The 2025 LVGL Checklist: 7 Critical Implementation Tips

// 1. Create a style
lv_style_t style_btn;
lv_style_init(&style_btn);
lv_style_set_bg_color(&style_btn, lv_palette_main(LV_PALETTE_BLUE));

// 2. Set the style for the pressed state ON THE SAME STYLE OBJECT
lv_style_set_bg_color(&style_btn, lv_palette_darken(LV_PALETTE_BLUE, 2));

// 3. Add the style to the object for both default and pressed states
lv_obj_add_style(btn, &style_btn, LV_STATE_DEFAULT);
lv_obj_add_style(btn, &style_btn, LV_STATE_PRESSED);

A poorly implemented display driver is the number one cause of bad LVGL performance. It’s tempting to copy-paste an example driver and call it a day, but this is where you need to be meticulous.

DMA is Your Best Friend

Your flush_cb function is called when LVGL has a portion of the screen ready to be sent to the display. If your CPU is busy bit-banging pixels over SPI or a parallel bus, it can't do anything else. Use Direct Memory Access (DMA) to handle this transfer. DMA allows the data transfer to happen in the background, freeing your CPU to start rendering the next frame. Your flush_cb should simply configure the DMA transfer and return immediately. Don't forget to call lv_disp_flush_ready() from the DMA transfer-complete interrupt!

Double Buffering is (Usually) Not Optional

Use at least two screen-sized buffers (or large partial buffers). This allows LVGL to render into one buffer while the other is being sent to the display via DMA. This technique, often called a Vertical Sync or VDB (Virtual Display Buffer), completely eliminates screen tearing and is essential for smooth animation.

4. Get Smart with Memory Management

Microcontrollers have limited RAM, and a GUI can be a memory hog. LVGL gives you control, but you need to use it wisely.

• Static Allocation: For maximum stability, you can configure LVGL to use a large, statically allocated array for its memory pool (LV_MEM_SIZE in lv_conf.h). This prevents heap fragmentation that can occur with standard malloc() and free() over long runtimes.
• Know Your Needs: Use LVGL's built-in memory monitor (LV_USE_MEM_MONITOR) during development to understand your UI's peak memory usage. This helps you size your static pool correctly without wasting precious RAM.
• Custom Hooks (LV_MEM_CUSTOM): If you're using an RTOS with a more robust memory management system or need to place the LVGL memory pool in a specific RAM region (like external PSRAM), use the custom memory hooks to integrate LVGL with your system's allocator.

Don't just set LV_MEM_SIZE to a random large number. Profile your usage and allocate what you need.

5. Leverage the Component Ecosystem (SquareLine & Beyond)

Writing a complex UI entirely in C code is slow and error-prone. The modern LVGL workflow embraces visual design tools. SquareLine Studio is the official UI editor for LVGL and is an absolute game-changer. It allows you or a designer to build the entire UI visually, create animations, and structure the flow, then export it as clean C code. Using SquareLine can cut development time by 80-90%.

Beyond SquareLine, the LVGL community is vibrant. Before you build a custom widget from scratch, check the LVGL Marketplace and official forums. Chances are, someone has already built that fancy chart, keyboard, or settings menu you need.

6. Don't Neglect Input Handling

A beautiful UI is useless without responsive input. LVGL's indev (input device) driver provides a clean abstraction for any kind of input:

• Touchscreens: Calibrate your touch controller! An uncalibrated screen is a frustrating user experience. Your read_cb for touch should provide both the state (pressed/released) and the X/Y coordinates.
• Encoders & Buttons: For non-touch UIs, physical buttons and rotary encoders are king. LVGL's group feature (lv_group_t) makes it incredibly easy to create focus-based navigation that works seamlessly with keypads and encoders. You can navigate between widgets without a single line of custom logic.

The key is to properly link your physical input driver (e.g., your I2C touch driver or GPIO button handler) to the LVGL indev callback. This keeps your hardware-specific code separate from your UI logic.

7. Profile, Profile, Profile!

You can't optimize what you can't measure. LVGL includes fantastic, low-overhead profiling tools that you should enable during development.

In lv_conf.h, set LV_USE_PERF_MONITOR to 1. This will display a small, real-time overlay showing critical stats:

• FPS (Frames Per Second): The ultimate measure of UI smoothness. Aim for 30+ FPS for a good experience.
• Render Time: How many milliseconds your CPU (or GPU) spends drawing a frame. If this is high, you need to simplify your UI or optimize your rendering path.
• Flush Time: How long it takes to send the frame to the display. If this is high, your display driver (Tip #3) is the bottleneck. DMA is the answer.

Similarly, enabling LV_USE_MEM_MONITOR gives you a real-time view of memory usage, helping you catch leaks and size your memory pools correctly (Tip #4).

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Conclusion: Build with Confidence

LVGL is an incredibly capable library that empowers developers to create UIs that were once unimaginable on microcontrollers. But with great power comes the need for great discipline. By following this checklist—optimizing your drivers, managing memory intelligently, using modern tools like SquareLine, and constantly profiling your performance—you're not just building a UI. You're engineering a professional, stable, and delightful user experience.

Now go build something amazing.