DTP en Graphics 1/dtpgraf1.zip/dtpgraf1/DTP/PICTHIS4/MANUAL6.TXT

Text File | 1991-12-31 | 51KB | 890 lines

         PICTURETHIS(TM) "SHAREWARE" VERSION

         RELEASE 4.00

         DECEMBER 31, 1991

         USER MANUAL, PART 6 OF 7 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.


         19.7. SHELLING TO DOS

           PictureThis allows you to "shell" to DOS, so you can use
         the normal DOS facilities WITHOUT a "normal" exit from
         PictureThis. At the files menu, press D. When you do this,
         one of two error messages might appear. If the valid
         COMMAND.COM file is not in the current directory or in a
         path specified in your COMSPEC specification (see your DOS
         manual), you get an error message, and you aren't allowed to
         shell to DOS. If COMMAND.COM is found, but there is
         insufficient memory to shell, you get an different error
         message, and you aren't allowed to shell to DOS.
           If no problems are encountered, the DOS prompt appears,
         and you can carry out normal DOS functions. (But note that
         the PictureThis program is still taking up a considerable
         amount of memory!) When you want to return to PictureThis,
         at the DOS prompt, key in "EXIT" (or "exit"), then press
         Enter. PictureThis reappears in the "FREE" state.

         19.8. PLOTTING DATA FROM A FILE

           This feature allows two-dimensional plotting of data
         points, using numerical data files. Point or line plots can
         be made, and (assuming that there is sufficient memory),
         objects can be copied to some of the points. Axes, labels,
         notes, etc., can be added to plots as desired.
           We recommend the file extension .DAT for data files used
         with PictureThis. Such data files must be in pure-ASCII
         format (capable of being edited by a text editor or word
         processor in "non-document" or "non-formatted" mode), with
         the following characteristics:
           1. Each line must end with a carriage return and a line
         feed.
           2. Each "comment" line must begin with an equals sign (=).
         Such lines are ignored by PictureThis. Any line containing
         only a carriage return and a line feed also is ignored.
           3. Each data line must contain alphanumeric strings
         (fields) separated by these delimiters: space (" "), tab
         (^I, "        "), comma (","), semicolon (";"), colon (":"),
         or dollar sign ("$"). Between any two fields, there can be a
         single instance of the one of the above delimiters, preceded
         and/or followed by one or more spaces. A data line can begin
         with one or more spaces, but there must not be any other

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         delimiter before the first field.
           4. Only numeric strings can be parsed by PictureThis for
         plotting. Attempts to use non-numeric strings for plotting
         will produce error messages. A valid numeric string can
         begin with a plus sign ("+"), a minus sign ("-"), a decimal
         point/period ("."), or a digit ("0" through "9"). It can
         have several digits (and a decimal point if necessary) in
         its mantissa (just how many digits, we're not sure; we do
         know that a 15-digit mantissa works fine), then an exponent
         (power of 10) beginning with "E" (same as "e") or "D" (same
         as "d"), and followed by a plus sign, a minus sign, or a
         digit. The exponent must be an integer. There must not be a
         space between the mantissa and the exponent. Acceptable
         numbers are between -1.7E308 and 1.7E308. A number with
         absolute value less than about 1E-45 is turned into zero.
           The next few paragraphs follow the steps in the plotting
         procedure; in general, you can press Esc to back out
         (usually, but not always, to the previous step).
           Assuming that PictureThis can access a valid data file
         (two such files are provided on one of the distribution
         disks: TEST1.DAT and TEST2.DAT), access the file menu by
         pressing F10, then press U (for "UseDAT"). Key in a new
         path, if necessary, press Enter to see your choices, and
         select a file as usual, or key in a file name and press
         Enter.
           PictureThis plots a series of points (x,y) (possibly
         connected by lines) on the drawing screen, with x measured
         along the horizontal direction and y measured along the
         vertical direction. You can choose which field in each of
         the lines of the data file corresponds to x, and which
         corresponds to y. In other words, the data file is treated
         as being organized into "columns" of data. The default for x
         is the first field in each row. Press Enter to confirm the
         default, or key in a different field (up to 99). Or you can
         key in "0" to input your own (equispaced) x values; you'll
         be prompted for a starting x and an x increment. Next,
         choose which field corresponds to y; the default is the
         second field. You can key in "0" for the y field ONLY if you
         DIDN'T key in "0" for the x field. Again, if you specify a
         field which contains a non-numeric string in any line,
         you'll see an error message.
           You see how many (x,y)-pairs are in the data file and how
         many pairs can be plotted (as endpoints), given the existing
         memory capacity of PictureThis. You are asked to enter the
         number of the starting pair (press Enter to confirm the
         default: the first pair in the file). The ability to choose
         the starting-pair number is important when you want to plot
         more points than memory allows, as discussed below.
           One way to get around memory limitations and/or make a
         plot easier to read is by plotting only every nth pair in
         the data file. The default for n is 1 (no pairs are
         skipped). The maximum allowable value of n is the number of
         pairs in the file minus the starting-pair number minus one,
         so that a minimum of two pairs will be plotted. That is,
         they will be plotted in theory -- assuming that there is
         enough memory, and that none of the pairs lie outside the
         boundaries to be specified by you (see below).
           Next, you see the total number of points which can be
         plotted, taking into account current memory limits. Each
         point plotted is one PictureThis curve. The number of points

