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PICLAB.DOC December 3, 1991 Piclab 1.91 is a public domain image processing program by Lee Daniel Crocker and the Stone Soup Group. It should be distributed with the following files: PL.EXE The program itself. PL286.EXE Faster, smaller version for 286 (and up) machines. PICLAB.DOC This file. PL.HLP Text file for the HELP command. PICLAB.PIF Windows 3.0 386 enhanced mode PIF. PICLAB.ICO Windows 3.0 icon. GAMMA1.MAP \ GAMMA2.MAP X Color maps for viewing grayscale and pseudo-color. PSEUDO.MAP / SSTOOLS.SMP Sample SSTOOLS.INI file. If you are missing one or more of these files, contact the author at one of the addresses listed at the end of this document. Overview ======== Piclab operates on "images", so I will begin by explaining exactly what an image is and how Piclab classifies them. For our purposes, an image is a data set that describes the reflectance of a 2-dimensional surface such as a photograph. In particular, an image is a 2-dimensional array of "pixels" (a short form of "picture elements"), each of which contains data for the small rectangular area of the image it represents. There are many systems in which image data represents "objects" rather than pixels. PostScript is probably the most notable example. The commands sent to a PostScript device tell it to draw lines or boxes or characters and let the device decide how it will perform the commands it gets. Piclab does not deal with object-based images or devices. Image data comes in several flavors, and while all are related in many ways, there are distinctions important to keep in mind. I will divide image data into four classes: bitmapped, grayscale, golor-mapped, and true-color. In all of these formats an image is represented as a rectangular array of pixels, each of which may contain some value. Bitmapped images are collections of on/off dots. That is, each pixel can be either "on" or "off", with no states in between. This type of image can be displayed on just about any type of computer and is especially suited to printer output. The disadvantages are the inability to represent color, and the lack of detail. With large bitmapped images, one can get a surprising amount of detail by simulating shades of gray by dot patterns. This process, called halftoning, is used by newspapers to print photographs. At this time, Piclab does not deal directly with bitmapped images, although it can treat them as grayscale and can output images to bitmapped devices. Grayscale images represent images by storing the intensity of light for each pixel on a scale of more than just on/off. Typically, a grayscale image will allow 64 to 256 shades of gray at each pixel. Very high quality renderings of black and white photographs can be stored in this format. As an aside, the term "black and white" is often used to describe both bitmapped images and grayscale images. For this reason, I will not use the term in this document. Another common term for grayscale is "monochrome", which is often used to describe monitors that can display only shades of one color (often green or amber). Color-mapped images are the ones most common on personal computers. Each pixel in an image is represented by a number (called an index) that is used to look up the pixel's actual color in a table (called the palette, much like an artist's palette). These images are popular because they can be very colorful, yet take up less memory than full-color images (described next). The size of the color palette varies among formats, but is typically 16 to 256. True-color images are the highest quality representation, and the largest files as well. Each pixel contains the complete color information for that pixel, usually expressed as the intensity of the red, green, and blue color components of the light at that location. Piclab deals directly with grayscale, color-mapped and true-color images, regardless of the display capabilities of the hardware on which it is running. In fact, Piclab can be used to enhance and print images on machines with no display at all. I must stress that there is no connection between the images Piclab deals with and the type of display on your computer. Piclab has a SHOW command that displays the image it is working with, but if the image is more detailed than your display can handle, Piclab will do its best to approximate the image on your display. Regardless of what the display looks like, the image itself is always stored and operated upon in full detail. So what's the point? You might think that having image data more accurate than your computer can display is wasteful, but it is not. One reason is that images get passed around to users of different machines, and the more