Speed and position when redrawing

Important: unclear posts may not receive useful answers.

Before posting

  • Get familiar with Markdown to format and structure your post
  • Be sure to update lvgl from the latest version from the master branch.
  • Be sure you have checked the FAQ and read the relevant part of the documentation.
  • If applicable use the Simulator to eliminate hardware related issues.

Delete this section if you read and applied the mentioned points.


What MCU/Processor/Board and compiler are you using?

What LVGL version are you using?

What do you want to achieve?

I’m running the code below with a while statement, and when I redraw or when I put an image on the screen at the initial start, the drawing speed is slow and I start drawing from the middle of the screen or from any position.

What have you tried so far?

Code to reproduce

Add a code snippet which can run in the simulator. It should contain only the relevant code that compiles without errors when separated from your main code base.

The code block(s) should be formatted like:


## Screenshot and/or video
If possible, add screenshots and/or videos about the current state.

Which MCU do you use with what kind of display (resolution, color depth, interface)?

I am using STM32L476RG board.
The LCD is 128*128 and the color depth is set to 8.
I2C communication is being used.

Probably the I2C will be the bottleneck. You need to send 128x128x8=1.3k bits. If the I2C has 100kHz clock speed, it takes 1.3s to send the whole frame. Even if the I2C were 1MHz, it’d take 0.13sec = 7FPS.