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         which can be plotted might not be as large as you want, but
         later, as explained below, you'll be able to make an EPS
         file with ALL of the data points you want to plot,
         regardless of memory constraints. An Enter accepts the
         default. Don't forget to leave some room in memory for non-
         plot curves (borders, tick marks, etc.) and text to be added
         later, if appropriate (such curves and text could be placed
         on a separate drawing and merged later; see below).
           If ALL of the x's in the data file (including those which
         won't be plotted "in theory") are greater than zero, then
         you're asked if the x-axis should be scaled logarithmically.
         Enter selects no logarithmic scaling. The same holds for
         logarithmic scaling of the y-axis.
           Now move the cursor to a position (XLOW, YLOW), such that
         all plotted x's are greater than or equal to XLOW, and all
         plotted y's are greater than or equal to YLOW (you'll be
         prompted to do this only if you have the help toggle set to
         "H+"). Press F3 to place a noted point and see the next two
         query boxes in turn: you can choose XLOW (the default is
         XMIN, the minimum x value in the data file) and then YLOW
         (the default is YMIN, the minimum y value in the data file).
         ANY (x,y)-PAIRS IN THE FILE WITH x LESS THAN XLOW OR y LESS
         THAN YLOW WILL NOT BE PLOTTED. Repeat cursor positioning and
         choice of values for (XHIGH,YHIGH). ANY (x,y)-PAIRS IN THE
         FILE WITH x GREATER THAN XHIGH OR y GREATER THAN YHIGH WILL
         NOT BE PLOTTED. PictureThis won't allow you to choose noted
         point positions or numerical values such that XLOW equals
         XHIGH or YLOW equals YHIGH.
           As noted above, data points can be plotted either as
         individual points (dots) or as lines connecting successive
         points. Plotted dots or lines are drawn as per current
         settings for weight, gray, linecap, dash, and join, as soon
         as you choose dots (press D) or lines (press L). (Dots will
         NOT appear on the Quickshow screen or PostScript output if
         they are dashed or if their linecap is not round.) Plotted
         lines automatically form a trail. Note that if the x's or
         the y's in the data file were not sorted in ascending or
         descending order, some of the lines might cross each other.
           The final report on plotting shows how many points
         actually were plotted -- note that data-file pairs lying
         outside the boundaries you specified were NOT plotted. Also
         reported is the number of the last pair actually plotted
         (not equal to how many points actually were plotted unless n
         was one, the starting pair was one, and no pairs read from
         the data file were outside the boundaries).
           NOTE: If, due to memory limitations, only SOME of the
         pairs in the file which you wanted to plot actually were
         plotted, you can save the current drawing and its EPS file,
         clear the screen, and plot more pairs on a second drawing,
         BEGINNING WITH THE LAST PAIR ACTUALLY PLOTTED AND USING THE
         SAME VALUES FOR n, XLOW, YLOW, XHIGH, YHIGH, AND DRAWING
         SCREEN PARAMETERS SUCH AS FRAME AND SCALING. This can be
         repeated as necessary, and then all of the resulting EPS
         files can be concatenated into a single file using a text
         editor or word processor which reads and writes pure-ASCII
         files. Before sending the consolidated file to a PostScript-
         compatible printer, you'll need to search for and remove the
         word "showpage" (which appears only once in each of the
         concatenated files) IN ALL BUT THE LAST OF THE CONCATENATED
         files, and, if you used fonts which must be downloaded to

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         your printer/typesetter, you'll need to make sure that ALL
         of the required fonts (specified at the end of each
         component file) are specified at the end of the consolidated
         file.
           You can use the noted points at opposite corners of the
         plotting boundary to help with positioning of axes and
         labels. You might want to draw a construction-line (-1
         weight) box connecting the noted points, then place scales
         along one or more of the box sides. We recommend the
         following procedure for adding scales: draw a vertical or
         horizontal scale of arbitrary size and position (possibly
         using a data file to aid positioning of tick marks --
         especially for a log scale), copy it so one point on the
         scale is where you want it, then scale it so a second point
         is where you want it.
           Since all plotted dots and lines are PictureThis curves,
         they can be manipulated in many ways. In particular, you can
         use plotted endpoints as positioning elements for other
         curves. If plotted dots/lines are construction lines, they
         won't show up in the final output. Provided that there is
         enough memory available, you can copy objects (for example,
         special plotting symbols, text characters, or even complex
         drawings) on top of plotted points (so each resultant
         plotted "point" could be, say, a 50%-gray diamond with a
         cross in it, or a 10-point "3" set in Palatino Italic, or a
         fancy logo). This is via automatic multicopying of objects
         to points on the plot (see Section 17.7). The plot must be a
         series of lines (automatically forming a trail) for
         multicopying.

