dashboard/DEVELOPMENT.md

Development

All the boiler plate needed to show screens has been written. To develop your own custom screens, however, you will need to know some SDL2. There is no real drawing api, to allow you to have as much control over the display as possible.

dashboard uses a few objects for displaying things to the screen however, to interact with the memory management.

The default configuration is similar to web development "Carousels". A series of panels are shown to the user by cycling through one by one.

A board is a singleton, and represents the physical display board. There is only one per instance of the program, and its has several panels

A panel is an object representing a slide on screen. This is a page with weather, a news feed, etc. It is one of the scrolling pages shown to the user. This is what you will need to write.

Each panel has a draw() function that you must implement. This will draw everything to the screen using SDL2's API. If you want functions for getting data, several threads, etc, it is the panel's responsibility to implement this. The board provides a memory API, however you do not have to use it.

The panel parent class has an update() and update_texture() function you must implement. Use update() to update the data for the panel. Use udpate_texture() to update the SDL_Texture _texture each panel has

Each panel also has an initTexture() function that you must implement. This should initialize the texture and should be called in your draw function. It is up to you to call this, to give you the option of lazy loading it. This must be called in draw() or later, not in the constructor. This is because SDL will not be setup when your constructor is called, and therefore will not be able to properly create the texture for the renderer.

The _time_on_screen value is in milliseconds, and will be the amount of time the board will display the panel before transitioning. This value can be modified at runtime if needed (ie displaying a dynamic length video).

The provided memory api stores textures (SDL_Texture), fonts (TTF_Font), and strings (SDL_Texture). Both static values can be added that will exist for the lifetime of the program, as well as dynamic versions that will be stored in a cache (As of writing, only dynamically cached strings are implemented). All functions related to looking up memory stored in these containers is performed in O(1) time.

The SDL_Window and SDL_Renderer are provided as static globals, accessible via the board object.

Each panel is also recommended to add its own config.hpp file for configuring possible settings. All static files that it needs should be placed in the main config.hpp file

See src/panel/sample_panel* for an example in code of a simple panel to help you get started

Things you need to implement as a panel creator

• void mypanel::draw()
• mypanel::mypanel()
• mypanel::~mypanel()
• size_t mypanel::_time_on_screen
• const_resources

And be sure to inheret from dashboard::panel !

FAQ

• I wrote my pannel, yet i keep seeing that SCREEN_WIDTH, SCREEN_HEIGHT, board::*, etc are not defined
  • Be sure to add #include "../board.hpp" at the end of your mypanel.hpp