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─────────────────────────────────────────────────────────────── LxPic V3.4 (c)1997 Stefan Peichl, Heidelberg, Germany ─────────────────────────────────────────────────────────────── LxPic displays color pictures in simulated shades of grey on monitors in B&W mode. It is specially designed for the HP Palmtops but runs also on any desktop. LxPic processes BMP,GIF,JPG,PCX and ICN files of any kind. BMP and PCX files may have 2, 4, 256 or True Colors (16 Mio). JPG files may have 256 gray scales or True Colors. GIF files may have Version 87a or 89a with up to 256 colors. The pictures may have any size and dimension, as long as you have enough storage capacity to keep them. The special HP Palmtop resize command 'H' corrects the dispro- portion of the Palmtops pixel ratio. LxPic is very small (9K) and needs as a COM file only 64K of main memory while running, no matter how large the picture is. LxPic uses a distinctive dither algorithm to get most of the color information into the B&W representation. Once the picture is transformed, you may adjust contrast, brightness, shadow, highlight and color and save it as a B&W PCX file with less storage requirement and much better display performance. LxPic has an interface, to use it as a 'subroutine' in other programs or batch files. See PROGRAMMERS INTERFACE section of this documentation for further information. LxPic recognizes your display adapter and sets the display to the best of the following modes, dependant on your hardware: - VGA (640x480) - EGA (640x350) - CGA (640x200) - HP95 (240x128) *The Graphics Interchange Format(c) is the Copyright property of CompuServe Incorporated. GIF(sm) is a Service Mark property of CompuServe Incorporated. ─────────────────────────────────────────────────────────────── REVISION HISTORY ─────────────────────────────────────────────────────────────── Version 1.0 -Only B&W BMP and PCX files Version 2.0 -BMP,GIF,PCX,ICN of any size and dimension -VGA,EGA,CGA,HP95 support -Dither for color pictures -Scrolling -Zoom In/Out -Edit functions -HP resize mode -B&W PCX conversion Version 2.1 -Programmers Interface added Version 2.2 -Intrasegment call added to Programmers Interface Version 2.3 -Zoom out 1:8 and zoom in 8:1 added -Programmers Interface improvements Version 3.0 -JPEG added -/S switch to scan drives or subdirectorys Version 3.1 -More speed: Output interrupted at any command Version 3.2 -Version 3.1 bug fixed Version 3.3 -Correct display of Fujifilm DS-7 JPEG files Version 3.4 -Rename/Move command {N} added -Select pixel aspect ratio command {F6} added New versions of LxPic will be available on my Internet homepage http://home.t-online.de/home/stefan.peichl ─────────────────────────────────────────────────────────────── SYSTEM REQUIREMENTS ─────────────────────────────────────────────────────────────── - Processor: 8088 - DOS : 2.11 - Adapter : HP95,CGA,EGA,VGA - Memory : 64 K - Storage : 9 K ─────────────────────────────────────────────────────────────── WHAT'S IN YOUR ZIP FILE ─────────────────────────────────────────────────────────────── LXPIC.COM the picture viewer LXPIC3_4.DOC this file LXPIC.ICN icon for use with system manager DEMO.PCX gray scale demo PCX file DEMO.GIF 256 color demo GIF file DEMO.JPG True Color demo JPG file CAM2JPG.COM converts CASIO QV-10A CAM format to JPEG For programmers only: DEMO.ASM source code of DEMO.COM for intrasegment calls DEMO.COM put all files in C:\PIC and enter DEMO LXPIC.ICN ─────────────────────────────────────────────────────────────── HOW TO USE LXPIC ─────────────────────────────────────────────────────────────── LxPic needs no installation. If called without parameters, LxPic searches the current directory for all files with the extension BMP,GIF,JPG,ICN or PCX and displays them in the order, as they are found in the directory. If no files are found, LxPix exits and displays the help screen. LxPic has no file select feature, but it behaves like the DIR command of DOS and it accepts the /S command line parameter to scan all subdirectorys too. Which files are displayed depends on how you name them and where you keep them. To display a specific picture, use its full or relative pathname as parameter for LxPic. The wildcards * and ? are allowed in the filename, to display a group of pictures with similar names. ─EXAMPLES─ LXPIC displays all pictures in the current directory LXPIC/S displays all pictures in the current directory and its subdirectorys LXPIC DEMO.