         20. UNITS AND POSITION BOXES

           PictureThis allows you to specify the units you want to
         work in. When PictureThis is loaded, the units initially are
         PostScript points (1 PS point = 1/72").
           PictureThis has two position boxes to tell you the
         distance of the cursor from the corner of the frame and the
         relative position of the cursor to some previously specified
         point.

         20.1. CHANGING THE CURRENT UNIT

           To change the current unit, press F9. The state changes to
         "MISC," and the miscellaneous menu appears. To change the
         current unit, press U. The unit menu appears. The first
         element in the menu shows the current units (abbreviated).
         To choose new units, press X for pixels ("PX"), I for inches
         ("IN"), P for picas and points ("PP"), T for points ("PT"),
         C for centimeters ("CM"), or M for millimeters ("MM"). (A
         (PostScript) point is EXACTLY 1/72"; a (PostScript) pica is
         12 points or EXACTLY 1/6".) If the chosen units are NOT
         pixels, you see a further prompt asking if you want to
         measure from the top or the bottom of the frame (the
         horizontal measurement is always from the left edge of the
         frame, positive from left to right). Pixels always are
         measured from the top of the frame (positive downward).
         Press T if you want to measure the vertical units from the
         top of the frame (positive downward), B if you want to
         measure from the bottom of the frame (positive upward). The
         "FREE" state returns, and measurements in the position boxes

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         are in the new units. If you have toggled on the status box
         (see Section 4.3), the current units (abbreviated) appear as
         the rightmost element in the box.
           Not only are the measurements shown in the current units,
         but also the cursor moves in increments related to the
         units. If the units are pixels, the cursor moves in pixels
         (the CGA screen is 320 pixels horizontally and 200 pixels
         vertically; EGA is 640 pixels by 350 pixels; VGA is 640
         pixetls by 480 pixels): either 1 pixel or 10 pixels. The
         cursor moves the same distance when a particular cursor key
         is pressed at any magnification, but it moves different
         distances for a cursor press in the horizontal direction
         than in the vertical direction, because CGA screen pixels
         are not square.
           For units other than pixels, the cursor moves in "real-
         world" units (or a multiple of real-world units), so the
         actual movement depends on the current magnification (see
         Section 6.1), scale (see Section 22.2), and aspect ratio
         (see Section 24). So, for one cursor press, the cursor moves
         24 times as far on the 2400% screen, 12 times as far on the
         1200% screen, six times as far on the 600% screen, three
         times as far on the 300% screen, and one-half as far on the
         50% screen as it moves on the 100% screen. The cursor
         movement for one cursor press at a cursor speed of 1 is
         shown in the following table.

         UNIT            CURSOR MOVEMENT INCREMENT

         inches          1/100 inch
         points          1 PostScript point (1/72")
         picas & points  1 PostScript point (1/72")
         centimeters     1/10 cm (1 mm)
         millimeters     1 mm

         If the (fast or slow) cursor speed is changed (see Section
         21.1), one cursor press will move the cursor n times the
         "cursor movement increment" in the above table, where n is
         the cursor speed.

         20.2. CURRENT POSITION BOX

           The current position box is toggled on by pressing P. (If
         you press P again, the relative position box also is toggled
         on (see Section 20.4). A third press turns both boxes off.)
           The current position box appears at the lower right corner
         of the screen; it contains two numbers. The left number is
         the horizontal distance of the cursor from the left edge of
         the frame, specified in the current units; the right number
         is the vertical distance of the cursor from the frame origin
         (top or bottom (see Section 22)), also specified in the
         current units. (Unless the current units are pixels, in
         which case the position box numbers are in "internal units"
         (see Section 20.3).) If the current units are picas and
         points, the numbers are displayed as XXX&YY, where XXX is
         picas and YY is points (example: 12&11 means 12 picas and 11
         points; remember, 1 pica equals 12 points).

