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Bitmap image conversions

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3 hours ago, Tursi said:

Looks great! For the astronaut one, you have a bit of black border at the left which is causing the first column of pixels to look stretched (as the black is considered more important to preserve than the detail in the moon's surface) - crop out the black border and it should convert better. 

First, I added a bunch more, with links to the source at APOD, plus 9918A versions.

 

I checked the astronaut picture, and the black border comes in because the image is 509 x 385. I had to crop out some white pixels on the edges.

Is the black bar just filling empty space then?

 

Here's some details of that one, before and after Convert9918:

 

plum_apollo16_big_crop_hist0.png.600ed03178cd8f3e8cef6ae12c1c29f1.png     plum_apollo16_big_crop_hist1.png.d917ea04dc0a005bc79595b5f18a0f44.png

 

 

 

 

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10 hours ago, FarmerPotato said:

I checked the astronaut picture, and the black border comes in because the image is 509 x 385. I had to crop out some white pixels on the edges.

Is the black bar just filling empty space then?

The new pics and the comparisons are nice! I know about APOD. :)

 

Yes on the sizing. Convert9918 will take whatever image you give it, and resize it to fit according to the "Fill Mode".

 

In "Default", the entire image is scaled to fit on the screen, with black bars filling the remains. If you watch the text output, you'll see that it checks each dimension, then checks the larger scale, scaling both axes by it. 509x385 will probably size to 253x192, leaving 3 pixels to be filled to get 256 across.

 

Generally, I prefer to crop the image to get more pixels, and that's what the other three modes do: Top/Left, Middle, and Bottom/Right just specify which part of the image you want to focus on. Most of the time you want "Middle", but Top/Left is usually good for portraits. This uses the smaller scale of the two axes, and lets the other axis hang off the edge to give you more pixels in the image -- in effect this fills the screen.

 

Alternately, for finer control, crop the image in your favorite PC tool then resize to 256x192, and the tool will know that no resize is needed. :)

 

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I updated Convert9918 last night after seeing the results @Asmusr gets with his 4x1 pseudo-mode. I already had a color-only conversion mode, but it only used the background color, giving 8x1. (There was a reason for that, but I didn't like the results so I didn't take it any further). Now it does the 4x1, with the assumption the pattern table is loaded as all 0xF0, and the results are not bad at all. So the advantage is that the image only needs 6k of data (you still need all the tables in VDP, of course, I haven't looked at how much the masking might help, if it does).

 

image.thumb.png.98d6b8aee00d0ec14eb4225d5755d862.png

image.thumb.png.8fe8932f5078aa9d3c09c14ebf0df686.png

image.thumb.png.6a52d8cd0c316420fa220d98ab4336dc.png

 

Would this have allowed a full-screen Dragon's Lair? It's the same amount of data, but... I think the answer is "not quite". It does result in a loss of resolution which is really too much. DL shipped with a horizontal resolution of 192, but this is only 64.

 

image.thumb.png.88104f318a7b4abe56731b8ffe8dc7eb.png

 

As always: http://harmlesslion.com/software/convert9918

 

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There was a short chat about black and white images in the Classic99 thread, so I did an experiment to see if treating the full palette as black and white resulted in better image conversion. It seems to, so I kept it. Of course, for it to work the output display needs to be a black and white monitor, or a color monitor with the saturation turned all the way down (you can do this in Classic99 too)... the palette doesn't have enough greys even with this to be fully successful, but it does come out a little better, and sometimes even looks better than the color version, since your eyes aren't fighting the dither and fringing as much:

 

p1.png.d63caf90bca083eeab293f029e866e9c.png

This is the greyscale bitmap output... normal 9918A but with zero saturation.

 

For comparison, here's the color:

t2.png.f7d830ad11a9e975de2715e443c27d7b.png

 

And here's the straight up monochrome:

t3.png.5f3fca649df93b4c8b592968c7c02739.png

 

Just to show the difference, the greyscale version with colors active looks like this:

t4.png.619ecba16f46d94b98ea34ebc825671c.png

 

Anyway, I've updated Convert9918 again to reflect this mode. ;)

http://harmlesslion.com/software/convert9918

 

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54 minutes ago, Tursi said:

Just to show the difference, the greyscale version with colors active looks like this:

t4.png.619ecba16f46d94b98ea34ebc825671c.png

Predator-vision engaged.  Thankfully, he only hunts in tropical climates.