* displays for example DEMO.PCX, DEMO.GIF and DEMO.JPG in the current directory LXPIC \PIC\V?.ICN displays for example V1.ICN and V2.ICN in the directory PIC of the current drive (good for Video command) LXPIC D:/S displays all pictures on your D: drive LXPIC C:\DEMO.JPG /S searches your whole C: drive for the file DEMO.JPG and displays it, if it was found If you use the scan switch /S, LxPic exits after all files have been displayed. Without /S, LxPic loops endless until you press ESC. Going back one picture is only possible within one sub- directory, so don't be confused with unexpected results using the last picture key 'P' in a scan. The /S switch is most useful to browse a CDROM on the desktop within seconds. Press the 'A' (=Autozoom) and 'V' (=Video) key to have the quickest and most informative overview of the pictures on a CDROM. Using a standard picture viewer under WINDOWS, it would take hours of mouse clicking to do the same job. If you want to add LxPic to the Application Manager of your HP Palmtop, copy LXPIC.COM and LXPIC.ICN into the directory, where your pictures reside, for example C:\PIC, and enter as path entry of the new application: C:\PIC\LXPIC.COM|70 ─────────────────────────────────────────────────────────────── COMMANDS ─────────────────────────────────────────────────────────────── The Help key F1 pops up a window with all command keys: ┌─────────────────────────────────────────┐ │ LxPic V3.4 (c)1997 Peichl, Heidelberg │ │Use: LXPIC [path]file.[BMP|GIF|JPG|PCX]/S│ ├────────────────────┬────────────────────┤ │F File info on/off│F1 This help screen│ │H HP resize on/off│F2 HP95|CGA|EGA|VGA│ │C Clear scr on/off│F3 Convert b&w2grey│ │I Invert on/off│F4 Save as b&w .PCX│ │Z Center on/off│F5 Save screen only│ │A Auto zoom on/off│F6 Pix aspect ratio│ │T Text zoom on/off│CU..Key Move screens│ │+=- Zoom in/no/out│PG..Key Move row/col│ │S Slide on/off├────COLOR PICTURES──┤ │V Video on/off│D Dither on/off│ │>< Sld/Vid qui/slo│RGB R|G|B color only│ │BAR Sld/Vid suspend│M Mix R+G+B colors│ │DEL Delete picture│/ Reset all values│ │N Ren/Move picture│7 8 Shadows - +│ │P Previous picture│4 5 Highlights - +│ │CR Next picture│1 2 Contrast - +│ │ESC Exit (or ^C)│0 . Brightness - +│ └────────────────────┴────────────────────┘ Press F1 again or press ESC to close the Help window. Almost all commands are single key strokes and I tried to assign meaningful keys to the commands. The action, taken upon a command, is valid for the actual and all following images. If you have a sequence of pictures with little contrast, you have to adjust contrast only once. If you hear a key click, the pressed key had no function at all or did not apply to the actual picture type, or you reached the end of a range. Use the cursor keys to scroll an image. Cursor keys scroll the image by one screen in the indicated direction. Page keys (Palmtop: Fn+cursor) scroll the image by 10 columns or 10 lines in the indicated direction. I exchanged the meaning of these keys for single key strokes on the Palmtop. I try to keep the x,y offset in consecutive pictures, to allow you zooming the same position in a slideshow. KEY FUNCTION F Display file and parameter information box: DEMO.GIF filename ┌───────────┐ │kbyte : 7│ filesize │type : COL│ picturetype: COL | GREY | B&W │deep : 8│ colordepth in bits: 1 | 4 | 8 | 24 │wide : 320│ pixelwidth of actual representation │high : 100│ pixelheight of actual representation │x_0 : 0│ pixelcolumn: upper left displayed corner │y_0 : 0│ pixelline : upper left displayed corner │mode : CGA│ screen mode: VGA | EGA | CGA | HP95 │ratio : 1:1│ pixel ratio: 1:1|1:.9|1:.8|1:.7|1:.6|1:.5 │zoom : 1:1│ zoom in/out: 8:1|4:1|2:1|1:1|1:2|1:4|1:8 │dither: ON│ dither mode: ON | OFF │color : RGB│ disp. color: RGB | RED | GRÜN | BLUE | GREY │shadow: 0│ shadow : 0=unchanged, 127=max, -127=min │hlight: 0│ highlights : 0=unchanged, 127=max, -127=min │contra: 0│ contrast : 0=unchanged, 127=max, -127=min │bright: 0│ brightness : 0=unchanged, 