         20.3. INTERNAL UNITS

           PictureThis saves the position of the cursor and all

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         elements of drawings in "internal units" (ius). These are
         integer values, so most internal calculations use integers
         instead of floating point numbers (making the calculations
         faster and the drawing files smaller). Ius are smaller than
         pixels on all screens except the 2400% screen (where each
         pixel corresponds to an iu), and this allows both extremely
         high resolution in the final output and precise cutting,
         smoothing, and object manipulations (scaling, rotation,
         etc.).
           You also can move the cursor in internal units for
         extremely fine cursor placement. To move in internal units,
         press I. The cursor now moves in 1 or 10 internal unit
         increments. To return to "external units," press I again.
         The fourth character from the right in the status box is an
         "I" if the cursor is moving in ius; it is an "E" if the
         cursor is moving in external units; it is a "G" if the grid
         is active (see Section 21.3)). The number following this
         indicator is the current cursor speed. When "I" is toggled,
         the numbers in the position box still are in the current
         units.

         20.4. RELATIVE POSITION BOX

           The relative position box gives information about the
         position of the cursor RELATIVE to a previously set point
         (which depends on the current state). It can be toggled on
         when the current position box is on by pressing P, and it
         can be toggled off again (along with the current position
         box) by pressing P again. (P is a 3-way toggle.)
           There are four standard components of the relative
         position box: horizontal difference, vertical difference,
         distance, and angle (measured in degrees clockwise from a
         (conceptual) horizontal line extending to the right of the
         previously specified point). These numbers all are expressed
         in the current units. (The distance for pixels is expressed
         in HORIZONTAL internal units; one vertical iu is NOT as long
         as one horizontal iu!) The previously specified point for
         each state is as shown in the following table.

         STATE     POINT MEASURED FROM

         LINE      first endpoint
         CURVE     endpoint associated with current control point
         CHANGE    endpoint associated with current control point
         BOX       original box corner
         SQUARE    original square corner
         OVAL      center of oval
         FRAME     original frame corner
         GRID      current grid origin
         MOVE      start point
         COPY      start point
         SCALE     anchor point until "F2"
         ROTATE    anchor point until "F2"
         FLIP      1st flipline point
         MEASUR    point at which you pressed "M"
         TMPMOV    start point
         USEDAT    (XLOW,YLOW)

         For states not included in the above table, the relative
         position box is empty.

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           There are three special relative position box values. If
         the relative position box is on while scaling an object,
         after you press F2 to set the 100% scaling line, the
         horizontal and vertical scale factors are shown (see Section
         17.3). During rotation of an object, the rotation angle is
         shown (see Section 17.4), and during inclination of an
         object, the inclination angle is shown (see Section 17.6).
           Note: The information displayed in the relative position
         box is calculated using floating point calculations for all
         units. If you do not have a math coprocessor, calculations
         are slower when the relative position box is toggled on. If
         you are not using the information, toggle the box off for
         more speed.

         21. CURSOR SPEED AND GRID

           Cursor movements can be changed in two more ways. The slow
         and fast cursor speeds can be changed, and the cursor can be
         restricted to snap-to a user-settable grid.

         21.1. CHANGING THE SLOW AND FAST CURSOR SPEEDS

           The cursor can move at either one slow cursor speed per
         press or at one fast cursor speed per press. You can toggle
         between these two speeds with the Ins key. The slow and fast
         cursor speeds are initially set to 1 and 10 cursor
         increments (as specified in the table in Section 20.1, e.g.,
         1 and 10 points) but can be changed to any value from .1 to
         99.9 (except if the current unit is pixels). To change the
         cursor speeds, press F9 to get to the miscellaneous menu.
         Then press C. A prompt appears with the current fast cursor
         speed shown on its first line. To change the fast cursor
         speed, enter a different value. You can then change the slow
         cursor speed similarly. The next-to-last element of the
         status box is the current cursor speed.

         21.2. SETTING THE GRID

           The cursor can be constrained to move on a user-settable
         grid. To set the grid, press F9 to get to the miscellaneous
         menu. Then press G. The state changes from "MISC" to "GRID,"
         and a prompt appears asking if you want to change the grid
         origin (the origin is a point which the grid goes through
         and other grid points are calculated from). The grid origin
         is initially set to be the top left corner of the initial
         frame, but it can be set to any on-screen point. (Note:
         Changing the frame does NOT change the grid origin.) If the
         current grid origin is satisfactory, press any key except Y
         or Esc. If you want to change the grid origin, press Y. A
         prompt appears (if "H+" is toggled): "Move then F3 to set
         grid origin," and a dotted line will be drawn from the
         current grid origin to the cursor. Move the cursor to a new
         grid origin (the dotted line will follow) and press F3. (Esc
         backs out to the prompt asking if you want to change the
         grid origin.)
           After you have established the grid origin (either by
         setting it or accepting the old one), a grid menu appears.
         The top line of this menu shows the grid parameters that you
         can change (the spacing of the grid, its form, and its
         color), and the word "Keep". The second line lists the

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         current parameters.

