SIFE.TXT››About Super-IRG Font Editor››by Bill Kendrick›kendrick@zippy.sonoma.edu››New Breed Software›http://zippy.sonoma.edu/kendrick/nbs/››November 1997››-------------------------------------›WHAT IS SUPER-IRG?››Super-IRG is a software-based›graphics mode, similar in concept›to APAC and ColorView modes, which›provides addition output capabilities›to a standard hardware graphics mode,›in this case, IRG, or multicolored›character mode. The SIFE mode was›first seen in my recently-released›game "Gem Drop." At the time, I was›using a simple monochrome font editor›I had written years earlier in BASIC.›Needless to say, i t wasn't easy, but›in doing I found that the graphics›mode met my expectations in quality.››As you probably know, plain IRG mode›allows you to represent a grid of›4 pixels wide by 8 pixels high using›one character. Each pixel can be›any one of four colors.››Super-IRG mode, by flickering between›two character sets (which is done›by simply toggling a flag byte and›setting the CHBAS variable in the›OS), allows you to create›combinations of colors by having›pixels set to different values in›each of the two character sets.››If your color palette contained the›colors black, red, green and blue,›plain IRG would let you display ›those four colors. Super-IRG mode›would let you display those four›colors as well (with no flicker›distortion), but would go beyond this›by providing the colors dark red,›dark green, dark blue, yellow,›cyan and purple. That's 10 colors›total. (This is not even taking›into consideration the "5th" color›available in IRG text modes when›you set a character's high bit›(turn it inverse)!)››-------------------------------------›ABOUT SIFE››SIFE was written using ID's Action!,›a high-level programming language.››SIFE allows you to edit a Super-IRG›character set (two standard 1K›character sets) using all 10 colors›available to it.››You can edit one character at a time›like in most font editors, or four›characters at a time (2x2) to easily›create tile graphics!››SIFE automatically dithers the six›mixed colors when it records the›10-color images you draw. This keeps›flickering to a minimum. (Compare›a solid color flashing on and off›compared to a checkerboard pattern›changing slightly between frames.›The dithering makes Super-IRG›graphics CONSIDERABLY more tolerable›than some graphics modes, like›ColorView, which are constrained by›the hardware from being able to›dither.)››-------------------------------------›USING SIFE››Simply [L]oad SIFE from DOS.›You can use a joystick with SIFE,›but it is not required.››The screen contains the following›information:››* A color palette at the top. The› arrow symbol shows which color is› selected for drawing.››* The editing grid in the middle.› This will be either 4x8 (one› character) to 8x16 (four),› depending on what mode you're in.)››* The current character(s) being› edited on the right. (One or› four (2x2) characters will appear,› depending on what mode you're in.)››* The character set at the bottom.››To select a character to edit,›press [CONTROL]+[Arrow]. The ›flashing cursor will move around›on the character set at the bottom.›(If you're in four character (2x2)›mode, left and right will move the›cursor four characters at a time.)››To edit a character, press [RETURN].›(You can still use [CONTROL]+[Arrow]›to select a new character.)›A flashing cursor will appear›on the editing grid in the middle›of the screen.››To stop editing characters, press›[RETURN] again. (The flashing cursor›will disappear from the editing›grid.) You can also press [ESC].›This will keep from copying the›edited image back into the character›set, thus aborting any changes you›have made.››To move the drawing cursor (in the›editing grid), use the joystick›or press [Arrow] (without [CONTROL]).››To draw in the selected color,›press FIRE on the stick or [SPACE].››To select a different color,›press [TAB] to select the next color›on the right, or [SHIFT]+[TAB] to›select the previous color on the›left.››To switch from one character editing›to four character (2x2) editing,›press [CONTROL]+[RETURN].››To copy one character into another,›use the "clipboard." Press [C] to›copy the currently-selected character›into the clipboard. Select the›character you wish to copy this›image into and press [P] to paste.›(If you're in four-character mode,›four characters will be copied to›and from the clipboard.)››You can load and save character sets›using the [L] key to load and [S]›key to save. If you try to load›a standard 1024-byte IRG font, the›first 1024 bytes will be duplicated›in the second 1024 bytes, thus›producing a solid-colored font.››SIFE comes with one example font,›"ATARI.SIF", which is an attempt›at reproducing the standard Atari›ROM font in Super-IRG mode.›The font is drawn in "color 2,"›(OS "blue") so that you can show›it in "color 3" (OS "red") by›storing the characters inscreen›memory with their high-bit set›(ie, in "inverse").››To quit SIFE and exit back to DOS,›press [SHIFT]+[CONTROL]+[ESC].››-------------------------------------›PROGRAMMING FOR SUPER-IRG››Unfortunately, I don't know›6502 Assembly (can you believe it!?),›so the only Super-IRG programming›example I have is in Action!.››Use Action!'s "INCLUDE" directive›to include the file "SILIB.ACT".››This contains two user functions,›"SIOn()" and "SIOff()" which turn›the Super-IRG mode Vertical Blank›Interrupt (VBI) on and off,›respectively.››Call "SIOn()", sending it the›byte address of the character set›you're using, to turn the mode on.››Call "SIOff()" (ONLY after "SIOn()"›has been called!) to turn the mode›off.››A small example program is included.›See the file "SIEX.ACT".››-------------------------------------›KEYBOARD SUMMARY››[CONTROL]+[Arrow]› Select a character to edit.› (In four character mode, left/right› will move 4 characters at a time.)››[RETURN]› Toggle edit / don't edit mode.› (Don't edit mode is faster.)››[ESC]› Toggle edit / don't edit mode.› Does not save the edited character› back when exiting edit mode (abort› changes).››[Arrow] / Joystick› Move drawing cursor in editing grid››[SPACE] / Fire› Draw in the selected color.››[TAB] / [SHIFT]+[TAB]› Select next/previous color.››[CONTROL]+[RETURN]› Toggle one character and four› character (2x2) editing mode.››[C] / [P]› Copy/paste a character to/from› the clipboard buffer.››[SHIFT]+[CONTROL]+[CLEAR]› Blank the edit grid (erase char.)››[L] / [S]› Load/Save the character set.› Files are in .SIF format,› 2048 bytes of character data› plus four bytes of color data.› Standard 1024 byte .FNT fonts› can also be loaded. The colors› will translate fine.››[SHIFT]+[CONTROL]+[ESC]› Quit SIFE.››-------------------------------------›WHAT'S PLANNED››This release of SIFE isn't a finished›product. I plan to add the following›features:››* More editing controls (flip,› slide, invert)›* Intelligent load/save of other› formats (save a SIFE 10-color› font as a standard 4-color IRG› font)›* Assembly and BASIC examples of› using Super-IRG mode.›* Anything you folks suggest!››-------------------------------------›CREDITS››SIFE was written by Bill Kendrick,›(c) New Breed Software 1997.››Contact me to send suggestions,›comments, donations, or if you have›questions:››Bill Kendrick›7673 Melody Drive›Rohnert Park, CA 94928 USA››kendrick@zippy.sonoma.edu›http://zippy.sonoma.edu/kendrick/nbs/››1-707-795-1234 ext.2›1-707-795-5678 FAX››