accurate the image data, the better each machine will be able to display it. You can also do things like print color images to a color printer even though you have no color display on your computer. Lastly, hardware to display images as accurately as Piclab stores them does exist, and is becoming more affordable every day. If you keep your images stored in their full accuracy, you will be better able to take advantage of any new hardware you may get. General Operation ================= After starting Piclab by typing "PL" at the system command line, the user may enter any of a number of commands, each of which is performed immediately. If you give arguments to the PL command, the first is taken as the name of a file containing Piclab commands, and the rest are treated as arguments to that program, accessed as %1, %2, etc., much like DOS batch file arguments. This feature can be used to create programs for specific tasks. Commands generally operate on two internal picture buffers called OLD and NEW. Most commands start by deleting OLD and renaming NEW to OLD. They then perform some transformation on OLD storing the result in NEW. The command UNDO swaps NEW and OLD--effectively reversing the last operation. OLD and NEW are stored on disk. This decision was made primarily because my taste in pictures is better than my budget for RAM. If you are dealing with simpler pictures, or if you have RAM to burn, you can direct Piclab to store OLD and NEW on a RAMdisk. In MSDOS and similar operating systems, this is done by typing "SET TMP=D:" at the system command line before running Piclab, where D: is the drive or directory specification of the RAMdisk. Piclab can read and write images in different file formats. The LOAD command is used to read an image in one of these formats into the edit buffers. The SAVE is used to write the contents of the edit buffers into one of these formats. Every session with Piclab will generally begin with a LOAD, and end with a SAVE (or perhaps a PRINT) with some processing in between. A file may be loaded from one file format and saved in a different one, thereby converting among formats. Command parsing in Piclab is roughly like that of the system command line. The line is broken into words that must be separated by spaces; the first word specifies the actual command and the remaining words are passed to the command handler as arguments. The individual command-handling routines are responsible for interpreting their arguments. Generally, a word may be shortened as long as it does not conflict with any other word in the same context. For example, the LIST COMMANDS command may be abbreviated LIS COM. Any words in the command line that begin with the '%' character are replaced as follows: if the remainder of the word is a number, the word is replaced with the argument to the PL command in that position (starting with 0). Otherwise, the word is replaced with the value of the DOS environment variable named by the word. For example, here is a short Piclab program (named V2E) to convert a VGA 256-color image into an EGA 16-color image: GLOAD %1 UNMAP RESCALE 640 350 EGAPAL MAP GSAVE %2 With this program in the current directory, typing "PL V2E IMG1 IMG2" will load IMG1.GIF, convert it to 16-color ega, and save that to IMG2.GIF. Piclab has many settings that can be changed to accommodate the user's needs or environment. From within Piclab, these are set with the SET command. Because many of these will need to be set identically each time Piclab is run, a mechanism is proved for putting initial settings into a startup file. This file, called SSTOOLS.INI, must be in a directory pointed to by the environment variables INIT or PATH. It is a plain text file that contains initial settings and preferences for many of the Stone Soup tools. The included file SSTOOLS.SMP is a good sample. Edit it to suit your system, rename it SSTOOLS.INI, and place it where it can be found with the INIT or PATH environment variables. Note that sections for each tool are marked by a line containing only the tool's name in square brackets. The lines in the Piclab section can contain any variable normally set by the SET command, but note the different syntax: there is no SET, and the variable name and value are separated by an = sign rather than a space. Commands ======== MAKEPAL Syntax: MAKEPAL Makes a palette appropriate for the NEW buffer. Operates on only true-color images. The variable PALETTE determines the number of colors in the new map, and the MAKEPAL command picks that many colors to best fit those in the image. The MAP command must be used to map the image onto the palette. EGAPAL Syntax: EGAPAL Makes a 16-of-64-color palette appropriate for the NEW buffer. Operates