Giga Display going white with LVGL v9.2.2—what is causing this? #1004
Description
I am having trouble with the screen turning white immediately on startup and not showing anything. I'm using an Arduino Giga with an Arduino Giga Display Shield, LVGL v9.2.2, and Arduino_H7_Video.
To test the display buffer, I replaced the code in the display buffer to colour the screen red (i.e., replaced the code in the second for loop with Display.set(x, y, 255, 0, 0);). I saw the red streak through the display in blocks, and then the blocks be trailed almost immediately by black as the red continued down the screen (whether or not I had the code for lv_obj_t * screen_black = lv_obj_create(NULL); there or not), then the screen turned white. I also put a serial print in the flush callback that was outputting to the monitor. So I know that the flush callback is being called and is working.
If I replace lv_obj_t * screen_black = lv_obj_create(NULL); with lv_obj_t * screen_black = lv_obj_create(lv_screen_active());, leave the rest of the code for the screen obj, and remove the code for creating the display and buffers, the screen does appropriately turn black (with a small white border).
Any ideas of what might be going on here?
#include <Arduino_H7_Video.h>
#include <Arduino_GigaDisplay.h> // v1.0.2
#include <Arduino_GigaDisplayTouch.h> // v1.0.1
#include <lvgl.h> // LVGL v9.2.2
#include <ArduinoGraphics.h>
Arduino_H7_Video Display(800, 480, GigaDisplayShield);
Arduino_GigaDisplayTouch TouchDetector;
void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
Display.begin();
lv_init();
lv_display_t * display = lv_display_create(800, 480);
static uint8_t buf1[800 * 480 / 10];
lv_display_set_buffers(display, buf1, NULL, sizeof(buf1), LV_DISPLAY_RENDER_MODE_PARTIAL);
lv_display_set_flush_cb(display, my_disp_flush);
lv_disp_set_default(display);
lv_obj_t * screen_black = lv_obj_create(NULL);
lv_obj_set_size(screen_black, 800, 480);
lv_obj_set_style_bg_color(screen_black, lv_color_black(), LV_PART_MAIN);
lv_obj_set_style_bg_opa(screen_black, LV_OPA_COVER, LV_PART_MAIN);
lv_screen_load(screen_black);
}
void loop() {
// put your main code here, to run repeatedly:
lv_timer_handler();
}
void my_disp_flush(lv_display_t *disp, const lv_area_t *area, uint8_t *color_p) {
// Cast the buffer to lv_color_t for proper interpretation
lv_color_t *color_map = (lv_color_t *)color_p;
// Start drawing to the framebuffer
Display.beginDraw();
// Loop through the area and set pixels
for (int32_t y = area->y1; y <= area->y2; y++) {
for (int32_t x = area->x1; x <= area->x2; x++) {
// Extract RGB565 from lv_color_t
uint16_t color = *((uint16_t *)color_map);
// Convert RGB565 to R, G, B components
uint8_t r = (color >> 11) & 0x1F; // Extract 5 bits for red
uint8_t g = (color >> 5) & 0x3F; // Extract 6 bits for green
uint8_t b = color & 0x1F; // Extract 5 bits for blue
// Scale to 8-bit values (0-255)
r = (r * 255) / 31;
g = (g * 255) / 63;
b = (b * 255) / 31;
// Set the pixel color
Display.set(x, y, r, g, b);
// Advance to the next color in the buffer
color_map++;
}
}
// End drawing operation
Display.endDraw();
lv_display_flush_ready(disp);
}