127=max, -127=min └───────────┘ H Resizes the picture to a pixel aspect ratio of 1:0.8. A picture with 640x240 pixel is resized to 640x200 pixel for example. The actual aspect ratio is displayed in the file info box. HP resize is off by default. See also the more general pixel aspect ratio command {F6}. C Clear screen between two pictures (default) I Invert screen. LxPic inverts pictures by default, if running on a HP Palmtop Z Center picture in the middle of the screen (default) A Auto zoom. If switched on, the zoom mode is selected, which displays most of the picture. Auto zoom is off by default. If switched on, you see the letter 'A' in the 'zoom' entry of the file info. T Text zoom out mode. Zooming out for B&W images is implemented by default as 'drop two, keep two' to prevent moraine effects from previously dithered pictures. This command toggles zoom out mode to 'drop one, keep one', which is better for viewing B&W pictures including text, like faxes for example. If switched on, you see the letter 'T' in the 'zoom' entry of the file info. Text zoom is off by default. + Zoom out to 1:2, 1:4 and 1:8 = Reset Zoom to 1:1 - Zoom in to 2:1, 4:1 and 8:1 S Perform a slideshow V Perform a video. Same as slideshow, but at maximal speed without clear screen between pictures. See VIDEO part of this documentation. > Slideshow/Video quicker up to maximal speed < Slideshow/Video slower BAR Suspend Slideshow/Video. Press Spacebar again to continue DEL Delete the actual displayed picture. You have to confirm, before the file is deleted N Rename/Move picture filename. You may not move the file to a different drive, because this would be a 'copy', which is not supported. After the rename, the next picture is displayed. P Display previous picture, as found in the directory. This command also changes the direction for Slideshow/Video. CR Display next picture, as found in the directory. This command resets the direction for Slideshow/Video to forward. ESC Exit LxPic. If you exit LxPic with ^C, an errorlevel of 1 is returned, which is useful in batch files. F1 Display Help window F2 Change screen mode if possible. The picture is resized to 100% or autozoomed, if selected F3 Converts B&W picture to a 8 bit grey picture. This enables you to edit a B&W picture with the commands, only avail- able for color or grey pictures. The performance slows down indeed. F4 Save the whole picture -as you see it- to a B&W PCX file. You are asked for a filename. You must use another filename than the original name and you have to add the extension PCX. BMP pictures end upside down, I don't change it, turn around your Palmtop! F5 Same as F4, but only the visible part of the picture is saved. If you want to select even a smaller part, switch with F2 to the HP95 mode and save from there. To invert a Palmtop topcard, load it, press 'I' and then F5 to save the inverted topcard. F6 Selects pixel aspect ration in a range from 1:1 to 1:0.5. Useful for distorted camera pictures and CGA monitors. The HP resize command {H} is the shortcut of {F6}{2}. The actual aspect ratio is displayed in the file info box. ─COLOR PICTURES ONLY─ The following commands are only available, if a picture with more than two colors is dispayed. D Switch Dithermode OFF/ON (ON by default) Without Dither, color values below 127 turn a pixel on, values above 127 switch it off R Display Red part of the picture only G Display Green part of the picture only B Display Blue part of the picture only M Mix Red, Green and Blue to Grey = 30%R + 59%G + 11%B / Reset Shadow, Highlight, Contrast and Brightness to 0. Set color to RGB. 7 Decrease Shadows: Colors <127 move towards Grey 8 Increase Shadows: Colors <127 move towards Black 4 Decrease Highlights: Colors >127 move towards Grey 5 Increase Highlights: Colors >127 move towards White 1 Decrease Contrast: All colors move towards Grey 2 Increase Contrast: Colors <127 move towards Black Colors >127 move towards White 0 Decrease Brightness: All colors move towards Black . Increase Brightness: All colors move towards White L Loop through Brightness: Displayes the picture contineously with decreasing brightness values ─────────────────────────────────────────────────────────────── JPEG ─────────────────────────────────────────────────────────────── You have to understand some basics of JPEG in order to use it most effectivly on the Palmtop. This applies only, if you have influence on the JPEG pictures, you want to display, that is, if you have a software to produce the (or convert to the) JPEG format. The LxPic implementation of JPEG supports the baseline mode of operation, which is the most common. I never saw any of the 3 other JPEG modes. Baseline is lossy, that is, when the JPEG picture is created, the information of the original image is reduced to save storage space. The amount of information, which is lost, may be determined by you. Before saving a JPEG file, a good software asks you for a quality factor. You may go down to zero quality and still have a good picture on the palmtop, because most of the quality is anyhow lost in the B&W representation on the Palmtop. JPEG supports grayscale and True Color images. True Color is represented by luminace and chrominace values instead of red, green and blue parts. Furthermore, the luminance part may be more weighted than the chrominace part of a picture, again, in order to save space. The luminace component of a JPEG image is nothing else than it's grayscale representation and gayscale JPEG images only have one luminace component. LxPic extracts this luminace component and displays it. The chrominance components are ignored. That means, you loose no information on the palmtop, if you use only greyscale JPEG, but you save space. If you want to use your images on the Palmtop and the Desktop at the same time, and you want to have colors on the Desktop, select a subsampling of 4:1:1, which means 4 times more luminace values than blue chrominace values and red chrominace values. As with the quality parameter, a good software let's you select subsampling. A True Color 4:1:1 JPEG image with zero quality may have a compression rate of 0.2 bit/pixel, which is about 4K for a full screen CGA image. The same BMP image needs 24 bit/pixel, which is a factor of 120 times bigger. That is, you save about 99% of storage capacity and loose only little quality. Compression rates with greyscale JPEGs are even better. Compared to B&W PCX images, which use 1 bit/pixel, you still need only 20% of storage space. LxPic performs best with zero quality greyscale JPEG images, which also produce the smallest files. The output speed relates strong with the quality, because the better the quality, the more time consuming calculation has to be done in the inverse descrete cosine transform (IDCT). ─────────────────────────────────────────────────────────────── DIGITAL CAMERAS ─────────────────────────────────────────────────────────────── Almost all new digital cameras use an incompatible 'JPEG based compression' for their proper storage format, apparently for no other reason than to force people to use the camera vendor's software and not anyone else's. This is really bad politic! LxPic will never support any of these non standard formats internaly. Just to show, how easy it would have been for CASIO, to implement real baseline JPEG, I wrote a tiny program called CAM2JPG, which converts CAM to JPEG. I will never do the other direction. This tiny program is based on an excellent reengineering work of Mr. Iwama and Mr.Yamamoto from Japan, which was needed, because CASIO refused to make their format public. Now, that I made CAM available for the Palmtop, this should *NOT* encourage you to buy their cameras. Wait until the vendors produce JPEG right out of the box, like the FUJIFILM DS-7 camera. If you have another digital camera, and want to find out, if it's format is JPEG compatible, rename the internal storage files to *.JPG and try to display them with LxPic. You may have luck, at least you get a message like 'unsupported signature/ version' or 'unsupported mode of operation'. You may also send me a MIME- or UUE-coded email with a demo file of the internal file format of your digital camera, and I will have a close look at it. ─────────────────────────────────────────────────────────────── ADVICE ─────────────────────────────────────────────────────────────── If you are concerned of little storage capacity, JPEG will be your preferred picture format on the Palmtop. But if