on only true-color images. This is designed primarily for reducing full-color images to a form better suited for display on an IBM EGA or similar device. The MAP command must be used to map the image onto the palette. MAP Syntax: MAP Maps NEW buffer onto the current palette. Operates only on true-color images, and produces a color-mapped image. The variable DITHER determines whether each pixel is simply mapped onto the nearest color in the map, or whether dithering is used to achieve a more accurate mapping. DITHER defaults to ON, and is recommended for most uses. The MAKEPAL command should be used to create the best possible palette for the image before mapping, but any palette may be used for special purposes such as mapping several images to the same palette. PLOAD Syntax: PLOAD file [offset [count]] Loads a MAP file into the current palette. First argument is the name of the MAP file which is assumed to be in the MAPDIR directory. If a second argument is given, the palette is loaded starting at that index. If a third argument is given, only that many colors are loaded. MAP files are plain text files that contain the RGB values for each palette index on one line. PSAVE Syntax: PSAVE file [offset [count]] Saves a MAP file from the current palette. First argument is the name of the MAP file which is assumed to be in the MAPDIR directory. If a second argument is given, the palette is loaded starting at that index. If a third argument is given, only that many colors are loaded. This can be used to save a palette created with MAKEPAL so that it need not be calculated again, or so that it can be used with other images. MAP files are plain text files that contain the RGB values for each palette index on one line. GRAYPAL Syntax: GRAYPAL file [offset [count]] Makes the specified MAP file the default colors used when displaying monochrome images or full-color images on a VGA. The default colors are equivalent to GAMMA1.MAP, but GAMMA2.MAP and PSEUDO.MAP can be useful in some situations. MAP files are plain text files that contain the RGB values for each palette index on one line. UNMAP Syntax: UNMAP Produces a true-color image from a color-mapped one. This must be done before applying true-color transformations such as rescaling. After transformations have been performed in true-color, the image may be reduced to a color-mapped one again with the MAKEPAL and MAP commands. HELP Syntax: HELP [subject] Looks like you have figured this one out already. CALL Syntax: CALL program [args]... Calls the external program named by its first argument passing along any subsequent arguments to that program. Many programs do not release all of the memory given to them when they terminate, so Piclab will reserve a large portion of memory for itself before calling a program. If you do not have much more memory than Piclab reserves, this may result in the program not being able to run in the memory left. If this is a problem, you can use the DOS or SHELL commands to exit to DOS with all of the free memory available. CANCEL Syntax: CANCEL Cancels the most recent operation. If there are point transformations pending that have not yet been saved with the TRANSFORM command, these are cancelled and no changes are made to the edit buffers. Otherwise, the NEW and OLD buffers are exchanged. There are some operations (like SAVE) that do not alter the edit buffers. If one of these operations was the last one performed, UNDO will undo the operation before that. No arguments. UNDO Syntax: UNDO Cancels the most recent operation. If there are point transformations pending that have not yet been saved with the TRANSFORM command, these are cancelled and no changes are made to the edit buffers. Otherwise, the NEW and OLD buffers are exchanged. There are some operations (like SAVE) that do not alter the edit buffers. If one of these operations was the last one performed, UNDO will undo the operation before that. No arguments. SHELL Syntax: SHELL [command] Calls up the DOS command line. All available memory is released to DOS when this command is given, and is reclaimed when DOS is exited. For this reason, some programs that cannot be CALLed may be run from with DOS. Any arguments to this command will be passed to the system as a command line, and will cause it to return immediately after the command is done. One particularly useful action of this program is "SHELL COPY /B PDAT PRN", which copies the print file to the printer. "SHELL DIR" can be used to view file directories when you want to see all files, not just pictures. DOS Syntax: DOS [command] Calls up the DOS command line. All available memory is released to DOS when this command is given, and is reclaimed when DOS is exited. For this reason, some