(You may want to pick a smaller font, or turn word-wrap off in your OS/2 system editor if this file is hard to read.) WINDOW DEVICE COMMANDS --------------------------------------------------------------------------- In Liberty BASIC windows are treated like files, and we can refer to anything in this class as a BASIC 'Device'. To open a window we use the OPEN statement, and to close the window we use the CLOSE statement. To control the window we 'print' to it, just as we would print to a file. The commands are sent as strings to the device. As a simple example, here we will open a graphics window, center a pen (like a Logo turtle), and draw a simple spiral. We will then pause by opening a simple dialog. When you confirm the exit, we will close the window: button #graph, Exit, [exit], LR, 5, 5 'window will have a button open "Example" for graphics as #graph 'open graphics window print #graph, "up" 'make sure pen is up print #graph, "home" 'center the pen print #graph, "down" 'make sure pen is down for index = 1 to 30 'draw 30 spiral segments print #graph, "go "; index 'go foreward 'index' places print #graph, "turn 118" 'turn 118 degrees next index 'loop back 30 times print #graph, "flush" 'make the image 'stick' [inputLoop] input b$ : goto [inputLoop] 'wait for button press [exit] confirm "Close Window?"; answer$ 'dialog to confirm exit if answer$ = "no" then [inputLoop] 'if answer$ = "no" loop back close #graph end WINDOW TYPES: ------------------------------------------------------------------------- Liberty BASIC provides different kinds of window types, to which you can add as many buttons as needed. Here's a list of the different kinds: graphics - open a graphic window graphics_fs - open a graphic window full screen (size of the screen) graphics_nsb - open a graphic window w/no scroll bars graphics_fs_nsb - open a graphic window full screen, w/no scroll bars dialog - open a dialog box window The way that you would specify what kind of window to open would be as follows: open "Window Title" for type as #handle where type would be one of the above descriptors. CONTROLLING SIZE AND PLACEMENT OF WINDOWS ---------------------------------------------------------------------------- The size and placement of any window can be easily determined before it is opened in Liberty BASIC (except for any window type with a _fs in its descriptor). If you do choose not to specify the size and placement of the windows that your programs open, Liberty BASIC will pick default sizes. However, for effect it is often best that you exercise control over this matter. There are four special variables that you can set to select the size and placement of your windows, whether they be text, graphics, or spreadsheet: UpperLeftX, UpperLeftY, WindowWidth, and WindowHeight Set UpperLeftX and UpperLeftY to the number of pixels from the upper-left corner (IN OS/2, FROM THE LOWER LEFT-CORNER) of the screen to position the window. Often determining the distance from the upper-left corner of the screen is not as important as determining the size of the window. Set WindowWidth and WindowHeight to the number of pixels wide and high that you want the window to be when you open it. Once you have determined the size and placement of your window, then open it. Here is an example: [openStatus] UpperLeftX = 32 UpperLeftY = 32 WindowWidth = 190 WindowHeight = 160 open "Status Window" for dialog as #stats This will open a window 32 pixels from the corner of the screen, and with a width of 190 pixels, and a height of 160 pixels. BUTTONS --------------------------------------------------------------------------- Buttons are easily added to Liberty BASIC windows. The format is simple: button #handle, "Label", [branchLabel], corner, distX, distY open "A Window!" for graphics as #handle By placing at least one button statement before the open statement, we can add button(s) to the window. Let's examine each part of the button statement: #handle - This needs to be the same as the handle of the window. "Label" - This is the text displayed on the button. If only one word is used, then the quotes are optional. [branchLabel] - This controls what the button does. When the user clicks on the button, then program execution continues at [branchLabel] as if the program had encountered a goto [branchLabel] statement. corner, distX, distY - Corner is used to indicate which corner of the window to anchor the button to. DistX and distY specify how far from that corner in x and y to place the button. The following values are permitted for corner: UL - Upper Left Corner UR - Upper Right Corner LL - Lower Left Corner LR - Lower Right Corner Whenever a running program sits idle at an input statement, it is possible for a button-press to effect some action. If any button is pressed while the program is busy doing something else, the button-press will be buffered and read later when an input statement is encountered. GRAPHICS --------------------------------------------------------------------------------------- (IN THIS BETA VERSION, NOT ALL OF THE LISTED COMMANDS ARE COMPLETELY SUPPORTED) Because graphics can involve many detailed drawing operations, Liberty BASIC does not force you to use just one print # statement for each drawing task. If you want to perform several operations you can use a single line for each as such: print #handle, "cls" print #handle, "fill black" print #handle, "pen up" print #handle, "home" print #handle, "pen down" print #handle, "north" print #handle, "go 50" Or if you prefer: print #handle, "cls ; fill black ; pen up ; home ; pen down ; north ; go 50" will work just as well, and executes slightly faster. print #handle, "\text" Display text at the current pen position. Each additional \ in the text will cause a carraige return and line feed. Take for example, print #handle, "\text1\text2" will cause text1 to be printed at the pen position, and then text2 will be displayed directly under text1. print #handle, "cls" Clear the graphics window to white, erasing all drawn elements print #handle, "fill COLOR" Fill the window with COLOR. For a list of accepted colors see the color command below. print #handle, "up" Lift the pen up. All go or goto commands will now only move the pen to its new position without drawing. Any other drawing commands will simply be ignored until the pen is put back down. print #handle, "down" Just the opposite of up. This command reactivates the drawing process. print #handle, "color COLOR" Set the pen's color to be COLOR. Here is a list of valid colors (in alphabetical order): black, blue, brown, cyan, darkblue, darkcyan, darkgray, darkgreen, darkpink, darkred, green, lightgray, palegray, pink, red, white, yellow print #handle, "backcolor COLOR" This command sets the color used when drawn figures are filled with a color. The same colors are available as with the color command above. print #handle, "goto X Y" Move the pen to position X Y. Draw if the pen is down. print #handle, "place X Y" Position the pen at X Y. Do not draw even if the pen is down. print #handle, "go D" Go foreward D distance from the current position, and going in the current direction. print #handle, "north" Set the current direction to 270 (north). Zero degrees points to the right (east), 90 points down (south), and 180 points left (west). print #handle, "turn A" Turn from the current direction using angle A and adding it to the current direction. A can be positive or negative. print #handle, "line X1 Y1 X2 Y2" Draw a line from point X1 Y1 to point X2 Y2. If the pen is up, then no line will be drawn, but the pen will be positioned at X2 Y2. print #handle, "posxy" Return the position of the pen in x, y. This command must be followed by: input #handle, xVar, yVar which will assign the pen's position to xVar & yVar print #handle, "size S" Set the size of the pen to S. The default is 1. This will affect the thickness of lines and figures plotted with most of the commands listed in this section. print #handle, "flush" This ensures that drawn graphics 'stick'. Make sure to issue this command at the end of a drawing sequence to ensure that when the window is resized or overlapped and redrawn, its image will be retained. To each group of drawn items that is terminated with flush, there is assigned a segment ID number. See segment below. print #handle, "print" Send the plotted image to the Windows Print Manager for output. print #handle, "font facename width height" Set the pen's font to the specified face, width and height. If an exact match cannot be found, then Liberty BASIC will try to find a close match, with size being of more prominance than face. print #handle, "circle r" Draw a circle with radius r at the current pen position. print #handle, "circlefilled r" Draw a circle with radius r, and filled with the color specified using the command backcolor (see above). print #handle, "box x y" Draw a box using the pen position as one corner, and x, y as the other corner. print #handle, "boxfilled x y" Draw a box using the pen position as one corner, and x, y as the other corner. Fill the box with the color specified using the command backcolor (see above). print #handle, "ellipse w h" Draw an ellipse at the pen position of width w and height h. print #handle, "ellipsefilled w h" Draw an ellipse at the pen position of width w and height h. Fill the ellipse with the color specified using the command backcolor (see above). print #handle, "segment" This causes the window to return the segment ID of the most recently flushed drawing segment. This segment ID can then be retrieved with an input #handle, varName and varName will contain the segment ID number. Segment ID numbers are useful for manipulating different parts of a drawing. For an example, see delsegment below. print #handle, "delsegment n" This causes the drawn segment identified as n to be removed from the window's list of drawn items. Then when the window is redrawn the deleted segment will not be included in the redraw. print #handle, "redraw" This will cause the window to redraw all flushed drawn segments. Any deleted segments will not be redrawn (see delsegment above). Any items drawn since the last flush will not be redrawn either, and will be lost. print #handle, "discard" This causes all drawn items since the last flush to be discarded, but does not not force an immediate redraw, so the items that have been discarded will still be displayed until a redraw (see above). print #handle, "trapclose branchLabel" (NOT SUPPORTED IN OS/2 v0.2 BETA) This will tell Liberty BASIC to continue execution of the program at branchLabel if the user double clicks on the system menu box or pulls down the system menu and selects close (see buttons1.bas example below). {Illustration was here} The trapclose code in buttons1.bas looks like this: open "This is a turtle graphics window!" for graphics_nsb as #1 print #1, "trapclose [quit]" [loop] ' stop and wait for buttons to be pressed input a$ goto [loop] And then the code that is executed when the window is closed looks like this: [quit] confirm "Do you want to quit Buttons?"; quit$ if quit$ = "no" then [loop] close #1 end Since this only works when the program is halted at an input statement, the special variable TrapClose permits detection of the window close when you are running a continuous loop that doesn't stop to get user input. As long as TrapClose <> "true", then the window has not been closed. Once it has been determined that TrapClose = "true", then