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10 hours ago, OLD CS1 said:

Predator-vision engaged.  Thankfully, he only hunts in tropical climates.

Which is absolutely is not here... ;)

 

image.png.86bde431912e976c47fc69ea8ed44a18.png

 

And that's getting warmer. ;)

 

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-17°C? I think last time I saw that temperature, I was at the top of a mountain in the Alps. We currently have the usual pre-Christmas +6°C warm weather here in Germany which means again abandon all hope for a white Christmas, but let's see what the next seven days are like. (lat. ~50°N)

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Not as bad here at -9o C but it's not even winter yet... 😬 We may still catch up with you Mike!

A little trivia: We've hit -40o F on several occasions with wind chill locally over the years, and at that temperature F and C are equivalent!

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If you did not grow up with one of these pinned to the wall next to the front door, you never truly lived.

 

2074141332_windchillchart(large).thumb.jpeg.752d2229358d628937105832b5153be3.jpeg

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7 hours ago, Tursi said:

Which is absolutely is not here... ;)

 

image.png.86bde431912e976c47fc69ea8ed44a18.png

 

And that's getting warmer. ;)

 

I'm thinking Alberta... like somewhere around Edmonton.

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13 hours ago, TheBF said:

I'm thinking Alberta... like somewhere around Edmonton.

Somewhere... ;)

 

image.png.21737c5ba79b5b4f2ba1477c2ee78f35.png

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15 hours ago, Vorticon said:

Not as bad here at -9o C but it's not even winter yet... 😬 We may still catch up with you Mike!

A little trivia: We've hit -40o F on several occasions with wind chill locally over the years, and at that temperature F and C are equivalent!

We warmed up a little today - not as much as predicted but it got to -1C. We're back down to -10 now and could be down to -22C by Monday.

 

-40 is possible here too, though seems it's less common than when I lived in Ottawa. ;)

 

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It's still interesting to see how different the climate areas are between the American continent and Europe. As I said, I'm living somewhere near 50°N latitude, while Ottawa is at 45°N, and in this year, up to today, we had minus degrees (C) probably on one or two days - at most -, early in the morning. Right now (taking a look at my weather station) we have 17:55h and about +7°C. If I remember correctly, last winter I did not even see a single snow flake. (Just checked, Vancouver is at 49°N, Calgary at 51°N.)

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8 hours ago, Tursi said:

Try Zed instead of Zee. ;)

I was today days old. Ugh, I hate that phrase.

 

Anyway, where I grew up we routinely had winter temperates in the negative teens. Plus the wind blows there a lot. My dad was working on out on the flight line one morning with a wind chill of -80.  During my last visit, one overnight temp was -18.

 

Call me crazy, but I miss that weather.

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12 hours ago, TheBF said:

I had never heard of -40C in Ottawa so I checked.

-38 is as cold as I can see there.

 

Ottawa ON Lowest Temperature Each Year - Current Results

 

I can't tell you what that webpage's source is, but it was most certainly colder than -40C in Ottawa when I lived there between 91 and 95. I checked the temp every morning before stepping outside to wait for the bus, and when my brother came out, I made him go for a walk in it. ;)

 

The website does say "Downtown Ottawa", which isn't where I lived at the time. Temps can vary... and the wind chill often took it lower. (I guess it's possible I only remember the post-wind-chill temp ;) )

 

 

Edited by Tursi
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10 hours ago, mizapf said:

It's still interesting to see how different the climate areas are between the American continent and Europe. As I said, I'm living somewhere near 50°N latitude, while Ottawa is at 45°N, and in this year, up to today, we had minus degrees (C) probably on one or two days - at most -, early in the morning. Right now (taking a look at my weather station) we have 17:55h and about +7°C. If I remember correctly, last winter I did not even see a single snow flake. (Just checked, Vancouver is at 49°N, Calgary at 51°N.)

Yeah, Calgary is definitely the furthest north I've lived since I was a kid (the furthest then was Fort St James, at 54 degrees). But the Rocky Mountains make a big difference in North America. It's nearly always much warmer on the west side of them than the east. ;)

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