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I was a 12 year old when I learned about them :) The idea of a pixel is that it's the smallest area of the screen that can be independently controlled, thus th
by gamacodre 6y ago
I was a 12 year old when I learned about them :)
The idea of a pixel is that it's the smallest area of the screen that can be independently controlled, thus the designation "pixel" for "picture element".
In most modern phone screens or monitors, each pixel is formed by a group of three smaller elements with fixed colors (usually red, green, and blue) but _variable brightness_. By controlling the brightness of these sub-elements, we can control what the overall color of the pixel appears to be - once you get more than an inch or two away from the screen, the light from the element group blends into what we see as a single color - so 100% green + 100% red + 0% blue looks like bright yellow. 50% each for red, green, and blue looks like a middling grey. You can usually see the structure of the pixel with a magnifying glass, though this is easier with an old TV or monitor than a modern phone.
These pixels are laid out on a regular rectangular grid, and your display controller will offer some way to set the color of each pixel and to then update them all at some (usually) regular interval, for example 60 times per second. In computers, it's common to keep a "frame buffer" around that stores separate values for the red, green, and blue components of every pixel on the screen. If these are 8-bit values, that implies that each R/G/B component can have 256 different levels of brightness, and in combination they allow each pixel to take on one of about 16,000,000 possible colors. So, a program can change pixel colors by writing different values into this buffer and waiting for the updated buffer to be processed by the display controller to change what the display is showing.
Of course, the electronics, physics, chemistry, timing, and logic of display generation have changed quite a bit since Pong. And not all displays even have pixels - vector displays used to be a thing, and are still used in some very specialized applications.
- aperrien 6y agoI appreciate the explanation, but it's not for me. I'm trying to find a good book to recommend to my grandkids. I've had fun teaching them how to use old retro computers (c64, Apple II, and such). It's been a fun experience, but I'd like to give them some references that aren't me! I've personally come a long way in my computing skills since I was staring at shiny new Pong screens :)
- TimBurr 6y agoThinking of when I was 12 (2005?), microscopes and magnifying glasses helped me understand. Depends on device DPI (cell phones have an insane number of pixels per inch; desktop screens are usually less dense). If you can zoom in enough to see subpixel elements, and pull up a color wheel, it's very intuitive to see that the screen is made of pixels, and the pixels are made of three elements. https://en.wikipedia.org/wiki/RGB_color_model#/media/File:AdditiveColor.svg https://en.wikipedia.org/wiki/RGB_color_model#/media/File:Ad... The Pico-8 might be a approachable way to explore retrocomputing. It's an in-browser console modelled after GameBoy-era consoles. https://news.ycombinator.com/item?id=18240375 https://news.ycombinator.com/item?id=18240375 I don't know about books, though. I remember reading the binary/computers chapter of How Things Work and being thoroughly confused at that age. There was some extended allegory about white mammoths and black mammoths.
- drewzero1 6y agoDid you have The Way Things Work or The New Way Things Work? I had the latter around the same time. I thought the extended computer section (Bill's Gates!) was very helpful. I still really like the visual in which the image of a mammoth is turned into a series of pumpkin/no pumpkin signals being launched through the air, then becomes a picture of a mammoth on the other side of the field. I think it got a bit too technical for me when it started showing how transistors are constructed-- I guess I should've stuck with the pumpkins. Now I have both editions and have looked through them side-by-side. It's a bit unfortunate that some pages were dropped to make room for the expanded digital section in the newer edition, but well worth the trade-off for more/better explanations in the digital realm.
- TimBurr 6y agoI'm not sure. Possibly both? Just took a look over my bookshelf, but they haven't made it with me through moves. I do still have Incredible Cross-Sections. That was another of my favorites to flip through. It looks like there are reprints and new versions. Would definitely recommend for kids. https://www.amazon.com/Stephen-Biestys-Incredible-Cross-Sections-Richard/dp/0679814116 https://www.amazon.com/Stephen-Biestys-Incredible-Cross-Sect...
- a9h74j 6y agoI once bought a schematic for a DIY pong. IIRC it used monostables and integrators to control timings -- scan frequencies yes but no strict pixels needed.