you want to have output speed, B&W PCX files have the best speed/size ratio. With other words, it makes no sense to keep BMP, GIF or color PCX files on your Palmtop. To convert color pictures to the speedy B&W PCX format, proceed as follows: - Press 'H' to have the exact width/height proportions - Adjust contrast, brightness, shadow, highlight - Zoom in/out, if needed - Press F4 to save the whole image or - Press F5 to save only the visible part of the image. If you want to select a smaller part than the HP100/200 screen, use F2 to switch to the HP95 mode and make your selection in the HP95 window and press F5 in the HP95 mode to save this smaller part only. - Delete the original color picture. I do not recommend to use B&W GIF files, because GIF's LZW decoding is slow compared to PCX's RLE decoding. The slightly smaller B&W GIF filesize does not predominate this drawback. NOTE: BMP and PCX files with less than 40K, GIF files with less than 30K and JPG files with less than 16K perform better, because the whole picture can be kept in the buffer of LxPic. Bigger files have to be loaded and reloaded in portions, which might be time consuming, if you use slow storage devices. ─────────────────────────────────────────────────────────────── VIDEOS ─────────────────────────────────────────────────────────────── LxPic and its video option allow to display a series of (B&W) pictures at maximal speed to simulate a video. Start with two ICN pictures. Use the build in ICN editor of your Palmtop. Produce two slightly different icons and save them to your C:\ drive as V1.ICN and V2.ICN. Run LxPic from the command line: LXPIC C:\V?.ICN Press the V key and adjust the speed with the < and > keys. If you want to use more than two ICN pictures, you have to take care of how they are stored in your directory. LxPic displays the files in the sequence as they are found in the directory. You cannot tell LxPic a different display order. First copy all files under new names in the sequence, you want to have them displayed and then delete the old files. Don't rename the files, because it does not change their directory position. Use the DIR command of DOS without any sort parameter to see the new order of the files. ─────────────────────────────────────────────────────────────── PROGRAMMERS INTERFACE ─────────────────────────────────────────────────────────────── LxPic has an internal interface for use with other programming languages or batch files. This interface allows you to output pictures at a desired position in an already filled application screen. You may select, if you want to gain back control immediately after the picture has been output to the screen, or if you want to pass intermediate control to LxPic and get back control, when the ESC key of LxPic is pressed. The application may then write around or even into the picture. Multiple pictures may be positioned or overlayed on one screen. The interface uses 7 bytes of the bios data area starting at the absolut address 00458h (40h:58h relative). The bios resevers these bytes for the cursor coordinates of the text pages 4-7 in an ascii text mode. In graphic modes, these bytes are zeroed and unused. Since LxPic works only in graphic modes, these bytes may be used as an interface for LxPic. ─INTERFACE SPECIFICATION─ byte 00458h Interface selection flag: 00h = do not use the interface (default) 01h = use interface, exit via DOS EXIT function 02h = use interface, exit via RET FAR instruction 03h = use interface, exit via RET instruction Set bit 7 in the interface selection flag, if you want to pass intermediate control to LxPic. byte 00459h Mode selection byte. This byte is bit coded. 