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Text File | 1991-01-08 | 21KB | 422 lines

Turbo and Microsoft C Mouse Routines - Release 1.0 -------------------------------------------------- Tue Jan 8, 1991. CONTENTS 1. What do these routines do? 2. How it works. 3. Variable and definition reference. 4. Function reference. 5. The test program. 6. Disclaimer and other stuff. 1. What do these routines do? ----------------------------- These routines will allow you to interface with the mouse driver in your programs. It works with Microsoft compatible mouse drivers (i.e. Logitech, PC Mouse, Dexxa, etc). The routines have the added feature of displaying a 'true' mouse cursor in text mode on an EGA or VGA by reprograming the font on the fly. The routines consist of several functions used to initialize, draw the cursor, and get mouse events (button presses). These routines do not handle drawing the mouse cursor in graphics mode, only text mode. If the routines detect the presense of an EGA/VGA adapter, it will use the 'true' mouse cursor, if not it will use a simple block cursor implemented by switch the foreground/background colors of the position the cursor is. 2. How it works. --------------- All character coordinates used by the mouse driver are zero based. I.e. in 80x25 text mode the range of values for x and y are 0-79 and 0-24. The routines should work in all memory models. The routines first check for the presense of a mouse driver, and if none is present, they return without doing anything. It is safe to call the routines such as MOUhide() and others even if a mouse is not installed, they will simply return. Once the presense of a Microsoft compatible mouse driver is verified, the routine checks the presense of DESQview and an EGA/VGA. If an EGA/VGA is in the system, and the program is not running under DESQview, the routines will choose to use a 'true' cursor, otherwise a simple block cursor will be used. A 'true' cursor is not used under DESQview because DESQview doesn't really like having it's font changed on the fly by a program. The 'true' mouse cursor would probably interfere with other programs running at the same time. The mouse driver does have a glitch that these routines have to work around, that being that when in text mode, the mouse driver returns the coordinates as multiples of 8 (i.e. 0, 8, 16, 24 ...). Since the 'true' cursor has a pixel resolution, we need to get the mouse driver to return coordinates in pixels (i.e. 0, 1, 2, 3 ...). To do this, we 'trick' the mouse driver into thinking it is in graphics mode (where coordinates are returned in pixels) by changing the current video mode. This is done by placing a value of 6 in memory location 0x0040:0x0049, 6 being the number for CGA 640x200 2 color graphics mode. We then tell the mouse driver to initialize again (using mouse driver function 0), and the mouse driver checks the video mode, sees that we are in graphics mode, and sets itself up accordingly. We then restore the mode byte at 0x0040:0x0049 to it's previous value. After this, the mouse driver returns all coordinates in pixels. I had to hack out this fix on my own, I called Microsoft and got nothing from them, but I remembered that when you are running the mouse driver in graphics mode on a Hercules graphics adapter, you have to do this 'trick.' It worked in this case as well. Next the initialization routine sets up the maximum x and y ranges for the mouse cursor based on the dimensions of the video mode. Lastly it installs a mouse function handler using mouse driver function 12 -- define handler. The handler is installed for mouse movement, and left or right button presses and releases. The handler is defined in the function 'void far mousehandler(void)'. This function is called by the mouse driver upon one of the events happening as defined in the call to mouse driver function 12. The handler will automatically update the mouse cursor, change the global variables mousex and mousey to the character (not pixel) coordinates of the mouse. It also checks for mouse events (button presses and releases) and stores them into a buffer if an event happens. This event is later retrieved with a call to MOUpreview() or MOUget(). The drawing of the mouse cursor on non EGA/VGA adapters is quite simple. It reverses the foreground and background color of the character where the mouse is located. This is the default text cursor that the mouse driver uses itself. On an EGA/VGA adapter, things get a little more complicated. A 3x3 character arangement is used to draw the cursor. The function plotegavgacursor() handles saving the 3x3 character array, restoring it later, and drawing the 3x3 array of characters that is redefined. The redefinition consists of reading the