programs that cannot be CALLed may be run from with DOS. Any arguments to this command will be passed to the system as a command line, and will cause it to return immediately after the command is done. One particularly useful action of this program is "DOS COPY /B PDAT PRN", which copies the print file to the printer. "DOS DIR" can be used to view file directories when you want to see all files, not just pictures. QUIT Syntax: QUIT [flag] Exits Piclab. If there is a point transformation pending, it must be cancelled or saved before exiting. If the exit command is given any arguments, it exits immediately regardless of pending transformations. Inside a program, QUIT merely sets a flag so that Piclab will exit after the program is complete. EXIT Syntax: EXIT [flag] Exits Piclab. If there is a point transformation pending, it must be cancelled or saved before exiting. If the exit command is given any arguments, it exits immediately regardless of pending transformations. Inside a program, EXIT merely sets a flag so that Piclab will exit after the program is complete. LIST Syntax: LIST [item] If given without an argument, shows what things may can be listed. If one of these things (e.g. FORMATS, COMMANDS, BUFFERS) is given as an argument, the appropriate items are listed. Especially useful are LIST COMMANDS if you forget the name of a command you are looking for and LIST BUFFERS to check the size and format of the image in the OLD and NEW edit buffers. PAUSE Syntax: PAUSE [time] With no arguments, Piclab waits for a key to be pressed before continuing. If one argument is given, Piclab waits for that number of seconds (but will break early if a key is pressed). This is for use within programs. PRINT Syntax: PRINT [x-offset [y-offset]] Prints the image in the NEW buffer into the file specified by the PRINTFILE variable. The current setting of the PRINTER variable determines what codes are sent to the file. Some versions of DOS do not correctly write to devices such as "prn" when opened as ordinary files. For that reason, Piclab treats the PRINTFILE "" as a special case, and sends data directly to the printer rather than through DOS. If arguments are given, the first two are used as the X and Y offsets of the first dot to print on the first page of output. RUN Syntax: RUN program [args...] Takes one argument--the name of a text file containing Piclab commands. These are interpreted as if they had been typed from the command line, but they are not echoed, and messages are turned off while a program runs. Subsequent arguments are passed along to the program as %1, etc. A program can also be run by giving its name as an argument to the PL command when starting Piclab. SHOW Syntax: SHOW [x-offset [y-offset]] Used to display as much of the image in the NEW buffer as will fit on the computer's display screen. If arguments are given, the first is used as a horizontal offset into the image buffer and the second as a vertical offset. This can be used to look at different parts of an image too big for the screen. Certain video modes allow scrolling with the arrow keys, but not all. If no arguments are given, the current values of the XORIGIN and YORIGIN variables are used. If any point transformations are pending, the image you see on screen reflects the image as it would be AFTER the pending transformation. This can be used to look at the effect of a transformation before saving or cancelling it. Because Piclab often stores data more accurately than the display can render it, what you see on the screen is only an approximation of the actual image. In particular, because Piclab does not yet support any true-color display hardware, true-color images will be shown in grayscale on displays capable of it, or in 8-color dither on others. SET Syntax: SET [variable [value]] Without any arguments, lists all Piclab variables and their current values. Variables can be numbers, character strings, or TRUE/ FALSE. Variables set system defaults and control the specifics of how many commands perform. If the set command is given one argument, the variable named is cleared. That is, set to 0 if it is numeric, to "" if it is a string, and to FALSE if it is TRUE/FALSE. If SET is given with two arguments, the variable named by the first is set to the value specified by the second. If a numeric variable is given a string value, it is set to 0. String values should not be put in quotes. TRUE/FALSE values may be set by the keywords TRUE/FALSE, YES/NO, ON/OFF, or by the numeric values 1/0. Within the SSTOOLS.INI file, the syntax is <variable>=<value>. Help on individual variables is available by typing HELP <variable>. HISTOGRAM Syntax: HISTOGRAM [RED | GREEN | BLUE]... If no arguments are given, plots