 Previous Messages |
Posted By
Murphy
on 2024-12-10
10:19:34
|  Re: Image file formats
Yes, something like that, but you can map the color memories and the bitmap "anywhere", and there are 4 additional color memories for the lower bitmap. My goal was just to demonstrate that there can be many different FLI formats.
At 200 high images, the memory allocation of the Bubis converter is a logical option.
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Posted By
Spektro
on 2024-12-10
10:27:10
 | Re: Image file formats
Okay, so you used the following memory configuration:
$4018 Luminance & color 0
$4818 Luminance & color 1
$5018 Luminance & color 2
$5818 Luminance & color 3
$6018 Unused
$60c0 Bitmap 0
$80c0 Bitmap 1
Did I get it right?
I looked at bubis's DFliConv and it seems to use the following memory configuration for displaying an MCFLI image (multicolor FLI, 160x200 px):
$2000 Luminance & color map 0
$2800 Luminance & color map 1
$3000 Luminance & color map 2
$3800 Luminance & color map 3
$4000 Bitmap
$6000 Color table for $ff15 and $ff16 (size: 456 bytes)
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Posted By
Murphy
on 2024-12-10
06:35:39
| Re: Image file formats
This question is tricky because so many formats are possible.
If you want to rasterize both $ff15 and $ff16 in every line, then those arrays are only temporary storage, as you need to generate a rendering routine that contains the register values.
Because this is a software video mode, many variations are possible. There could be an FLI image where you don't rasterize the colors or only rasterize the $ff16 register. But there are also versions where even $ff07 is adjusted line by line, further improving the achievable image quality.
For instance, IstvanV’s converter supports images up to 248 pixels high. This means it uses two bitmaps and eight color memories, as that's the only way to display such an image physically. He even uses a trick where the bitmap and color memory are shifted by 24 characters, so the machine's internal counters reset only at the end of the 25th line, rather than in the middle of the line as would normally happen in the 26th character row. The lower bitmap and color memories can now start with the first byte of their page.
I also use the same technique in the Carrion's 121 Colors slideshow.
https://plus4world.powweb.com/software/Carrions_121_Colors
So, in this case, the upper bitmap data starts not from $6000 but from $60c0, and the associated color memories start not from $4000 but from $4018.
So, it might not make sense to talk about an image format without having a real file format as a reference.
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Posted By
Spektro
on 2024-12-09
06:58:50
| Re: Image file formats
I completely made it up. It's not based on anything. I created it so that we have something to start with.
So, for starters I need to reduce the number of luminance-color arrays to 4. What about the two color arrays that I imagined to be used for changing the color registers $ff15 and $ff16 on every raster line?
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Posted By
Luca
on 2024-12-08
11:31:00
 | Re: Image file formats
What Murphy said.
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Posted By
Murphy
on 2024-12-08
12:51:19
| Re: Image file formats
@Spektro There can be many different FLI modes, which is why it is difficult to write about. What editor format did you describe?
If there are 8 colormaps, can this be interlace mode? We usually use 4, because of the double badlines. Colormap 6 is mentioned 2 times in the description, the last one I think is 7.
It is very difficult to check the numbers now, because you write the values in decimal mode. As a programmer, this is strange to me, because I always think in hexadecimal numbers for memory addresses.
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Posted By
Spektro
on 2024-12-08
07:24:43
| Re: Image file formats
There is now a FLI format description but it really needs to be reviewed. Someone who has made a FLI viewer should take a look if the file format makes any sense.
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Posted By
Spektro
on 2024-12-07
07:41:57
| Image file formats
Hi, in the Plus/4 Encyclopedia there is now an Image File Formats article with a little help from Luca.
FLI image formats are missing from the article because I couldn't find enough info on them. Can anyone help with that? It would be great if FLI file formats were documented there, too.
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