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Volume Number: | 1 | |
Issue Number: | 9 | |
Column Tag: | Basic School |
"A Fat Bits Approach to Cursor Editing"
By Dave Kelly, Hybrids Engineer, MacTutor Editorial Board
Let's take a look at one of the Macintosh ROM routines which can be called from MSBASIC (version 2.0). By using the method described here, you can customize your own cursors for use within your programs.
Pages 298 and 299 of the MS BASIC manual explain the Mouse Cursor Handling Routines. The program 'Cursor Editor' in this article demonstrates how to build your own cursor using the CALL SETCURSOR (VARPTR( cursor %(0))) function. It would be helpful to enter the program and run it as you read the explanation here.
Fig. 1 Cursor Edit Program Menu
When you run the program, the main BASIC menus are replaced by a new File and Cursor menu. The Cursor menu allows you to edit the current custom cursor. The Arrow is the default cursor and cannot be edited unless you duplicate it as a custom cursor of your own. Choosing 'Hand' sets the cursor to a hand. An examination of the 'Hand' routine at the end of the program may help you to understand how the cursor%(0) array is setup.
By selecting 'Arrow' in the cursor menu you may clear the cursor to be edited to a blank. The editor is set to a blank (i. e. no cursor) when the program starts. Select 'Edit Cursor' from the menu. The bit parameters for the screen grid are set up and a blank grid is printed on the screen.
Fig. 2
Now just point and click the mouse to select what the cursor will look like. The program will appear to run a bit slow here while the correct bit is being selected. This takes longer in Basic than in most other languages, so be patient. When the cursor is finished click the OK button.
Now a new grid comes up to create a mask for our new cursor. The cursor mask selects which bits behind the cursor will be allowed to be seen through the cursor (the entire 16X16 grid). The program allows you to exper-iment with different masks until you get it just right. To test it out you can move the cursor over a black area of the screen and then over a white area and see what part of the background is allowed to be seen through the cursor. It is purely subjective so you can keep on trying till you are happy with it. For our example, I have filled in the inside of the cursor to make the mask. Any pixels of the screen which are behind the mask will not be allowed to be displayed. Click the OK button to continue.
Fig. 3 Creating the Mask
Next we set the hot spot of the cursor. The hot spot is the active area of the cursor that determines where it is pointing to. It is the intersection of the corners of the pixels. For our example, we want the hot spot to be at the tip of the pencil so we click there. A small square appears to mark the spot. You may want to try other locations for the hot spot if you don't quite understand the significance of the hot spot. Click OK to continue.
Fig. 4 Setting the Hot Spot
Now the new cursor will appear. WARNING: If the cursor which was defined had no pixels selected (i. e. a blank cursor), then it will be very difficult to select anything from this point on because you will not be able to see the cursor. If this happens you may have to abort (use command-period to halt a basic program). Basic will reinitialize the arrow cursor when you exit the program.
Your new cursor can now be stored in a file on the disk by using the file menu and loaded at a later time. The load routine may be copied for use in your own program to read in a custom cursor for your own programs. After the cursor data is stored to disk, the program will change the file type to "CURS" to enable the load routine to recognize only those files which contain cursor data. Any filename type may be changed so that the routine which reads the data may only select files of the same type.
Hopefully this program provides an easy way to customize your own cursors. A good way to create a library of cursors is to do a screen dump to disk of the MacPaint screen. Then load the dumped sceen and look at the cursors used by MacPaint using Fat Bits and dump each of them to the printer from the Fat Bit screen. Then the cursor can be copied bit by bit into the cursor editor program and saved. The program is available on disk if you don't want to have to type. Have fun!!!