7 6 5 4 3 2 1 0 = bit number | | | | | | | | | | | | | | Meaning if bit is set | | | | | | | --------------------- | | | | | | |___clear screen before output | | | | | |_____invert picture | | | | |_______center picture | | | |_________autozoom | | |___________HP resize | |_____________dither off |_______________text zoom on byte 0045Ah Zoom factor. Valid values are: -3 = 1:8 -2 = 1:4 -1 = 1:2 0 = 1:1 1 = 2:1 2 = 4:1 3 = 8:1 if the value is not valid, 0 is assumed. word 0045Bh Pixel row. If the pixel row is not valid in the actual graphic mode, 0 is assumed. word 0045Dh Pixel column. If the pixel column is not valid in the actual graphic mode, 0 is assumed. NOTE: LxPic output always starts and ends at pixel columns, that are multiples of 8. -----1.Example------ -----2.Example----- Pixel width = 40 Pixel width = 41 Pixel column = 16 Pixel column = 15 LxPic output = 16-56 LxPic output = 8-56 no blanc columns blanc columns 49-56 ─RETURN CODES─ LxPic exits via DOS funktion 04Ch or a RET FAR or a RET instruction leaving behind return codes in register AL. The codes and their meaning are: 0 errorfree execution -1 (reserved for DOS) -2 file not found -3 invalid screen mode -4 unsupported signature/version of picture file -5 uncompressed PCX file -6 compressed BMP file -7 unknown GIF image descriptor -8 invalid LZW code in GIF file -9 unsupported JPEG mode of operation -10 unsupported arithmetic coding in JPEG -11 unsupported Y sampling factor in JPEG -12 no default DQT table support in JPEG -13 no DNL support in JPEG -14 no OS/2 DIB support in BMP ─DETAILS─ If LxPic finds at address 00458h a value other than 0, it takes it and puts back 0. That is, you always have to fill in the interface, if you want to use it. If the value was not 0, LxPic checks for a valid graphic video mode. If no valid graphic video mode has been set by you, LxPic exits without action. Valid graphic modes are: HP95 = 20h CGA = 06h EGA = 0Fh VGA = 11h Any change of the video mode or any clear screen, performed using BIOS or DOS functions, resets the interface to 0. That is, fill in the interface AFTER you configured the screen. If you selected 'center picture' in the mode byte, the pixel row and pixel column values are ignored. If you selected 'autozoom' in the mode byte, the zoom factor, the pixel row and pixel column values are ignored. ─TURBO-C SAMPLE CODE FOR USE OF LXPIC VIA SYSTEM CALL─ /*-----------------------------------------------------------*/ /* This example assumes, that LXPIC.COM and DEMO.PCX are */ /* stored in the directory C:\PIC of your computer. */ /* Because of inline assembly, you have to use TCC from the */ /* command line, to compile this example */ /*-----------------------------------------------------------*/ #include <stdio.h> #include <string.h> #include <process.h> /* function prototype */ int picture(char mode,char zoom,int line,int column,char *pic); /*-----------------------------------------------------------*/ main() { /* set a valid graphic mode */ asm mov ax,6 /* select video mode 6 */ asm int 10h /* set it */ /* your code goes here */ printf(" this is DEMO.PCX"); /* output DEMO.PCX half sized at line 10, column 16 */ picture(0,-1,10,16,"C:\\PIC\\DEMO.PCX"); /* your code goes here */ printf("\n\n\n\n\n\n\n\n this was DEMO.PCX"); } /*-----------------------------------------------------------*/ int picture(char mode,char zoom,int line,int column,char *pic) { char lxpic[100]="C:\\PIC\\LXPIC "; /* full LXPIC pathname */ /* fill in the interface */ asm push ax /* save AX */ asm push bx /* save BX */ asm push ds /* save DS */ asm mov ax,0 /* load DS... */ asm mov ds,ax /* ...with segment 0 */ asm mov bx,0458h /* load bx with offset */ asm mov al,1 /* flag = use DOS EXIT */ asm mov [bx+0],al /* set flag */ asm mov al,mode /* load mode selection */ asm mov [bx+1],al /* set mode selection */ asm mov al,zoom /* load zoom factor */ asm mov [bx+2],al /* set zoom factor */ asm mov ax,line /* load pixelline */ asm mov [bx+3],ax /* set pixelline */ asm mov ax,column /* load pixelcolumn */ asm mov [bx+5],ax /* set pixelcolumn */ asm pop ds /* restore DS */ asm pop bx /* restore BX */ asm pop ax /* restore AX */ /* display the picture */ return(system(strcat(lxpic,pic))); } /*-----------------------------------------------------------*/ ─USE OF LXPIC AS A SUBROUTINE─ To use LxPic as a subroutine, using intersegment calls, you have to do the following: 1- allocate a whole segment of continuous memory (=64K), say with segment address SEG. 2- load the LxPic code at SEG:100h using the DOS loader/exec function 04Bh (subfunction AL=3) 3- set a valid graphic video mode 4- fill in the command tail at SEG:80h with the filename of the picture you want to display. See a DOS documentation for the structure of the command tail in the PSP. 5- fill in the interface, using interface selection flag = 2 6- set DS=ES=SEG and execute LxPic as a subroutine via CALL FAR SEG:100h. LxPic saves and restores all registers except AL, which holds the return code. ...repeat steps 4-6... 