3.2 Display Module API Manual

Attention

This module has significant changes starting from firmware version V0.7. If you are using firmware prior to V0.7, please refer to the old version of the documentation.

1. Overview

This manual is intended to guide developers on using the Micro Python API to call the CanMV Display module for image display functionality.

2. API Introduction

2.1 init

Description

Initializes the Display path, including the VO module, DSI module, and LCD/HDMI. Must be called before MediaManager.init()

Syntax

init(type=None, width=None, height=None, osd_num=1, to_ide=False, fps=None, quality=90)

Parameters

Parameter Name	Description	Input / Output	Notes
type	Display device type	Input	Required
width	Resolution width	Input	Default value depends on type
height	Resolution height	Input	Default value depends on type
osd_num	Number of layers supported in show_image	Input	The larger the number, the more memory it occupies
to_ide	Whether to transfer screen display to IDE display	Input	Occupies more memory when enabled
fps	Display frame rate	Input	Only supports VIRT type
quality	Sets Jpeg compression quality	Input	Only effective when to_ide=True, range [10-100]

Return Value

Return Value	Description
None

2.2 show_image

Description

Displays an image on the screen.

Syntax

show_image(img, x=0, y=0, layer=None, alpha=255, flag=0)

Parameters

Parameter Name	Description	Input / Output	Notes
img	Image to display	Input
x	X value of the starting coordinate	Input
y	Y value of the starting coordinate	Input
layer	Display on the specified layer	Input	Only supports OSD layer, for multiple layers set osd_num in init
alpha	Layer blending alpha	Input
flag	Display flag	Input

Return Value

Return Value	Description
None

2.3 deinit

Description

Performs deinitialization. The deinit method will shut down the entire Display path, including the VO module, DSI module, and LCD/HDMI. Must be called before MediaManager.deinit()
Must be called after sensor.stop()

Syntax

deinit()

Return Value

Return Value	Description
None

2.4 bind_layer

Description

Binds the output of the sensor or vdec module to the screen display. This allows continuous image display without manual intervention. Must be called before init

Syntax

bind_layer(src=(mod, dev, layer), dstlayer, rect=(x, y, w, h), pix_format, alpha, flag)

Parameters

Parameter Name	Description	Input / Output	Notes
src	Output information of sensor or vdec	Input	Obtainable via sensor.bind_info()
dstlayer	Display layer to bind to display layer	Input	Can be bound to video or osd layer
rect	Display area	Input	Obtainable via sensor.bind_info()
pix_format	Image pixel format	Input	Obtainable via sensor.bind_info()
alpha	Layer blending alpha	Input
flag	Display flag	Input	LAYER_VIDEO1 not supported

Return Value

Return Value	Description
None

3. Data Structure Description

3.1 type

Type	Resolution (width x height @ fps)	Notes
LT9611	1920x1080@30	Default value
	1280x720@30
	640x480@60
HX8377	1080x1920@30	Default value
ST7701	800x480@30	Default value Can be set to portrait mode 480x800
	854x480@30	Can be set to portrait mode 480x854
VIRT	640x480@90	Default value
		IDE debugging only, does not display content on an external screen Users can customize resolution (64x64)-(4096x4096) and frame rate (1-200)

3.2 layer

K230 provides support for 2 video layers and 4 OSD layers. Listed as follows:

Display Layer	Description	Notes
LAYER_VIDEO1		Only usable in bind_layer
LAYER_VIDEO2		Only usable in bind_layer
LAYER_OSD0		Supports use in show_image and bind_layer
LAYER_OSD1		Supports use in show_image and bind_layer
LAYER_OSD2		Supports use in show_image and bind_layer
LAYER_OSD3		Supports use in show_image and bind_layer

3.3 flag

Flag	Description	Notes
FLAG_ROTATION_0	Rotate 0 degrees
FLAG_ROTATION_90	Rotate 90 degrees
FLAG_ROTATION_180	Rotate 180 degrees
FLAG_ROTATION_270	Rotate 270 degrees
FLAG_MIRROR_NONE	No mirroring
FLAG_MIRROR_HOR	Horizontal mirroring
FLAG_MIRROR_VER	Vertical mirroring
FLAG_MIRROR_BOTH	Horizontal and vertical mirroring

4. Sample Program

The following is a sample program:

from media.display import *  # Import the display module to use display related interfaces
from media.media import *    # Import the media module to use media related interfaces
import os, time, image       # Import the image module to use image related interfaces

# Use LCD as display output
Display.init(Display.ST7701, width=800, height=480, to_ide=True) 
# Initialize media manager
MediaManager.init()

# Create an image for drawing
img = image.Image(800, 480, image.RGB565)
img.clear()
img.draw_string_advanced(0, 0, 32, "Hello World!，你好世界 ！ ！ ！ ", color=(255, 0, 0))

Display.show_image(img)

try:
    while True:
        time.sleep(1)
        os.exitpoint()
except KeyboardInterrupt as e:
    print(" User stopped:", e)
except BaseException as e:
    print(f" Exception: {e}")

Display.deinit()
MediaManager.deinit()