' Cursor Editor ' By Dave Kelly ' ©MACTUTOR 1985 DEFINT i,j,k DIM Cursor%(34), Bstatus%(512), Bound0%(256), Bound1%(256), Bound2%(256), Bound3%(256) editor%=0:NewYork=2:Bold=1 Plain=0:Geneva=3 WINDOW 1,"Cursor Editor", (2,40)-(510,340),1 ' Erase BASIC menus FOR i=3 TO 5:MENU i,0,0,"":NEXT MENU 1,0,1,"File" MENU 1,1,1,"Load Cursor" MENU 1,2,1,"Save Cursor" MENU 1,3,1,"Quit" MENU 2,0,1,"Cursor" MENU 2,1,1,"Edit Cursor" MENU 2,2,1,"Arrow (Clear Cursor)" MENU 2,3,1,"Hand" ON MENU GOSUB Checkmenu: MENU ON IF editor%=0 THEN MENU STOP:GOSUB InitEditor:MENU ON loop:GOTO loop Checkmenu: menunumber=MENU(0) menuitem=MENU(1):MENU IF menunumber=1 THEN filemenu ON menuitem GOSUB Editor,Arrow,Hand RETURN filemenu: ON menuitem GOSUB load.cursor, save.cursor,quit RETURN InitEditor: x=20:y=20:offsetx=0:offsety=0:editor%=1 TEXTFONT(NewYork) TEXTSIZE(14):TEXTFACE(Bold) LOCATE 5,1 PRINT"Please wait.... Initializing Editor." MENU 1,0,0:MENU 2,0,0 FOR i=0 TO 33: cursor%(i)=0:NEXT i PICTURE ON FOR j= 0 TO 15 FOR k=15 TO 0 STEP -1 rectangle%(0)=y+offsety bound0%((j*16)+k)=rectangle%(0) rectangle%(1)=x+offsetx bound1%((j*16)+k)=rectangle%(1) rectangle%(2)=y+offsety+12 bound2%((j*16)+k)=rectangle%(2) rectangle%(3)=x+offsetx+12 bound3%((j*16)+k)=rectangle%(3) bstatus%((j*16)+k)=0 offsetx=11+offsetx FRAMERECT(VARPTR(rectangle%(0))) NEXT k offsety=11+offsety:offsetx=0 NEXT j PICTURE OFF grid$=PICTURE$ MENU 1,0,1:MENU 2,0,1:CLS RETURN Editor: MENU 1,0,0:MENU 2,0,0 TEXTFONT(NewYork) TEXTSIZE(14):TEXTFACE(Bold) LOCATE 5,1:PRINT"Please wait for Setup of Editor." GOSUB Bitstatus ' set up new cursor GOSUB print.pic LOCATE 2,26:PRINT"Define New Cursor" GOSUB Print.message GOSUB Draw.Datapixels GOSUB Define ' set up new mask GOSUB print.pic LOCATE 2,26:PRINT"Define New Mask" GOSUB Print.message GOSUB Draw.Maskpixels GOSUB Define ' set hot spot GOSUB print.pic LOCATE 2,26:PRINT"Set Hot Spot" GOSUB Print.message GOSUB define.hotspot CLS:BUTTON CLOSE 1 TEXTFONT(NewYork):TEXTSIZE(14) TEXTFACE(Bold) LOCATE 5,1:PRINT"Please wait." GOSUB Cursor.done SETCURSOR (VARPTR(cursor%(0))) CLS:MENU 1,0,1:MENU 2,0,1 RETURN Print.pic: CLS:PICTURE,grid$ TEXTFONT(NewYork) TEXTSIZE(14) TEXTFACE(Bold) RETURN Print.message: TEXTFACE(Plain) TEXTSIZE(12) LOCATE 4,35:PRINT"Click to continue" 'Note: Space must be ^^^^^ here BUTTON 1,1,"OK", (310,40)-(350,80),1 RETURN define.hotspot: GOSUB Draw.Datapixels CALL PENSIZE(4,4):CALL PENMODE(10) CALL MOVETO((cursor%(33)*11)+x, (cursor%(32)*11)+y) CALL LINE(0,0) WHILE DIALOG(0)<>1 IF MOUSE(0)>0 THEN GOSUB hotspot WEND CALL PENNORMAL BEEP RETURN hotspot: xpos=MOUSE(1):ypos=MOUSE(2) IF xpos<x THEN xpos=x IF ypos<y THEN ypos=y IF xpos>x+16*11 THEN xpos=x+16*11 IF ypos>y+16*11 THEN ypos=y+16*11 CALL LINE(0,0) cursor%(33)=INT((xpos-x)/11) cursor%(32)=INT((ypos-y)/11) CALL MOVETO((cursor%(33)*11)+x, (cursor%(32)*11)+y) CALL LINE(0,0) RETURN Draw.Maskpixels: maskpixel=1 FOR