it must be reset to "false" via the BASIC LET statement. See clock.bas for an example. print #handle, "when event branchLabel" This tells the window to process mouse events. These events occur when someone clicks, double-clicks, drags, or just moves the mouse inside of the graphics window. This provides a really simple mechanism for controlling flow of a program which uses the graphics window. For an example, see the program draw1.bas. Sending print #handle, "when leftButtonDown [startDraw]" to any graphics window will tell that window to force a goto [startDraw] when the mouse points inside of that window and someone press the left mouse button down. Whenever a mouse event does occur, Liberty BASIC places the x and y position of the mouse in the variables MouseX, and MouseY. The values will represent the number of pixels in x and y the mouse was from the upper left corner of the graphic window display pane. If the expression print #handle, "when event" is used, then trapping for that event is discontinued. It can however be reinstated at any time. Events that can be trapped: leftButtonDown - the left mouse button is now down leftButton Up - the left mouse button has been released leftButtonMove - the mouse moved while the left button is down leftButtonDouble - the left button has been double-clicked rightButtonDown - the right mouse button is now down rightButton Up - the right mouse button has been released rightButtonMove - the mouse moved while the right button is down rightButtonDouble - the right button has been double-clicked mouseMove - the mouse moved when no button was down PROGRAMMING DIALOG BOXES --------------------------------------------------------------------------------------- Using windows of type dialog, we can add several kinds of objects (called child windows) in addition to buttons and menus to our Liberty BASIC programs. These let us add functionality and visual appeal. Below are kinds of child windows we can add: LISTBOX --------------------------------------------------------------------------------------- Listboxes in Liberty BASIC can be added to any windows that are of type graphics, window, and dialog. They provide a list selection capability to your Liberty BASIC programs. You can control the contents, position, and size of the listbox, as well as where to transfer execution when an item is selected. The listbox is loaded with a collection of strings from a specified string array, and a reload command updates the contents of the listbox from the array when your program code changes the array. Here is the syntax: LISTBOX #handle.ext, array$(, [branchLabel], xPos, yPos, wide, high #handle.ext - The #handle part of this item needs to be the same as the handle of the window you are adding the listbox to. The .ext part needs to be unique so that you can send commands to the listbox and get information from it later. array$( - This is the name of the array (must be a string array) that contains the contents of the listbox. Be sure to load the array with strings before you open the window. If some time later you decide to change the contents of the listbox, simply change the contents of the array and send a reload command. [branchLabel] - This is the branch label where execution begins when the user selects an item from the listbox by double-clicking. Selection by only single clicking does not cause branching to occur. xPos & yPos - This is the distance in x and y (in pixels) of the listbox from the upper-left corner of the window. wide & high - This determines just how wide and high (in pixels) the listbox is. Here are the commands for listbox: print #handle.ext, "select string" Select the item the same as string and update the display. print #handle.ext, "selectindex i" Select the item at index position i and update the display. print #handle.ext, "selection?" Return the selected item. This must be followed by the statement: input #handle.ext, selected$ This will place the selected string into selected$. If there is no selected item, then selected$ will be a string of zero length (a null string). print #handle.ext, "reload" This will reload the listbox with the current contents of its array and will update the display. ' Sample program. Pick a contact status options$(0) = "Cold Contact Phone Call" options$(1) = "Send Literature" options$(2) = "Follow Up Call" options$(3) = "Send Promotional" options$(4) = "Final Call" listbox #status.list, options$(, [selectionMade], 5, 35, 250, 90 button #status, Continue, [selectionMade], UL, 5, 5 button #status, Cancel, [cancelStatusSelection], UR, 15, 5 WindowWidth = 270 : WindowHeight = 180 open "Select a contact status" for window as #status input r$ [selectionMade] print #status.list, "selection?" input #status.list, selection$ notice selection$ + " was chosen" close #status end [cancelStatusSelection] notice "Status selection cancelled" close #status end Control of the listbox in the sample program above is provided by printing commands to the listbox, just as with general window types in Liberty BASIC. We gave the listbox the handle #status.list, so to find out what was selected, we use the statement print #status.list, "selection?". Then we must perform an input, so we use input #status.list, selection$, and the selected item is placed into selection$. If the result is a string of length zero (a null string), this means that there is no item selected. COMBOBOX --------------------------------------------------------------------------------------- Comboboxes are a lot like listboxes, but they are designed to save space. Instead of showing an entire list of items, they show only the selected one. If you don't like the selection, then you click on its button (to the right), and