histograms for all planes; if one or more arguments are given, a histogram is plotted for each plane specified as an argument. The histograms plotted reflect the image as it would be after any pending transformations, so you can look at the results of many processes before saving or cancelling them. Each vertical bar of the histogram represents the total number of pixels in the image with values in the range beginning with the value listed below the histogram in hexadecimal. Each bar covers a range of four values and there are 64 bars. The height of each bar is in logarithmic proportion to the frequency of occurrence of values in the range it represents. The bars are automatically scaled so that the tallest one is made 20 characters high. NEGATE Syntax: NEGATE [RED | GREEN | BLUE]... Arguments are handled as in HISTOGRAM. Inverts each value in the lookup table for the planes specified. This can be used after digitizing a negative or for special effects. DARKEN Syntax: DARKEN [[RED | GREEN | BLUE] value]... Subtracts a constant value to each point in the planes specified. If only one argument is given, all planes are brightened by that amount. Otherwise, arguments are interpreted in order, and any arguments that specify planes determine which plane the next numerical argument will affect. For example, DARKEN RED 10 BLUE 15 would subtract 10 from the values in the red plane and 15 from those in the blue. Any values that would be taken out of the 0..255 range by the transform are clamped. Because this darkening is a linear operation, the image to be brightened or darkened should be encoded with a gamma of 1.0. That is, there should be a linear relationship between values in the image and intensities on the display. If this is not the case, gamma correction may be applied with the GAMMA command before adjusting brightness. BRIGHTEN Syntax: BRIGHTEN [[RED | GREEN | BLUE] value]... Adds a constant value to each point in the planes specified. If only one argument is given, all planes are brightened by that amount. Otherwise, arguments are interpreted in order, and any arguments that specify planes determine which plane the next numerical argument will affect. For example, BRIGHTEN RED 10 BLUE 15 would add 10 to the values in the red plane and 15 to those in the blue. Any values that would be taken out of the 0..255 range by the transform are clamped. Because this brightening is a linear operation, the image to be brightened or darkened should be encoded with a gamma of 1.0. That is, there should be a linear relationship between values in the image and intensities on the display. If this is not the case, gamma correction may be applied with the GAMMA command before adjusting brightness. CONTRAST Syntax: CONTRAST [[RED | GREEN | BLUE] value]... This stretches or squeezes the contrast of an image. Arguments are interpreted like those in BRIGHTEN. If a given value is positive, the image contrast is stretched so that values that were equal to the given value become 0, and those that were equal to (255-value) become 255. If the given value is negative, the inverse operation is performed. Because contrast is always stretched equally around the midpoint of the range, it is a good idea to brighten or darken an image as necessary to center its histogram before performing a contrast stretch. Also, the contrast stretching formula operates on color values assuming a linear relationship between these values and the intensities they represent (as do the BRIGHTEN and DARKEN commands). Therefore, if an image has been scanned with a device with a gamma value not equal to 1.0, the image should be gamma corrected before contrast stretching. GAMMA Syntax: GAMMA [[RED | GREEN | BLUE] value]... The color values of the specified planes are adjusted so that values encoded for display on a monitor with a gamma value equal to the argument become linear. For example, images encoded for display on PCs usually expect a monitor with a gamma near 2.0. The GAMMA 2.0 command will convert these values to a linear scale. Images encoded on Macintoshes and similar equipment have linear values already. Such images can be adjusted for display on PCs with the inverse transformation, i.e. GAMMA 0.5. See Piclab.DOC for more background on gamma correction. COLOR Syntax: COLOR [mapfile] Converts a grayscale image into a color-mapped image. If the first argument is the name of a MAP file, the image is pseudo-colored with that map, otherwise the color map will contain the original grays. GRAY Syntax: GRAY Converts true-color or color-mapped image to grayscale. The formula used for conversion to grayscale is the same as used by black and white televisions and is designed to mimic the eye's response: gray = (.299 * red) + (.587 * green) + (.114 * blue). TRANSFORM Syntax: TRANSFORM Saves the result of a series of point-process transformations to the edit buffer. This must be done before any other transformation may be performed on the image. If you wish to cancel the pending transformations without saving them, use UNDO or CANCEL. MEDIAN Syntax: MEDIAN [WEIGHTED] Reduces spot noise in an image. Each point is replaced by the median of the points in its 3 x 3 area. That is, the nine points in this area are sorted and the fifth one is taken. If the one argument to this routine is WEIGHTED, then the center point is added twice more to the list and the sixth of the 11 points is taken. The median filter results in some smoothing, but not as much as with the SMOOTH command. This effect is a little less drastic with the weighted median filter. Repeated application of this operation will result in an oil-paint texture appearing on the image. This filter will not help reduce periodic or other noise--only small spot noise such as from dust on a lens. SHARPEN Syntax: SHARPEN [value] Applies what is called (somewhat inaccurately) a LaPlace transform to the image. The effect is that edges in the image are sharpened as if the image had been re-focused. Unfortunately, it also increases the amount of noise in the image, making it appear more grainy. The command can be given a single numerical argument, which specifies the severity of the transform. It is basically a tradeoff between sharpness and noise, and defaults to 1.0. This value provides a noticeable increase in both sharpness and noise, and is about the best value for sharpening when the purpose is to bring out information. When applying to a real image, a less severe value of .2 to .5 is often better. Values greater than 1.0 should be used only when trying to locate specific objects in an image. They produce too much noise for accurate reproduction. This function works by amplifying the differences between each point and its neighbors. This has the effect of amplifying high spatial frequency details such as edges and noise. SMOOTH Syntax: SMOOTH [value] Replaces each point with the average of the values of the nine points in its neighborhood. This has the effect of smoothing the image and reducing high frequency effects like aliasing and noise, as well as high frequency details. If an argument is given, it is taken as a value of the severity of the transform as with the SHARPEN command. A value of 1.0 is exactly as described. Values less than 1.0 change the center value less than if a straight average had been done. Values greater than 1.0 are not recommended. If more smoothing is desired, perform SMOOTH more than once rather than with a high value. ADD Syntax: ADD [WRAP] Adds the OLD and NEW edit buffers storing the result in the NEW buffer. If the only argument to the command is WRAP, then values that are taken out of the 0..255 range by the addition are taken mod 255; otherwise, values are clamped. SUBTRACT Syntax: SUBTRACT [WRAP] Subtracts the NEW edit buffers from the OLD buffer storing the result in the NEW buffer. If the only argument to the command is WRAP, then values that are taken out of the 0..255 range by the addition are taken mod 255; otherwise, values are clamped. AVERAGE Syntax: AVERAGE Averages the OLD and NEW buffers, storing the result in NEW. This can be used to reduce random digitizer noise by averaging the results of different samplings. Can also be used to produce a double exposure effect when two different images are averaged. No arguments. CLIP Syntax: CLIP [x-size y-size] If no arguments are given, image is clipped from (XORIGIN,YORIGIN) to lower right corner (upper right for bottom-up images). If two arguments are given, the image is clipped from (XORIGIN,YORIGIN) to the horizontal and vertical size specified by the arguments. XORIGIN and YORIGIN are set to 0 after this operation. One argument is an error; more than two are ignored. EXPAND Syntax: EXPAND x-size y-size [(BLACK | WHITE | value) [value]...] This command increases the size of the image to the width and height specified by its first two arguments by adding extra rows and columns of pixels. If a third argument is given, it can be either BLACK or WHITE to indicate what color the extra pixels should be. If three numeric arguments are given after the bounds arguments, they are taken as the red, green, and blue value of the extra pixels. Multiple images can be placed in a montage by using EXPAND and OVERLAY. Parts of an image may be joined with these functions as well, but it is not recommended for separately digitized image pieces, as no mosaicking is performed. For color-mapped images, the third argument is treated as a color map index rather