i= 256 TO 511 IF bstatus%(i)=1 THEN rectangle%(0)=bound0%(i-256): rectangle%(1)=bound1%(i-256): rectangle%(2)=bound2%(i-256): rectangle%(3)=bound3%(i-256): PAINTRECT(VARPTR (rectangle%(0))): FRAMERECT(VARPTR (rectangle%(0))) NEXT i RETURN Draw.Datapixels: maskpixel=0 FOR i= 0 TO 255 IF bstatus%(i)=1 THEN rectangle%(0)=bound0%(i): rectangle%(1)=bound1%(i): rectangle%(2)=bound2%(i): rectangle%(3)=bound3%(i): PAINTRECT(VARPTR (rectangle%(0))): FRAMERECT(VARPTR (rectangle%(0))) NEXT i RETURN mousepress: GOSUB getpixel 'see which pixel is selected IF pixel%=256 THEN RETURN IF Bstatus%(Pixel%+maskpixel*256)=0 THEN Bstatus%(Pixel%+ maskpixel*256)=1 ELSE Bstatus%(Pixel%+ maskpixel*256)=0 rectangle%(0)=bound0%(Pixel%) rectangle%(1)=bound1%(Pixel%) rectangle%(2)=bound2%(Pixel%) rectangle%(3)=bound3%(Pixel%) INVERTRECT(VARPTR(rectangle%(0))) FRAMERECT(VARPTR(rectangle%(0))) RETURN getpixel: Pixel%=256 FOR i = 0 TO 255 IF bound0%(i)<MOUSE(2) AND bound2%(i)>MOUSE(2) AND bound1%(i)<MOUSE(1) AND bound3%(i)>MOUSE(1) THEN Pixel%=i:i=256 NEXT i RETURN Cursor.done: FOR j=0 TO 31 cursor%(j)=0 FOR k=14 TO 0 STEP -1 cursor%(j)=(Bstatus%((j*16)+k)*(2^k))+cursor%(j) NEXT k IF Bstatus%((j*16)+15)=1 THEN cursor%(j)=cursor%(j)+&H8000 NEXT j RETURN Define: WHILE DIALOG(0)<>1 IF MOUSE(0)>0 THEN GOSUB mousepress WEND BEEP RETURN Bitstatus: FOR j=0 TO 31 t%=cursor%(j) FOR k=15 TO 0 STEP -1 IF t%<0 THEN Bstatus%((j*16)+k)=1:t%= t%-&H8000:GOTO endloop IF t%<2^k THEN Bstatus%((j*16)+k)=0 IF t%>=2^k THEN Bstatus%((j*16)+k)=1:t%= t%-2^k endloop:NEXT k NEXT j RETURN load.cursor: filename$=FILES$(1,"CURS") IF filename$="" THEN exitload OPEN filename$ FOR INPUT AS #1 FOR i= 0 TO 33 INPUT #1,cursor%(i) NEXT i CLOSE #1 exitload:CALL SETCURSOR(VARPTR(cursor%(0))) RETURN save.cursor: filename$=FILES$(0) IF filename$="" THEN exitsave OPEN filename$ FOR OUTPUT AS #1 FOR i=0 TO 33 PRINT #1,cursor%(i) NEXT i CLOSE #1 NAME filename$ AS filename$,"CURS" exitsave:CALL SETCURSOR (VARPTR (cursor%(0))) RETURN quit: BUTTON CLOSE 1:MENU RESET TEXTFONT(Geneva):TEXTFACE(Plain) TEXTSIZE(12) END Arrow: INITCURSOR FOR i=0 TO 33: cursor%(i)=0:NEXT i RETURN Hand: ' Cursor Data Cursor%(0)=&H0:Cursor%(1)=&H0 Cursor%(2)=&H700:Cursor%(3)=&H1900 Cursor%(4)=&H2200:Cursor%(5)=&H4700 Cursor%(6)=&HC7FE:Cursor%(7)=&H8C01 Cursor%(8)=&H97FE:Cursor%(9)=&HE410 Cursor%(10)=&H87E0:Cursor%(11)=&H8420 Cursor%(12)=&HC7C0:Cursor%(13)=&H7F80 Cursor%(14)=&H0:Cursor%(15)=&H0 ' Cursor Mask Cursor%(16)=&H0:Cursor%(17)=&H0 Cursor%(18)=&H700:Cursor%(19)=&H1F00 Cursor%(20)=&H3E00:Cursor%(21)=&H7F00 Cursor%(22)=&HFFFE:Cursor%(23)=&HFFFF Cursor%(24)=&HFFFE:Cursor%(25)=&HFFF0 Cursor%(26)=&HFFE0:Cursor%(27)=&HFFE0 Cursor%(28)=&HFFC0:Cursor%(29)=&H7F80 Cursor%(30)=&H0: Cursor%(31)=&H0 Cursor%(32)=7 'Vertical hot spot Cursor%(33)=16 'Horizontal hot spot SETCURSOR(VARPTR(cursor%(0))) RETURN
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