         21.2.1 CHANGING THE SPACING OF THE GRID

           To change the spacing of the grid, press S. A prompt
         appears, showing the current horizontal spacing of the grid
         in the current units (i.e., pixels, inches, etc.) and
         requesting that you enter a new horizontal spacing. (The
         initial spacing is one inch by one inch.) If the horizontal
         spacing is satisfactory, press Enter. If you want to change
         it, key in a new spacing in the current unit and then press
         Enter. (Pressing Esc backs out to the grid menu.)
           A new prompt appears, asking if you want square spacing.
         (Square spacing means that the distance in the horizontal
         and vertical direction are the same.) If you answer Y, the
         vertical spacing is calculated to be square, and the grid
         menu reappears with the new spacing in the second line. If
         you press any other key (except Esc), a prompt appears
         showing the current vertical spacing in the current unit,
         and requesting that you enter a new vertical spacing. Press
         Enter if the current vertical spacing is acceptable, or key
         in a new vertical spacing and press Enter. The grid menu
         reappears with the new horizontal and vertical spacings on
         the second line.

         21.2.2. CHANGING THE FORM OF THE GRID

           The grid can be invisible (its initial form), or it can
         show as dots on the screen at each grid point or as
         horizontal and vertical dotted lines intersecting at each
         grid point (mesh). To change the form of the grid, while in
         the grid menu, press F. A grid form menu appears. If you
         want the grid to be invisible, press N (for "None"). If you
         want the grid to appear as dots, press D. If you want the
         grid to appear as a mesh, press M. The grid menu reappears
         with the new form on the second line. Pressing Esc backs out
         to the grid menu with no change in form.

         21.2.3. CHANGING THE COLOR OF THE GRID

           The color of a visible grid can be any of four colors. To
         change the color of the grid, while at the grid menu, press
         C. A grid color menu appears. If you want the grid to show
         in the background color (sometimes useful with a template),
         press B. If you want the grid to show in the foreground
         color (the color in which curves and endpoints are drawn),
         press F. If you want the grid to be shown in one of the two
         CGA template colors, press 1 or 2. (For EGA and VGA there
         are more than two template colors, other than the
         background, pressing 1 or 2 just uses different reasonable
         colors.) The initial color is template1. The grid menu will
         reappear with the new color indicated. Esc backs out to the
         grid menu with no changes.

         21.2.4. SAVING THE GRID PARAMETERS

           To save altered grid parameters (including a new grid
         origin), press K (for "Keep") or Enter. The entered grid
         parameters become the current ones, the screen is redrawn
         with the new grid (even if invisible), and the state returns

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         to "Free."
           If you press Esc while on the grid menu, any changes to
         the grid (including a new grid origin) are NOT saved, the
         state returns to "MISC," and the miscellaneous menu
         reappears.
           The current grid parameters are saved with the current
         drawing (see Section 19.2), so when you retrieve a drawing,
         the grid is reset to that associated with the drawing.

         21.3. USING THE GRID

           The grid's main purpose is to restrict cursor movements to
         the grid points. To toggle on the snap-to grid, press G. The
         cursor moves to the nearest grid point (visible or
         invisible). If the status box is on, the third indicator
         from the left changes to "G." While the snap-to grid toggle
         is on, the cursor moves ONLY to grid points. Pressing a
         cursor key moves the cursor to the next grid point in the
         appropriate direction. Note: At high magnifications and
         large grid settings all of the grid points can be off-
         screen; the snap-to grid is automatically toggled off if you
         scroll to such a screen. The fast cursor speed toggle (Ins)
         and the internal unit movement toggle (I) have no effect
         while the snap-to grid is toggled on, except to change the
         cursor movements when the snap-to grid is toggled off again.
           While the snap-to grid is toggled on, the cursor will not
         move in any direction beyond the grid point closest to the
         edge of the screen in that direction. If you move the cursor
         off the grid by cursor movements not tied to the grid
         (finding endpoints, going to frame corners, etc.),
         PictureThis will check your position at the END of the
         movement, and automatically toggle the snap-to grid OFF if
         the cursor is not on a grid point.
           To toggle the snap-to grid off, press G again.

         22. CHANGING THE FRAME AND SCALING THE DRAWING

           The size and shape of the rectangular frame determines
         which portion of your drawing is printed (and shown on the
         Quickshow screen). This frame can be changed at any time.
         The scale of the frame in "real-world" coordinates can also
         be changed. This means that you can set the width or height
         of the frame to represent a different size in the current
         unit. A frame that is 8 inches wide can be set to 4 inches
         wide. It will still look the same on the screen, but moving
         an "inch" on the screen will move the cursor twice as far as
         before.

