Hi chenjun,
LVGL (v7.10.1) in GUI Guider v1.2.0 only supports portrait mode on 720x1280 display of i.MX RT1176. When the width of APP is greater than the height, the APP will be displayed in top partial area of the display. In order to support landscape mode, the MCU needs to rotate the frames either by software or by PXP or GPU.
The rotation function by CPU is implemented in LVGL v7.11.0+, GUI Guider v1.3.0 in Jan/2022 will support LVGL v8.x, the landscape mode will be supported in the release.
Best Regards,
Zhenhua