dar@telesoft.UUCP (David Reisner @shine) (10/27/85)
I was sitting at a Mac today, and I noticed how much nicer the Mac screen looked than the Amiga screen (I've only seen the Amiga with the 1080 monitor). In particular, the Amiga characters and icons look fairly course (especially visible horizontal gaps between lines) and the Mac characters and icons look nice and dense - much more "paper-like". Traditionally, color screens aren't supposed to look as dense as black and white screens, so that may be the difference. On another hand, the number of dots per inch has a lot to do with the perception of whatever-fuzzy-characteristics-I'm-alluding-to. The Mac has a much smaller screen than the Amiga, so a similar number of pixels total translates to a larger number of dots per inch. Has anyone tried using an Amiga with - a "small" (9"?) color monitor? - a black and white monitor, large or small? - a "very high quality" color monitor? How does it look? I'm particularly interested in text, window, and icon appearance. Perhaps someone has an Amiga and can borrow some monitors and try them out? I'd also like to reiterate the request for comparisons of the 1070, 1080, and other color monitors when used with the Amiga. I'd really like to hear from someone who has used all three. -David sdcsvax!telesoft!dar
rbt@sftig.UUCP (R.Thomas) (10/29/85)
> I was sitting at a Mac today, and I noticed how much nicer the Mac > screen looked than the Amiga screen (I've only seen the Amiga with the > 1080 monitor). In particular, the Amiga characters and icons look > fairly course (especially visible horizontal gaps between lines) and > the Mac characters and icons look nice and dense - much more "paper-like". > > ... > > -David > sdcsvax!telesoft!dar Actually, the gaps between lines are probably caused by the 640x200 resolution of the screen. That particular aspect would undoubtedly look better if you were using 640x400 resolution. But then you would probably notice flicker, and that would make you unhappy too. It almost looks like there is no way out. But wait! Has anybody tried looking at 640x200 text with a 'scan-doubler' (which replicates each line in the first half-frame into the line immediately below it in the second half-frame.)? I'll bet that the text and icons would look quite acceptable that way. Has anybody tried a simple software kludge that sends out interlaced 640x400 to the monitor, but the second half-frame is just an exact copy of the first half-frame? With a simple hardware patch to replace the software kludge, it should take half as much memory as full 'hires' and produce good looking text and icons that dont flicker. Obviously you wouldn't want to use it for hi-res graphics (a long persistence phosphor would be better there, unless you wanted to do animation. Then you could probably get away with scan-doubled 640x200, because motion tends to obscure jaggies and other things that would be objectionable in low-res still pictures.) But for text and icons, it should be acceptable. Would somebody with an amiga try it and report back, please? How does it look? Hey, you folks at Commodore/Amiga, what about it? Is the hardware patch feasible? How does it look to you? Rick Thomas ihnp4!attunix!rbt
knf@druxo.UUCP (FricklasK) (10/29/85)
>I was sitting at a Mac today, and I noticed how much nicer the Mac >screen looked than the Amiga screen (I've only seen the Amiga with the >1080 monitor). In particular, the Amiga characters and icons look >fairly course (especially visible horizontal gaps between lines) and >the Mac characters and icons look nice and dense - much more "paper-like". >...The Mac has a much smaller screen than the Amiga, so a similar number of pixels total translates to a larger number of dots per inch. The Mac has square pixels, which I think also gives much more dense "paper-like" graphics, due to the lack of space between the pixel sides. '`'` Ken '`'`'
jerem@tekgvs.UUCP (Jere Marrs) (10/30/85)
In article <213@telesoft.UUCP> dar@telesoft.UUCP (David Reisner @shine) writes: >the Mac characters and icons look nice and dense - much more "paper-like". > It's important to realize that the Macintosh monitor (Samsung) is not your standard black-and-white monitor. It operates at a higher scan frequency and has an extraordinary bandpass. Couple this with a high-quality character generator and you have the Mac. You'll have to concentrate to see any flicker. > The Mac has a much smaller screen than the Amiga, so a similar number of > pixels total translates to a larger number of dots per inch. > Comparing the color monitor to a black-and-white really isn't fair. A pixel in color is three times the size of a pixel in a monochrome monitor of equivalent bandpass. To get a color resolution equal to the Mac's B&W resolution will require thousand(s) of dollars. >Has anyone tried using an Amiga with > - a black and white monitor, large or small? Yes, the spatial resolution is much sharper and this is probably the solution for text work. > - a "very high quality" color monitor? I just obtained a SONY KV-1311CR, and I can comment after I solve the great cabling maze. Also, I need to take delivery of my Amiga. >How does it look? We'll see. Jere Marrs Tektronix, Inc. Beaverton, Oregon tektronix!tekcrl!tekgvs!jerem
mikel@ccvaxa.UUCP (10/30/85)
I didn't buy their monitor when I get my system. What I am running until I find the monitor I really want to use is a VT240 head. I made some cables up to connect up (you need the external sync also) the analog RGB outputs. I also have a small 9" high res (or at least they say it is) that looks good.
