williams-et-al-1983-apple-ii-computer-graphics

..46 APPLE II COMPUTER GRAPHICS[ b ..(_·-- -·t--t-t--t--+-+-1t--t--t-+-···;···+ ·! ···+ + + ·; ·+· !·-+-+-+ +- +-, +-+-+-t-,_,._._,c-; -1 -··· t- + - 1 t -+ ··lI · + ·· ! + ··! t-+-t-t- ····'--1-+-+J.+-+-+-+- +·+ ·+ ·! · l ·· +··· i···+··-·I· ·+ -+-+-+; -++-++ _,._,_-.-.+-+-• +1+•+•++++-+ t-+-i t-+- +-+-+-+•-++ + + +±+ +++ - r+-+-f+-•H I•-t ·-······i + --f··- · ·+··· +-··+ ·++ ++-+ -+-+-i; --t-t- r--t-1-t- - --+++-···1-·····f···+· +- ·· + + +++ __,_f.,..!-+-· +-+-+···+···-·•··-·+···-!···-+ + ·+-+·+-i·-··+-t ++-+--+-+-+-+-+-+-! t-J:>-i I ·-]' J!--' J. -H t t-· t-++ +· + - ·l· · + -···!-- +-+-+1 +-+-+-:r+-+- 1 JIFigure 6-4. Apple block diagram.Next, decide which of the Low-Res colors you wish to use in your appleand indicate them on your block drawing. With all of that done, you arenow ready to begin putting the picture onto the screen. There are twomethods of accomplishing this. The fi rst technique is to make use of thePLOT, HLIN, and VLIN statements and place those within your program;the second involves using a Low-Res editor program (described later in thisapple directly onto the screen, and then record thecontents of Low-Res memory..chapter) To plot theHatching a PlatThe brute-force method uses the PLOT, HLIN, and VLIN commands; simplysit down with the blocked figure and develop a list similar to Listing6-2 which creates the apple by drawing an obnoxious number of horizontallines.1 REM PLOT APPLE