than a color value. MIRROR Syntax: MIRROR Flips the image horizontally. No Arguments. OVERLAY Syntax: OVERLAY [x-offset [y-offset [threshhold]]] Overlays the image in the NEW buffer on top of the OLD buffer. The image in the NEW buffer must not be larger than the image it is to overlay. If two arguments are given, they are used as the horizontal and vertical offsets into the base image at which the overlay image is to be placed. Otherwise, XORIGIN and YORIGIN are used. If a third argument is given, all values in the overlaying image less than the give threshhold are treated as transparent. This feature is primarily for grayscale and color-mapped images. Using it on full color images produces bizarre results, because the threshholding is applied to each RGB component separately, rather than to the whole color value. RESCALE Syntax: RESCALE value | (x-size y-size) Resamples the image at a different resolution. This is useful for scaling images up to a larger size for printing, or for scaling them down for display. It is recommended that image data always be saved at its original sampling resolution to preserve as much data as possible and only scaled when necessary to conform to hardware. If only one argument is given, horizontal and vertical resolution are both increased in the given proportion. For example, if a 320 x 240 image is in the NEW buffer when the command RESCALE 1.5 is given, the NEW buffer will contain the same image at 480 x 360. More useful, though, is the case where two arguments are present. In this case, the arguments are treated directly as the new horizontal and vertical resolution of the image. The transformation above could be expressed as RESCALE 360 480. This is most often used to compensate for differing aspect ratios. For example, a 320 x 400 from an Amiga can be rescaled to 320 x 200 to be viewed on a VGA, or to 720 x 540 for printing on the HP PaintJet. Because RESCALE interpolates color values, it cannot be used on color-mapped images. REVERSE Syntax: REVERSE Changes the storage order of an image from top-down to bottom-up or vice versa. This is used primarily to save an image loaded from a file in one format (like PCX) to a format requiring the opposite order (like GIF). Targa files can be stored either way, and contain information in the header specifying which way they are stored. Thus, any image can be saved in Targa format at any time with minimal memory usage. ROTATE Syntax: ROTATE value Rotates image in 90-degree increments. The single argument is the number of degrees through which to rotate. Only 90, 180, and 270 are currently supported (well, 0 and 360 work too, but they aren't very exciting.) This is very useful for rotating screen-oriented images for printing on paper. Because this operation requires large amounts of memory for large images, it is recommended in this case to rotate the image before scaling it up to size for printing. DIR Syntax: DIR [directory] Lists all files in the PICDIR directory in the current file format. If an argument is given, files in that directory are listed. No other file specifications can be given. If FILEFORMAT is set to GIF or TARGA, statistics on the files will be listed as well. GDIR Syntax: GDIR [directory] Lists only GIF files from PICDIR or from the directory given as sole argument. Statistics are listed from each file as well. TDIR Syntax: TDIR [directory] Lists only Targa files from PICDIR or from the directory given as sole argument. Statistics are listed from each file as well. LOAD Syntax: LOAD file [args]... Loads a file in the current file format into the NEW buffer, moving the current contents of the NEW buffer to OLD. Any arguments are passed along to the function that handles loading for the current format and are interpreted by that routine. The first argument is always the file to be loaded, but other arguments vary with the format. LIST FORMATS will give you a list of all the available file formats, and HELP is available for each. GLOAD Syntax: GLOAD file Loads image in GIF format regardless of the current setting of variable FILEFORMAT. Sole argument is filename. TLOAD Syntax: TLOAD file Loads image in Targa format regardless of the current setting of variable FILEFORMAT. Sole argument is filename. RLOAD Syntax: RLOAD file x-size y-size [COLOR | MONO] Loads image in RAW format regardless of the current setting of variable FILEFORMAT. The width and height of the image must be specified as the second and third arguments to RLOAD. A fourth argument may be either of the words COLOR or MONO to specify the number of planes. COLOR is default. Color-mapped RAW files must be loaded as MONO, then colored with the COLOR command after the palette is loaded with PLOAD. SAVE