TI994A TMS9918 palette file for GNU Gimp?

[jrhodes]

 Does anyone have a palette file that i can import into Gimp to limit a image to the exact colors of the TMS9918?

[atrax27407]

Check this thread - there is some info that might be of value there.

 

RELEASE: GIF 99 Viewer for V9938/58 Systems v1.05 by O.P.A. - TI-99/4A Development - AtariAge Forums

 

[Gary from OPA]

23 hours ago, jrhodes said:

 Does anyone have a palette file that i can import into Gimp to limit a image to the exact colors of the TMS9918?

Check out this neat program by @Tursi called Convert9918 it does wonders to match the color set on the 9918.

 

http://www.harmlesslion.com/software/convert9918/

 

Quote

This program can convert most modern graphics into a form compatible with the TMS9918A bitmap mode. It supports a drag-and-drop interface and handles resizing and scaling, several forms of user-configurable dithering, adjustable color selection, and more.

It also supports multi-color (64x48) mode, a dual-multicolor mode with flicker, and a half-multicolor mode that flickers multicolor with bitmap to get more colors.

Finally, it also supports two palette modes for the F18A VDP replacement - a 16-color palette mode, and a per-scanline palette mode (this mode uses most of the VDP RAM and requires the GPU to update the palette every scanline, but because it runs on the GPU the host CPU is not impacted at all!)

While it supports writing raw data for pattern and color tables, it also supports writing MSX SC2, Coleco CVPaint, Adam PowerPaint, ColecoVision ROM, and TI Extended BASIC images.

 

[Tursi]

That said... the TMS9918A doesn't /have/ exact colors.

 

If you search the forum, you will find a lot of discussions, some heated, over what is "correct". But this is an analog device. The taps inside the 9918A for color were hand-set, and even the chip designer (IIRC) was not 100% sure the datasheet values are correct. After that, it runs through analog filter circuitry that varies per platform, to a display with (usually) manually adjusted settings for hue, brightness and contrast.

 

I have the palette I use in Classic99 -- and Convert9918A will dump that palette into the configuration file if you want an easy way to pull it. But I have half a dozen other palettes that are also logically likely.

[Tursi]

As for the download link above - please don't repost my software. Would prefer to only support the latest version

 

[Gary from OPA]

16 minutes ago, Tursi said:

As for the download link above - please don't repost my software. Would prefer to only support the latest version

 

Sorry about that. Maybe a moderator can remove the attachment. I put the direct url to your site. I can't edit the post in this forum.

Edited May 12 by Gary from OPA

[+OLD CS1]

Just now, Gary from OPA said:

Sorry about that. Maybe aod can remove the attachment. I put the direct url to your site. I can't edit the post in this forum.

Done.

[Gary from OPA]

Just now, OLD CS1 said:

Done.

Thanks for that.

[Gary from OPA]

23 hours ago, jrhodes said:

 Does anyone have a palette file that i can import into Gimp to limit a image to the exact colors of the TMS9918?

Some more info:

 

1.1) Colours

Taken from mess/vidhrdrw/tms9928a.c in MESS, by Raphael Nabet.

The first 3 columns are taken from the TI datasheet (in volts). The next 3 
columns are based on this formula:

	Y = .299*R + .587*G + .114*B (NTSC)

The coefficients are likely to be slightly different with PAL. I assumed the 
"zero" for R-Y and B-Y was 0.47V. The last 3 coeffs are the 8-bit values.

Colour           Y     R-Y   B-Y   R     G     B     R    G    B
0 Transparent
1 Black         0.00  0.47  0.47  0.00  0.00  0.00    0    0    0
2 Medium green  0.53  0.07  0.20  0.13	0.79  0.26   33  200   66
3 Light green   0.67  0.17  0.27  0.37  0.86  0.47   94  220  120
4 Dark blue     0.40  0.40  1.00  0.33  0.33  0.93   84   85  237
5 Light blue    0.53  0.43  0.93  0.49  0.46  0.99  125  118  252
6 Dark red      0.47  0.83  0.30  0.83	0.32  0.30  212   82   77
7 Cyan          0.73  0.00  0.70  0.26	0.92  0.96   66  235  245
8 Medium red    0.53  0.93  0.27  0.99	0.33  0.33  252   85   84
9 Light red     0.67  0.93  0.27  1.13! 0.47  0.47  255  121  120
A Dark yellow   0.73  0.57  0.07  0.83	0.76  0.33  212  193   84
B Light yellow  0.80  0.57  0.17  0.90	0.81  0.50  230  206  128
C Dark green    0.47  0.13  0.23  0.13	0.69  0.23   33  176   59
D Magenta       0.53  0.73  0.67  0.79	0.36  0.73  201   91  186
E Gray          0.80  0.47  0.47  0.80	0.80  0.80  204  204  204
F White         1.00  0.47  0.47  1.00	1.00  1.00  255  255  255

 

[jrhodes]

On 5/10/2024 at 9:43 PM, atrax27407 said:

Check this thread - there is some info that might be of value there.

 

RELEASE: GIF 99 Viewer for V9938/58 Systems v1.05 by O.P.A. - TI-99/4A Development - AtariAge Forums

 

The MSX palette from this thread is perfectly fine for my use, thanks for pointing it out to me.

[atrax27407]

Tursi's Convert9918A is a really valuable program for converting PC pics to a TI-ARTIST format ( i.e., _P and _C files). I have used it to convert a bunch of pics for use with the SPLASH program by @InsaneMultitasker. Will GIMP handle those files?

  

[Artoj]

On 5/11/2024 at 12:25 PM, jrhodes said:

Does anyone have a palette file that i can import into Gimp to limit a image to the exact colors of the TMS9918?

Using the palette Gary supplied, I colour tested each one in GIMP.

 

R        0.0     37.3    50.6    32.9    48.6
G        0.0     77.3    85.1    33.3    46.3
B        0.0     33.3    51.0    89.4    95.7
HTML    000000   5fc555  861982  5455e4  7c76f4

R        77.3    47.5    91.4    93.3    82.0
G        35.7    91.0    38.0    50.6    76.1
B        32.2    95.3    35.7    48.6    39.6
HTML    c55b52   79e8f3  e9615b  ee817c  d1c265

R        88.6    32.9    73.3    80.0    100
G        81.2    68.2    38.0    80.0    100
B        54.1    29.8    71.0    80.0    100
HTML    e2cf8a   54ae4c  bb6165  cccccc  ffffff

 

[+Vorticon]

On 5/12/2024 at 7:14 AM, atrax27407 said:

Tursi's Convert9918A is a really valuable program for converting PC pics to a TI-ARTIST format ( i.e., _P and _C files). I have used it to convert a bunch of pics for use with the SPLASH program by @InsaneMultitasker. Will GIMP handle those files?

  

I use Convert991A to convert a PC image to a TI Artist format, then use TI Artist to clean up the image as needed. Fantastic tool.

[Tursi]

On 5/12/2024 at 6:14 AM, atrax27407 said:

Tursi's Convert9918A is a really valuable program for converting PC pics to a TI-ARTIST format ( i.e., _P and _C files). I have used it to convert a bunch of pics for use with the SPLASH program by @InsaneMultitasker. Will GIMP handle those files?

  

Convert9918A will export PNG

 

[atrax27407]

Thanks, didn't know that!