definitions of the characters, preforming an AND and OR of the mouse cursor onto the existing definitions, then copying those modified definitions to a new location. I copy to characters 0xd0 to 0xd8. Then the characters 0xd0 to 0xd9 are placed in the 3x3 grid where the mouse cursor is located, thereby drawing the cursor. The mouse cursor is a simple array of dwords (32 bit unsigned long) that is used to update the character definitions. The cursor can be changed from the default one provided, as defined in the mouse driver documentation for defining graphics cursors. It consists of two masks: the screen mask, and the cursor mask. The screen mask is bitwise AND'ed to the existing character definitions, then the cursor mask is bitwise OR'ed to the existing character definitions. The functions MOUshow(), MOUhide() and MOUconditionalhide() perform as their counterpart functions provided by the mouse driver. MOUconditionalhide() is a special function (that some 'clone' drivers _don't_ have) that allows you to update a rectangular region on the screen without distrubing the mouse (if it is not in the region). It is called with the character coordinates of a rectangular region on the screen. If the mouse is in that region, or if the mouse moves into that region, the mouse cursor will automatically turn off. A call to MOUshow() cancels the rectangular region. You can't make multiple calls to MOUconditionalhide() between calls to MOUshow(). Various 'glitches' arise by using a 'true' mouse cursor. They are listed as follows: 1. On the VGA adapter, standard text mode consists of 9 by 16 characters. The character are not actually 9 bits wide, but 8. The VGA duplicates the rightmost bit for the border characters (characters 176 to 218). The 'true' cursor uses (rather redefines) characters 208 to 216 (0xd0 to 0xd8 hex), thereby having its rightmost bit duplicated. If another set of characters is used, the cursor appears to have a 'gap' in the middle of it. The problem lies in that if the cursor is moved over a character that has some of its rightmost bit set, the rightmost bit will be duplicated. Characters such as the lower case 'm' are examples of this. It is much easier to see the effect of this than explain it. Run the TEST program that comes with the routines and place the cursor over a lower case m on the screen. You will notice the effect. I can't see any way around this. This doesn't happen on an EGA as the EGA uses 8 pixel width characters (not 9). 2. Since the 'true' mouse cursor is larger than one character, moving the cursor into areas of the screen with different foreground colors will cause the cursor to take on that color. If the cursor is at the border of two different foreground colors, it will appear that the cursor is in two colors. I got around this by always using the same foreground color for all characters on the screen (i.e. WHITE) and just using different background colors to show differences on the screen. 3. DESQview doesn't like its font changed on the fly. It interfers with the 'true' cursor to the point where it's disfunctional. The mouse routines will automatically detect DESQview and fall back to a normal block cursor if running under DV. 4. Since the font is changed, characters 0xd0 to 0xd8 are not available for use by the program. These characters are the IBM border characters used to connect double line and single line boxes together. I don't use these characters in my programs, and they aren't really needed. If you need to have a single line join a double line graphics character, just place them side by side. They won't actually 'join' as it would by using a double to single line character, but they will line up closely. I find it an acceptable loss to provide a 'true' mouse cursor on the EGA/VGA. For a description of how to change fonts on the EGA/VGA adapters, I highly recommend the book by Richard Wilton, _Programmer's Guide to PC & PS/2 Video Systems_. An excellant book if you are doing any kind of video programming. For a description of the mouse driver interface, I can recommend Logitech's Mouse Programmer's Toolkit, Microsoft Press's Mouse Reference Guide, and Ralf Brown's Interrupt List (updated periodically). I initially learned the interface to the mouse driver from an article in PC Magazine (I can't remember what issue), and I use Ralf Brown's Interrupt List for reference now. 3. Variable and definition reference. ------------------------------------- The following variables and defintions are included in MOU.H: MOUINFOREC This is the definition for the structure returned by the functions MOUpreview() and MOUget(). It contains the following fields: word buttonstat: bits in this field indicate what event occured. See them below. int cx, cy: character coordinates