         22.1. CHANGING THE FRAME

           To change the frame (only when in the state "FREE"), move
         the cursor to the desired position for any corner of the new
         frame (unless you want the default frame (see below)) and
         press F. The state becomes "FRAME," and a prompt appears
         asking if you would like the default frame. (The default
         frame is the initial frame when PictureThis is started. It
         is as large as the 100% screen, and is in the middle of the
         50% screen.) If you press Esc, the state returns to "FREE"
         with no change to the frame. If you press Y, the current
         frame is erased, the default frame is drawn, and the state

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         returns to "FREE." If you press any other key, the old frame
         is erased, and a prompt (if "H+" is toggled) appears: "Move
         then F3 to set frame." Move the cursor to the diagonally
         opposite corner of your new frame. A dotted box follows the
         cursor. Notice that you can still use the Ctrl Home, Ctrl
         PgUp, etc., keys to jump to the corners of the old frame,
         even though it is not visible. When the new frame is
         satisfactory, press F3. The new frame is established; the
         state returns to "FREE." If the current position box is
         toggled on, the numbers in it will change, since the
         position is measured from the frame origin (top or bottom
         left corner of the frame). Pressing Esc while changing the
         frame returns the old frame and returns the state to "FREE."
         Note that if you want to fill a standard 8-1/2" by 11" page,
         make your frame 8" by 10-1/2"  (to account for .25 inch
         margins on all sides), otherwise if you use the default EPS
         settings, your drawing will print on 4 pages (3 probably
         blank). The file STANDARD.DRW can be imported; it has a 8"
         by 10-1/2" frame and a margin at a standard indentation from
         the frame.
           Changing the frame does NOT change the drawing scale: the
         distance on the screen that represented an inch before the
         frame change will still represent an inch. To change the
         drawing scale, see Section 22.2.
           The frame is saved with a drawing (see Section 19.2), so
         if you retrieve a drawing, the frame changes to that saved
         with the drawing.

         22.2. SCALING THE DRAWING

           To change the scale of the drawing, press F9 to see the
         miscellaneous menu. The state becomes "MISC." Then press S.
         A menu appears, asking you to choose whether you want to set
         the horizontal or vertical frame size. (You only can scale
         one of these; the other is scaled proportionally.) After you
         press H or V to choose which frame dimension you want to
         scale, a prompt appears showing the current frame size (in
         the chosen direction and in the current units (inches are
         used if the current units are pixels)) and requests that you
         enter a new frame size (in the current units). If you are
         satisfied with the current frame dimension, press Enter; the
         "FREE" state returns. If you want to change the frame size,
         key in a new size and press Enter. (If you enter an illegal
         number, you are given another chance.) Another prompt
         appears, asking if you want to scale the line weights. If
         you answer Y, the line weights change in proportion to the
         difference between the previous size and the new size. For
         example, if the previous frame width was 8 inches, and you
         change it to 4 inches, a 10 point curve changes to a 5 point
         curve. It looks exactly as it did before on the Quickshow
         screen. (The frame now represents 4 inches, so 5 point
         curves now appear the same as 10 point curves did before.)
         If you press any other key, the line weights do not change.
         In the above example, the curves now appear twice as thick
         on the Quickshow screen.
           You should NOT change the scale of the drawing
         frivolously. The only GOOD reason to change the scale is to
         enable you to work on a drawing which you need to be a
         specific size, in units that represent that specific size.
         If your final drawing is to be 5 inches wide, and you have

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         specific measurements for parts of your drawing, it is
         convenient to set the frame size to 5 inches wide. Of
         course, an inch on the screen will be larger than a real
         inch unless you have a very small screen or unless the frame
         is smaller than the 100% screen's width. (The initial frame
         is 8 inches wide and goes all the way across a screen which
         is typically about 8 inches wide, so an inch on the 100%
         screen represents an inch on the drawing.) If you change the
         scale in the middle of a drawing, two endpoints that were a
         certain distance apart will now be a DIFFERENT distance
         apart. It is generally best to change the scale BEFORE you
         begin a drawing, if at all.
           You CANNOT change the scale of the drawing if it contains
         any text. You MUST change the scale BEFORE any text is
         entered. (If you have deleted all text blocks, you can't
         change the scale unless you save the drawing and bring it in
         again.) For drawings with text, often it is important to
         scale a drawing to the final size with this operation,
         rather than scale it when writing its EPS file. This is
         because the fonts then will be the specified size, rather
         than a scaled size (however, for some drawings, EPS-scaling
         is desirable). So when using text, set your frame to the
         appropriate size and scale your drawing BEFORE you actually
         begin drawing.
           When you change the drawing's scale, the grid changes in
         appearance, but it represents the same distance between grid
         points.
           Scaling the drawing is not the only way to change the size
         of the final output. When you create a PostScript file for
         the drawing (see Section 19.6), the default size is
         determined from the drawing scale and frame size, but you
         can change the size as you wish.
           When you save a drawing (see Section 19.2), the frame and
         drawing scale are saved with it. When you retrieve a
         drawing, the drawing brings this information with it.

