Lightpen Colour Graphic Software ================================ Lightpen Colour Graphic Software -------------------------------- The Lighten Colour-graphic Software pack enables the user to become a designer, whether it be of simple line drawings or of more complex diagrams. The colour fill facility establishes a unique and pleasing way for the user to represent graphically his inner artistic tendencies. Some of the features in this comprehensive pack include point plotting, line, square, triangle, circle, X,Y rulers, all of which are available with rubber banding facility. Introduction ------------ The RH Electronics Lightpen Colour Graphic program provides a totally new way of utilizing the extremely powerful graphic capabilities of the BBC Microcomputer. The program has been developed with the same care and thoughtfulness as with the Lightpen itself and accompanying software driver routines, by our software experts who know the Lightpen and interfacing techniques inside and out. Mode 2 has become the most popular format for graphical representation on the BBC Microcomputer, as it provides the highest resolution containing all sixteen colours, it was therefore considered the best mode for this kind of application. After a few hours of use you will wonder how you ever managed without the Lightpen Colour Graphic Program. Gone are the days of typing lines and lines of Basic, hammering away at cursor control keys or fiddling with joysticks. The Lightpen goes straight to the desired point on the screen with the minimum of effort. An option is available within the program to enable drawing to any pixel, the smallest plottable point on the screen. One of the smallest microswitches in the world has been fitted in the nose of the pen to give a featherlike touch when signals are required to be sent to the computer. Hours and hours have already been enjoyed by our staff, during the program's development, using it to draw flow charts, circuit diagrams, exhibtion stand layouts, title pages for other programs, kitchen plans, dream houses, gardens, maps, people, animals and numerous other things. One picture has already been used for the front cover of a magazine. We now have pleasure in passing this privilege on to you. Many thanks to the authors of the program (Jay Myrdal and Igor Thomas) who provided most of the technical information for this manual. Auto-Calibrate -------------- After this program has loaded, press the tip of the Lightpen against the small white line, at the centre of the screen, until a continuous high-pitched note is heard. After approximately three seconds, a number will appear. The Lightpen is now calibrated to suit your system. The display will last a few seconds longer, in case you wish to change the calibration number for any reason. For a positive number press one of the keys 0 to 9. For a negative number hold the shift key down when pressing one of the numbered keys. We now introduce two new words for those not fully conversant with computing terms, "TOGGLE" and "INTERLACE". The word toggle will be found throughout this manual and is intended to mean "to alternate two different states by using the same action", e.g. a push button light switch, press for on, press for off. Interlace is a word used to describe how part of a TV picture is generated. Here we are interested in the effect produced on the screen by interlace, not so much what causes it. If you are using a colour monitor or television set, the screen may flicker uncomfortably, usually when interlace is on. The Auto-calibrate program toggles the interlace every time it is run. To toggle interlace re-run the program by pressing the ESCAPE key. If the BREAK key is pressed, the program will be lost and will need re-loading. Once the light pen is setup and the word GRAPHIC covers the screen in different colours re-start your tape recorder and wait for the main program to load. Colour Graphic Program (Menu Operation) --------------------------------------- After the program has loaded the background colour will change to cyan and a menu will appear along the bottom of the screen. Immediately, most of the options will be obvious, however some will not. After reading the following instructions and trying some of them out all the characters will soon become familiar. Try pointing the Lightpen at, for example, the rectangle, third from the left. It should change from blue to white. If you press the nose of the pen gently against the screen the background of the rectangle should change from magenta to cyan. The rectangle has now been toggled on, and rectangles can be drawn on the screen by ploting just two points with the Lightpen. Position the cursor by pointing the pen at the desired place on the screen and press gently. Then plot a second point somewhere else using the same method. A rectangle will appear in red. The rectangle at this stage is what we call 'soft drawn', it can still be erased if desired. The red rectangle will change to black and will be 'fixed', when you select 'Move' or go on to draw another shape. Repeat this operation on some of the other characters. Not all of them will respond exactly as you expect. Summary Of Menu Select And Toggle Options ----------------------------------------- Forty different options are available from two menus which have twenty on each. Menu 'a' contains shape and mode selection options. Menu 'b' contains colour selection options and can be thought of as a palette to dip the Lightpen in. (Menu 'a') . \ 0 T S R C M a D ___________________________________________________________ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 (Menu 'b') 0 1 2 3 4 5 6 7 8 9 10 P A I N T ... M b D ___________________________________________________________ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Whichever menu is selected you can change to the other one by pressing the Lightpen against the character at position 19. You will notice from the following tables that all the menu options are simultaneously duplicated on one or more of the keyboard keys. There are also some keyboard options not available on either menu. K/B Menu 'a' Position Menu 'b' ___ ________ ________ ________ f0 Paint points 1 Black f1 Paint lines 2 Red f2 Paint squares 3 Green f3 Paint triangles 4 Yellow f4 Paint circles 5 Blue f5 Paint text 6 Magenta f6 Area colour fill 7 Cyan f7 Toggle music 8 White f8 Toggle soft paint 9 Flashing Black/White f9 Toggle rubberband 10 Flashing Red/Cyan 1 Toggle cursor 11 Flashing Green/Magenta 2 Toggle Y ruler 12 Flashing Yellow/Blue * 3 Toggle X ruler 13 Flashing Blue/Yellow * 4 Cursor left 14 Flashing Magenta/Green * 5 Cursor up 15 Flashing Cyan/Red * 6 Cursor down 16 Flashing White/Black * 7 Cursor right 17 Toggle dotted lines 8 Move 18 Move 9 Toggle menu 19 Toggle menu 0 Delete 20 Delete * See section on Paint Control Key Options ------------------- The control key options are only available on the keyboard. Hold the control key along with the desired key when selecting an option. CTRL-N Clear screen to cyan and select menu a CTRL-L Load picture file from cassette CTRL-S Save current picture file CTRL-C Catalogue cassette CTRL-_ Reset trim calibration to 0 CTRL-CAPS LOCK Reset trim calibration to 0 Left And Right Handed Keyboard Options -------------------------------------- Q or Cursor left key Move cursor left W or Cursor right key Move cursor right A or Cursor up key Move cursor up S or Cursor down key Move cursor down Space Move to new point TAB or Return key Toggle menu Z or Delete key Delete last entry Copy or Shift Lock key Duplicate pen switch Details Of Program Operation ---------------------------- Immediately after the program has loaded certain menu options are already selected, appearing on the menu line with a cyan background. The startup mode of operation is called the 'default' mode. You will notice a double black line above the menu. This space is also readable as menu area, by the Lightpen. Because there is less light around the edges of the screen the extra light radiated ensures correct menu operation when using the Lightpen. There is an invisible 'no man's land', one character height, along the top of the upper black line. This area is not readable by the Lightpen, it acts as a buffer between the menu and the graphics area. You can however enter this area with the cursor control keys, the shift function or with colour fill. The options selected in default mode are as follows: Menu 'a' selected Paint lines Music on Soft paint on Cursor on The colour black is selected on menu 'b', although not displayed. Any of the other options may be selected before, and at any time during creation of a picture. Menu 'a' -------- . \ 0 (Positions 1 2 3 4 & 5) When each of the above options are selected, the corresponding shape will be created (in the current colour) on the screen. The number of points necessary to plot each shape is indicated in brackets. . Draw dots (1 point) \ Draw lines (2 points) Draw triangles (3 points) Draw rectangles (2 points) 0 Draw circles (2 points) T (Position 6) -------------- This is Text option. When selected the graphics cursor is replaced by a text cursor. It appears as two parallel horizontal lines which can be moved and 'fixed' to any point on the screen. Once 'fixed', text can be entered from the keyboard (in the current colour) starting at the text cursor position. Pressing the RETURN key will terminate the current line of text. The text cursor then returns to the screen, where it is once again available for moving and entering text. To exit from text mode, select another draw option from the menu. (Position 7) -------------- When selected, this option enables you to fill an area in the current colour. The area to be colour filled should be surrounded by a continuous boundary. If a gap exists then the colour will leak out and fill an unwanted area. You may change to another colour at any time, by selecting menu 'b' and then selecting the new colour. The fill option remains until another draw option is selected. To fill a shape, position the Lightpen cursor anywhere inside the selected area and simply press the nose of the Lightpen against the screen. The area will now fill to the current colour. If you have difficulty in positioning the Lightpen cursor in, for example, a very small shape, another useful function is available; the 'Shift' function. The 'shift' function enables fine control over the movement of the Lightpen cursor. When the SHIFT key is held down during a Move and 'fix' operation the Lightpen cursor will move one point at a time instead of the normal eight. (Position 8) --------------- When selected, different sounds will be produced every time points and shapes are drawn on the screen and when menu options are toggled. This option has no other effect than to switch sound on or off. S (Position 9) -------------- When the program is first loaded, Soft paint is selected (the character 'S' at position 9 has a cyan background). You may toggle Hard paint on by toggling Soft paint off and vice versa. Both operations are carried out at the same menu location. Hard paint allows you to draw shapes, lines or dots directly to the screen in the current colour. Soft paint