screenshots on website

[not_a_commie]

I noticed that the new CivilFEM screenshots posted were in JPEG format. That's an embarrassing faux pas in my book. They should be PNG. I see this all the time. I'm not sure how to educate people on this.

[FlyingIsFun1217]

I noticed that the new CivilFEM screenshots posted were in JPEG format. That's an embarrassing faux pas in my book. They should be PNG. I see this all the time. I'm not sure how to educate people on this.

So...?

FlyingIsFun1217

[Virion]

They should be PNG.

why?

[Spintz]

WOW, I'm convinced, I'm not used JPG anymore.........................

[not_a_commie]

why?

JPG is for photos. It was designed for photos. Photos usually have no two pixels of the exact same color. The compression used in JPG takes advantage of how our eyes are sensitive to color to toss color information and thus reduce the size of the image. It chops it into 8x8 blocks, converts each to YUV, runs the discrete cosine transform on each channel in each block, quantizes the results (depending on the channel), etc.

This is a fine plan for photos, but a terrible plan for black text on a white background. PNG is lossless; it's not going to blur your text. In the average screen shot, it is typical to have an entire row of pixels all the same color. PNG, GIF, and other RLE image compression techniques can take advantage of this to store that information in a very small space. ("200 Whites" vs. "white, white, white...") PNG is not an RLE scheme per se, but uses a prediction technique that leads to a similar result. For the average screenshot, PNG will produce a file that is totally lossless and smaller than a JPG that blurs the text. If you crank the JPG quality on a screenshot to a level that you can see no blurring at all, it will likely be larger than a raw BMP of the screenshot.

[hybrid]

Since 3d rendering aims at producing photo-realistic results in real-time it seems to be reasonable to keep JPEG for a while

[3ddev]

I agree that JPG might not be the best format, but then again, if anyone finds the download times are an issue due to the increased sizes, they should consider getting a better internet connection. I really wish PNG would have better transparency support and also support for animation, like GIF.

[Ico]

Maybe you confuse something? PNG has a full alpha channel while GIF only supports one transparent palette entry?

Oh and there is an "animated" format featuring PNG/JPEG out there called MNG.

Would be great to somehow use it (or another animated format) for animated textures.