7- release the 64K memory block To use LxPic as a subroutine, using intrasegment calls, see DEMO.ASM for an example. LxPic recognizes the intrasegment call and shrinks its internal buffers, to fit in the rest of the 64k segment. If you want to create COM files, you have to use intrasegment calls. Proceed as follows: 1- find the first free paragraph in your 64k segment, say at address FREE. 2- load the LxPic code at FREE+100h using the DOS loader/exec function 04Bh (subfunction AL=3) 3- set a valid graphic video mode 4- fill in the command tail at FREE+80h with the filename of the picture you want to display. 5- fill in the interface, using interface selection flag = 3 6- set DS=ES=FREE and execute LxPic as a subroutine via CALL FREE+100h. LxPic saves and restores all registers except AL, which holds the return code. ...repeat steps 4-6... NOTE: Programs, using the LxPic interface may not be distributed commercially without license. Details are available from the author. ─────────────────────────────────────────────────────────────── TECHNICAL ─────────────────────────────────────────────────────────────── A Grey value is build from 30% Red + 59% Green + 11% Blue. This takes into account the luminescence of the colors instead of simply calculating Grey as R+G+B/3. A Grey value of 0 means Black, a Grey value of 127 means Grey and a Grey value of 255 means White. B&W pictures use only a palette with two colors. The index into the palette is 0 or 1, represented by the corresponding pixel. The index 0 in the grey palette means a Grey value 0, which is Black, the index 1 means a Grey value of 255, which is White. The simple method of writing the index values of a B&W picture directly to the screen, instead of translating them before, is correct for white on black monitors, but leeds to an inverted image on the Palmtops black on white monitor. The dither mode uses Floyd-Steinberg error diffusion, where the color error of a pixel is distributed to the adjacent pixels. The inverse discrete cosine transform (IDCT) of JPEG uses an algorithm with only 4 multiplications, which I developed to make things go at some speed on the Palmtop's 80186. LxPic does not use internal bitmap representation because of restricted memory. It decodes directly to the screen via a line buffer. Any action leeds to a completely new decoding of the picture. LxPic is developped on a HP200LX. It is written in Assembler. Yes, this language still exists and tends to produce small and quick code. LxPic is also a demonstration of what can be done in graphics with 9K code in 64K memory. Think of what could be done in 1MB code and 32MB memory with 80568 processor and compare it with todays reality! ─RESTRICTIONS─ - no uncompressed PCX files - no compressed BMP files - only sequential DCT (baseline) JPEG mode of operation - only first image of multi image GIF files - interlaced GIF files display at half height - zooming in is restricted to 1600 pixel in width for color pictures. Exceeding columns are cut off ─────────────────────────────────────────────────────────────── DISCLAIMER AGREEMENT ─────────────────────────────────────────────────────────────── LxPic is copyrighted freeware. LxPic may not be distributed commercially or bundeld with commercial products without license. This applies also to programs, which use the internal interface of LxPic. Users of LxPic must accept this disclaimer of warranty: "LxPic is supplied as is. The author disclaims all warranties, expressed or implied, including, without limitation, the warranties of merchantability and of fitness for any purpose. The author assumes no liability for damages, direct or consequential, which may result from the use of LxPic." ─────────────────────────────────────────────────────────────── AUTHOR ─────────────────────────────────────────────────────────────── Address your comments and suggestions to Stefan Peichl Karl-Ludwig-Str.4 69117 Heidelberg Germany Phone:0049-6221-184867 eMail: 06221184867@btxgate.de Internet: http://home.t-online.de/home/stefan.peichl