of where this event occured. byte shiftshate: the status of the shift keys at the time of the event. See definitions below. MOUSEBUFFERSIZE This is the size of the mouse buffer. The buffer is where mouse events are held for the program until is retrieves them with MOUget(). MOUSEMOVE, These defines are for the field buttonstat in the LEFTBPRESS MOUINFOREC structure. By checking the bits of LEFTBRELEASE, buttonstat, you can find out what event occured, RIGHTBPRESS, for example, "if (m.buttonstat & LEFTBPRESS)" will RIGHTBRELEASE be true if the event was caused by the press of the left mouse button. LEFTBDOWN, These defines are used for the value returned by RIGHTBDOWN the function MOUbuttonstatus(). I.e. "if (MOUbuttonstatus() & LEFTBDOWN)" will be TRUE if the left mouse button is currently down. SHIFT_RIGHTSHIFT, These defines are for the shiftstate field in the SHIFT_LEFTSHIFT, MOUINFOREC structure. It allows you to check for SHIFT_SHIFT, such things as shift-clicks. I.e. SHIFT_CTRL, "if (m.shiftstate & SHIFT_LEFTSHIFT)" will be TRUE SHIFT_ALT, if the left shift key was held down during the SHIFT_SCROLLLOCK, mouse event. SHIFT_SHIFT is defined as both SHIFT_NUMLOCK, shift keys. SHIFT_CAPSLOCK, SHIFT_INS word mousehidden This variable will be true (non-zero) if the mouse is currently hidden. It is undefined if mouseinstalled is false. Don't write to this variable, it's just provided for your reference. boolean mouseinstalled This variable will be true (non-zero) if a mouse driver is installed and operating and the mouse routines are active and reading the mouse and drawing the cursor. If it is false, the mouse driver routines will not operate, calling them will do nothing (but calling them is not harmful). volatile int mousex, These variables hold the current location of the mousey mouse cursor. They are updated by the mouse handler. Note that their value may changed at _any_ time. Don't depend on them being constant. If you need to reference them, I recommend declaring a couple of variables to hold their values (i.e. int x, y; x = mousex; y = mousey;) and using those instead of mousex and mousey. Only reference mousex and mousey when you need to update the position. 4. Function reference. ---------------------- /* Initialize the mouse routines -- must be called. */ void FAST MOUinit(void); This function initializes the mouse routines, checks for presense of the mouse driver, DESQview and an EGA/VGA. What it does is described above in "How does it work?". /* Deinitialize the mouse routines -- must be called on shutdown. Failure to call it will most likely result in a system crash if the mouse is moved. */ void FAST MOUdeinit(void); This function will deinitialize the mouse routines. It will stop the mouse driver from calling the handler, and erase the mouse cursor. You can call MOUinit() if you wish to use the mouse driver routines again. You MUST call this function before you quit your program. Failure to do so will most likely cause your computer to crash next time the mouse is moved. If you don't call it, the mouse driver still calls the mouse hander, even after the program has quit. /* Hide the mouse cursor */ void FAST MOUhide(void); This hides the mouse cursor. The mouse cursor must be hidden with this function (or MOUconditionalhide() below) before doing any screen updating. This prevents overwritting the mouse cursor. The prefered way to hide the mouse is MOUconditionalhide(). But if you are clearing the screen, or updating all of it at once, use this function. This function counts how many times it has been called, i.e. if you call it twice, you have to call MOUshow() twice to get the cursor back on the screen. /* Hide the mouse cursor if it moves or is in a specific rectangular region of the screen. */ void FAST MOUconditionalhide(int x1, int y1, int x2, int y2); This function hides the mouse automatically if it is in, or is moved in, the retangular region defined by this function. If possible use this function to hide the mouse, as if the mouse isn't near the area being updated, it won't 'blink' like it would calling MOUhide(). The coordinates are zero based and x1 must be <= x2 and y1 must be <= y2. Call MOUshow() after you want the cursor to reappear (if it was hidden by this function). /* Show the mouse cursor */ void FAST MOUshow(void); This turns on the mouse cursor after a previous call to MOUhide() or MOUconditionalhide(). This function may be called as many times as you like, once the cursor is not hidden, any other calls will have no effect. /* return TRUE if there are events waiting in the buffer. */ boolean FAST MOUcheck(void); This function returns true (non-zero) if there are events in the buffer, if not it returns false (zero). /* look at the next event in the