a list appears. Then you can browse the possible selections, and pick one if so desired. When the selection is made, the new selection is displayed in place of the old. If you don't want to make a new selection, just click on the combobox's button again, and the list will disappear. Comboboxes in Liberty BASIC can be added to any windows that are of type graphics, window, and dialog. They provide a list selection capability to your Liberty BASIC programs. You can control the contents, position, and size of the combobox, as well as where to transfer execution when an item is selected. The combobox is loaded with a collection of strings from a specified string array, and a reload command updates the contents of the combobox from the array when your program code changes the array. Here is the syntax: COMBOBOX #handle.ext, array$(, [branchLabel], xPos, yPos, wide, high #handle.ext - The #handle part of this item needs to be the same as the handle of the window you are adding the listbox to. The .ext part needs to be unique so that you can send commands to the listbox and get information from it later. array$( - This is the name of the array (must be a string array) that contains the contents of the listbox. Be sure to load the array with strings before you open the window. If some time later you decide to change the contents of the listbox, simply change the contents of the array and send a reload command. [branchLabel] - This is the branch label where execution begins when the user selects an item from the listbox by double-clicking. Selection by only single clicking does not cause branching to occur. xPos & yPos - This is the distance in x and y (in pixels) of the listbox from the upper-left corner of the window. wide & high - This determines just how wide and high (in pixels) the listbox is. Height refers to how far down the selection list reaches when the combobox's button is clicked, not to the size of the initial selection window. Here are the commands for combobox: print #handle.ext, "select string" Select the item the same as string and update the display. print #handle.ext, "selectindex i" Select the item at index position i and update the display. print #handle.ext, "selection?" Return the selected item. This must be followed by the statement: input #handle.ext, selected$ This will place the selected string into selected$. If there is no selected item, then selected$ will be a string of zero length (a null string). print #handle.ext, "reload" This will reload the listbox with the current contents of its array and will update the display. For a sample program, see the included file dialog3.bas. TEXTBOX --------------------------------------------------------------------------------------- The textbox command lets you add a single item, single line text entry/editor box to your windows. It is useful for generating forms in particular. The syntax for textbox is simply: TEXTBOX #handle.ext, xpos, ypos, wide, high #handle.ext - The #handle part must be the same as for the window you are adding the textbox to. The .ext part must be unique for the textbox. xpos & ypos - This is the position of the textbox in x and y from the upper- left corner of the window. wide & high - This is the width and height of the textbox in pixels. Textbox only understands two commands. These are: print #handle.ext, "a string" This sets the contents of the textbox to be "a string". print #handle.ext, "!contents?" This fetches the contents of the textbox. This must be followed by: input #handle.ext, varName$ The contents will be placed into varName$ ' sample program textbox #name.txt, 20, 10, 260, 25 button #name, "OK", [titleGraph], LR, 5, 0 WindowWidth = 350 : WindowHeight = 90 open "What do you want to name this graph?" for window_nf as #name print #name.txt, "untitled" [mainLoop] input wait$ [titleGraph] print #name.txt, "!contents?" input #name.txt, graphTitle$ notice "The title for your graph is: "; graphTitle$ close #name end STATICTEXT --------------------------------------------------------------------------------------- Statictext lets you place instructions or labels into your windows. This is most often used with a textbox to describe what to type into it. The syntax of this command is: STATICTEXT #handle, "string", xpos, ypos, wide, high #handle - This must be the same as the #handle of the window you are adding the statictext to. "string" - This is the text component of the statictext. xpos & ypos - This is the distance of the statictext in x and y (in pixels) from the upper-left corner of the screen. wide & high - This is the width and height of the statictext. You must specify enough width and height to accomodate the text in "string". 'sample program statictext #member, "Name", 10, 10, 40, 18 statictext #member, "Address", 10, 40, 70, 18 statictext #member, "City", 10, 70, 60, 18 statictext #member, "State", 10, 100, 50, 18 statictext #member, "Zip", 10, 130, 30, 18 textbox #member.name, 90, 10, 180, 25 textbox #member.address, 90, 40, 180, 25 textbox #member.city, 90, 70, 180, 25 textbox #member.state, 90, 100, 30, 25 textbox #member.zip, 90, 130, 100, 25 button #member, "&OK", [memberOK], UL, 10, 160 WindowWidth = 300 : WindowHeight = 230 open "Enter Member Info" for dialog as #member input r$ [memberOK] print #member.name, "!contents?" : input #member.name, name$ print #member.address, "!contents?" : input #member.address, address$ print #member.city, "!contents?" : input #member.city, city$ print #member.state, "!contents?" : input #member.state, state$ print #member.zip, "!contents?" : input #member.zip, zip$ cr$ = chr$(13) note$ = name$ + cr$ + address$ + cr$ + city$ + cr$ + state$ + cr$ + zip$ notice "Member Info" + cr$ + note$ close #member end