libpng Decoder

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libpng is an LVGL interface to the official PNG reference library, which supports almost all PNG features, is extensible, and has been extensively tested for over 28 years.

For a detailed introduction, see: http://www.libpng.org/pub/png/libpng.html .

Install

bash

sudo apt install libpng-dev

Adding libpng to Your Project

Cmake:

cmake

find_package(PNG REQUIRED)
include_directories(${PNG_INCLUDE_DIR})
target_link_libraries(${PROJECT_NAME} PRIVATE ${PNG_LIBRARIES})

Usage

Set LV_USE_LIBPNG in lv_conf.h to 1.

See the examples below.

It should be noted that each image of this decoder needs to consume

width × height × 4

bytes of RAM, and it needs to be combined with the Image Caching feature to ensure that the memory usage is within a reasonable range. The decoded image is stored in RGBA pixel format.

Example

Open a PNG image from file and variable

lv_example_libpng_1.c