Syntax: SAVE file [args]... Saves the image in the NEW buffer to the file specified by the first argument. Subsequent arguments are passed along to the file save routine of the current file format. LIST FORMATS will give you a list of all the available file formats, and HELP is available for each. GSAVE Syntax: GSAVE file [INTERLACE] Saves the NEW buffer to the file named by the first argument in GIF format regardless of the current setting of variable FILEFORMAT. If the second argument is the word INTERLACE, image is interlaced. TSAVE Syntax: TSAVE file [bits] Saves the NEW buffer to the file named by the first argument in Targa format regardless of the current setting of variable FILEFORMAT. If the second argument is 16, 24, or 32, it is used as the number of bits per pixel stored in the file. RSAVE Syntax: RSAVE file Saves image in RAW format regardless of the current setting of variable FILEFORMAT. No arguments. Warnings and Errors =================== "Command arguments ignored" This warning occurs when you give a command more arguments than it needs. Review the syntax of the command for an explanation. "Open files were closed" This indicates that a command halted for some reason while files were open. Piclab has closed the files but data may be lost. "Probable information loss" This warning is very common and should be taken lightly. It indicates that some transformation has been performed that is not reversible. Most of the time, the initial image will be safely stored in a disk file, or recoverable with UNDO, so this is unimportant. "Assertion failure; contact author" The is printed only in places I think are unreachable. This message indicates a serious error, and action (such as saving the working file and exiting the program) should be taken immediately. "Insufficient memory" There is not enough memory to perform the command issued with the current environment. This is most common in frame processes like ROTATE, and with GIF loading with MULTIIMAGE and MULTIMAP set ON. In the latter case, those variables can be set to OFF before loading. In the former, there is not much alternative but to clip the image to a smaller size or try to provide more memory. "Miscellaneous file I/O" File open or write failed. Could be bad or full disk. Retrying may help. "Unexpected end of file" File read failed. This may occur when loading a file that is not encoded in the correct format, or when loading a RAW or IP file when the size is specified incorrectly. CLIP may sometimes be used to recover. "LZW compression/decompression" Usually the result of a bad GIF file. "Unrecognized file format or bad file" The LOAD command encountered something in the file not consistent with the file format being loaded. Usually this is because you specified the wrong format, but may also occur on a bad or incorrectly encoded file. "Image buffer empty" You attempted a transformation when no image is in the edit buffers. "Point transform pending; issue TRANSFORM command" The command you issued cannot be performed until any pending point transformations are either saved with the TRANSFORM command or cancelled with the UNDO command. "Illegal parameter values" This is a catch-all command syntax error. Review the syntax of the command you are issuing. "File not found" File open in LOAD command failed. Check that the file is in the proper directory by issuing a DIR command. Also check for correct spelling. Acknowledgements ================ Though I wrote 90% of the code, this project was definitely a group effort. The Graphics Support Forum Developer's Group on CompuServe was instrumental in helping to inspire, create, optimize and test this program. I cannot acknowledge them all (or even name them all) but a few deserve special mention: John Bridges' Image Tools package served as an inspiration and a performance yardstick for many of this program's functions, and some of his generously donated code appears in the display code. John is the author of the GRASP animation package. Bert Tyler, Timothy Wegner, and the rest of the Stone Soup Group inspired several features and did some testing as well. John Swenson, who knows more about how to use the program than even I do, provided invaluable insights. Thanks to Charles Marslett and STB Systems, Inc., for helping me suuport HiColor boards such as STB's PowerGraph Ergo. 'GIF' and 'Graphics Interchange Format' are trademarks of CompuServe Incorporated, an H&R Block company. Author ====== Lee Daniel Crocker 5506 Camden Ave #D3 San Jose, CA 95124 The best way to reach me is to type GO PICS on CompuServe and leave mail to user ID [73407,2030]. I read these messages two or three times a week. I am also reachable on Usenet as "lee@mport.com" (uunet!mport!lee).