Scrybble Sync - Think analog, organize digital
reMarkable tablets are super neat devices for taking notes at work,<br>studying, researching, sketching, journaling, planning and more.
If you ever wondered what's going on behind the scenes, this is the<br>article for you. In this article, we'll be looking at how reMarkable's<br>coordinate system works.
Note that this article is an explorable explanation, all the examples<br>are interactive, meaning you can learn from them by playing with them.
Coordinates
The reMarkable lines format stores lines in a coordinate system. A<br>common coordinate system in computer science is the cartesian coordinate<br>system. It's the same one used on high school graph paper where you have<br>an x-axis and a y-axis.
Quick recap on coordinate systems
This article is going to go dive into some detail behind these<br>coordinate systems. A little bit of background knowledge on a few core<br>concepts will make things a lot clearer to understand. We'll quickly<br>cover the cartesian coordinate system, what origin coordinates are and<br>the "screen coordinate system".
The cartesian coordinate system
A "cartesian coordinate system" is just a fancy term for the coordinate<br>system you're already used to. There's an x-axis and a y-axis. The<br>y-axis is vertical and the x-axis horizontal. Nothing special here.
Why's it called cartesian? It was named after René Descartes (you might<br>know him of "I think therefore I am" fame!).
Note there is one coordinate in this system that is really important,<br>it's called the origin coordinate, the origin<br>coordinate is always set to (0, 0).
Computers do it sliightly differently than what you're used to
When these graphs appear on paper, the origin coordinate is often<br>visually in the center. This makes sense, because when working with<br>mathematical functions, you want to show what the function does both<br>above and below 0 for both the axes.
Another common example is with bar graphs, line charts and the like,<br>where the origin coordinate tends to appears in the bottom left.
But computers are a bit of an odd duck here. If you're playing a game or<br>editing photos in photoshop, the programmers who make the pixels appear<br>on the screen are working with choices that deviate from most charts you<br>see in everyday situations:
The (0, 0) coordinate is actually in the top-left of the canvas
As you go down the y coordinate, y increases rather than<br>decreases
This system is called the Screen Coordinate System .<br>These two differences have advantages for computer programming, if<br>you're curious to learn more you can read<br>this excellent article.
That's all you need to know about the cartesian coordinate systems,<br>simple!
Now, on to the reMarkable coordinate system
reMarkable's system deviates slightly from the traditional Screen<br>Coordinate System, let's call it the<br>reMarkable coordinate system .
In the reMarkable coordinate system, the origin coordinate isn't in the<br>center, not in the bottom-right and not even in the top-left. Nope!<br>Instead, the origin coordinate is in the top middle. It<br>did make the same choice as the Screen Coordinate System to<br>increase the y-coordinate as you go down.
Where they also deviate from the Screen Coordinate System is that you<br>usually can't actually achieve a negative y coordinate. In a game, a<br>negative y-coordinate (going up) would leave your cursor above your<br>monitor. Whoops!
On the reMarkable, this is possible, because you can pan the<br>view and go above a pdf or notebook to add margin notes.
Let's look at reMarkable's tablets
As of the moment of writing, reMarkable have a total of 5 tablets. Note<br>that the rM classic and rM 2 share the same resolutions but the newer<br>tablets have different resolutions, screen sizes and DPIs!
Device<br>Resolution (px)<br>DPI (Dots per inch)<br>Screen size (mm)
rM classic<br>1404 × 1872<br>226<br>157 × 209
rM 2<br>1404 × 1872<br>226<br>157 × 209
rM paper pro<br>1620 × 2160<br>229<br>180 × 240
rM paper pro move<br>954 × 1696<br>264<br>91 × 162
rM paper pure<br>1404 × 1872<br>226<br>157 × 209
On top of these tablets different tablet sizes, reMarkable also have a<br>phone app and a webapp where your drawn annotations, highlights and<br>typed text need to show on an almost infinite variety of screen sizes<br>and aspect ratios!
Now, let's look at what happens if you tried to fit these tablets on the<br>regular Screen Coordinate System.
Note how the tablets are all anchored to the top-left origin coordinate.<br>So far, this looks totally fine.
For comparison, let's look at how this looks in the reMarkable<br>coordinate system:
Where this starts mattering is when you add pinch to zoom!
Zoomies
If you own a smartphone (or maybe a reMarkable tablet?), chances are<br>zooming feels like the most natural thing in the world to you. There's a<br>little bit of math hiding behind it! When zooming happens, you might<br>have noticed that zooming always happens around a point between<br>your fingers, this point is called the anchor .
Zoom in? Everything moves away from the anchor. Zoom out? Everything<br>moves towards...