Miosix GUI library

1.00

Introduction

Mxgui is a lightweight and configurable GUI library for 32bit microcontrollers. It can drive monochrome and color displays using microcontrollers with limited amounts of RAM memory and that cannot in general perform double buffering because of that. Its target are microcontroller down to 32KB of FLASH and 8KB of RAM memory.

It is designed to work together with the Miosix kernel, which provide a threadsafe C and C++ standard library as well as posix threads.

Library design

The library is divided in two "levels", named Mxgui level 1 and Mxgui level 2, to address embedded systems with different level of complexity.

• Mxgui level 1 is an abstraction of a generic display device, providing methods to write text with different fonts, even variable width and antialiased ones, drawing images, providing clipping facilities and simple graphic primitives, such as line drawing. It also provides basic support for concurrent access to the same display by multiple threads.
• Mxgui level 2 which is currently in very early stage of development, is designed to handle multiplexing of a number of different applications on a single display device, providing input event dispatching from devices such as touchscreens, and also featuring a basic set of display widgets such as buttons, etc.

Mxgui tools

The library comprehends a set of tools designed to run on a Linux host PC to aid in the design of graphical user interfaces for embedded systems, namely

• pngconverter, a tool to convert images in .png format into a set of .cpp and .h files to be able to embed images into an embedded firmware
• fontrendering, a tool to generate font lookup tables from standard .ttf and .bdf file format. These lookup tables are again designed to be embedded into a firmware
• resourcefs a tool to generate a filesystem image specifically designed to store large amounts of images on an external flash memory to design rich user interfaces even on microcontroller with little FLASH memory
• Mxgui simulator a pixel-perfect simulator of the mxgui library making possible to debug the visual aspect of an user interface on an host PC instead of directly on the embedded device

Getting started

The mxgui library depends on the Miosix kernel, so you should start by downloading the kernel before. You can find it at http://gitorious.org/miosix-kernel . If this is the first time you are downloading Miosix, you need to install the Miosix specific compiler, you can find a guide to do so here: http://www.webalice.it/fede.tft/miosix/miosix_toolchain_1.54_linux.html . Once you have downloaded the Miosix kernel, download the mxgui library in the miosix-kernel directory. A simple way to download both Miosix and mxgui is to use git, like this:

git clone git://gitorious.org/miosix-kernel/miosix-kernel.git
cd miosix-kernel # To download mxgui within the miosix-kernel folder
git clone git://gitorious.org/miosix-kernel/mxgui.git

The miosix-kernel folder is from now named the 'top level directory' of your project.

Now you need to edit the Makefile in the top level directory to tell Miosix that it needs to compile the mxgui library. To do so locate the SUBDIRS variable and append the "mxgui" string, like this:

##
## List here subdirectories which contains makefiles
##
SUBDIRS := miosix mxgui

Also change the SRC variable by replacing testsuite.cpp with main.cpp

Lastly, replace the content of main.cpp with this code:

#include "mxgui/entry.h"
#include "mxgui/display.h"

using namespace mxgui;

ENTRY()
{
    Display& display=Display::instance();
    {
        DrawingContext dc(display);
        dc.write(Point(0,0),"Hello world!");
    }
    for(;;) ; //To prevent application shutdown
}

If you don't have a board such as an stm3210e-eval to test the code, you can test it in the Mxgui simulator.

Examples

Examples on how to use the library are available in the mxgui/examples folder. The range from a simple hello world to a 3D rendering engine. To try the examples, copy the corresponding directory in the top level directory, and edit the Makefile (or CMakeLists.txt if targeting the simulator) accordingly.

Author:

Terraneo Federico