sketches the particular shape, line or dot on the screen temporarily, in a contrasting colour. When you are satisfied that it is in the correct position, it may be entered in the current colour by moving to a new position, selecting a new shape or re-selecting the current shape. The major difference between hard and soft painting is when you want to delete the last shape, line or dot drawn. Deleting, when hard paint is selected, can be carried back to the last three positions. This, however, leaves behind a cyan coloured hole in anything bisected during deletion. Deleting when soft paint is selected overcomes the above problem. The shape is only a temporary sketch and will leave no trace behind it when removed. You are limited to deleting only the last shape, line, or dot drawn when in soft paint. R (Position 10) --------------- When Rubberbanding is selected, it allows you to see the shape before it is drawn onto the screen. This option can be toggled on or off in the usual manner. Imagine a rubberband around three nails in a piece of wood. One of the nails is lifted out to slightly above the surface and moved around (hence Rubberbanding). There is no easy way of describing the exact effect when using this option. Therefore, I suggest you toggle rubberbanding on and try it in conjunction with options one to five. Once selected there is no need to press the Lightpen against the screen. Rubberbands follow the tip of the Lightpen automatically. You will find some shapes apparently disappear when a rubberband is placed over the top of them, they may also appear incomplete when partly covered. This is quite normal when Soft paint is currently selected at the same time. Everything will right itself when the currently rubberbanded shape is finally drawn onto the screen. In fact, we normally have rubberband on when using the program. C (Position 11) --------------- This option simply toggles the Lightpen cursor on or off. With the Lightpen cursor off and Rubberbanding on, a small rubber point will appear on the screen at the tip of the Lightpen. This is often found to be more useful than the normal Lightpen cursor, especially when working in fine detail. When saving a picture on cassette the cursor is automatically turned off, so that it will not appear on the picture when reloaded. (Positions 12 & 13) --------------------- In order to guide the Lightpen and line up different shapes, vertical and horizontal rules are available. They may be displayed on the screen separately or together. They may be toggled on or off whenever needed. The vertical ruler is at position 12 and the horizontal ruler is at position 13. Neither one can be drawn onto the screen, they are for guidance only. You will notice that cursor movement becomes slower when the rulers are selected, also the Lightpen may be guided more easily into the darker areas of the screen, such as solid red or black areas. This is afforded by the illumination of the rulers. (Positions 14, 15, 16 & 17) -------------------------------- When the Lightpen reaches the edge of the screen, it is unable to move the cursor any further. Lines and shapes can however be drawn to imaginary points off the screen. The cursor arrows allow this to be done. By pressing the Lightpen against the appropriate arrow on the menu, the cursor will move one point at a time, as opposed to the normal eight, in the selected direction. The keyboard cursor control keys may also be used, as can the Q, W, A and S keys. The keyboard's auto-repeat action may prove useful. M (Position 18) --------------- Move can be thought of as moving a paintbrush from the last point to a new one, still charged with the same coloured paint. Of course, if, in the mean time it has been dipped in a different colour then that new colour will be displayed on the screen, whether drawing shapes or filling areas. Move is performed as follows: Select Move on menu 'a' Point the Lightpen at the desired location on the screen then press gently and firmly to 'fix' the position (If Music is toggled on you will hear the draw sound as every point is created) This operation can be repeated at different locations all over the screen. You will notice whichever shape you are drawing wil be connected to the last point drawn unless Move is selected each time you move to a new position. a (Position 19) --------------- The option at this position is common to both menus. When lower case 'a' is displayed, menu 'a' is selected. When lower case 'b' is displayed, menu 'b' is selected. To toggle between the two menus, press the nose of the Lightpen against this position. The RETURN key may also be used to toggle menus. D (Position 20) --------------- The option at this position is common to both menus. When you wish to Delete a recently drawn shape press the Lightpen against position 20 on the menu. If music is toggled on you will hear the Delete last shape or Delete last point around. If you try to Delete farther backwards than is allowed you will hear an error bleep, however, this will not corrupt your picture. You may find that you cannot Delete as far back as you would like. This can be overcome by redrawing precisely over the unwanted shape and then Deleting it. Details on how many backward steps that can be taken, will be found in the section on Hard and Soft painting. Loading ------- CHAIN"" (RETURN) The first program on the tape is the Auto-Calibrate program. A message will appear to instruct you to stop the tape. If you cassette motor is controlled from the BBC Microcomputer, the tape will stop automatically. Loading ------- CHAIN"" (RETURN)