5. Application Development Process

GFBG is primarily used to display 2D graphics by directly operating physical video memory. Its core functions use efficient video-memory management and graphics overlay to provide smooth display. It meets the high-performance, low-latency display requirements of embedded systems while supporting flexible resolution and color-depth configuration.

The GFBG application development process is shown below. Developers can design, develop, and debug the application step by step according to the flowchart and actual requirements. Proper video-memory allocation and parameter configuration maximize GFBG performance and provide a high-quality graphics-display experience.

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Figure 5.1 GFBG Application Development Flowchart

The development steps are as follows:

  • Open the VO device through the public VO API.

  • Call open to open the GFBG device.

  • Call ioctl to set the GFBG display position, pixel format, screen width and height, and other parameters. See the next section for the GFBG ioctl interface.

  • Call ioctl to obtain the physical video-memory size, stride, and other information allocated to GFBG for subsequent video-memory access.

  • Call mmap to map the physical video memory allocated to GFBG into user space and obtain its virtual address.

  • Operate on virtual memory to complete drawing, enable display, and, in standard mode, set the virtual display resolution to twice the panel resolution for higher display precision.

  • Call munmap to unmap the memory

  • Call close to close the GFBG device.