DISPLAY API

The DISPLAY API provides the following interfaces:

Function	Description
sp_init_display_module	Initialize the display module object
sp_release_display_module	Destroy the display module object
sp_start_display	Create a video display channel
sp_stop_display	Close the video display channel
sp_display_set_image	Send image data to the video display channel
sp_display_draw_rect	Draw a rectangle on the display channel
sp_display_draw_string	Draw a string on the display channel
sp_get_display_resolution	Get the resolution of the connected display

sp_init_display_module

[Function Prototype]

void *sp_init_display_module()

[Description]

Initializes the display module object. This module supports displaying video image data on an HDMI-connected monitor and provides functionality to draw rectangles and text overlays on the displayed image.

[Parameters]

None

[Return Type]

Returns a pointer to the DISPLAY object on success; returns NULL on failure.

sp_release_display_module

[Function Prototype]

void sp_release_display_module(void *obj)

[Description]

Destroys the DISPLAY object.

[Parameters]

• obj: Pointer to an initialized DISPLAY object

[Return Type]

None

sp_start_display

[Function Prototype]

int32_t sp_start_display(void *obj, int32_t chn, int32_t width, int32_t height)

[Description]

Creates a display channel. The RDK S100 development board supports 4 channels: 2 video layers and 2 graphics layers. The maximum supported resolution is 1920 x 1080 at up to 60fps.

[Parameters]

• obj: Pointer to an initialized DISPLAY object
• chn: Channel number (0–3). If using a desktop system, channel 0 is reserved for the graphical system, so applications should use channel 1. Channels 2 and 3 are typically used for drawing rectangles or overlaying text.
• width: Display output resolution – width
• height: Display output resolution – height

[Return Type]

Returns 0 on success; returns -1 on failure.

sp_stop_display

[Function Prototype]

int32_t sp_stop_display(void *obj)

[Description]

Closes the display channel.

[Parameters]

• obj: Pointer to an initialized DISPLAY object

[Return Type]

Returns 0 on success; returns -1 on failure.

sp_display_set_image

[Function Prototype]

int32_t sp_display_set_image(void *obj, char *addr, int32_t size, int32_t chn)

[Description]

Displays the image data located at addr on display channel chn. Only NV12 format YUV images are supported.

[Parameters]

• obj: Pointer to an initialized DISPLAY object
• addr: Image data buffer (only NV12 format is supported)
• size: Image data size, calculated as: width * height * 3 / 2
• chn: Display channel, corresponding to the channel number used in sp_start_display

[Return Type]

Returns 0 on success; returns -1 on failure.

sp_display_draw_rect

[Function Prototype]

int32_t sp_display_draw_rect(void *obj, int32_t x0, int32_t y0, int32_t x1, int32_t y1, int32_t chn, int32_t flush, int32_t color, int32_t line_width)

[Description]

Draws a rectangle on the graphics layer of the display module.

[Parameters]

• obj: Pointer to an initialized DISPLAY object
• x0: X-coordinate of the rectangle's first corner
• y0: Y-coordinate of the rectangle's first corner
• x1: X-coordinate of the rectangle's second corner
• y1: Y-coordinate of the rectangle's second corner
• chn: Display output layer; layers 2–3 are graphics layers
• flush: Whether to clear the current graphics layer buffer
• color: Rectangle color (in ARGB8888 format)
• line_width: Line width of the rectangle

[Return Type]

Returns 0 on success; returns -1 on failure.

sp_display_draw_string

[Function Prototype]

int32_t sp_display_draw_string(void *obj, int32_t x, int32_t y, char *str, int32_t chn, int32_t flush, int32_t color, int32_t line_width)

[Description]

Draws a string on the graphics layer of the display module.

[Parameters]

• obj: Pointer to an initialized DISPLAY object
• x: X-coordinate of the string's starting position
• y: Y-coordinate of the string's starting position
• str: String to be drawn (must be encoded in GB2312)
• chn: Display output layer; layers 2–3 are graphics layers
• flush: Whether to clear the current graphics layer buffer
• color: Text color (in ARGB8888 format)
• line_width: Line width of the text

[Return Type]

Returns 0 on success; returns -1 on failure.

sp_get_display_resolution

[Function Prototype]

void sp_get_display_resolution(int32_t *width, int32_t *height)

[Description]

Retrieves the resolution of the currently connected display.

[Parameters]

• width: Output parameter for the display width
• height: Output parameter for the display height

[Return Type]

None.