         23. NOTING POINTS AND MEASURING DISTANCES

           Sometimes it is useful to mark a point on the screen to
         which you want to return later, but the point is not an
         endpoint. And sometimes it is useful to be able to measure
         the distance between two arbitrary points or to move to a
         position that is a certain proportion of the distance
         between two points. PictureThis has two facilities to help.

         23.1. NOTED POINTS

           To "note" a point to which you can return later, move the
         cursor to the point and press N. A small cross appears at
         the cursor's position (you must to move the cursor to see
         the cross). Up to 25 points can be noted. To return to a
         noted point, press (simultaneously) Shift and Del. The
         cursor jumps to the nearest noted point. You then can jump
         to other noted points using Space, +, and/or -, just as when
         you are finding endpoints. Pressing Esc backs out to your
         original cursor position. Pressing Enter stops the cursor at
         the noted point it is on. Any other key stops at the noted
         point AND carries out whatever operation the key would
         normally carry out (e.g., F1 sets an endpoint).
           To erase an individual noted point, move the cursor to the

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         noted point (as above) and press N again. The noted point is
         erased. To erase ALL currently noted points, press 0 (zero;
         NOT on the numeric keypad). A prompt appears, asking if you
         want to erase all the noted points. Answer Y if you want to
         erase all noted points, or press any other key if you do not
         want to erase all noted points.
           Noted points are saved with drawings, and they are
         retrieved with drawings.

         23.2. MEASURING DISTANCES

           The current position box and (especially) the relative
         position box give you information about distances when you
         are drawing curves, moving objects, etc. Sometimes you need
         this information when you are performing an operation which
         doesn't register on the relative position box, such as
         noting points. Or you might like to move to the midpoint
         between two arbitrary points without doing any calculations.
         To perform these operations, while in the "FREE" state, move
         the cursor to the point you want to measure from (the
         "initial point") and press M. Now move the cursor; a dotted
         line follows. If you have the relative position box toggled
         on, the horizontal and vertical differences, the distance,
         and the angle from the point at which you pressed M all are
         shown. When you reach the point to which you want to measure
         (the "measuring point"), press F3. A prompt appears: the
         first line states the current percentage distance from the
         first point; the second line requests that you enter a
         percentage distance. If you press Enter, the current
         percentage is used; or you may key in a different
         percentage. The cursor moves to the percentage distance
         "between" the two points, and the percentage is saved for
         use the next time you measure. For example, 100% leaves the
         cursor at its position when F3 is pressed; 50% moves the
         cursor half way between the two points. Percentages greater
         than 100 are legal. For example, 200% moves the cursor along
         the line from the initial point to the measuring point twice
         as far as the measuring point. Negative percentages are also
         legal. For example, -100% moves the cursor in the OPPOSITE
         direction from the measuring point, on the same line, the
         same distance as the first point is from the measuring
         point. Try it. If the cursor would end up off the screen,
         you hear a beep, see an error message (if toggled on), and
         get another chance to enter a percentage. Pressing Esc gives
         you another chance to set the measuring point. If the cursor
         is moved successfully, the state returns to "FREE," and the
         dotted line is erased.

         24. ASPECT RATIO

           Pixels on a typical CGA and EGA screen are not square. The
         ratio of the height to the width of a pixel is usually about
         1.20 to 1 for CGA, 1.37 to 1 for EGA, and 1 to 1 for VGA.
         This ratio is called the aspect ratio. The initial aspect
         ratio for PictureThis is set to 1.20 for CGA, 1.37 for EGA,
         and 1 for VGA. Some screens are adjusted (and some are user-
         adjustable) to have different aspect ratios. If your circles
         or squares drawn with PictureThis are not the proper shape,
         then your screen's aspect ratio is not the default for the
         current screen mode. Not only will your circles and squares

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         appear distorted on the screen, but also the PostScript
         output will be distorted in relation to the screen
         representation. To reset the aspect ratio, press F9 to
         access the miscellaneous menu and change the state to
         "MISC." Then press A. A menu appears in which you can choose
         to set the aspect ratio by cursor movement or direct entry.
         The first time you perform the operation, you should set it
         by cursor movement, to determine the correct aspect ratio
         for your screen. To do this, press C. The screen shows a
         large oval with a rectangle around it. The current aspect
         ratio appears in a small box in the bottom left corner. If
         the oval is indeed a circle, and the rectangle is square
         (you can measure to be sure), the current aspect ratio is
         correct for your screen. Otherwise, adjust the aspect ratio
         by moving the cursor at the top of the oval either up or
         down. The oval and rectangle are adjusted via the cursor
         movement, and the aspect ratio changes. When the oval is a
         true circle, and the rectangle is a square, note the aspect
         ratio in the box and press F3. Alternately, you can enter
         the correct aspect ratio (if you know it) by pressing D at
         the menu. You see a prompt informing you of the current
         aspect ratio and asking you to enter a new one.
           After you have set the aspect ratio by either method, a
         prompt asks if you want the aspect ratio saved in the
         configuration file (PICTHIS.CFG) which is read when you run
         PictureThis. If you want the aspect ratio automatically set
         to the new value when you start PictureThis, answer Y;
         otherwise, press another key. This saved aspect ratio is
         used every time that you start PictureThis UNLESS you change
         to a different screen mode; when a different screen mode is
         selected, the default aspect ratio for that mode is used and
         you will have to reset the aspect ratio if it is wrong.

