CanvasX

I have this design description to create:

Step 1: Default state is type on white background.

Step 2: Cursor tracks and you draw.

Step 3: If you fill the whole screen red, then cursor draw changes to white colour.

Step 4: You draw in white.

Step 5: If you fill the full screen with the drawing, you're back to step 1 with a full white background.

I have completed the task till Step 2 but unable to change color once entire screen is filled with red color.

So in short, Once the users fills the box with red color, I want to change the color to white. And in same way once the box is filled with white color I want to change it back to red.

Please check the codepen for code - https://codepen.io/chiragjain94/pen/dyOzqGy

Shouldn't field be undefined on line 50? It was my understanding that inner nested classes did not have visibility to outer classes, as I ran into on line 65... Just seems kind of inconsistent and I would love to have a better understanding of the outer nested classes visibility to avoid any confusion in the future.

I found a beautiful script for making a snipp from actual window here on Stackoverflow and I'd love to use it in the personal application that I'm creating. But I think I'm missing something big here and I don't understand why it's not working.

I apologize for the code, it's in a state I'm actively playing with.

In Konva JS, I'm creating labels. Which is basically a group, it has a shape and text element. The shapes are drawn dynamically from a database, and each db row has the coordinates, the shape (square, circle etc), size and rotation. These are multiplied by a scale depending on screen size. I had a working solution, which I've been using for weeks, but I also have a function that changes the shape of a shape. So I press a button, it updates the database (e.g changes square to circle) and then redraws the canvas. Because going from a square to a circle changes from a shape that's drawn from the top left to one that's drawn from center, it messes up the coordinates. I decided to switch to drawing rectangles with an offset of width/2 so that rectangles are drawn from the center too.

I have subsequently kept breaking it further and I now can't get text centered at all. I need text centered regardless of shape, size or rotation.

current code

I'm making and UI for a Tangram (puzzle with different polygons) using tkinter in Python and I'd like to keep track of the coordinates of each point of each polygon when they move around my canvas.

To do so, I created this class:

I tried to see the difference between a window coordinate and a canvas coordinate by giving a canvas a callback that prints the coordinates of a mouse click in both types. I expected the two types of coordinates to have different values, but they didn't. Also, I tried to pass window coordinates to the find_closest method which, as stated in the documentation, accepts canvas coordinates, and there was no error.

Although the code work just fine if we draw the rectangle without scrolling the canvas or page. But in case we do scrolling, the rectangle do not appear on the screen from the point where we start to drag the mouse.

I've got a Javascript file which draws a canvas with circles. If I click on a circle, the color must change. This works, but the eventHandler fires many times with one click. Because of this, the program lags a lot. How do I improve this?