Difference between revisions of "GDISP"
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== Multipel displays == | == Multipel displays == | ||
| − | + | The GDISP module can drive more than just one display. See [[Multiple displays]]. | |
== Remote displays == | == Remote displays == | ||
Revision as of 23:58, 2 July 2014
The GDISP module provides a simple interface for graphic displays and a feature rich set of highlevel functions to draw primitive shapes such as lines, circles and rectangles, but also font rendering, clipping and other advanced features.
Whilst most other graphics libraries require the use of a framebuffer, GDISP does not necessarily need one. This allows to drive graphics displays on microcontrollers and other low-performance systems that have insufficient RAM for a frame buffer.
Some LCD controllers offer hardware accelerated drawings for complex drawing operations such as circles or ellipses. The GDISP module is based on a software emulation layer: When the LCD controller does not support these features (most cases), the GDISP module emulates these drawing operations. Therefore, the exact same application code can be used on very different hardware platforms.
Furthermore, you can drive more than just one display with GDISP. They don't even need to have the same display driver. Please refer to the multiple displays section for more information. Especially interesting might be the use of one or more remote displays.
Contents
Board file
The board file API for the GDISP module looks like the following:
static void init_board(GDisplay *g); static void post_init_board(GDisplay *g); static void setpin_reset(GDisplay *g, bool_t state); static void set_backlight(GDisplay *g, uint8_t percent); static void acquire_bus(GDisplay *g); static void release_bus(GDisplay *g); static void write_index(GDisplay *g, uint16_t index); static void write_data(GDisplay *g, uint16_t data); static void setreadmode(GDisplay *g); static void setwritemode(GDisplay *g); static uint16_t read_data(GDisplay *g);
For more information about the, see GDisplay.
Examples and a template file can be found under /drivers/gdisp/xxx/.
Drawing
ToDo
Images
The GDISP module provides built-in decoders for a variety of image formats. See Images.
FrameBuffer
ToDo
Hardware acceleration
ToDo
Multipel displays
The GDISP module can drive more than just one display. See Multiple displays.
Remote displays
ToDo
GDisplay
ToDo
struct GDisplay { // The public GDISP stuff - must be the first element GDISPControl g; #if GDISP_TOTAL_CONTROLLERS > 1 const struct GDISPVMT const * vmt; // The Virtual Method Table #endif void * priv; // A private area just for the drivers use. void * board; // A private area just for the board interfaces use. uint8_t systemdisplay; uint8_t controllerdisplay; uint16_t flags; #define GDISP_FLG_INSTREAM 0x0001 // We are in a user based stream operation #define GDISP_FLG_SCRSTREAM 0x0002 // The stream area currently covers the whole screen #define GDISP_FLG_DRIVER 0x0004 // This flags and above are for use by the driver // Multithread Mutex #if GDISP_NEED_MULTITHREAD gfxMutex mutex; #endif // Software clipping #if GDISP_HARDWARE_CLIP != TRUE && (GDISP_NEED_CLIP || GDISP_NEED_VALIDATION) coord_t clipx0, clipy0; coord_t clipx1, clipy1; /* not inclusive */ #endif // Driver call parameters struct { coord_t x, y; coord_t cx, cy; coord_t x1, y1; coord_t x2, y2; color_t color; void *ptr; } p; // In call working buffers #if GDISP_NEED_TEXT // Text rendering parameters struct { font_t font; color_t color; color_t bgcolor; coord_t clipx0, clipy0; coord_t clipx1, clipy1; } t; #endif #if GDISP_LINEBUF_SIZE != 0 && ((GDISP_NEED_SCROLL && !GDISP_HARDWARE_SCROLL) || (!GDISP_HARDWARE_STREAM_WRITE && GDISP_HARDWARE_BITFILLS)) // A pixel line buffer color_t linebuf[GDISP_LINEBUF_SIZE]; #endif };
