shows that my Creative Labs Graphic Blaster RIVA 128ZX has accepted a new definition of the rarely used NeXT mode 1152x864. This was done with Power Strip.
My redefinition is:
Direction H V Pixel Rate 60 Hz 69 KHz 69.315 MHz Pixels 1152 864 Front Porch 0 pixels 0 lines Sync 8 pixels 2 lines Back Porch 0 pixels 0 lines
and these are all minimums for the front and back porch, but the sync vertical must, of course, be a multiple of 2, while the sync horizontal is the minimum. So this mode doesn't pad by two in available hardware and it does look like James Waldby was right about my factoring. That's a lot of pixels for about a 70 MHz pixel clock, but the zoomability is key, not the lack of retrace.
No conventional analog CRT can display this mode, but I intend to build or configure one to do exactly that. I will need a stereo audio amp, two signal generators with trigger or phase lock, and either my Tek scope or a monitor I can pull apart, at the minimum.
Doug Goncz Replikon Research Falls Church, VA 22044-0394
shows a slightly modified version of the redefinition in the referenced post, but this seems to be a more correct timing calculation. Here is the modeline and associated information:
Now you must understand this is designed to be displayed *diagonally*! The second active pixel in the first scan line will show, with the correct deflection waveforms, at screen coordinates (2,2), using a 1 basis for the origin in the upper left, that is, an origin of (1,1). I have not checked common factors for this "mode".
Doug Goncz Replikon Research Falls Church, VA 22044-0394
ClearEdge VM wideband velocity modulation improves the definition at picture edges, creating sharper images by slowing the CRT (cathode-ray tube) beam's horizontal scanning during demanding work--say, when rendering transitions from light to dark parts of an image--and speeding it up when scanning easily rendered sections, like broad dark areas.
So it seems there are some possiblities for other than standard constant velocities in raster scanning.
Doug Goncz Replikon Research Falls Church, VA 22044-0394
I would do this by running the sync signals into the line inputs and writing a program to synchronize wave outputs or perhaps MIDI outputs to the amp if it there were any reason to keep the hardware compact and PC based. There would be some drift and constant correction because the video and audio use separte clock crystals.
Doug Goncz Replikon Research Falls Church, VA 22044-0394
It will require less hardware. The drive for H and V is the same circuitry operating at the same potentials. A conventional audio amp can be used for drive.
Phase requirements can eventually be met to provide a clear picture.
The method *is* a raster method; the subblocks are not scanned. (In an image processing analysis, I scanned the subblocks and applied transforms. Good results comparing conventional sawtooth raster, full raster diagonal, and sub-block diagonal at ftp://users.aol.com/DGoncz)
If PowerStrip's flexbility is any indication, random adapters will work with random monitors. Note that such a diagonal monitor is capable of a nearly continuous range of modes starting with 4x6, through 480x640 (padded), on up to huge resolutions like 4096x4096 (padded), which can be displayed with no flicker at low frame rates due to some characteristics of the eye I have looked at.
Coprime H and V scanned without blanking padding produces a display that doesn't loop. The presence of a *sole* common factor of 2 between H and V allows looping. No retrace, no high voltage flyback. The cell basis underlying the monitor idea is a minor refinement: transmitting pixels in this order preserves something called adjacency, keeping interruptions in transmission to small areas. Strangely enough, even multidimensional blocks of data can be scanned diagonally with subblocks to preserve adjacency.
Actually for the modes listed, padding by two (n=2) does cause the loop to exit on the first try through the while. There's no point in padding by one as below. The modes really need to stay even/even.
Here is some program output that does:
I note that the 13th colum is all twos. The 13th headder is ## (+2, +2) So we agree. All the modes listed here can be padded by two to get a sole common factor of two. All the modes (not an identical list) in Modes.gif can be padded by two to get this same sole common factor. It works. Yes, my program wasn't well written.
Thanks very much, I should read up and PowerStrip writes modelines for me now. There are many more modes available with diagonal scan than manufacturers have agreed on so far, and they are available in flexible ways with little variation in screen results when rates are pushed.
As soon as I get a nag screen in PowerStrip I'll pay since I *am* using it.
Here's the smallest diagonal mode that loops:
x a i h p q w j b o g r k v n c s f l m u t d e
Where pixels 1-24 in the 4x6 block are label a-x. The first pixel is one from the corner, but it's a loop, so that doesn't matter....
Doug Goncz Replikon Research Falls Church, VA 22044-0393
I noticed some kind of adjustable pixel clock in PowerStrip and wonder if any pixel clock is the same as or can be locked to the sample rate of an audio stream.
Doug Goncz Replikon Research Falls Church, VA 22044-0394
you'd be hard pressed to find any pixel clocks below 500Khz, (most are well over 5Mhz) but audio can possibly be resampled or interpolated to get a similar effect.
I have written a Mathcad worksheet using what I call the "snarl transform", which is 1-to-1, to load the R, G, and B planes with X, Y, and Z data. It takes a minute to run, but it does what it is supposed to. The display will be imperfect if I don't get the modeline above to work under Windows 98.
I suppose I could live with an imperfect display, but for any real potential to be had from this monitor design, I need an unblanked display mode that simply streams pixels out at variable rates in a frame with even edges but no other common factor between edges.
*sigh*
Is this a hardware or a software limitation?
Doug Goncz Replikon Research Falls Church, VA 22044-0394
(which mentions a tweaking program that might be useful to you) I thought that typical PC display hardware requires a bunch of those numbers to be multiples of 8; however, that web page mentions resolution 360x270 so I now don't know what the hw limit is.
BTW, I think "X Windows System modeline" would be a bit better phrase than "Linux modeline", and that you should attach an [OT] marker to the subject for rec.crafts.metalworking.
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