not a tutorial we're having here. You can, of course, refer to the description in the "Menus" section of this manual, but you lose points for doing so.) It's probably pretty hard to guess how the "Size" and "Point" edit tools work. A hint: tiny little boxes are for clicking on. "Set Color" is used to set an object to the current color (which you can select from the "Palette" menu.) Ditto for "SetLinTyp" and the "LineType" menu. 6) Cloning, Parts Although "Clone" is an item in the "Draw" menu, it *feels* to your hand like an editing tool: it *feels*, in fact, exactly like the "Move" tool. Sooner or later you're going to wish you could somehow Clone an object you drew in some other IntroCAD session--as part of some other drawing, so that you can include it in your current drawing without having to draw it all over again. Well, you can, but we don't use the word "clone" to describe the process. Select "Open" from the "Part" menu. You will get a file requester. The names listed are names of Parts--which live on disk. Click on one of the names and then click on the "OK" gadget of the requester. Now your situation is EXACTLY as it would be if you had selected an object in your drawing using the Clone tool, but the object hanging off the end of your mouse pointer came from disk. When you've drawn an object you can't bear to part with, save it as a Part: select "Save As" from the "Part" menu and select the object you want to save (as if you were planning to use an editing tool on it.) A file requester will come up. Type the name you want the Part to be called and click the "OK" gadget. The object will be written to disk. In case you were wondering... Yes, you can include an entire Drawing in your current drawing by Opening it as a Part. 7) Groups: This is relatively advanced stuff, but it's easy to use. You will probably come to use groups a lot in drawing and editing. Select "Group" from the "Part" menu and draw a box completely around several objects. The enclosed objects are now grouped. You can ungroup them at any time with the "UnGroup" tool, also from the "Part" menu. (The "UnGroup" tool *feels* like an editing tool in that you begin using it by selecting an object. Try it.) As you might have expected, or at least hoped, you can treat a group of objects EXACTLY as if it were a primitive: you can apply any of the editing tools to a group; you can also Clone a group, and you can save it to disk as a Part. What if you group objects, some of which are already in different groups? The groups merge into a single group; no object can be in more than one group at a time. 8) Snapping to the grid: Select a grid type from the "Options" menu. Select the drawing option "Snap to/Grid" and draw some stuff. Notice that circles and arcs aren't snapped point-by-point while drawing (that would be kind of stupid, don't you agree?) The individual mouse clicks which specify the center and radius of the circle or arc *are* snapped, however, so you can, for example, center a circle on a grid intersection. Text is not snapped at all (*that* would be disastrous!). But, again, the mouse click used to place text (when you use "Cursor" from the "Draw" menu) is snapped. Also notice that grid snapping is usually suspended when you aren't actually drawing anything. When you are grouping objects, for example, snap would be annoying, and so is disabled. Select the editing tool "Snap/Naively" and apply it to a couple of different objects. Notice that EVERYTHING, even text, snaps point-by-point to the grid when this tool is applied. This is a *DANGEROUS* *TOOL*! We suggest you play with this tool a LOT before you start a serious drawing. After this tool has trashed a couple of your practice drawings, it will be a safer tool in your hands. Select the editing tool "Snap/No Distort" and apply it to several objects. This tool used in much the same way as the "Point" edit tool. "Snap/No Distort" is much safer than "Snap/Naively". This is the way to align, say, one corner of a box with the grid. 8) Snapping to the drawing: Select "Snap to/Drawing" from the "Options" menu. Draw a line which begins very near an existing object, and see if the line gets snapped. You have to be fairly close--within several screen pixels--to trigger the snap. The tolerance of this Option has been carefully set so that you can do nearly normal drawing while "Snap to Drawing" is enabled. Try, using the "Line" tool from the "Draw" menu, to draw a closed triangle with and without "Snap to/Drawing". Try to draw the letter "T" by hand. You can snap an existing object to the drawing using the editing tool "Snap/Naively" or "Snap/NoDistort". In the latter case, the point nearest your confirming SELECT click is snapped; the rest of the object is dragged along with it. 9) And the rest... The "Palette" and "LineType" menus are left to your unassisted exploration. They are completely described in the "Menus" section, of course, and their names alone give you the degree of understanding we are attempting to convey in this section.