         25. VIEWSCREEN, PALETTE, AND SCREEN TOGGLES

           There are several ways to manipulate the appearance of the
         PictureThis screen. These include the viewscreen, changing
         the palette, and various screen toggles.

         25.1. VIEWSCREEN

           To view the entire drawing at any magnification WITHOUT
         the endpoints and frame showing, press V. To return to the
         drawing screen, press Esc. It is not possible to draw on the
         viewscreen: there's no cursor! The viewscreen is NOT clipped
         at the frame; you can scroll and "zoom" the viewscreen (see
         Section 6). The template shows on the viewscreen, but it can
         be toggled off by pressing T (press T again to restore the
         template). The main use of the viewscreen is to check how
         full the PictureThis curve space is (see Section 31.2).
         Another use is for low-resolution screen "dumps" (say, to a
         dot-matrix printer) of a drawing in progress.
           Drawings can be saved and retrieved while on the
         viewscreen (see Sections 19.1 and 19.2).

         25.2. CHANGING THE PALETTE

           In CGA mode, you might prefer to use PictureThis with a
         screen palette other than the default. Press F9 to see the
         miscellaneous menu. Then press P. A palette menu appears,

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         showing the current palette number (the initial setting is
         1). For the default palette (gray, magenta, cyan), press 1.
         For the second palette (brown, red, green), press 2. For the
         third palette (gray, red, blue), press 3. (Use the main
         keyboard number keys.)
           For the corresponding palettes at high intensity, press
         the appropriate number keys simultaneously with the Shift
         key. Some EGA and VGA video boards and monitors don't show
         the CGA palettes as described above; you'll need to
         experiment to determine which palettes are best with your
         equipment. EGA and VGA mode palettes cannot be changed.

         25.3. SCREEN TOGGLES

           To erase ALL curves comprising the current drawing
         IRRETRIEVABLY (unless you have saved the drawing previously,
         as described in Section 19.2), press C. A prompt appears
         ("Clear current drawing? (Y/N)"). If you DO want to erase
         the current drawing press Y. If you DON'T want to erase the
         drawing, press any other key. If you have set any text
         parameters, or made any margins other than the default
         margin, you will be asked if you want to erase these also.
           To redraw the current screen, press D. This redraws the
         screen without making changes to the drawing. This is useful
         when unattractive "garbage" appears on the screen. Most
         PictureThis operations leave no garbage, but sometimes extra
         or missing dots result from an operation (especially when
         manipulating objects). "Garbage" also can appear when the
         position boxes (see Section 20) and/or the status box (see
         Section 4.3) is on the screen and a curve is drawn through
         parts of them. Then, if the box is removed, parts of the
         curve can disappear.
           On the 50% screen, the template is "compressed" to fit the
         available space: one pixel on the 50% screen corresponds to
         four pixels on the 100% screen. The compression algorithm
         used by PictureThis is simple: the 100% screen is divided
         into boxes with four pixels each (two across by two down),
         and the color of ONE pixel in each box is used to determine
         the color of the pixel on the 50% screen which corresponds
         to that box. You can choose the position (top left, top
         right, bottom left, or bottom right) of the pixel in each
         box used to determining colors during compression by
         repeatedly pressing D AT THE 50% SCREEN. Following each of
         four successive key presses, the screen is redrawn with a
         different "compression color pixel" position used for
         producing the template. Since there are four possible
         positions for the "compression color pixel" used, four
         successive presses of the D key return the template to the
         way it started. If you subsequently change to another
         magnification and then return, the template appears the way
         it did when you left the 50% screen. Being able to choose
         between the differently compressed templates is useful if
         some features appear clearly only on some of them.
           To remove the drawing TEMPORARILY, press R. This redraws
         the screen with the curves removed, allowing a better view
         of the template. To restore the drawing, press R again. The
         R key WON'T remove or restore a drawing on the viewscreen,
         but you can press R while the viewscreen is on so that
         curves don't show when you return to the drawing screen.
           To remove the template TEMPORARILY, press T. To restore

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         the template, press T again. This works on the drawing
         screen AND on the viewscreen.
           Note: All of the features described in this section
         require redrawing of the screen, so they are possible ONLY
         in the "FREE" state.

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