buffer, but don't pull it out. */ void FAST MOUpreview(MOUINFOREC *mouinforec); This function passes the next event to the MOUINFOREC passed to it. It does not remove the event from the buffer. If there are no events in the buffer, the MOUINFOREC returned will have the current mouse position in the cx and cy fields of the MOUINFOREC, the shiftstate field set to the current state of the shift keys, and the buttonstat field blank (zero, or no events). /* get and remove next event from the buffer. */ void FAST MOUget(MOUINFOREC *mouinforec); This function passes the next event to the MOUINFOREC passed to it. It will remove the event from the buffer. If there are no events in the buffer, the MOUINFOREC returned will have the current mouse position in the cx and cy fields of the MOUINFOREC, the shiftstate field set to the current state of the shift keys, and the buttonstat field blank (zero, or no events). /* return the current status of the mouse buttons (see defines above). */ word FAST MOUbuttonstatus(void); This will return the current status of the mouse buttons. It can be ANDed with LEFTBDOWN and RIGHTBDOWN to see if either button is currently being held down. This function could be used to detect dragging of the mouse. 5. The test program. -------------------- Included with the routines is a small test program that will allow you to see the 'true' mouse cursor (if you have an EGA/VGA adapter). Included is a makefile for NDMake and Turbo C. If you don't have a makefile, you can compile it like this: tcc -ml test.c mou.c or under MSC as: cl /AL test.c mou.c Note: with Turbo C, you will require to have TASM in your path as the routines have inline assembler in them. MASM isn't required for MSC (MSC has a built in assembler, though it's a bit dumb at times). It's a simple program that will tell you the current mouse position and the status of the mouse buttons. The mouse routines will work in ALL EGA/VGA text modes. I've run it in 80x25 and 80x50 mode and the 'true' cursor will be drawn in both those modes. My VGA supports a 132x60 mode as well, and the 'true' mouse cursor works prefectly in that mode as well. The test program requires ANSI.SYS to be installed. 6. Disclaimer and other stuff. ------------------------------ I orginally started working on these routines when I first saw the new version of Norton's Utilities (version 5.0). I was impressed with the 'true' mouse cursor it was drawing in text mode, and wanted to know if I could write a set of routines to do the same thing. In Jan. of '91, a discussion on the group comp.os.msdos.program about the way Norton does the 'true' mouse cursor arose. I replied to a message by Brian K. W. Hook who indicated that he doubted Norton changed the font on the fly the implement a 'true' mouse cursor in text mode. He stated he was 'baffled' by the way that Norton did it. I stated that Norton did do it by changing the font on the fly, and that I had written some routines to do it as well. Brian asked me for the routines, as well as a couple of other users, so I cleaned them up, made them independant of my text window library (I've written a library for text window routines that I use in my programs) and otherwise prepared to unleash them on unsuspecting Usenet victims. :) These routines also illustrate interfacing to mouse driver function 12, which seems to be a common question on comp.os.msdos.program (How to I do interface to the mouse driver?). I'll supply support for these routines as my time permits, and I can be reached by any of the following methods of communication: Email: UUCP: {uunet,ubc-cs}!van-bc!rsoft!mindlink!a563 Usenet: a563@mindlink.UUCP zoid@threewave.wimsey.bc.ca Internet/Bitnet: Zoid@cc.sfu.ca a563@mindlink.UUCP is prefered, Zoid@cc.sfu.ca would be the next one to try. Mail: #801-9835 King George Hwy. Surrey, BC Canada V3T 5H6 Phone: 604-585-8844 or 604-439-7770 I do hope you enjoy these routines, and have an 'edge' on the competition by having a flashy 'true' cursor on the EGA/VGA. Wow! DISCLAIMER Dave Kirsch makes no warranty of any kind, either express or implied, including but not limited to implied warranties of merchantability and fitness for a particular purpose, with respect to this software and accompanying documentation. IN NO EVENT SHALL DAVE KIRSCH BE LIABLE FOR ANY DAMAGES (INCLUDING DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR OTHER PECUNIARY LOSS) ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF DAVE KIRSCH HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Programmers may incorporate any or all code into their programs, giving proper credit within the source. Publication of the source routines is permitted so long as proper credit is given to Dave Kirsch. Copyright (C) 1990, 1991 by Dave Kirsch.