LLi.ES@Xerox.ARPA (10/30/85)
From: LLi.ES@Xerox.ARPA Is there a hardware limitation which prevents the Amiga to send 640x400 NON-interlaced to a monitor which can display at that resolution? If so, where is the pinch point? Leonard.
mjg@ecsvax.UUCP (Michael Gingell) (10/31/85)
> > Has anybody tried looking at 640x200 text with a 'scan-doubler' (which > replicates each line in the first half-frame into the line immediately > below it in the second half-frame.)? I'll bet that the text and icons ........ > > Rick Thomas > ihnp4!attunix!rbt A scan doubler for the Amiga is not such a trivial matter as on the IBM PC. There the RGB etc. signals are digital and can be stored in a simple memory scheme for repeating the line. This is how the Princeton Graphics Scan DOubler board works on the PC giving a very nice looking 31.5 kHz scan rate. On the Amiga the video output is analog RGB, that's the only way you can get so many colors. So a scan doubler would have to have a method of storing a line in analog form. No easy matter. There is a digital RGB output port on the Amiga but I don't know if anyone uses it. If they did they would have to use a non-Amiga monitor and would lose the color range. - Mike Gingell ...decvax!mcnc!ecsvax!mjg
Felton.PA@Xerox.ARPA (11/01/85)
From: Felton.PA@Xerox.ARPA Yes, There is a limitation which prevents the Amiga from sending 640x400 non-interlaced to a monitor which can display at that resolution. I was at a lecture at Stanford yesterday which was given by Jay Miner. He said that it wasn't possible. I'm not hardware oriented but it seems to me that this is due to limited bandwidth. Displaying non-interlaced 640x400 would require moving twice as much data to the screen every 60th of a second. John
rick1@sbcs.UUCP (Guest account) (11/04/85)
> Has anybody tried looking at 640x200 text with a 'scan-doubler' (which > replicates each line in the first half-frame into the line immediately > below it in the second half-frame.)? I'll bet that the text and icons > would look quite acceptable that way. Has anybody tried a simple > software kludge that sends out interlaced 640x400 to the monitor, but > the second half-frame is just an exact copy of the first half-frame? > With a simple hardware patch to replace the software kludge, it should > ... > > Rick Thomas > ihnp4!attunix!rbt No need, I remember reading in the ROM Kernel manual that AMIGA already supports interlacing by doubling scan lines. It requires just a few lines of C code (and away you go). Perry S. Kivolowitz
bees@infoswx.UUCP (11/05/85)
>>Has anyone tried using an Amiga with >> - a black and white monitor, large or small? > Yes, the spatial resolution is much sharper and this is probably >the solution for text work. What kind? Which connector on the Amiga? Cabling? >> - a "very high quality" color monitor? > I just obtained a SONY KV-1311CR, and I can comment after I solve >the great cabling maze. Also, I need to take delivery of my Amiga. According to the Sony product information that I have, the KV-1311CR has an Aperature Grill Pitch of .37 mm. This is better than the 1080 monitor (.39 mm), but not as good as the 1070 (.31 mm). I'd be interested to know how well it works out, and what kind of cabling you came up with. I'd also be intested to know what a Sony CPD-900 or CPD-1201 monitor looks like on the Amiga. They both have a .25 mm pitch, but have 640x240 and 800x240 (respectively) dot resolution. Would the difference in dots cause the screen to look screwy and out of proportion? Ray Davis
cem@intelca.UUCP (Chuck McManis) (11/08/85)
