openhandhelds/lvgl-opengl

OpenGL ES 2.0 Implementation of LVGL

lvgl-opengl

This is an example SDL application for OpenGL ES 2.0 implementation for LVGL aimed for to run on PinePhone.

OpenGL ES 2.0 fork of the LVGL can be found here.

SDL Driver can be found here.

Screenshot

Quick Start

Requirements

• OpenGL ES >= 2.0
• cmake
• SDL2
• libepoxy

Cloning the repository

$ git clone https://github.com/rainlab-inc/lvgl-opengl
$ cd lvgl-opengl
$ git submodule update --init --remote --recursive

Building

CMake

$ mkdir build
$ cd build
$ cmake ..
$ make -j4
$ ./lvgl-opengl

Draw Functions

Rectangle

• draw_shadow
• draw_bg
  • plain rect ✅
  • radius mask ✅
    • TODO: more efficient corner rendering (Use same buffer for all 9 pieces per rectangle.)
    • TODO: do antialiasing with respect to radius, not with an arbitrary constant,
  • TODO: other masks? gradients?
• draw_bg_img
  • maybe call draw_img with rect borders?
• draw_border
• draw_outline

Image

• Hash textures with LRU cache ✅
• draw_img ✅
  • TODO: hash textures, avoid creating same textures if they are used more than once. ✅
  • TODO: handle recolor operation more wisely
  • TODO: handle masks

Letter

• Hash glyphs with LRU cache ✅
• TODO: Look for pixel perfect alignment for glitches.
• TODO: Test for CJK characters.
• TODO: Pack glyphs to efficient rendering.

Arc

TODO: Look for how to draw efficient arcs with GL.

Line

TODO: It will be probably easy - efficient if we draw with shaders.

Polygon

TODO: Look which components use draw polygon.