> From: LLi.ES@Xerox.ARPA > > Is there a hardware limitation which prevents the Amiga to send 640x400 > NON-interlaced to a monitor which can display at that resolution? If > so, where is the pinch point? > > Leonard. I asked a similar question a while back and follows is the reply from Dale Luck of Commodore-Amiga. The problem is that AGNUS is not capable of shoving the bits out to the video circuit any faster. This is a pretty common problem for most graphics hardware since there are lots of variables to account for when accessing the RAM data. ('frinstance access time, whether or not a refresh is happening, and how many pixels you get in one read.) This is necessated by the fact that the 68K shares the memory that the video stuff uses and if you tried to get 640 X 400 4 bit pixels out to the monitor every 60th of a second there would take a transfer rate of 7.68 Mbytes/sec leaving only 4% of the available 8Mhz bus to the CPU and other peripherals. --Chuck McManis ------- Begin Forwarded Message ------ Date: Thu, 31 Oct 85 10:22:18 pst From: sun!decwrl!pyramid!amiga!dale%tooter (Dale Luck) Subject: Re: Resolution and Flicker - Rumors/Solutions Organization: Commodore-Amiga Inc., 983 University Ave #D, Los Gatos CA 95030 Cc: If you think this is of interest to the rest of the net.micro.amiga please post it. You conceptually split the graphics hardware into two areas: 1 raster operations and generation of bitmap. 2 conversion of bitmap to video stream of display on monitors. details of 1. AGNUS (blitter chip) is currently capable of blitting, linedrawing, areafilling,floodfilling,clearing,text in max 1k X 1k bit area. (k = 1024 in this discusion) Couple this with AGNUS's maximum address range of 512k bytes. A 1kx1k image is 128k bytes. So it seems that a maximum of 4 bitplanes at this resolution would fit. This however leaves no room for disk buffers, copperlists, sprite buffers, audio buffers, all of which need to reside in this lower memory. details of 2. The display hardware (AGNUS & DENISE) were designed to put out standard NTSC scan rates of pixels. We extended it do go double horizontal resolution by relying on rgb monitors for crisp display, and an excellant motorola rgb to ntsc chip that does good filtering to remove much of the color aliasing. AGNUS can only display a theoretical maximum of about 240 non-interlaced lines or about 480 interlaced lines. (The actual numbers maybe 230 and 460). Horizontally AGNUS/DENISE can display nearly 350/700 pixels by stretching data fetch starts and stops. You however need a good rgb monitor to see this. The graphics.library allows you to specify display regions up to this sizes as well as split your screen into several displays. However the current version of intuition only allows displays of the size 320/640 horizontal 200/400 vertical. The display hardware is capable of dealing with bitmaps up to 64k x 64k. It however can only display as many pixels as the above paragraph describes. You can smooth scroll around in the larger bitmap though to help get around the lack of resolution. We are not saying this is the answer for everyone's problems, we do not want to over spec it, just present the facts. If you can use to help you in your work and play, and you get one, I hope we don't disappoint you. Thanks, Happy hacking Dale Luck -- - - - D I S C L A I M E R - - - {ihnp4,fortune}!dual\ All opinions expressed herein are my {qantel,idi}-> !intelca!cem own and not those of my employer, my {ucbvax,hao}!hplabs/ friends, or my avocado plant. :-}